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18th International Petroleum and Natural Gas Congress and Exhibition of Turkey
- Conference date: 11 May 2011 - 13 May 2011
- Location: Ankara, Turkey
- Published: 11 May 2011
1 - 100 of 163 results
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Energy Safety in the Mediterranean
More LessThe surroundings of the Mediterranean Sea has long been considered from the viewpoint of its natural characteristics and historical richness the most desirable region to live in. Despite that it is not the most prosperous part of the world and neither is it the safest. The reason for these infirmities lies in its cultural diversity and the unequal degres of develpment of the societies that inhabit its shores. Around the Mediterranean a prosperous and a free north faces a poor south suffering from a number of tyrranies. In the present state of the world, however, the tyrannies of the south posses much richer energy resources than the free north and this asymmetry has long been a concern not only for the inhabitants of the Mediterranean region, but for the entire world. Moreover, the Mediterranean sits across some of the most critical shipping lanes that also transport energy sources. Under these circumstances the geologist is often questioned by administrators and by the population as to what the future holds in store for the Mediterranean energy situation. To answer that question, one must take stock of the present situation.
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Distribution of Methanogens in Petroleum Reservoirs of Garzan, Dodan, Silivanka, Çamurlu Areas
Authors N.D. Güngör, E.İ. Sungur, H. Hoşgörmez and A. ÇotukPetroleum reservoirs are important natural habitats for microorganisms. Biodegradation of petroleum results in a decrease in its hydrocarbon content and an increase in oil density, sulphur content, acidity and viscosity. These changes have negative economic consequences for oil production and refining operations. It has been established that methanogens constitute an important microbiological community inhabiting oilfields. Petroleum hydrocarbons (PHC) are degraded to methanogenic substrates such as acetate, CO2, and H2 by diverse bacteria, and methanogenesis is a final degradation process of organic matter by methanogenic archaea in anoxic petroleum reservoir environments.There is a limited information about petroleum biodegredation of methanogens. It is important to develop a method for methanogens activity and determine the effects of methanogens in this environment. The aim of this study was to determine the distribution of metanogens in petroleum reservoirs. For this purpose oil samples were collected (9 petroleum and 5 petroleum-water phase) from Garzan, Dodan, Silivanka and Çamurlu areas. Samples were inoculated in media under pure gases N2. After then inoculated samples were gassed with H2-CO2 (80:20) atmosphere. All incubations were made in the dark at 30ºC for 21 days. Methane was measured by gas chromatograph. It was found that methanogens were isolated only one out of 9 petroleum (10 cell ml-1) and two out of 5 petroleum-waterphase (15 cell ml-1). These results showed that petroleum reservoirs contain a low number of methanogen but this results should be supported by molecular methods. It is important to understand the ecology of methanogens in petroleum reservoir. In future studies, molecular techniques should be applied to characterize methanogens in petroleum reservoirs in Turkey.
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Oil Pollution Response Activities
By C. AnulOil accidents are incidents that damage economy, society and environment and affect local, regional or national communities. Oil accidents cause serious damage to countries, humans, corporations and most of all, environment. In order to be prepared for and respond to an oil pollution incident, its crucial to have national, regional, local and facility emergency response plans. Extensive and accurate planning is the key to oil pollution preparedness. Organizations must have oil pollution based emergency response plans and equipment, materials and trained personnel that are required to execute and carry out these plans. A full response can be achieved by; preparing detailed plans and determining the response procedures, administrative and technical considerations, equipment and materials that meet the quality standarts, trained personnel and carefully planned drill scenarios. Emergency response service centers that have adequate equipment and trained personnel can provide response to local, regional and national oil pollution incidents. Main Topics of Oil Pollution Response Activities: Emergency Response Planning: - Risk Assessment and Case Specific Modelling Studies - Determining Response Equipment and Personnel - Response Organization - Logistics and Communications - Notifications and Reporting - Public Relations Management - Waste Management - Safety and Worker Protection - Rehabilitation Activities - Training and Drills Emergency Response Service: - Tier 1 Emergency Response Service - Tier 2 Emergency Response Service - Tier 3 Emergency Response Service.
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Introduction: Tectonic Assembly of Anatolia: Implications for Hydrocarbon Prospectivity
Authors A.H.F. Robertson, A.İ. Okay, O. Parlak and T. UstaömerIn this talk we will discuss some of the major recent advances and controversial aspects bearing on the tectonic assembly of Anatolia. The Precambrian rocks of the NW Pontides are widely seen as one or several circum-Gondwanan terranes that originated off NW Africa and, following eastward terrane dispersal, amalgamated to Eurasian by early Paleozoic and mid mid-Carboniferous time. The Palaeozoic units of the Taurides and Anatolides are commonly seen as having been located along the southern margin of a wide Palaeotethys, although some palaeontological data question the existence of any wide ocean during this time. The Variscan Pontide magmatic rocks are commonly interpreted as a subduction-related arc that was located along the southern margin of Eurasia. However, a location on the opposite side of Palaeotethys near Gondwana is also proposed. There is also a discussion about the direction of subduction; i.e. beneath Eurasia, beneath Gondwana, or both. In different interpretations, Palaeotethys was either entirely closed by latest Triassic or remained open and evolved into Neotethys by means of subduction and seafloor spreading. Triassic subduction is generally seen as northwards beneath Eurasia but some envisage southward subduction. Units like the Karakaya Complex are commonly seen as accretionary prisms but continental rift scenarios are still popular. Debate persists as the location, size and timing of closure of the Mesozoic Neotethyan oceans. Multiocean scenarios are gaining acceptance (e.g. Izmir-Ankara; Inner Tauride; S Neotethys) but are still questioned. Some see the Izmir-Ankara ocean as closed by latest Cretaceous but for others is remained partially open until Mid-Eocene. The S Neotethys (assuming its existence) closed in latest Cretaceous, Eocene, or Early Miocene time in different views. Probably all of the large emplaced ophiolites (mostly Late Cretaceous) formed above subduction zones and not at spreading ridges, significantly changing traditional views. The above and other tectonic scenarios directly or indirectly influence hydrocarbon prospectivity (e.g. presence or absence of buried continental platforms/slopes; regional heat flow variations, burial/exhumation and terrane dispersal. In the talk we will indicate the alternatives and some of our preferred solutions to the tectonic problems and we will emphasise where more work is needed to solve outstanding issues.
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Tectono-Sedimentary Evolution of the Upper Cretaceous – Middle Eocene Central Anatolian Basins, Turkey: Summary and New Tectonic Model
Authors S. Nairn, A. Robertson, U. Ünlügenç, K. Taslı and N. İnanIn central Turkey, a strand of the former northern Neo-Tethys Ocean (İzmir-Anzara-Erzincan ocean) subducted northwards under the Pontide active margin during Cretaceous – Early Cenozoic time. Subduction generated accretionary complexes and emplaced ophiolites onto the former passive margins of microcontinents (e.g. Tauride-Anatolide Niğde-Kırşehir). The resulting suture zones encompass Upper Cretaceous to Middle Eocene basins including the Kırıkkale, Haymana, Tuz Gölü and Çankırı basins. The basement comprises the Ankara Mélange, a mainly Cretaceous accretionary complex together with the western margin of the Niğde-Kırşehir Massif, an inferred microcontinent. New geochemical data from beneath the Kırıkkale Basin identifies mid ocean-ridge basalt, here interpreted as Upper Cretaceous Neo-Tethyan oceanic crust. During the latest Cretaceous, the Kırıkkale and Tuz Gölü basins formed in deep water on MORB crust, bordered by the Niğde – Kırşehir microcontinent to the east. Further west, the Haymana Basin is an accretionary forearc basin constructed on the Ankara Mélange. The Çankırı Basin further north developed on accretionary mélange bounded by the Pontide active margin to the north. Palaeocene sedimentation was dominated by shallow-marine coralgal reef facies. Latest Palaeocene – Middle Eocene facies include shelf-type Nummulitic limestone, locally deposited on unconformity surfaces. In one model, the basins formed on obducted ophiolites following Late Cretaceous closure of a single northern Neo-Tethyan ocean. In an alternative model, the basins evolved in a forearc setting associated with northward subduction until the Middle Eocene. We propose a new model in which two north-dipping subduction zones were active during the late Mesozoic in the northern Neo-Tethyan region (distinct from the S Neotethys). In the south, ophiolites formed above a N-dipping subduction zone consuming oceanic crust adjacent to the Tauride-Anatolide continent (Inner Tauride Ocean) until the southward retreating trench collided with the northern margin of the continent emplacing ophiolites (e.g. Alihoca ophiolite). In the north, subduction initiated outboard of the Eurasian margin within the İzmir-Ankara ocean, triggering the genesis of supra-subduction zone oceanic lithosphere. The subduction zone then rolled back southwards until it collided with the Niğde – Kırşehir microcontinent, again emplacing ophiolites (e.g. Çiçekdağ) during latest Cretaceous time. However, vestiges of Neotethyan MORB remained to the west of the Niğde – Kırşehir microcontinent, forming the basement of the Kırıkkale and Tuz Gölü Basins. Continuing latest Palaeocene – Middle Eocene northward subduction culminated in final continental collision and the development of an Anatolia-wide unconformity, although strong uplift was delayed until Plio-Pleistocene.
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Pre-Salt Structures in the Tuz Gölü and Çankırı-Çorum Basins, Central Anatolia: Implications on Oil Explorations
By B. CoşkunFollowing recent oil discoveries of nearly 16 billions barrels of recoverable oils in the allochthonous sub-salt and autochthonous pre-salt structures by Petrobras in Brasil’s offshore areas, these sub and pre-salt structures became very interesting exploration targets in the world. Evaluation of seismic and well data indicate that pre-salt structures exist also in the Tuz Golu and Cankiri-Corum basins in Central Anatolia. In the Tuz Golu basin, previous exploration and drilling activities aimed to test the Caldag reefs, sandstones in the Kirkkavak and Haymana formations, sandstone pinch-outs and fault-related closures at the flanks of the salt structures. In the Cankiri-Corum basin, Malibogazi reefs, sandstones in the Incik formation and structures at the flanks of salt bodies are considered as the main prospects. Of course, all these above structures are obviously very important for oil exploration, but the pre-salt structures, orinated by pull-up movements during the ascension of salt deposits and non-explored in Turkey so far, are excellent oil accumulation sites in these sedimentary basins. Upward movements of salt bodies under the gravity and tectonic forces, for exemple eastward movement of the Menderes Massif and westward displacement of the Kirsehir Massif evidenced by subsurface diabasic intrusion, created fractured anticlinal structures which are very attractive for oil exploration. Evaluation of seismic and well data reveal certain interesting pre-salt structural trends in the Tuz Golu and Cankiri-Corum basins. Evaluations and testing these pre-salt structures in the Tuz Golu and Cankiri-Corum basins and even in the eastern Mediterranean offshore areas, will open a new exploration concept for future oil researches in Turkey.
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The Neogene Dynamics of the Balkan Fold-Thrust Belt. Possible Effect on the Hydrocarbon Accumulations
By R. NakovThe Alpine geodynamics of the eastern Balkan Peninsula is determined by several episodes of extension and compression. After the final closing of the Vardar Ocean during the Late Cretaceous-Early Paleogene the main episode of compression and deformation in the Balkan FTB occurred in Middle Eocene time, creating a well expressed fold-thrust pattern. At this time the belt was overthrusted to the north on the Foreland (Moesian Platform). After this main episode of compression, excepting local thrusting in its easternmost part during the Oligocene, the frontal part of the belt was thought to be inactive. Since Late Eocene extension is the main form of deformation. The extension is spread between the Aegean subduction system to the south and the Moesian Platform (the southern edge of the Balkan Range) to the north. During the Neogene, extension has created numerous extensional continental basins (grabens) to the south of the Balkan Range. They occurred in several well distinguished consecutive stages of extension. Instead, to the north of the range was created the marine (Miocene) to brakish (Pliocene) basin which western part belonged to the Central Parathetys (Fore-Carpathian basin) and the eastern to the Eastern Parathetys (Euxinian) basin.
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Tender Assist Drilling (TAD)
By A. ŞahinPlatform rig is an immobile offshore structure from which development wells are drilled and produced. The degree of a platform rig has an important effect in the field development cost. In offshore, development wells can be drilled by a giant platform rig that can also has production and processing facilities as well as living accommodations for the people. Alternatively, these functions may be conducted on different platforms that are much smaller than a giant platform. This can be achieved by using Tender Assist Drilling (TAD) which has a split drilling unit. The unit that is immobile is a fixed platform and the other unit is mobile that provides logistic to fixed platform. TAD system requires employing a Tender Support Vessel (TVS) during the drilling phase of a well development to provide drilling utilities to the platform drilling equipment package. In the first years of the TAD’s, barges mainly were used as tender to fixed platforms in shallow water and good weather conditions but, it was seen that they easily became inoperable and unsafe in deep water and rough weather. Alternatively, in 1980’s, the use of the tender assist barges in harsh weather, existing mobile offshore drilling units (MODU), Semi-submersible platforms, were converted to Semi-Submersible tender for fixed platform. This study aims to review tender assist drilling (TAD) and its applications in the world. Besides, my goal particularly is to present an application of tender assist drilling performed by Turkish Petroleum Corporation (TPAO) in Turkey. TPAO constructed a fixed platform in Akçakoca Natural Gas Development Field, Düzce and a tender assist barge was chosen for that fixed platform.
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MWD&LWD and Stethoscope Applications for Subsea Wells
By F. DumanPore pressure modeling and understanding has great importance while drilling a wild cat well in deep offshore. Not only given fracture and leak off margin is so small, but also keeping well in optimum overbalance condition are vital for the safety. After BP’s Moconda incident in the Gulf of Mexico, now understanding of pore pressure regime as well as nature of the high pressure fluid while drilling becoming more and more critical especially in deep water where the riser and well control devices are apart few hundred meters. In addition deep water environment play its critical role being young deposits and buried not deep from the sea bed, and leak off margins are most of the time in “wellbore breathing” range. Phenomenon variously called “Breathing wellbore” or “Ballooning effect” is a result of slow mud returns while drilling ahead followed by mud returns after the pumps have been turned off, such as during a connection or flow check. Usullay any flows during these periods are cause for a concern as they may be due to influx of formation water, liquid hydrocarbon or gas. Any influx from the formation can result in a well control problem, the magnitude of which is dependent on its volume and composition. On the other hand lithologies under deepwater conditions usually show relatively reduced effective stress, due to reduced lithological column. This translates into narrow mud weight windows, driven mainly by shear failure or pore pressure in over pressured conditions, and by minimum horizontal stress gradients. Drilling operations should consider wellbore collapse, kick and losses as the primary hazards. These should be investigated and predicted during well planning, and should also be appropriately monitored during drilling.
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Ultra-Deep Offshore Well Casing Design Process
By B. KayaelDrilling an ultra-deep water well is one of the most challenging tasks that an Exploration and Production Company can undertake. Not only are there technical, logistical and environmental issues, but the high operating costs makes every aspect of the well planning and execution process critical. As in any other well delivery process, the casing design is one of the most important deliverables as this will affect the lead time for procuring equipment, the most likely time estimate for drilling the well and finally the cost. The first step of casing design involves coming up with a robust conductor design as this is the main support structure for the well. Detailed bending studies should be carried out because it will carry hundreds of thousands of pounds. Secondly any possible shallow flow (shallow water and gas flow) should be considered which needs to be isolated by an additional casing string. Once initial studies are done for first two sections, rest of the well design will be mainly limited by pressure gradients (PP and FG). As rule of thumb in a hole section the pore pressure at section TD should not exceed last casing shoe’s fracture gradient. If this happens mud losses will occur which could become a costly event and lead to an influx or kick. To eliminate this risk a detailed PPFG study should be carried out by geological and geophysical experts, because this study will be the guide for planning engineers to make casing design. As nature of offshore environment, the higher the water column the slower the overburden gradient increases as depth increases. This will directly affect the fracture gradient and make it increase slowly also. In case of having any pressure ramp at pore pressure the gap between PP and FG will decrease significantly which will cause more casing or liner strings to be run. In Black Sea region the most complicated casing design up to now had 8 (eight) casing strings starting with 36” conductor and ending with a 7” production liner. The number of strings to be run is affected by geological properties of lithologies, pressure profile of the well and technical limitations. These factors should be examined in detail to make the casing design effective and suitable for well conditions.
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A Study on the Mud Losses in the Ultra Deepwater Operations in Black Sea
By A. MazlumIn ultra deep offshore operations, one of the major problems during both well planning and drilling is that pore pressure and fracture pressure gradients are very close. As these gradients come closer, possibility of having losses while drilling increases. One of the important problems of Black Sea offshore operations was losses in which TPAO has one partnership and two operatorships. The mud weights that was considered as sufficient with respect to the expected pressure values exceeded the fracture pressure gradients, which led to revision on previous hydraulic programs. In order to stop those losses, as common in the industry, loss prevention chemicals were used. Moreover, the casing depths were changed after the real time pressure measurements. At first, losses were tired to be cured by monitoring the drilling parameters such as equivalent circulating density (ECD) and penetration rate (ROP) , which are fairly less easy and reduced in cost. Using synthetic or oil based mud in Black Sea should also be considered after experiencing the water based mud. In this study, mud losses; which is one of the major problems in Black Sea ultra deep water operations, will be presented by analyzing the drilling parameters, mud and formation properties.
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General View of Oil Exploration-Production Sector in Turkey as a Field of Investment and Its Contribution to Economy
More LessFollowing 1963 when development plans first came to the agenda, unfortunately petroleum sector is not even mentioned in 1, II, IV, V, VI, VII, VIII. Development Plans. The sector is considered as a sub title of mining sector. This situation is a clear indication of viewing petroleum sector which plays an important role in the development of our country. [8] Recognition of the sector has started to be exercised with market laws enacted in 2001 and 2003; first market laws were enacted and sector is identified, and the remaining exploration and production sector has continued in its former position. It is necessary to view the subject in two main axes when examining the activities of exploration and production sector. First is the investments of the licensee which we call the owner of petroleum right, that is, the capital owner. The second is the activities of those producing the services within the licenses, that is, the activities of companies providing technical services. In this paper, 1. Structural changes, status of legislation, breakdown of the activities and the amounts of investments made in the scope of Foreign Direct Investor (FDI) from the point of domestic and foreign countries as of December 2009 in USD currency is examined within the section of historical processes of 1926-2010. 2. Contribution of the investments in the oil exploration and production sector to the country’s economy, comparison of the public and Foreign Direct Investments (FDI) from the point of investments, detailed activities and estimations against these investments, and as a result, reserves which are the assets, and production quantities of the actors of sector are put forth. 3. The factors which influence the investment activities, the reasons of insufficient investment in the sector, the structures and activities of companies operating depending on the competitive power of the sector are assessed concerning the status of the sector and the basins in our country for investment are determined. 4. Identifications and proposals that our country is not sufficiently explored, that there are still unexplored basins, that reserve quantity of 33 identified basins in our country may be around a magnitude of billion barrels, investment amount in 500 licensing for this purpose may sum up to about 20 billion dollars, the way of meeting such an amount as well as the matter of increasing the investments in the sectors are put forth. As a result; it is aimed with this paper to put forth the reality of the necessity to make much more investment because the investments made up to now hasn’t reached the desired level yet.
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The Study on Petrophysical Properties of Zonguldak Formation Located in Black Sea Region by Using Well Logs
Authors N. Küçükkuş, T. Ayyıldız and Ö. ŞahintürkThe clastic levels of Zonguldak Formation penetrated by 3 wells drilled between Zonguldak- Amasra, which are located in the Western Black Sea Region, are the main topic of this research. The age of the Zonguldak Formation is Carboniferous. The Çakraz, Zonguldak and Alacaağzı Formations are penetrated in the studied wells. The unit largely consists of economic coalfields. In addition to the coalfields, the unit consists of sandstones, conglomerates and shales. The petropyhsical specifications are studied through using the log datas of Gamma Ray, Caliper, Sonic Interval Transit, Neutron, Bulk Density, Resistivity, and SP, which are taken from the 3 wells that penetrated the Zonguldak Formation. From the well logs, it is detected that there are sandstonesconglomerates, shale and coal as dominant lithology. In the X well which is evaluated through RHOB and PHIN together, 0.21-0.44% porosity rates are obtained in the sandstones between 1490-1530 metres. In the Y well, the datas are notably low excluding some levels which reach up to 0.3%. The values of 0,20-0,67% in the first 20 metres, 0,18-0,44% between 50-74 metres, 0.18-0.44% between 2400-2450 metres are obtained through the Sonic log datas in the Z well. According to the datas obtained, the potential of reservoir rocks in the Zonguldak Formation is poor in the studied wells.
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Two Way Competition, Resource vs Market
By M. KorucuAs we all know, Turkey is in the proximity of two oil and gas rich regions, namely CIS and Middle East. Considerable volumes of those resources produced in these areas have already been contracted by the relevant resource rich countries. These countries are working on the alternative evacuation options for their remaining resources by considering an optimum balance between maksimizing the monetary values of their resources and keeping a political equilibrium among the major players. Having such vast resources, both areas are under close attention of major consumers, global players and other resource rich rivals. While the consumers are struggling for their energy security, sustainability and diversification, the rivals (other producers) are trying to increase their powerfull strategic position as a supplier and at least keep the current status quo of the energy dependency of the consumers. In this context, there are ongoing substantial bilateral and multilateral discussions among the regional / global players leading to important political developments in the region, which would also ultimately define the routes of the resources in line with the strategies of the relevant players.
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Evaluation of Turkish Natural Gas Law and Applications
More LessIn the presentation, sector activities which are now dominated by private companies through licences issued by Energy Market Regulatory Authority are reviewed. Licences issued by Energy Market Regulatory Authority for import, export, wholesale, storage, transmission, CNG, distribution activities are considered in quantitative terms and from the point of ownership. The problems encountered due to implementation of Law No 4646 and limitation of activities of public companies are examined and changes planned to be made in Law No 4646 are evaluated. Proposals for forming a vertical integrated public structure in petroleum and natural gas sector are made. Proposals are made for changes in existing applications.
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Design of an Ideal Petroleum Law: Economic Approach
By F. DemirmenPetroleum laws, otherwise known as “upstream fiscal systems” in the industry, are known to \frequently cause conflicts of interest between the host government and the contracting oil company. These conflicts arise after major changes in oil price, fiscal regime, or production rate. As a result, host governments frequently resort to revision of the fiscal system (in the “middle of the game”) to the displeasure of the contracting company; or the contracting company pleads for changes in the terms to accommodate “changing circumstances.” The petroleum law suffers instability, and neither the interests of the host government nor those of the contracting company are served. Such situations arise either from poor understanding of the objectives of a petroleum law or, more frequently, form insufficient flexibility of the petroleum law. Apart from generalities such as “meeting national interests,” an ideal petroleum law is one that: (1) encourages exploration, (2) promotes development of small as well as large petroleum reserves, (3) allows special incentives for difficult-to-explore or difficult-to-develop situations, and (4) enables equitable sharing of economic benefits between the host government and the contractor under different circumstances including oil-price and field or production outcomes. Equitable sharing of economic benefits is the most contentious issue. It is best judged from the relationship between the Government Take and the investor’s Internal Rate of Return (IRR). Equitable sharing will materialize if the Government Take and the contractor IRR show positive correlation under different scenarios of profitability. The best way to achieve an ideal petroleum law is through economic modeling. Economic models constructed to represent various scenarios, e.g., reserves, capex, oil price, can be evaluated under the proposed contractual terms. The inefficiencies can then be removed by adjusting the fiscal terms, e.g., income tax rate. The approach can be viewed as a form of fiscal simulation. The models should depict host-country situations (mainly “geology” and cost structure) as realistically as possible. The Production Sharing System, but not Royalty/Tax or Service System, is best suited for economic modeling to achieve flexibility. As an example, it will be shown that Turkey’s Draft Petroleum Law No. 5574 is economically inefficient, hence far from ideal.
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The Petroleum Law/Regulation Systems of Turkey and the World and Its Importance
By N.Ö. ÇiftçiIn today’s world, the fierce competition witnessed in petroleum sector can only be coped with a petroleum policy and financial policy systems having well designed legal basis. The governments and the petroleum investors may achieve the development goals through long lasting and durable relations in a comprehensible, stable and reliable legal ground. Energy is the leading factor among the most important factors that determine a country’s economy, and the basic purpose of all these efforts is to carry the public welfare to the highest level by increasing the economic strength of the country. The day by day increase of energy requirement in our country, the global changes and the liberal market regulations as well as the requirement for determination of the players, rules, audit processes and the authorities during the process from exploration and production of Petroleum until it reaches to the consumer have revealed the need for introduction of a new legal regulation. In this context, understanding the legal development of the Petroleum Sector in our country and in the world is extremely important for comprehending the innovations experienced and for finding legal solutions to the problems encountered in the sector.
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Some Suggestions with Regard to a New Turkish Petroleum Law
More LessNew Turkish Petroleum Draft Law numbered 5574 was prepared to change the existing Petroleum Law of 6326 with effective date of 1954 and with the reasoning of alignment with European Union acquis; exploration, development and production of Turkey’s petroleum resources in a fast, effective manner and in alignment with today’s market conditions. However, with the new proposed law, it seems unrealistic to reach the expected results while guarding the national interests; therefore, a hybrid model as used in some countries in the world is suggested. With this model, several suggestions are made with regard to: transparent, objective and competetive environment for licensing procedures in which only technically and financially pre-qualified companies participate; realization of significant exploration investments, auditing, and sanctions to be applied, in case of commercial discovery, sharing of the profit between the investor and the state fairly.
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The Interpretation and Recommendations on the Draft Oil Law of # 5574
By O. KonyaThe maximum use of domestic resources and export goal of minimizing the import oil of the dependency have been discussed on different platforms and have long been trafficked. The underground resources as oil & gas occupy an important place in our natural resources. Exploration, production and marketing are in the scope of the regulations of the “oil law” which was about the spoken one of the topics and conversations during the past years but; the topics were squeezed between with the law currently in force dated 1954, No. 6326 and the draft oil law dated 2007, No.5574. Turkey’s oil activities; M.T.A. was played as a national company’s role until of the year 1954 and 1954 after this task is undertaken by T.P.A.O., with domestic and foreign private companies in the oil Law No. 6326 any oil-related activity was opened in front of. Naturally, from the international oil/gas agreements the expectation of the parties is to obtain profit. To maximize the resources of the Government with the national values, private oil companies (domestic-foreign) will want to obtain the maximum profit. If the private companies have low vision on profit, or who are seeing their detachment from making investment, they should be far away from investment. In this context; with the changes in the oil law to be made public in the industry thought and needs to be analyzed in conjunction with the reorganization of the national company. This study of the Oil with the law dated 1954, No. 6326 and 2007, No. 6326 Draft Oil Law that in the case of contradictions and restructuring of the TPAO’s are discussed.
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Turkey and the European Union’s Fuel Prices and Taxes
By Ü. AydınTurkey and the European Union’s Fuel Prices and Taxes Turkey’s economic development within the basic entries is among the energy sources of oil which is expected to continue the importance of maintaining the position today and in the future. Oil and products meet 30% of the need for energy of the country which are used from production to consumption. We import almost 100% of the consumption and the domestic oil prices has been affected in the same way leading to movements in world oil prices, according to the fall of world oil prices in 2010, comparison to 2009, the pump prices was not fallen by the same amount in Turkey as a controversy. The pump prices of oil products are mostly consisted of taxes, oil and oil product prices are affected as well as the exchange rates in the world prices and refinery output prices of fuel products, Special consumption tax (PCT) and obtained through value added tax (VAT). In this study; fuel pump sales prices in our country, analysis of PCT and VAT and our country’s tax revenues from fuel taxes is compared and searched with the EU countries. The fuel prices in Turkey are quite high compared to in EU countries.
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Quantification of Uncertainty in Petroleum, Natural Gas and Geothermal Engineering Applications
Authors Ö.İ. Türeyen and M. OnurThe ultimate goal in any petroleum, natural gas or geothermal reservoir engineering study is to make performance predictions. Some of the variables to be predicted are pressures, recoverable oil, recoverable gas, recoverable heat from geothermal reservoirs, water cut, gas oil ratio and etc. Making predictions is vital for the economical exploitation of the resources. What is more important is the quantification of the uncertainty related to the predictions. Uncertainty in all future predictions is inherent due to (i) measurement errors or noise in the data, (ii) lack of data, (iii) modeling errors, (iv) span of the available observed data and (v) the non-linear relationship between the data and the model response. In this study we present an overview of the methodologies used to quantify the uncertainty in future predictions from oil, gas and geothermal reservoirs. We will present synthetic applications of various techniques for quantifying the uncertainty of gas in place for gas reservoirs, of heat in place for geothermal reservoirs, of water cut from oil wells and of pressure and temperature predictions using tank models for geothermal reservoirs. The techniques discussed will cover the Monte Carlo method, the analytical uncertainty propagation equation, the gradual deformation method, the randomized maximum likelihood method and the more recent Ensemble Kalman Filter method.
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Assessment of Uncertainties in Oil and Gas Reserves Estimations By Various Evaluation Methods
Authors M.F. Tuğan and M. OnurThe ultimate target of all oil companies is to increase their income by producing oil and/or gas. The key parameter to produce oil/or gas is the investments, such as purchasing licenses, drilling wells and constructing production facilities. Companies program their investments to a particular field by analyzing the ultimate recovery from that field. In this study, two most-widely used reserves estimation methods, volumetric method and material balance method are applied to estimate the Gas Initially in Place (GIIP) in a TPAO gas field, Çayırdere Field. Meanwhile, the importance of probabilistic approach to reserves estimation is emphasized by showing the change in estimated values by producing time. In addition to estimate reserves in probabilistic fashion, analytic uncertainty propagation method (AUPM), a simple, yet quite accurate alternative uncertainty quantification method to the well known Monte Carlo method is used to assess the uncertainty in GIIP of Çayırdere Field and is discussed in detail.
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Probabilistic Petroleum and Natural Gas Reserve Calculations by Volumetric Methods and Probabilistic Aggregation of Field Resource
Authors C. Karacaer and M. Onurod. It is proved that AUP method can be used in volumetric reserve estimations. To determine the total potential of more than one field or reservoir, two different methods are examined and “Sorting Diagrams Method” is developed to determine correlation coefficients between two fields which is indispensable component of realistic estimations. Also, applicability of AUP method to simulation applications is investigated and for this purpose two different methods are developed. The usability of these methods is discussed.
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Estimation of Shear Force for Blind Shear Ram Blowout Preventers
By A. TekinThe explosion of the Deepwater Horizon oil rig in the Gulf of Mexico showed once again that during the oil/gas drilling operation any failures of blowout preventers (BOPs) may result in death, injury and massive oil spills that have huge impact on the environment. During drilling operations, all formations’ high pressure fluids and gases in the earth are controlled by borehole pressure, which consists of hydrostatic pressure of drilling mud, pump pressure, and friction pressure loss in the annulus. If for any reason the borehole pressure falls below the formation fluid/gas pressure, the formation fluids/gases would enter the hole and a pressure “kick” occurs. If a kick cannot be controlled properly, uncontrolled formation fluids/gases would reach to the surface where the drilling rig is located. Such a catastrophic event is known as blowout.
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Vertical and Horizontal Wells Productivity Index Comparison and Performance Prediction with Tank Type Reservoir Model in the Single and Double Porosity; Isotropic and Anisotropic Reservoirs
Authors H. Kırmacı and M. OnurIn today’s world, increasing demand of energy has forced Petroleum Companies to search different ways to increase their production. Therefore, Petroleum companies test wells which take longer time and they try to find out the most economic production scenarios to increase the oil/gas production of the wells. As a result, modelling the reservoir as realistic as possible, determining the performance of reservoirs and the productivity of wells are more important. In this work, we present productivity index equations for vertical and horizontal wells, productivity in homogeneous, isotropic or anisotropic closed reservoirs and couple them with a tank model for performance prediction. By using the model developed during the course of this work, we compare the results for different well and reservoir types. The results show that the models presented in this work provide a simple, yet quite accurate performance predictions for vertical and horizontal wells producing in isotropic/anisotropic single or double porosity reservoirs.
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Controlled Burn Operations, Gulf of Mexico, Deepwater Horizon
More LessDeepwater Horizon accident lived in USA at Gulf of Mexico is one of the biggest oil spill and cause huge amount of environmental pollution but this accident also create a big opportunity to test “In-Situ” burning application in real life. In-Situ burning which means burning of oil in place depends on many factors requires some special equipments and controls. Basics of Controlled Burning; In order to succeed a successful burning there are several factors that has to be taken in to consideration. These are Physical and chemical properties of oil, either the oil are already ignited or un-ignited, Nature & Magnitude of spill, Location, Wind and Sea conditions, Visibility, Vegetation and Debris. Tools and Tactics: Burning oil requires the right combination of conditions – oil type and sea conditions. When conditions are right burning can remove vast amounts of oil from the marine environment Fire boom booms contain the oil and keep it under control during burning. Ignition systems are of the essential tools used for igniting oil efficiently and safely. Besides these there must be good vessel and aircraft support in order to maximize the amount of oil destruction. Tank Tests, Field Trials & Actual Spill Burns Fire booms have been developed and tested over twenty years. During these tests many information’s obtained about performances of fire booms and environmental effects of in-situ burning but none of these small scale tests were not as experienced in Gulf of Mexico. Deepwater Horizon Blowout During DWH blowout mainly three types of fire booms used; these are Elastec American Marine production water cooled Hydro Fire boom, and Ceramic boom and Applied Fabrics production Pyro Boom. In these operations more than 400 burns were conducted, of which 376 were counted as successful burn, eliminating between 220.000 bbl and 310,000 bbl oil. Conclusion; Over the last twenty years many of the manufacturers have tried to produce fire resistant booms. As a result of these efforts it is understood that burning oil is definitively a proven response option. Many lessons learned about boom performances; rigid construction booms (first generation) exhibited a poorer wave response; this is due to their construction and lower buoyancy to weight ratios while second generation booms held oil better in wave conditions. Second generations booms are also easier to handle, less time spend deploying, recovering and repairing equals more oil burnt.
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Rehabilitation of Crude Oil Contaminated Areas and Waste Disposal
Authors B. Ekizer, E. Gökçek, Ş.D. Atay, N. Köse and E. BuzpınarVarious types of waste ocur as a resuls of Hydrocarbon exploration, drilling and production activities. One of the waste type resulting from these activities is crude oil contaminated waste. It is often considered as hazardous waste crude oil contaminated waste and is able to cause environmental pollution by effecting water soil, air. Crude oil contaminated wastes are petroleum contaminated soil, packaging materials, absorbents, wiping cloths and protective clothes. It is necessary for these types of wastes disposal in order to prevent damaging to the environment. Soil pollution occurs as a result of petrolleum spilling due to the problems that occur during crude oil, of which hazardous waste type, production and transportation with pipelines. One method for removal of oil contaminated soil is the elimination with the application of “Bioremediation Process” used widely by means of TPAO and also other international companies. Bioremediation which is a method of biological treatment of natural microorganisms using the hazardous waste, is defined as a reduction of less toxic or nontoxic compounds. One of the most important factors of soil rehabilitation is to provide in-situ bioremediation application. Cellulose fibers obtained from recycled processes and bioremediation products comprising nitrogen and phosphorous components that are necessary for he survival of those bacteries exist in the sport even thoguh there are groups of bacteria in the product. Those bacteries being in contact with water and hydrocarbon divide and increase rapidly. Adsorbed hydrocarbon waste (activities of bacteria) converts to the completely harmless bioenergy by means of bioremidetation process in 90-240 days. One of the another method used for soil rehabilitation and used by means of TPAO is notralization-stabilization. In this method, contaminated soil is rehabiltated with the certain portion of ash, clay, lime, soil or cement, which is determined according to petroleum content. In addition to two methods, mentioned above, packaging materials, wiping cloths and protective clothes, and so on disposed in mobile incineration systems (waste incinerator) located at the activity areas.
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Health, Safety and Environment Study in Cudi-1 Exploration Well
More LessTo date, Turkey Petroleum Corporation (TPAO) which is the leader in the integration of Turkey oil fields and all petroleum industry; has adopted , concept of Occupational Health, Safety and Environmental Protection determining to the concepts of configuring and operating principles in all work areas in these matters and is continuing its activities in accordance with legal regulations in all petroleum areas. TPAO, which carries out the national and international hydrocarbon exploration and production activities, creates partnerships with foreign oil companies onshore as well as offshore. In these projects in parallel with technical operations, TPAO plans and executes the aspects of health, safety and environmental awareness. Cudi-1 exploratory well operations, which is one of these activities; in the Southeastern Anatolia IX. Oil Field, with the registration number of AR/TPO-CET-NTP/2763, was carried out under the partnership of TPAO, Chevron and NVT Perenco, in which TPC was the operator. The operations in the Cudi-1 wells, which is 25 km north-east of Silopi, Sirnak, were completed between May 2009-May 2010. In Cudi-1 exploration well studies, The Health, Safety and Environmental (HSE) Department of TPC, collaborated with other relevant technical departments from the beginning of the Project both planning stage and during drilling operation. In line with TPC HSE Department procedures, the preparation and implementation of well-specific emergency plans, waste management plans, the organization of meetings auditing activities and maintenance of clerical (paper) work of HSE, HSE Observation Card Application, Staff ID Card Application, daily HSE reports have been conducted. The barrel type incinerator has been used on a regular basis as a waste disposal system For the first time in land wells; the professional services of “Hydrogen Sulfide (H2S) Detection and Protection System (Cascade) Service” and “24-hour Emergency Medical Response Service”, which includes an assigned doctor, a medical technician and an ambulance service, were provided by local firms. In this paper, Cudi-1 well experiences which is the best practises of HSE Standards in very high risky area is aimed to sharing
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Cretaceous Tectonic Evolution of the Western and Central Black Sea Region
By O. TüysüzThere are different views on the tectonic evolution of the Pontides, one of the main tectonic units of Turkey. Şengör and Yılmaz (1981) divided the Pontides (sensu Ketin, 1966) into Rhodope-Pontide and Sakarya continental fragments separated by an Intra-Pontide Suture. The Pontides were subdivided into Istanbul, Istranca and Sakarya zones by Okay et al. (1994). The most controversial issue on these different tectonic models is the relationships between Istanbul and the Sakarya zones (Western and Central Pontides) and oceanic realms (Palaeotethys, Neotethys and Black Sea) separating these continental fragments. Data from the Daday-Azdavay-İnebolu region and from the Kargı Massif shed light onto this discussion. Our data indicate that the Western and Central Pontides juxtaposed along the Intra-Pontide Suture at the beginning of Late Cretaceous. The ophiolites in the Kargı Massif and around the Çankırı Basin represent the İzmir-Ankara-Erzincan Ocean, which was consumed by northward subduction during the Triassic-Late Cretaceous interval. In this presentation I will describe tectonic units of the Cide-Sinop-Tosya area and discuss their Cretaceous evolution.
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The Black Sea Formed Wıthın Old Eurasıan Contınental Lithosphere: Implications For Pre Black Sea Reconstructions and Controls on Black Sea Tectonic Evolution
More LessHeat flow data and lithosphere rheology and tomography models suggest that the lithosphere beneath the Black Sea is cold and strong. Comparison of the regional distribution of Black Sea rift structures with other back-arc basins and models of back-arc basins suggest that the lithosphere beneath the Black Sea is cold and strong. Inverse numerical models of tectonic subsidence of the margins of the Black Sea compared to those of other modern and paleo back-arc basins suggest that the lithosphere beneath the Black Sea is cold and strong. From this, it is concluded that the Black Sea formed (mainly) within old Eurasian continental lithosphere. Indeed, reconstructions based on regional tectonic arguments suggest that continental crust on both sides of the modern Black Sea were contiguous parts of the Eurasian plate since at least Early Palaeozoic, if not even Neoproterozoic times. Further, this Eurasian continental lithosphere around the Black Sea has been in a (trans)extensional tectonic environment since at least the Late Palaeozoic, the geological record of which can be found on the margins of the Black Sea and in subsurface data from the shelves of the Black Sea. The back-arc rifting that led to the present configuration of the Black Sea, which occurred in the Cretaceous, was therefore superimposed on the structural consequences of a series of earlier rifting and basin forming events (Late Devonian-Carboniferous, Permo-Carboniferous, Permo-Triassic, Jurassic). The crust that was thinned during Cretaceous rifting was already strongly thinned by these earlier events, which otherwise had been mostly thermally equilibrated on the lithosphere scale. The thin crust underlying the deep basins of the western and eastern Black Sea is not (sub)oceanic crust but is highly thinned continental crust, akin to a lower (continental) crustal metamorphic core complex. The implications of these observations and inferences for pre Black Sea tectonic reconstructions and controls on its origin and evolution will be enumerated and explored.
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Source of the Carboniferouıs flysch of the İstanbul Zone: Sandstone Petrography and Detrital Zircon-Rutile Geochronology
More LessThe Lower Carboniferous flysch of the Istanbul Zone is an over 1500-m-thick turbiditic sandstone-shale sequence marking the onset of the Variscan deformation in the Pontides. It overlies Lower Carboniferous black cherts and is unconformably overlain by the Lower Triassic continental sandstones and conglomerates. The petrography of the Carboniferous sandstones and the geochronology and geochemistry of the detrital zircons and rutiles were studied to establish its provenance. The sandstones are feldspathic to lithic greywackes and subgreywackes with approximately equal amounts of quartz, feldspar and lithic clasts. The amount of feldspar decreases upwards in the sequence at the expense of quartz and lithic fragments. The lithic fragments are dominated by intermediate volcanic rocks followed by metamorphic and sedimentary rock fragments. Coarse lithic fragments are generally granitoidic. In the discrimination diagrams sandstone samples lie mainly in the field of dissected arc. 218 detrital zircons and 35 detrital rutiles from four sandstone samples were analysed with laser ablation ICP-MS. The detrital zircons show a predominantly bimodal age distribution with Late Devonian to Early Carboniferous (390 to 335 Ma) and Cambrian-Neoproterozoic (640 to 520 Ma) ages. About 9% of the analyzed zircons are in the 1700-2750 Ma range; zircons of the 700-1700 Ma age range are absent. The REE patterns and Th/U ratios of the zircons indicate a magmatic origin. With one exception (Neoproterozoic), the rutile ages are Late Devonian - Early Carboniferous and their geochemistry indicates that they were derived from amphibolite facies metamorphic rocks. Sandstone petrography and detrital zircon-rutile ages suggest one dominant source for the Lower Carboniferous sandstones: a Late Devonian to Early Carboniferous magmatic and metamorphic province with overprinted Neoproterozoic basement. Late Devonian - Early Carboniferous magmatic and metamorphic rocks are unknown from the Eastern Mediterranean region. They are, however, widespread in central Europe. The Istanbul Zone is commonly correlated with the Avalonian terrranes in central Europe, which collided with the Armorican terranes during the Carboniferous resulting in the Variscan orogeny. The Carboniferous flysch of the Istanbul Zone must have been derived from a colliding Armorican terrane, as indicated by the absence of 700- 1700 Ma zircons and by Late Devonian - Early Carboniferous magmatism, typical features of the Armorican terranes. This suggest that during the Carboniferous the Istanbul terrane was located close to the Bohemian Massif and has been translated by strike-slip along the Trans European Suture Zone to its Cretaceous position north of the Black Sea.
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The Darius Programme: Investigation of Foldbelts and Related Sedimentary Basins from the Black Sea and Anatolia to Central Asia
More LessThe DARIUS Programme is a consortium-type programme funded by major oil companies, participating universities and the French research funding agency CNRS. It aims at investigating the 6000 km-long continuous deformed belt from Crimea-Anatolia in the west to the Tien-Shan in the east, through the Caucasus, northern Iran and Zagros. Its major objective is to acquire newly documented observations on the tectonic and stratigraphic evolution of the constituent orogenic domains and associated basins of this belt. The former resulted from the collision of Gondwanan blocks with southern Eurasia from the Mesozoic (Cimmerian blocks) until the Cenozoic (India, then Arabia). Accordingly, the DARIUS Programme funds scientific projects on the basis of proposals submitted by invited geoscientists. For 2010-2011, 38 projects were selected covering most of the DARIUS’s area of interest. These scientific projects involve some 40 research institutions and universities from about 15 countries, and scientists from about 150 organisations in Europe, the Middle East and western Central Asian countries. The expertise of the participants of DARIUS includes structural geology and tectonics, stratigraphy and sedimentology, mechanical and thermal modelling, kinematics and geophysics. A number of thematic working groups, tasked with integrating the results of individual projects within regions or disciplines of the DARIUS Programme, have been established to start working in 2011. Two of these – “Tectonic Evolution of Anatolia” and “Evolution of Caucasus: from Basins to Orogenic Belt” – are of direct relevance to Turkey. The thematic working groups will make an essential contribution to the final objectives of DARIUS, which include, most importantly, a new regional geological synthesis of the Middle East-Central Asia study area, realised mainly through a set of palinspastic maps depicting the tectonic evolution since the Late Palaeozoic. It’s hoped that these will form a major contribution to new interpretations and new debates regarding the geological and tectonic evolution of the northern Middle East-Central Asia region. This presentation is made on behalf of the Board of the DARIUS Programme: Eric Barrier (leader), Marie-Françoise Brunet and Bruno Vrielynck (ISTEP, Université Pierre et Marie Curie-CNRS, Paris, France); Andrea Zanchi (Università degli Studi di Milano Bicocca, Milano, Italy); Franz Fürsich (GeoZentrum Nordbayern der Universität Erlangen, Germany); Marc Sosson (GeoAzur-CNRS, Valbonne, France); Jaume Vergés (Institute of Earth Sciences Jaume Almera, CSIC, Barcelona, Spain) and the presenter.
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Hole Enlargenment Operations at Deep Water Wells
By Y. KumThe difficulties in deep water drilling have been stimulating new technologies and nem advances. One of the most challenging issue about deep water drilling is certainly that narrow window between fracture gradient and pore pressure. Narrow window between the fracture and pore pressure force to run different size of holes and casings. To use different sizes of casing push engineers for devoloping new drilling tools and advances. The biggest one of these is underream tools that engineers have presented as a solutions . There are two main different systems to operate this kind of tools. The main disparity between these mechanism is activating system of blades. One of is needs a ball to activate or deactivate blades and another of no drop ball mechanism that utilize pressure loss around the blades to activate and disactivate. Rhino Reamer that we used in deep offshore wells needs a ball to activate blades but not necessarily drop a ball to deactivate. Inspite of the fact that there are some advantages and disadvantages when comparing with each other. I want to mention about working principles of Rhino Reamer and its applications at Yassıhöyük-1, Sürmene-1 wells at ultra deep water. As a summary, at Yassıhöyük-1 well, Original hole Enlarged to From To S/N Reamer 18 1/8’’ 22’’ 2815 m. 2950 m. Rhino 1600 16 ½’’ 20’’ 2950 m. 3335 m. Rhino 1600 14 ¾’’ 17 ½’’ 3335 m. 3600 m. Rhino 14250 Sürmene-1 well, Original hole Enlarged to From To S/N Reamer 18 1/8’’ 22’’ 2610 m. 3014 m. Rhino 1600 16 ½’’ 20’’ 3014 m. 4308 m. Rhino 1600.
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Top Drive Casing Running System Success in Turkey for TPAO on the Black Sea Deep Water Project
By B. WarmerdamResults, Observations, and Conclusions: The Top Drive Casing Running & Drilling system was used on two subsea wells, respectively Yassihouk and Surmene, over a 7 month period for running various casing string sizes: - 18” 128# P110, ran one liner string, length 206 meters - 16” 96# 125HC, ran two liner strings, length 650 meters - 13-5/8” 88.2# 125HC, ran one casing string, length 1560 meters - 9-5/8” 53.5# 125HC, ran one liner string, length 910 meters The Top Drive Casing Make-up Tool combines a power tong including independent torque-turn monitoring, main hoisting elevator, fill-up and circulation tool, single joint handling and a thread weight compensator, The thread weight compensator eliminated any cross threading and damage of threaded connections. None of the casing joints were damaged or laid out, which reduces nonproductive time (NPT) during casing running operations. This system eliminates much of the manual handling of traditional casing running equipment on the rig floor and the need for working on rig floor scaffolds. The system also incorporates link tilt bail arms including remotely operated single joint elevator to align the casing for makeup, eliminating the requirement of having a stabber working in the derrick. The client and drilling contractor classified the system as a “hands-off” system, eliminating activities when using conventional equipment: - Manual pipe stabbing - Power tong positioning and door closing - Pinch points in respect of manual handling As the system is connected to the top drive, the total casing running operation is mainly in control of the driller, enabling an increase in casing running efficiency and consistency compared to conventional running equipment. This reduces the “open” hole time and the potential for differential sticking or cave-in of the well bore. As some of the casing running operations were executed in bad weather conditions (heavy winds / rig motion) the casing running operations could continue as they may have been stopped if conventional equipment would have been be used. The remotely operated system is completely portable and requires no permanent interface into the rig structure.
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Investigation of Reservor Rock Characteristics of Çaldağ Formation, Tuzgölü Basin (Central Anatolia), Turkey
Authors Ş.O. Ergene and T. AyyıldızPaleocene aged Çaldağ Formation with reefal character which exposures in the Tuzgölü Basin is an important unit for petroleum exploration. In the Karapınar Measured Section (MS), conglomerates belonging to Karapınar formation is overline unconformably Asmaboğazı formation which is composed of limestones blocks in the upper part, derived from the Çaldağ Formation as an olistostromal characterics. In addition to this, it can be also observed as different sizes of blocks in the basin. The other MS’s are characterized by reefs and reef complex facies. Paleontological data indicate that limestone deposition of the Çaldağ formation is initiated at Danian and Tanesian at the eastern and western part of the basin, respectively. According to petrographic determination, vugs, fractures and rare intergranular pores are observed. Fractures are mostly filled with calcide, and iron oxide cement. According to the analytic measurements on porosity and permeability for limestones cores from the Mezgit Limestone Mining and Dulayşe Garden MS’s are determined as % 0.5 - % 1.7, 0.01 – 0.04 md and % 0.7 - % 2.9, 0.01 – 0.02 md, respectively. Petrographic and laboratory analysis shows that reservoir rock characters of the formation have weak to moderate; however; it can be considered as good where fracture porosity developed well.
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Solid Expandable Tubular Technology in Monodiameter Drilling
By H.M. SalmanThe introduction of expandable tubular technology has revolutionized the oil and gas industry which has converted the dream of monodiameter well into reality.It has now spread all over the world. It has played its role in drilling, completion and production. The main products of this technology are: 1: Expandable open hole liner system. 2: Expandable closed hole liner system. 3: Expandable liner hangers. 4: Expandable completion screens. This technology assures its complete allegiance to the following three basic requirements: 1: Conservation of hole size. 2: Isolation of selected zones. 3: Maximization of well life. Monodiameter wells eliminate the telescoping effect, allowing operators to slim down the top of well while increasing the well diameter at TD. A constant inside diameter from top of well to its target depth is achieved by solid expandable tubular products .This technology permits the installation of drilling liners of same size without decrease in internal diameter. The concept behind this fact involves the expansion of tubular by a mechanical expansion device, known as expansion cone or mandrel. This device permanently deforms the tubular up to the desired inter or external diameter by a plastic deformation process known as cold drawing. This paper is primarily based upon review, case study and environmental effects of monodiameter drilling. The cost comparison of conventional drilling with monodiameter drilling has also been discussed in this paper.
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Geomechanical Wellbore Stability Assesment for Sayındere, Karaboğaz, Karababa Formations in Batı Gökçe Field
More LessWellbore stability problems make up huge over-costs worldwide. Since in recent years declining resource volumes and favorable oil prices are encouraging operators to drill deeper, more complex well trajectories drilling for hydrocarbons have turn into a much more challenging task. Furthermore, the complexity and variations of those wells have added the weight to planning and problem anticipation at both drilling and production stages. The article will describe the geomechanical wellbore stability analysis of Sayındere, Karaboğaz and Karababa formations drilled in Batı Gökçe field, Adıyaman. The analysis assumes validity of linear elastic theory for porous media and requires drilling reports, well logs, laboratory tests and core analysis. At the end of the work with the assessment of geomechanical wellbore stability analysis mud weight window, which includes minimum mud weight and maximum mud weight will be determined for the studied formations.
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Latest Advances in Sucker Rod Beam Pump Automatıon
By N. SadekWorldwide, as conventional oil resources are depleted, beam pumping system is becoming the most common type of artificial lift methods for onshore wells. With the growing number of beam pumped wells, the value of automation and real-time data is continuously increasing. Oil companies might have different views of the meaning of “automation”. Some companies will apply cycling timers and others will have a basic rod pump controller but the technology driver nowadays is to gather all possible data about and around the well in one smart well manager system. This smart system will use the gathered information to optimize the well by decreasing lifting costs and increasing production. It will not only rely on surface information but also uses intelligent downhole pump analysis and calculations to identify downhole conditions. Finally, all the information is transmitted to the field and main office over a SCADA system for 24/7 remote monitoring and control. Sucker Rod Well Automation is essential for the well operation as it plays a major role in the well optimization leading to less failure, less operation costs, less downtime and higher production accordingly. This presentation will discuss the latest technology in beam pump optimization, remote monitoring, and control. It will highlight the benefits achieved by applying downhole analysis control in beam pump controllers and variable speed drives, as well as the use of expert supervisory control software which analyzes the wells using artificial intelligence. Actual well data will be shown from successful field results.
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Development of Akçakoca Gas Field in Western Black Sea, Offshore Turkey
By M. SarıçiçekExploration and development activities in the Turkish sector of Black Sea have been ongoing with a growing trend since Ayazli Gas Field was discovered in late 2004. Three tripods, a trunk offshore pipeline were installed off the western Turkish coast up to 78 meters water depth, 18.5 km of onshore pipeline and Cayagzi Natural Gas Processing Facility in the shoreline was constructed to receive, process, compress and send the produced gas to the national gas grid in Phase-I development. Akcakoca Gas Field was discovered in late 2006 after Akcakoca-3 exploration well was successfully drilled and tested by a semi-submersible rig. Field is located about 14 km off the coast of Akcakoca/Duzce in the Western Black Sea where the water depth is about 94 meters. Akcakoca Field Development, also called Phase-II, encompasses design, fabrication and installation of a 4-Legged Drilling/ Wellhead Platform with a two level Topside over the two pre-drilled wells, installation of a 12 inch 7 km long offshore pipeline, tie-in to the existing subsea pipeline system, tie-back of the existing wells and drilling & completion of two or three additional wells via a platform rig installed on main deck of the platform. An advanced FEED study for Akcakoca Platform and offshore pipeline was performed which was followed by an international tendering process for an EPCI type service agreement. Platform was constructed by the Contractor GSP in Agigea Yard/Constanta in Romania, transported to Turkey and installed by a shear-leg heavy lift barge owned them. Offshore pipeline was installed using S-Lay method by a pipelay vessel again owned by GSP. In this paper, Akcakoca field development phases are introduced, particulars and different aspects of design and construction activities are presented. Akcakoca Platform is currently the deepest shallow water installation in the Turkish territorial waters and is expected to reach its total peak production rate from the platform wells after all the wells are drilled and completed in the third quarter of 2011.
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A Field Application with Liquid Surfactant for Production Optimization
By Ö. SunalLiquid loading in gas wells is a major concern that causes reduced production and shortening of the well life. Liquid loading arises when a gas well is unable to remove the produced liquids from the wellbore. Gas rates below the critical rate are inefficient to remove the liquid and lead to liquid accumulation in the bottomhole which eventually might kill the well. There are various methods to deliquify gas wells, each of which can be implemented as the optimum method in different cases based on the well specifications. Most of these methods can be unfeasible for highly depleted wells with low reservoir pressures and low flow rates. This study introduces a new field application of deliquification of a gas well in Thrace region in Turkey by continuous liquid surfactant injection down the well. The study focuses on increasing production and recovery from a low pressure gas well with water buildup issue. Laboratory tests have been conducted with brine samples taken from the well to identify the best performing foamer product. The concentration and dosage of the foamer have been determined based on the results of well modeling study. This project is of great importance due to the fact that it is the first application in Turkey in which continuous liquid surfactant injection is performed to unload the accumulated liquid in a gas well. It is an ongoing study; the results of the application will be presented in the paper.
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Electrical & Control Systems of an Unmanned Platform: Akçakoca
By S. SaydereAt this presentation we will introduce basis of electrical power, safety, control, telecommunication and instrumentation systems of an unmanned gas platform. The electrical and control systems are designed according to redundancy, fail safe philosophy and as simple as possible. Except equipments in the control room, all the electrical or electronic equipments are ex-proof or in the ex-proof Junction boxes. The main systems are as follows: Generators: Gas Turbine and Diesel generators, which both of them are exproof. The main advantages are low maintenance, working between %0-100 loads, no problem at following transient currents, etc. Diesel Generator is the redundant one. MCC:) With two ATS, Motor Control Center (MCC) can make selections of the power supplies and all the main power is observed with a power analyzer. MCC is withdrawer type. DC UPS: It is designed for 50 amp nominal. Whenever there is a blackout, it has 3 days DC backup at worst case. It has 12x80 amp charger for fast charging. Control Room is a positive pressured room that is taking it air from unclassified are. It has fully redundant heating, airconditioning and ventilation system. It has special extinguishing, air flow, gas and smoke detections. Nav-Aids is a system to warn with voice and lights surrounding area of the platform according to Solas (Safety of Life at Sea). It consist of 4 lanterns, 1 horn, control systems, batteries, chargers, etc. If there is a blackout, it uses 2 solar rays of panels for supply and charging Auxiliary Equipments: Lighting is consisting of 5 power lines, which consist of both emergency and normal lightning. False loads are for the diesel generator for low power consumption. Heaters are for helping protection from freezing of some equipments and piping. Also, there are various kinds of equipments like intrusion detector, vibration detector, receptacles, etc. Fire detection systems: Fusible pug panel that has 28 fusible plugs around the platform with two lines. As an additive, fire detectors, gas detectors, esd and fire stations, safety transmitters and switches, horns and beacons, etc. Skid base instrumentation systems mainly consist of transmitters, switches, control valves, etc. Wellhead control is with a dedicated wellhead control panel systems which is at side. PLC, telecommunication, onshore control, IO connections. System is with hot redundant PLC, all the Safety Integrity Systems are fail safe IOs.
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The Geothermal Energy Exploration Activities of MTA in Turkey
More LessAs is known, our country has a great potential in terms of geothermal energy. Our Directorate-General plays an important role in the discovery and evaluation of this potential and produces significant projects in this respect. The theoretical geothermal energy potential of Turkey is accepted as 31,500 MWt. In our country, the first geothermal energy exploration studies were initiated by MTA in 1962 in İzmir Balçova. Up to now, 504 wells, having a total depth of 252.515m, have been drilled, and a total of 190 geothermal fields have been discovered, and including the natural discharges, a total of 4550 MWt heat energy has been produced. The number of discovered geothermal fields has increased from 173 to 190 with the drilling activities. In Turkey, geothermal energy is mainly used in thermal tourism, space heating, greenhouse applications, electricity production and industrial mineral (CO2) production. In Turkey, there are 18 geothermal fields, discovered by MTA, which are suitable for geothermal power production. Within these fields, there are 7 fields which are currently used for electricity production and/or in project stage with license. In our country power production from geothermal energy is expected to reach 600 MWe by the end of 2013. The direct use applications of geothermal energy in our country include district heating, greenhouse heating and thermal tourism. Currently, there are 18 settlements which use geothermal for central house heating (81060 Residance Equivalence, 729 MWt), there are 15 fields where greenhouse heating is applied (1989500 m2, 379 MWt) and there are a total of 306 thermal resorts which offer medical treatment and thermal tourism applications. In our department, drilling studies have been initiated in a total of 26 wells that were programmed in 2010, and 19 of these wells have been completed, reaching a total geothermal drilling depth of 21533.15 m. With the completed wells, about 119,38 MWt of energy has been added to the country potential, and only with the wells drilled by our directorate the geothermal energy potential has reached 3906 MWt.
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Geothermal Energy Potential of Turkey
Authors E.D.K. Başel, Ü. Serpen and A. SatmanIn this study the stored heat in the first 3 km depth of Turkey, identified geothermal capacity of known 279 occurrences and geothermal potential of fields in terms of power generation and direct use applications are estimated. Our results revealed that the geothermal resource potential of rocks shallower than 3 km is 3±1x1023 J. The current identified geothermal capacity of the known 279 geothermal localities has reached about 5550 MWt and 5944 MWt on a reference temperature of 20 oC and 15 oC respectively. A total of 122 potential geothermal fields (25 fields suitable for electric power generation, 100 are suitable for nonelectric usages and three of them could be classified for both usages) are evaluated using volumetric reserve estimation method. Monte Carlo type of simulation technique is employed for calculations of estimations. According to Monte Carlo simulation results, 122 fields have a lower limit of 28 500 MWt (cumulative probability; P10) thermal potential assuming that all fields are exploited for direct use only. Taking the results of the Monte Carlo Simulation studies for high temperature geothermal fields the results of P10, P50 and P90 values are calculated as 1055, 1469 and 2105 respectively. The lower limit of Turkey geothermal potential for electricity generation for those 25 high temperature fields is estimated to be 1055 MWe and the corresponding value for direct use to be 22 450 MWt for a reference temperature of 100 oC and 15 oC, respectively. In case of integrated exploitation of those 25 high temperature fields, the corresponding potential for direct use is 12 860 MWt. In case of integrated exploitation of the 25 high temperature fields for both electricity generation and direct use, and the direct use exploitation of all other fields, the direct use potential corresponding to P10 value is 18 910 MWt. Capacity and the potential values given here apply only to known and identified fields already discovered in Turkey. Geothermal heat pumps, the EGS applications, and undiscovered fields are not taken into consideration. With the consideration of these possible applications in future, the potential and capacity values would be much higher than the current values.As a final part of this study the subsurface temperature distribution maps at 500 m and 1000 m depths generated for Turkey and as well as for the Southeastern Anatolia and Thrace Regions are presented.
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Determination of Protection Areas in Geothermal Fields
Authors B. Akan and H. DağıstanAs a general belief, the geothermal systems are regarded as endless natural reservoirs and therefore, they are put into use without the knowledge of the hydrodynamic behavior of the aquifer, an essential knowledge required for an efficient management that will sustain the reservoir. The concept of sustainability has great importance in all energy resources including geothermal energy. From this point of view, the sustainability of geothermal resources related with potection of geothermal springs. In this case the protection areas are of vital importance so as prevent contamination of geothermal reservoir and take measures to prevent possible negative change of pressure and temperature conditions at reservoir. According to data from geology, hydrogeology study and well tests results, the boundary of protection zone of geothermal area should have determined to protect the geothermal reservoir. These boundaries should have shown at geology map and public improvements map. In these boundaries the measures should be taken and put into practice.
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Research of Geothermal Fields by Utilising Potential Field Data
Authors S. Tufan, A. Özdemir and M. DoğanayGravity and magnetic methods, are oriented to potential theory, main geophysical survey methods. Generally, on the exhaustive fields, available to research of the whole mineral property (mineral, oil, geothermal etc.), detailed geological survey, other geophysical survey and drilling studies oriented for determining target fields and additionally, in the world and Turkey, fields of application are on the increase on the grounds that these methods are low-priced. Gravity method is affected from the gravitational field and magnetic method is affected from the magnetic field. Underground, heterogenous structure, consists of mineral condensations form to magmatic, sedimentary, metamorphic and economical richness. These rocks and mineral condensations are different density and magnetic susceptibility at the different depths and sizes. All of the differences cause to variations on the vertical component of the acceleration of gravity and magnetic field. These variations are measured by special improved tools and the basis of gravity and magnetic methods is evaluation and interpretation of these measurements. The bouguer correction of the magnetic data, transformation of magnetic data to gravity data, approximation from the power spectrum to geological structure depth, determination of approximately boundaries of the geological structure causing to this anomaly, geologically 2B modelling of the aerial magnetic data and 3B modelling by means of prisms methods use for the interpretation of the aerial magnetic data and modeling of the geological structure causing to this anomaly. Determination of the compatibility to the geothermal survey of a field, at first, local geology, geophysical (aerial magnetic and regional gravity), elevation and satellite image data should be analysed in common. And later, detailed surveys (geological mapping, geochemical sampling, geophysical and drilling works) should be done. It is clear that if it is standardised to be done of locally preliminary investigations with potential field data (aerial magnetic and regional gravity) before than licence purchase, field purchase-recirculate and detailed surveys, it will make a great contribution to the sector. In this study, research of geothermal fields by utilising the aerial magnetic and regional gravity data investigated by examples. Advantages of locally preliminary prospecting by using potential field data before than detailed researches at the geothermal surveys and best available results have been presented by this study.
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Sedimentary Facies and Depositional Environments of the Upper Triassic Carbonate-Evaporite Succession of Denizli-Kızılyer (SW Anatolia, Turkey)
Authors H. Alçiçek, B. Varol and A. GandinThe Upper Triassic carbonate-evaporite Kızılyer unit, which outcrops mainly in southeastern Denizli area (SW Turkey), occurs as a tectonic slice within the carbonate and ophiolithic units of allochthonous Lycian nappes (Alçiçek et al, 2003; Gündoğan et al., 2008). It consists of interbedded layers of sulphates (anhydrite/gypsum), dolostone and dolomitic limestones represented by: Lithofacies-I: dark gray homogeneous dolostone, including three microfacies: mudstone: dolomicrite, with rare ostracods and ghosts of foraminifers; wackestone-packestone: dolobiomicrosparite, including peloids, foraminifers, rare ostracods and echinoderm plates with syntaxial overgrowths; and bioclastic packstone: composed of ostracods, ossicles of echinoderms/crinoids and peloids; and Lithofacies-II: light-dark grey dolomitic limestone with fenestral fabrics, including two microfacies: cryptalgal boundstone composed of discontinuous cryptalgal laminae which fragments are separated by dolosparitic or sulphate cements and ostracod/peloidal packstone-grainstone: made up of alternating layers containing ostracods, algal aggregates and traces of hyaline foraminifers. Sedimentological and micropalaeontological evidences indicate that Kızılyer succession was deposited in protected environments of the peritidal zone of a shallow inner ramp under a tropical/arid climate.
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Mineralogical and Petrographic Features of the Hydrothermal Alteration Around Sandıklı (Afyon) Geothermal Field
Authors D. Okur, İ. Gündoğan, İ.H. Kahramanderesi, Y. Yücel-Öztürk, C. Helvacı and E. KanlıThe study area is located in the Sandıklı district, 40 km southwest of Afyon city. The area was intensely affected by hydrothermal alteration and geothermal systems related to tectonic and volcanic activities during the western Anatolian Neo-tectonic period. Miocene volcanic activity in the Sandıklı district produced alkaline lavas and calc-alkaline pyroclastic rocks. There are many examples of hydrothermal alteration and mineralization occurrences within the investigated area. The basement rocks consist of low-grade metamorphic rocks of the Afyon zone. The hydrothermal alteration can be traced from Hüdai thermal water to the north and east in the Sandıklı volcanic rocks. The borehole data indicate that the effects of hydrothermal alterations continue further depths. Mineral paragenesis of the alteration is studied and revealed by mineralogical and petrographic studies from the borehole samples. Silicification and chalcedony plus hematite occurrences are extensive at the depth of 50-60 meters of AFS 12 and 13. Marcasite and sericite with pyrite and hematite abundances increases further depths. Euhedral Fe-Ti oxides are seen at the interval of 110-180 m interval. In addition to these, sanidine and euhedral pyroxene (augite) with primary apatite and titanomagnetite minerals are also observed. The Seydişehir formation is cut at the depth of 316 m of AFS 15. Furthermore, fractured and sulfured zones are cut at the depth of 136, 179, 217, 452, 484 and 598 meters, respectively. The Seydişehir formation is cut at the depth of 312 m of AFS 16, and fractured and sulfured zones are cut at the depth of 244, 246, 396, 478, 634, 638, 654, 678, 916 and 920 meters, respectively. In the AFS 17, the Seydişehir formation is cut at 332 m and sulfured zones are observed at the depth of 156, 260, 304, 380, 762 and 960 meters. The borehole data indicate that Hüdai quartzite is second reservoir rock. Hüdai quartzite is observed at 500 meter. The project aims are targeted to obtain higher temperatures at 7 holes studied, in addition to the previous bore holes. The basement rocks show different sequences in these 7 holes. Main production zone is revealed from Hüdai quartzite. In the Hüdai quartzite, hydrothermal mineralization riches and thermal water temperature increases with depth. Production temperatures are given depend on productions. The study is still on progress in order to obtain further data from the geothermal field. Key words: Hydrothermal alteration, Alteration mineralogy, Geothermal resources, Western Anatolia, Sandıklı geothermal field.
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3D Subsurface Modeling of Gümüşköy Geothermal Area, Aydın, Turkey
Authors S. Akar, O. Atalay, Ö.Ç. Kuyumcu, U.D. Solaroğlu, S. Arzuman and B. ÇolpanIn this study, 3D subsurface model of the Gümüşköy Geothermal Area was generated to identify geology and geothermal system using existing information of various sources. In this perspective, Petrel® modeling software was used to prepare 3D lithology, structural geology, resistivity, and temperature models within the study area. Western Anatolia, where the study area is placed, exhibits a unique importance as it governs most of the geothermal producing systems in Turkey. BM Engineering and Construction Inc. started early exploration studies for Gümüşköy region in 2005 and during five years of period different sources of data including geology, geochemistry, geophysics and well logs have been collected. Geothermal System of Gümüşköy can be defined as hot-water dominated convective hydrothermal resource with deep circulation of water along fractures settled in the Büyük Menderes Graben (BMG). The methodology that we followed was composed of four stages; Data input, Structural Modeling, Property Modeling and Uncertainty. Data input stage includes both conventional and GIS format data. Structural modeling defines the skeleton of the 3D model including Fault Model, Grid mesh, Model Horizons and Zones. Property Modeling is the output stage where, 3D subsurface models like lithology, resistivity, temperature, and pressure were generated. Lithology model has been built using both deterministic and stochastic approaches. Deterministic approach gave more realistic results but there is always uncertainty which can be corrected with the new wells drilled. Resistivity/ Temperature model built with different algorithms such as; Minimum Curvature, Gaussian Random Function Simulation (GRFS), trend operation and co-krigging. On the whole, GRFS with collocated co-krigging found to be the optimum solution. Uncertainty expresses the quality of the work done and defines the level of ambiguity. An uncertainty analysis has been conducted to the selected model with probabilistic calculations. All of the relevant data have been investigated to build a suitability model and consistency of the model has also been proved by the new well drilled in the area. Constructing a 3D subsurface model helped for visualizing and understanding of structural framework, geology and interactions of geothermal system. This model will be used as the basis of a 3D numerical modeling (dynamic) of the reservoir.
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Supplemantary Cementitious Materials in Geothermal Wells
By B. AlpIn Geothermal and hot wells, conventional cement slurries, which is cement and silica mixture composition, prepared in Turkey and also in TPAO. To catch up with the required properties for the slurry (thickening time, fluid loss, strength..etc), too much additives need to be used. This increases the costs of the cementing operation. Therefore, pplicability cementitious materials like slag and fly ash were added to cement with silica. Their performance was investigated according to the results of the analysis; thickening time, strength, fluid loss and flow properties. The aim of this study is to increase the pplicability of these additives in geothermal wells.
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Acoustic Structure of Eastern Black Sea Continental Slope, Shallow Gas and BSRs: Preliminary Results
Authors S. Okay, G. Çifçi, D. Dondurur, S. Özel, H.M. Küçük, S. Gürçay, D.C. Kim and S.-H. Baents, geology of the seafloor and existence of the mud volcanoes to understand the economical potential of the area. This is a collaborative bilateral project which is funded by both TÜBİTAK and KRF in Korea. The second leg of this Project was the acquisition of high resolution multichannel seismic reflection and chirp data with the participation of Institute of Marine Sciences and Technology (IMST) and Pukyong National University (PKNU) in the Easternmost Black Sea. The aim of the project; the formation and destabilization of gas hydrates, the various forms of hydrocarbon seepage (seabed pockmarks, mud volcanoes, leaking faults)and the mapping of shallow gas and gas hydrates in both Eastern Black Sea and Gwangway Bay in south Korea. Thereby geophysical and geological investigations will determine the hydrocarbon reserves of Easternmost Black Sea. Data acquisition was held in October 2010 onboard R/V K.Piri Reis which belongs to Dokuz Eylül University. Data acqusition and processing are carried out by acoustic and seismic equipments of SeisLab at IMST. Big amount of slumps and slides at the eastern Black Sea continental slope area are evident. And also wide zones of shallow gas accumulations and BSR’s are observed. There are few extant investigations on gas accumulations and gas hydrate formations at the Eastern Black Sea coasts of Turkey.
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Gas and Gas Hydrate Accumulations on the Western Black Sea Continental Slope
Authors Ö. Özel, D. Dondurur, S. Gürçay, S. Okay, H.M. Küçük, H. Sarıtaş, M. Er, M. Korkmaz and G. ÇifçiThe investigation of possible gas and gas hydrate accumulations and determination of possible reservoirs in marine environments have both economical and strategical importance. Today, the Black Sea is an important area for hydrocarbon accumulations. Shelf and slopes with high sedimentation rates is considered as methane sources and gas seeps are observed around the basin. In order to investigate gas and gas hydrate accumulations in the Western Black Sea continental slope, approximately 355 km of high resolution multichannel seismic data was collected in 2008. The data was processed using conventional processing steps. Anomalous zones of gas accumulations were determined on the final migrated sections using seismic attribute analysis (instantaneous polarity, phase and frequency as well as reflection strength). In one limited area, a Bottom Simulated Reflection (BSR) indicating gas hydrate formations was also observed. Shallow gas accumulations have generally been observed below the ridge structures forming anticline-type formations. The accumulations are located generally 150-250 ms below the seabed, and the reflections from top of the gas reservoirs are distinguished by their distinctive negative polarity. Below these bright reflections is gassy sediments as semi-transparent dim zones. The instantaneous frequency sections show low frequency local anomalous zones, indicating a higher attenuation of seismic signal due to the gas accumulation.
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Observed Gas and Gas Hydrate Accumulatıons Offshore of Zonguldak-Kozlu
Authors H.M. Küçük, D. Dondurur, G. Çifçi, M. Ergün, S. Gürçay, M. Er, Ö. Özel and M. KorkmazBlack Sea is known as consist of a basin with two part and largely sediment thickness. East and west basins are divided by Andrussov and Archengelsky ridges and study area is located in the western basin. Previous studies in the area point out to gas and gas hydrate accumulations from continental slope to abyssal plain at west, central and east side of Black Sea. For this purpose, multichannel seismic reflection, chirp and multibeam bathymetry data were collected at offshore of Zonguldak – Kozlu region from shelf to abyssal plain of Black Sea in 2010. Preliminary results show gas and gas hydrate accumulations and wide spread BSR reflections. BSR reflections are clearly seen on migration sections with general processing stages after verification of common offset sections of approximately 1600 km high resolution multichannel seismic reflection data. In addition, It is known that Akçakoca-1 well which is near the study area produces gas considerably and study area offers very high potential in terms of energy resources from continental slope to abyssal plain.
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Tectonic – Oil Potentıal Relationships of the Akçakoca (Offshore) Region, Western Black Sea, Turkey
By A. ÜnalAkçakoca region (offshore) is one of the natural gas producing area in Turkey. The splays of the North Anatolian Fault, formed during the collision of the Anatolian and Russian plates in Miocene influenced reservoir characteristics and distribution in the investigated region. Study of seismic sections and well data, indicating deepening of the area towards NW, show that the anticlines, reverse – thrust faults and pinch – outs, considered as stratigraphic traps, constitute principal factors which influenced oil and gas possibilities of the region. The stratigraphic column of the study area is rather rich in reservoir, source, cap rock contents. Altough Eocene Kusuri and Cretaceous Çağlayan formation in the upper part of the stratigraphic column are accepted on good source rocks, further studies reveal & deeper Carboniferous source rock origin for the natural gas in Akçakoca – 1 well, which has been discovered by TPAO in 1976. The tectonic elements influencing the oil and gas possibilites of the investigated area, are the anticlines, reverse – thrust faults and pinch – outs, generated by collision of the Anatolian and Russian plates.
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Subsea BOP, Secondary Intervention System
By F. DumanSubsea BOP Safety is the most important issue for all industry, especially for offshore operations. That’s why BOP control systems are of the utmost importance. BOP functions in the event of total loss of the primary control system, Secondary intervention systems the last line of defense in preventing and/or minimizing environmental event, human injuries and loss of lives. Subsea BOP (Blow Out Preventer) control systems are required to remotely operate blowout preventers that are located on the seafloor in floating drilling operations. The primary components of the BOP control system are the redundant control pods located on the BOP stack. These pods direct the flow of high pressure hydraulic fluid, used to operate the BOPs, from the surface to the BOPs on the seafloor. There are two primary types of control systems: Hydraulic and E/H (Electro- Hydraulic). The key difference between the two systems is the method employed to send a signal to the control pod to initiate the desired BOP function. With a hydraulic system, the signal is hydraulically transmitted from the surface to the valves in the control pod. These valves then direct the hydraulic fluid to initiate the BOP function. The signal travels this distance in 5 to 30 seconds depending on water depth and hose type. With an E/H system, electrical signals transmitted from the surface actuate solenoids within the control pods in a fraction of a second. The control pods then hydraulically activate the BOP function. Thus, the BOP function response time is a combination of the signal transmission time and the main hydraulic fluid flow time. Because the BOP function activation signal reaches the pod in an E/H system much faster than in a hydraulic system, the E/H system is particularly well suited to ultra deepwater applications. In these operations fast electrical signal response times are required to minimize the time it takes for risers to decouple and for annular and ram-type BOPs to close. Secondary intervention can be described as an alternate means to operate BOP functions in the event of total loss of the primary control system or to assist personnel during incidents of imminent equipment failure or well control problems. A secondary intervention system can be completely independent and separate or utilize components of the primary BOP control system. These systems are of the utmost importance and offer the last line of defense in preventing and/or minimizing environmental and safety incidents. An advanced knowledge of secondary intervention systems and their shortfalls could prevent an environmental event, human injuries, and/or loss of lives. Systems and practices vary considerably from rig to rig, geographic area and regulatory agency.
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AC Drilling Rigs in Turkish Petroleum Corporation
More LessNew technologies and necessities in drilling activities lead to new designs for drilling rigs. In recent years, one of the preferred technologies is the AC (Alternating Current) which has also been started to be utilized by Turkish Petroleum Corperation. TPAO has 3 AC electrical rigs on its own inventory. The aim of this study is to outline working principles, equipment and technology of the AC Drilling Rigs, Furthermore, it summarizes the Rig upgrade experiences of TPAO starting from 2001 up to now and informs about the new developments in rig technology.
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Logistics Operations in Sürmene-1 Ultra-Deepwater Drilling
By M.T. ÖztürkUltra-deep water drilling operations are conducted in water depths more than 1000m and they are the most challenging tasks in the oil industry. Such kind of high risk and high cost tasks includes variety of sub-tasks and logistics operations are one of them. In order to provide link between rig site and land, shore base plays key role in terms of supplying every kind of material to the rig according to operational necessities complying with required rigging, lifting and handling procedures. In 2010, November, TPAO started to drill Sürmene-1 well and logistics operations are conducted in Trabzon Shorebase from September 2010 to March 2011. Logistics base established one month prior to the spud of the Sürmene-1 well and nowadays operating with reduced crew for the next operations. During active period of the Trabzon base, all equipment related to rig site send from base via 2 platform supply vessels (PSVs) Siem Danis & Siem Louisa. Dedicated mud plant of 5000bbl total capacity is operated in the base in order to mix drilling fluid and supplying back-up drilling fluid in case of severe losses. Bulk materials that required during operations are provided with bulk units established in the base. On the other hand prior to sending casings to the rig, inspection activities conducted such as non-destructive test, drifting and thread control. One key item used in shore base during Sürmene-1 well was the bucking machine. Bucking machine used in order to make-up and break-down all wellhead running tools, liner running tools, cement heads and all casing accessories in order to gain from rig time. All activities conducted during active period of the Trabzon Shorebase, no lost time incidents (LTI), no accidents happened. Moreover, during drilling of Sürmene-1 well, Logistics-Non Productive Time of the operation rated as 0%. In this work, Shorebase activities conducted fully complying with offshore industry standards during Sürmene-1 well is assessed and key factors of such kind of successful operation is defined.
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Petrographic Examination of the Southeast Anatolian Asphaltite Occurrences and Their Utilisation
More LessAsphaltite is a form of natural organic material, which is solid, hard, black, black-brownish colored, and of petroleum source (Kavak, 2011). Its fusion temperature is about 200-315°C. It is soluble in Carbon Disulfide. It is also defined as a solid petroleum based mine formed with metamorphism. Liquid and semi liquid component of heavy petroleum solidifies in a suitable environment (as fracture, void etc.) and settles with effects of migration controlled with hydrostatic pressure, gas pressure, capillarity, gravitation and heat. Mobile asphalt passes through various fractures and cracks up to surface. There are various forms of asphaltites in nature and it is mostly observed in Sirnak region in Turkey and settled within fault and fracture cavities. In spite of high sulphure, ash and volatile matter content, asphaltite is utilized as heating fuel and even has been known as “coal”. It is possible to produce a great deal of material from asphaltite and also used in production of paint, varnish, car-tires, electric insulation, battery preservation, expanded natural rubber, floor tiles and waterproof cables.
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Rig NOV2000 TD 500 PAC Utilization and Advantages for Drilling
By S. KuruTD (Top Drive) drilling system, which have been used by petroleum industry since 80’s, entered TPAO inventory at 2002 with TD 500 PAC model produced by NOV(National). This electric TD has 500 tonnes hookload and 1750 HP drawworks capacity. It is used in Rig F-320 by TPAO for an important project, The Silivri Natural Gas Storage Project firstly. After that, it is used in NOV- 2000 Rig and drilled successfully the deepest well of Türkiye, Yuvaköy-1 (TD:7216 m). Currently it’s being used in NOV-2000 rig in Adıyaman District. As the TD 500 PAC’s (which had a cost of 1 billion dollars to TPAO) benefits and importance recognized over time, from 2002 to 2010, this 8 years ended up in switching 8 Kelly drilling systems to TD systems. And this revision is still on progress. TD drilling system not only brings the advantages gain time while drilling thus lowering the costs; but also provides a high performance on tripping, fishing, horizontal drilling and extended reach operations. Moreover, TD usage is much safer than Kelly system according to Health&Safety. This presentation will inform you about TD 500 PAC’s usage, the differences from Kelly system, the benefits of TD system and the experiences gained during the important projects such as, The Silivri Natural Gas Storage Project, Karbeyaz and Yuvaköy wells.
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Modeling of Cuttings Transport in Horizontal Wellbores Using Computational Fluid Dynamics
By M. SorgunAccurate modeling of cuttings transport mechanism in horizontal wells becomes more critical while predicting frictional pressure loss and transport velocities. Since drillstring is usually rotating during drilling operations, it increases the complexity of the behavior of the drilling fluid and cuttings transport inside the wellbore. Experimental and numerical results demonstrated that pipe rotation significantly improves the cuttings transport ability of the fluids inside the wellbore, especially if the drillstring is in an eccentric position. Drilling fluid velocity is the most important drilling parameter affecting hole cleaning. The critical fluid velocity required for effective hole cleaning considerably decreases as pipe rotation is introduced. Moreover, a decrease in the pressure loss is observed due to the bed erosion while rotating the pipe. In this study, cuttings transport in fully eccentric horizontal annulus is modeled using Computational Fluids Dynamics (CFD) software for different flow rates, pipe rotation speeds and rate of penetrations. Extensive experimental studies have been conducted at Middle East Technical University, Petroleum & Natural Gas Engineering Flow Loop using water flow velocities from 0.64 m/s to 3.05 m/s, rate of penetrations from 0.00127 to 0.0038 m/s, and pipe rotations from 0 to 120 rpm. Pressure loss within the test section and stationary and/or moving bed thickness are recorded. Model predictions are compared with over 90 experimental frictional pressure loss values. Results show that, model can estimate frictional pressure loss within an error range of ± 20 %.
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Drilling Results 2007 – 2009 in the Western Black Sea Targeted on Neogene Deep and Shallow Water Sediments
Authors A. Gray, A. Sefünç and H. YıldırımPrior to 2007 the only drilling in the West Balck sea ( west of Istanbu) were the Karadeniz-1(1970), Igneada-1(1971), and Limankoy 1 and 2 (1999). The resuslts of all of these wells were negative . Despite this, during the period 2006 to 2009 Toreador Turkey embarked upon an exploration campaign in the western Black Sea. Well Karaburun-1(2007) was located adjacent to the Kırklareli area to the Southwest of the previously drilled wells İgneada-1 and Karadeniz-1, The Karaburun-1 well location was defined by seismic surveys conducted during 2007. Karaburun targeted a basement high structure thought to be overlain by Sogucak reefal carbonates. This premise was found to be false and the well finished in volcanics of Yemislicay with no resrvoir potential being encountered. Durusu-1 well was identified by a 1500 km 2D marine seismic survey which was acquired in 2006. Tertiary sediments cover the basement rocks of Istrandja Massif and the Paleozoic istanbul Unit in Thrace Area. Basement rocks are overlain by different stratigraphic units from Early – Middle Eocene to Miocene – Pliocene rock associations.The main and secondary aims of Durusu-1 were to test the hydrocarbon possibilities of the Middle-Late Oligocene aged deltaic Osmancık Sandstones and Late Oligocene-Early Miocene aged Danismen deltaic sandstones. The Osmancık Sandstones together with Ergene and Danismen Sandstones were encountered in Durusu-1 at the expected depths. No DST’s were performed. No core was taken in the well. Drilling was continued down to 2510 m and Durusu-1 exploration well was completed as a dry well on 27.08.2009. Structural and stratigraphic evaluations of 2D seismic data laid the ground for a consistent regional framework. Seismic attributes and sequence stratigraphy indicated that the main Osmancik reservoir interval is part of a large lowstand submarine fan system. Analogies with recent successes in West Africa were noted. The well results are thought to confirm the sedimentological model but unfortunately a source and migration combination were missing.
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New Giant Hydrocarbon Dıscovery in Sirte Basin, Libya
Authors M. Zanatı, R. Sarı and H. CanalesIn January of 2002, Waha Oil Company discovered a new giant oil field in the SE region of the Sirte Basin. This discovery is situated north of Waha’s giant Gialo oil field, which produces hydrocarbon from Oligocene, Eocene & Paleocene. The new oil field is a combination structuralstratigraphical trap produced from the highly fractured Pre-Upper Cretaceous Nubian sandstones which developed on the northern flank of the Gialo Basement High. Currently, the estimated STOOIP is over five billion barrels of OIP of 43° API gravity. The exploration activities for hydrocarbons in the North Gialo area dates back to the early 60’s. In the 70’s four exploration wells were drilled in Waha acreage and the Nubian formation was tested without encountering any commercial hydrocarbon accumulation. In the mid 90’s, a new hydrocarbon entrapment concept was proposed, asserting hydrocarbon accumulation in the Nubian formation, leading to the acquisition of new 3D seismic. Based on which Waha proposed in November 2001, the spudding of the discovery well 6J1-59. The well encountered a 1600-foot gross oil column before reaching the oil water contact. To date, we have drilled 17 appraisal wells, of which 16 have tested positive for oil and gas, to delineate the extent of the reserves. In the most favorable reservoir location a 1639 foot thick oil column has been encountered. Waha estimates, given the present data, that the field covers more than 108 square kilometers. The eastern and southern extensions of the field are still to be defined by recently acquired 3D seismic data. The discovery of this new giant oil field which is in a mature exploration area and is based on an alternative interpretation of the geological and geophysical data, adds value to the potential reserves to be found in the Sirte Basin. We hope that our discovery will be taken as an exploration model by the oil industry in Libya and will instigate a new generation of giant oil fields.
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New Oil Discoveries in Area 147/3-4, Murzuq Basin, Libya
Authors A. Tandırcıoğlu, R.Ö. Temel, H. Can and Y. KumruArea 147/3-4 is located in northeastern part of the Murzuq Basin, southwest of Libya and covers an area of 2783 km2. The block is awarded to Turkish Petroleum Overseas Company (TPOC), a wholly owned subsidiary of Turkish Petroleum Corporation (Türkiye Petrolleri Anonim Ortaklığı, TPAO), in the Second International Bid Round of Libya in 2005. The Exploration and Production Sharing Agreement (EPSA) signed between TPOC and National Oil Company of Libya (NOC) became effective on December 10, 2005. The EPSA for Area 147/3-4 calls for a minimum work commitment of two exploration wells and 500 km 2D and 300 km2 3D seismic acquisition in a 5-year exploration period. The exploration period was extended for 1.5 years until June 10, 2012. TPOC initiated a vigorous exploration program in the area starting with the reprocessing of previously acquired approximately 3400 km 2D seismic data in the TPAO data processing center in 2006. In addition, TPOC acquired 573 km 2D and 352 km2 3D seismic data in 2007 and conducted detailed G&G studies and determined the hydrocarbon prospectivity of the Area. The Paleozoic section constitutes the main hydrocarbon system. Organic-rich lower Silurian “Hot shales” of Tanezzuft Formation are the primary source rock as widely recognized and proven in the North Africa. Silurian Tanezzuft Formation is also the main seal in the Area 147/3-4. The primary reservoirs are the middle and upper Ordovician glacio-marine and fluvio-deltaic sandstones of Memouniat and Hawaz formations. Furthermore, Devonian Aouinet Ouinine sandstones were tested and yielded significant amount of oil. There are several trapping types in the block such as buried hills, simple anticlines, fault bounded structures. The exploration wells drilled by TPOC tested different play types and resulted in oil discoveries. TPOC drilled a total of 11 exploration wells in Area 147/3&4 and 7 of them resulted as new oil discoveries. TPOC will acquire new 2D and 3D seismic data in 2011 and drill additional exploration wells. Furthermore, following the completion of the appraisal program, TPOC plans to put these oil discoveries on stream as early as possible.
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NATURALHY (The Potential of Existing Natural Gas Network for Hydrogen Delivery) Project Objectives and Some Results
By A. YıldırımThe defining feature of global energy markets remains high and volatile prices, reflecting a tight balance of supply and demand. Renewable energy remains a small share of total global energy use, but most renewable sources experienced rapid growth in 2009. The use of hydrogen as an important energy carrier is an essential element for global sustainable development. However, there are many significant challenges for implementing all the components of a complete energy system based on hydrogen. Urgent progress towards the development of a full hydrogen system requires a practical strategy within the context of an existing, extensive natural gas system which has resulted from substantial capital investment over a long period of time. The NATURALHY project investigates the conditions under which hydrogen (pure or as a part of a hydrogen containing gas mixture) can be added to natural gas with acceptable consequences. The main objectives of the NATURALHY project are: • to define the conditions under which hydrogen can be added to natural gas in the existing natural gas system (transmission, distribution, end use, infrastructure and appliances) with regard to: § acceptable safety risks; § benefits; § impact on the integrity of the system; § consequences for gas quality management and for the end user. • to develop technical options (particularly membranes) to separate hydrogen from hydrogen/ natural gas mixtures; • to assess the socio-economic and life cycle aspects of the NATURALHY approach, thus illustrating the real value of the NATURALHY project. The project results show that existing natural gas grid has a potential for the transmission of hydrogen. However, there are also some technical limitations for delivery of hydrogen depending on the specific local situation of the natural gas network.
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Gravitational Production Method
Authors YalçıY.n Ermiş and A. GümüşA method consisting of intersecting production wells and resulting in improved recovery in oil fields is introduced in this paper. It is called “Gravitational Production Method” and its advantages over the traditional methods are discussed.Implementation of this method is possible whenever a vertical well and a horizontal well are intersected. The aim of such configuration is to increase the production rate and hence the recovery. The advantages are numerous: both wells can be used for production purposes, the combined drainage area is extended, the gravitational pressure gain wherever a dip of stratum between wells exists helps to increase the reservoir pressure gradient and yields higher production rate, the occurance of water coning is delayed due to the horizontal part of the configuration, and finally a higher production rate becomes possible by setting the production pumps at deeper locations in wells. Although the initial investement is higher due to the additional costs for implementing the technologies involved in intersecting process of the wells, however, the rate of return is expected to be shorter because of increased recovery. The design of such method for Caylarbasi oil reservoir is discussed and the preliminary results of the field application in Batı Raman oil reservoir conducted recently are presented.
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Prediction of Temperature Change of Hydrocarbon Gases Using A Two- Parameter Z-Factor Correlation Under Isenthalpic Flash Conditions
Authors C. Uğur and Ş. YamanlarIsenthalpic expansion processes of real gases through restrictions are usually accompanied by a temperature change of the gas phase. This phenomena is known as the Joule-Thomson cooling (or heating). The temperature change depends on the initial and final pressures and initial temperature as well as the composition of the gas phase. Natural gases cool down at moderate pressures upon expansion in downhole perforations or in surface chokes whereas gas condensates may heat up when expanded at elevated reservoir pressures and temperatures. The direction and the magnitude of the temperature change may be predicted by using an isenthalpic flash calculation procedure. The constant enthalpy expansion of a real gas may result with condensation of a liquid phase due to the lowered gas temperature. In such processes, simultaneous solution of mass and enthalpy balance equations is required. If there is no liquid condensation after the expansion, the enthalpy balance equation should be solved for downstream temperature given up and downstream pressures and upstream temperature. An equation of state or a two-parameter z-factor correlation can be used to model the PVT behavior of the single phase natural gas in constant enthalpy flash calculations. Two-parameter z factor correlations are simpler to code and reduce computational time. However their accuracy in energetic computations is not well understood. In this paper, predictive capability of Abu Kassem-Dranchuk z-factor correlation is studied when used in calculating temperature changes during a constant enthalpy flash process. The results are compared to Peng-Robinson equation of state and to a leading reference thermodynamic fluid properties program results.
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Matrix Fracture Interaction in Sandstone Rocks During Carbon Dioxide Injection
Authors S. Bülbül and M. ParlaktunaThe aim of the study carried out is to investigate matrix-fracture interaction during CO2 injection. In the study, an experimental work is being carried out to understand the mechanisms of the gasoil gravity drainage (GOGD) concept by the means of CO2 injection. Experiments are conducted by using sandstone core samples and n-decane is used as the oil phase. One of the purposes of the study is to improve the understanding of the influence of a fracture on the GOGD process. In the fractured case, a space is created around the core sample inside the core holder and the space is considered as a surrounding fracture. During the experimental study, pressure, temperature and recovery measurements are conducted.
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Cap Rock Integrity in Co2 Storage
Authors C. Dalkhaa and E. OkandanOne way to reduce the amount of CO2 in the atmosphere for the mitigation of climate change is to capture the CO2 and inject it into geological formations such as depleted oil and gas reservoirs, aquifers, oceans and unmined coal beds. The most important public concern about carbon capture and storage (CCS) is whether stored CO2 will leak into groundwater sources and finally into the atmosphere or not, since CO2 at high concentration is hazardous. During underground CO2 storage, the containment of CO2 will be crucially dependent on the cap rock integrity above the CO2. Thus, it is important to assess how the CO2 might impact cap rocks, since this could control the ultimate longevity of CO2 storage. Although supercritical CO2 is normally inert, when it dissolves in water or brine, it makes water acidic. This acidic water can react with the surrounding rock minerals and thus geochemical reactions, dissolution of primary minerals and precipitation of secondary minerals, take place. These reactions can alter the porosity and the permeability and furthermore affect the sealing capacity of cap rocks. The objective of this research is to identify the geochemical reactions of the dissolved CO2 in the synthetic formation water with the rock minerals of the Sayındere cap rock by laboratory experiments. It is also aimed to model and simulate the experiments using ToughReact software. Sayındere formation is the cap rock of the Caylarbasi, a southeastern petroleum field in Turkey. The mineralogical investigation and fluid chemistry analysis of the experiments show that calcite was dissolved from the cap rock core as a result of CO2- water- rock interaction. Using the reactive transport code TOUGHREACT, the modeling of the dynamic experiment is performed. Calcite, the main primary mineral in the Sayındere is dissolved first and then re-precipitated during the simulation process. The decreases of 0.01 % in the porosity and 0.03% in permeability of the packed core of the Sayındere cap rock are observed in the simulation. The simulation was continued for 25 years without CO2 injection. However, the results of this simulation show that the porosity and permeability are increased by 0.001 % and 0.004 %, respectively due to the CO2-water-rock mineral interaction. This shows that the Sayındere cap rock integrity must be monitored in the field if application is planned.
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Chemistry of Oilfield Water and Hydrocarbon Seepage on Surface along Abu Jir Fault Zone, West and Central Iraq
Authors S.M. Awadh and M.S. BayraktutanAlong Abu Jir fault zone, Hydrocarbons were flowed in association with the spring waters on surface in Hit area. These springs rich in H2S gas which moved upward with spring water, then eventually escapes to the atmosphere. Sometimes peoples ignite gas forming mass of flam on water surface. Hydrochemistry of many spring waters were investigated. These waters characterized by very high concentrations of total dissolved solid (TDS) where SO4= and Cl- as dominant anions. Hydrocarbon accumulations also intruded by hydrostatic pressure within gypsum beds of Fatha Formation (Miocene), and can be clearly seen as piles on surface. These hydrocarbons are generated and trapped at depth and leak in detectable quantities to the surface. The geochemical anomalies are close association with the fault zone which extends of several kilometers toward N-S approximately. Bacterial degradation has been happen within the reducing zone. Water salinity and leaking gas affect the environment and reflect the specific geobotany.
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Stratigraphic Framework of the Saudi Arabian Cambrian - Ordovician Successions, and Correlation with SE Turkey in the Arabian Platform
Authors M. Şenalp and N. BozdoğanBeing an asymmetric wide basin, Arabian Plate deepens towards the east and reaches its maximum depth in the Zagros Collision Zone. The oldest Paleozoic succession is the Early Cambrian Siq Formation, a fluvial to marine deposition that consists of thick, red colored sandstones. During the Middle Cambrian, regionally Arabia and Turkey were under the shallow marine conditions represented by a carbonate-dominated sequence with clastic interbeds. Named as Burj Formation in Jordan and Arabia and as Koruk Formation in SE Turkey, this sequence is a key level in the region.
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Stratigraphic Correlation of the Silurian-Permian Successions Between Saudi Arabia and SE Turkey in the Arabian Plate
Authors M. Şenalp and N. BozdoğanSaudi Arabia, Qatar and Oman located on the Arabian Platform, produce enormous amount of gas and oil from both the carbonate and sandstones of the Paleozoic successions. The purpose of this study to make an attempt to correlate the well-established Paleozoic Sequence Stratigraphy of Saudi Arabia with SE Turkey to promote the exploration potential and in order to understand the affect of the Aleppo and Mardin type highs form stable blocks between this intraplate deformation zone.
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Miocene Stratigraphy and Hydrocarbon Potential of Northern Batman
Authors T. Özdoğan, Ö.Ç. Kaya, İ. Açıkbaş, İ. Bahtiyar and M. Siyakoates during the geological stages, have gained their final forms by the effect of the thrusts formed at Miocene and Late Miocene-today’s neo-tectonism on the Arabian Plate. At this study which is carried out within these fields, to explain the activities occured during and after Miocene, it has been focused on especially stratigraphic and depositional model and Lice Formation’s facies which the Miocene thrusts moved over, passing from marine to terrestrial has been mapped. The results of this study were correlated with ancient studies (Yılmaz and Duran 1997, Sarıdas et al. 1991, İsbilir and Dincer 1991) and the differences were found. Under the scope of this study, it is thouht that Miocene units may present source, reservoir and cap rock properties in the area.
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Problems Faced in Diyarbakır XI Region Wells and the Proposed Solutions
By Y. TengizThe area studied is located in Diyarbakır city territory inside XI. Oil Exploration and Production Region. In this study, reasons of the problems appearing in a time span and frequently faced, causing production loss and abandonment of the producing wells and consequence of those problems have been analyzed. For the wells to be drilled in the region, the points to pay attention during • Casing set depth, • Open hole logging, • Cementing, • Casing corrosion prevention, • Perforation interval selection, • Acidizing operations, reasons of rising watercut values, the effect of wrong x-y coordinate measurements, CDR logs taken minimum or none in deviated holes on preparation of misleading location maps and structural maps respectively and the consequence of these are explained. In the study, geology, drilling, reservoir, logging, production and workover data and information of total 87 producing and/or abandoned wells existing in the Southeast Anatolia, Diyarbakır XI. Region, where approximately for 40 years exploration and production activites are resumed, have been evaluated in details. Production loss during producing wells’ life span, reason/result relations of the problems causing to abandon wells have been examined and solution proposals have been presented for new wells to be drilled where similar problems can be encountered.
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Gas Seepage and Oil Resources and Their Related Reservoirs, West Rawa and East Hahitha Cities, Western Iraq
Authors F.R. Al-Rawi, T. Al-Ameri and S. M. Al-DulemyGas seepage has been taken place at shallow depth through two boreholes drilled for the purpose of ground water at west Rawa city, western Iraq. The depth reached by drilling is about 42 meters only, when gas blown out suddenly. A flame of fire to a height of 3 meters can be seen where local people put fire on it. The positions of the two boreholes are projected and their locations are along the northern fault of Anah graben. The possible source of the gas could be at great depth and has migrated to shallow depth through the faults system in the area. Also, this could be an extension of the giant Akkas gas field on the other side of Euphrates River. The same situation is also found where admixture of oil and water pumped from two boreholes drilled to depths of 117 and 230 meters for ground water purposes at east Haditha city, south of Anah graben. Such gas and oil indications may be used and encourage oil companies to consider such area in Al-Jazzera region for further studies and could be prolific reservoirs. The two regions are situated to the east of Euphrates River where there are series of large grabens crossing the region and at the same time most attentions for oil and gas explorations are concentrated to the west and north of them. Akkas gas field to the west has a dry gas at depths of 3570-3650 meters, while to the north, Khalesia well showed also gas. Seismic sections around the two regions in addition to the information from many deep boreholes drilled in the adjacent areas indicated the existence of large variations in the formation thicknesses and their continuation which are characteristics of the Paleozoic sequence in western Iraq. The expected hydrocarbon reservoirs in Al-jazzera region are within the Paleozoic formations as in the Akkas area and Anah graben.
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Co-Combustion Performance of Oil Shale and Biomass Fuels
Authors E. Özgür, M.V. Kök, B.G. Miller and S.F. MillerCo-combustion performance of two oil shales and four biomass types were investigated. Differential scanning calorimeter and thermogravimetric analyser were used to analyze the samples. The oil shale samples are from Ulukışla and Himmetoğlu regions in Turkey. The biomass samples used in the study are hazelnut shell, wheat bran, poplar, and miscanthus. The aim of this study was to evaluate the co-combustion performance of oil shale and biomass at different biomass proportions (10, 20, and 50 wt.%) in blends at three different heating rates (10, 30, 50 oC/min). The ignition temperatures of the parent fuels and blended fuels were investigated to identify any improvement in combustion performance with the addition of biomass. All results were investigated statistically to identify possible relationships between ignition temperatures and physical properties of the fuels.
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The Element Enrichments of the Rocks Rich in Organic Matter around Karanlıkdere (Göynük / Bolu)
More LessThe study area is located at southwest of Göynük (Bolu) in Paleocene-Eocene Hatıldağ Formation. A Scaled Stratigraphic Column has been done with 323 m thickness and total of 113 samples were collected from study area. Interbedded oil shale, bituminous marn and limestone layers are dominant throughout the stratigraphic section. The geochemical analyses were carried out on collected samples and the contents of major, trace and REE (Rare Earth Elements) have been determined. The element enrichments of bituminous rocks were determined in studied area within the scope. Obtained element abundances were correleted with the organic rocks belonging to the certain earth’s redox/sulfidic depositional enviroments and the amounts of enrichment were determined. Considerable element enrichments in studied area are Ti, Fe, Mg, Ca and K as major elements and As, Cr, Mn, Ni, Rb, Sr and Zn as trace elements.
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Search of a Sustainable Solution to the Energy Problems of Turkey
By İ. PalazIt seems quite clear that petroleum will remain significant in the energy make up for the world in the 21st century. The petroleum industry is old, dirty, and unpopular but alternatives appear almost as illusive now as before anytime in the history. It is clear therefore until a viable alternative becomes available, we must continue to meet all challenges this industry presents. We know it works and if we continue to meet challenges we can sustain our way of life as we know now. This is by no means to stop searching for alternatives or stop diversifying energy solutions. Turkey’s energy is met by nearly 60% oil and natural gas. Turkey depends on imports by 95% and 97% oil and natural gas respectively. Volatility in the global oil price not only impacts oil consumers but also oil indexed natural gas consumers in every segment of the entire population. These combined with the fact that Turkey is increasingly becoming addicted to natural gas puts Turkish economy overly sensitive to global oil price. Turkey has a vibrant growing economy with young population presenting itself as one of the most promising countries in the world. Vulnerability of Turkish economy to oil prices hangs over its potential as dark clouds. The questions we must ask at the moment are where Turkey would be at when oil is $175/bbl or then, $200/bbl? Turkey has to find solutions to oil and gas dependency on foreign oil and gas. Are there solutions? How to eliminate this dependency or how to reduce it in the near term while aiming in the long run for independence? The fact is when we look at the other economies in the world Turkey is not alone as there are large number of countries with growing economies and with significant oil and gas import dependency hence we may adopt some of the solutions other have implemented.
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History Matching of Well Test Pressure and Geostatistical Data by Ensemble Kalman Filter Method
Authors M. Onur and Ö.İ. TüreyenIn recent years, the ensemble Kalman Filter (EnKF) method has become popular due to its favorable computation speed over the gradient (such as Gauss-Newton and Levenberg Marquardt) based methods in history matching and quantification of uncertainty in performance predictions for oil and gas reservoirs. In this work, we examine the use and applicability of EnKF method for history matching of well test pressure and geostatistical data and for performance prediction using the estimates of reservoir parameters obtained by EnKF history matching. For our investigation, we use a forward or direct model based on pressure diffusion for a slightlycompressible, single-phase fluid flow in a three-dimensional porous medium, where it is assumed that the viscosity is constant, and combine this forward model with the EnKF method for performing history matching. We demonstrate the advantages and disadvantages associated with the EnKF method by considering synthetic example applications. The results indicate that the EnKF method looks promising, particularly due to its superior computational performance compared to gradient based history matching methods for history matching of well test and geostatistical data in heterogeneous reservoir systems, but the number of ensembles to be used, and the prior variogram to be chosen to generate ensembles seem to be critical. Some guidelines are also given for effective use of EnKf method.
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3D Geostatistical Model of the Alt Sinan Reservoir in the Batı Kozluca Heavy Oil Field
Authors S.T.T. Kamanlı, Y.Ş. Karakeçe and M.Ö. TürkmenB.Kozluca Field is located within the boundaries of provience of Şırnak in southeast Anatolia. The field was discovered in 1984 and began oil production in 1985. B.Kozluca is a heavy oil field with the gravity of 12.6 0API. The basis of this study is based on reservoir modelling and simulation study created in 2001. By using data of 12 wells drilled after 2006 and updated structure contour map; detailed 3D geological model was created with geostatistical methods. 3D geological model was created with “PETREL” software. Wells, log data, structure surface of Alt Sinan Formation, fault models and sedimentological studies were input into the model. Main reservoir rock is Alt Sinan carbonates. The formation is divided into three different flow units according to the log data and petrographic facies. Variogram maps has been created by using petrophysical properties of wells. Petrophysical properties on the basis of flow unit, were distributed to area as three-dimensional. And orginal oil in place was calculated. This model will be input to run the simulation.
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3D Reservoir Model of the Bozova Oil Field
Authors M.Ö. Türkmen, C. Çetinkaya and Y.Ş. KarakeçeBozova Field is located in Bozova Town in the province of Şırnak in South East Anatolia. Oil production in the Bozova Field, which was discovered in 1995, is made from a horizon called Reservoir Interval. This interval between Alt Germav Formation and Karababa-C Formation is made up of bioclastic limestone with intragranular medium porosity having a thickness ranging between 27-40m. In Bozova Field, 8 wells have been spudded up to date and 5 of these wells have been completed as oil producers. In this study, detailed 3D reservoir model of Bozova Field is formed based on the Reservoir Evaluation Study of Bozova Field which is carried out in 2002 by TPAO Production Group. All the available well and well log data, updated Reservoir Interval surface map, fault models and sedimentological studies were implemented in the model. Petrophysical parameters which are calculated from well logs are upscaled according to flow units and are distributed to the modeling area. These distribution maps are utilized in the oil in place calculation of the field. Constituted model is in usage in ongoing simulation and uncertainty studied related to the Bozova Field.
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Uncertainty Evaluation Through Ranking of Simulation Models for Bozova Oil Field
Authors M.M. Tonga, S. Akın and Ş. DüzgünProducing since 1995, Bozova Field is a mature oil field to be re-evaluated. When evaluating an oil field, the common approach followed in a reservoir simulation study is: Generating a geological model that is expected to represent the reservoir; building simulation models by using the most representative dynamic data; and doing sensitivity analysis around a best case in order to get a history-matched simulation model. Each step deals with a great variety of uncertainty and changing one parameter at a time does not comprise the entire uncertainty space. Not only knowing the impact of uncertainty related to each individual parameter but also their combined effects can help better understanding of the reservoir and better reservoir management. In this study, uncertainties associated only to fluid properties, rock physics functions and water oil contact are examined thoroughly. Since sensitivity analysis around a best case will cover only a part of uncertainty, a full factorial experimental design technique is used. Without pursuing the goal of a history matched case, simulation runs are conducted for all possible combinations of: 19 sets of capillary pressure/relative permeability curves taken from special core analysis data; 2 sets of PVT analysis data; and 3 sets of water oil contact. As a result, historical production profiles from 114 cases are presented for screening the impact of uncertainty related to aforementioned parameters in the history matching of Bozova field. The reservoir simulation models that give the highest match with the history data are determined by the calculation of an objective function; and they are ranked according to their goodness of fit. This study constitutes a solid basis for further studies which is to be done on the selection of the best matched models for history matching purposes.
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Quantification and Analysis of Uncertainties in Reservoir Modeling Using Multiple-Point Geostatistics
Authors M.M. Fadlelmula, S. Akın and H.Ş. DüzgünRecent research has revealed that the two-point based traditional geostatistical simulation technique is ineffective in capturing complex geological structures while modeling subsurface heterogeneities. On the other hand, it has proven that the newly developed Multiple-Point Geostatistics (MPG) based simulation is a powerful technique to model such complex structures. This simulation is dependent on conceptual geological models called Training Images (TI). This study as its name implies, is aiming at quantifying and analyzing the uncertainties of reservoir models which are generated by MPG method. The uncertainties to be quantified are either model related or parameter related. The former which is related to the model structure (i.e. TI structure) will be modeled utilizing the Stanford Geostatistical Modeling Software (SGeMS). The latter is related to the input parameters such as porosity and permeability and will be modeled utilizing the “Advanced First Order Second Moment (AFOSM)” reliability method. Accordingly, this study is divided to three main parts. First of all, the impact of training images on predicted reservoir model will be investigated. Next, other sources of uncertainties in the model are going to be examined. Finally, a sensitivity analysis of the uncertainty sources found will be conducted.
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Surface Geochemical Evaluation of Murzuq Basin (Libya)
Authors F.A. Uğur, H. Çorbacıoğlu, Y.H. İztan and Ş. ÖzsoyThe surface geochemical surveys as having a growing importance in petroleum exploration, primarily determine and evaluate the light hydrocarbon (C1-C4) surface microseeps from active oil and natural gas reservoirs at depth. A surface geochemical prospection was conducted in northern Murzuq basin (Libya) and a total of 700 soil gas samples were collected over a 500 km2 survey area from a depth of 1.2 meters with a specially desinged soil gas probe system and analysed by gas chromatography for methane, ethane, propane and n-butane. Selected components were used to produce light hydrocarbon contour and dot maps, pixler diagrams etc. in order to evaluate the distribution, magnitude and the type of the hydrocarbons trapped in the subsurface reservoirs beneath. Since the surface anomalies can also be originated from the fractured rocks and faulted zones, these linear anomaly features in the study area were characterized and differentiated by using the subsurface geological and geophysical data. As a conclusion, the Murzuq basin survey has revealed that both the correlation of the results with the post drilling activities, low costs and short project deadlines gives a positive indication for the more extensive use of the method in the petroleum exploration.
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Hydrocarbon Exploration with GORE™ Sorber Survey and Case Histories from Turkey
Authors T.E. Sökmensüer and K. GürgeyThe majority of early oil discoveries until the 1950’s resulted from drilling wells near active seeps or other surface features thought to be related to underlying hydrocarbon accumulations. This led to the development of techniques referred to surface prospecting tools. Surface geochemical techniques were first applied by Laubmeyer and Sokolov almost 60 years ago with both success and failure. For over 50 years, oil & gas exploring earth scientists have developed and tested methods which can image hydrocarbon filled reservoirs by measuring near surface parameters. These traditional techniques have included direct soil analysis, active soil gas measurement and microbial techniques. Unfortunately, these traditional methods suffer from some limitations including the poor adsorptivity of soils in 1 of 5 exploration sites, sampling difficulty due to poor soil permeability, low analytical sensitivity, limited data sets of C1-C5 hydrocarbons (methanepentane). Modern surface geochemical technique is GORE™ Survey. This technique uses a passive signal collector that can work in dry, saturated soils or directly in water. It is sensitive enough to work in areas with overburden that are relatively impermeable and have extremely low ppt concentrations.
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Detection and Utilization of Volatile Organic Compounds in Drill Cutting Samples Prior to Well Testing and Completion: A Preliminary Study
Authors K. Gürgey, A.H. Silliman, T.E. Sökmensüer and M. İşçiPrior to well testing and completion efforts; detection of hydrocarbon rich reservoir (HRR) intervals, vertical continuity between HHR intervals, hydrocarbon types (normal oil, heavy oil, natural gas, condensate, solid bitumen etc.,) and quality (API gravity, occurrence of biodegradation) which have long been done with assessment of well log, core sample and drill stem tests. These operations, however, if the number of HRR intervals is greater than 1-2 (sometimes, HRR number>10) are very expensive particularly in offshore basins such as in Gulf of Mexico Basin in U.S.A., South Caspian Basin in Azerbaijan and Bohai Bay Basin in China and in onshore basins such as in Gediz Graben Basin in Turkey etc. For this reason, a reduction of the expenses made prior to well testing and completion was planned and parallel to the purpose, volatile organic compound (VOC) and semi-VOC (SVOCs) present in the drill cuttings were thought to be useful. In this study a total of 329 drill cutting samples were collected along the Sarıkız-2 (for every 15 m.) and -3 oil (for every 3m.) wells drilled in Alasehir, Gediz Graben of western Turkey. These cutting samples were then subjected to passive treatment with GORE™ Modules that use unique adsorbents to adsorb VOC and SVOCs in the range of C2 to C20. GORE™ modules were analyzed by thermal destruction/gas chromatography/mass spectrometry (TD/GC/MS) to detect over 45 VOC and SVOCs in a ng (10-9 g) level. An assessment of the GORE™ data (329 samples x 45 variable) with both conventional and statistical methods gave the following preliminary however encouraging results: 1) Detection of HRR intervals is possible, 2) For well testing purposes, HRR intervals can be ranked from significant to insignificant, 3) Vertical continuity between HHR intervals can be determined, 4) Seal rock efficiency can be checked, 5) Up-dip migration front can be estimated and 6) Hydrocarbon type and quality in HHRI can be approximated. Regardless of the successful results obtained in this study, the technique do not replace conventional methods yet, however do complement and enhance traditional approaches.
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Modeling Petroleum System: Case Study from Northeast Netherlands Carboniferous-Permian Basin
Authors E.M. Gauthier and N. KaymakçıComputer based petroleum system modeling of Groningen Gas Field is carried out by using geophysical and borehole data. The basin is considered as mature in terms of hydrocarbon exploration and production where Carboniferous Westphalian units are the main source rocks. In this study, stratigraphical and tectonic evolution of the basin is established by using borehole and 3D seismic data which in turn, combined with geological, geophysical and geochemical data used for 1D and 2D modeling of its petroleum system. Results show that the most recognized traps were formed during pre-Zechstein (Upper Permian), and the major generation, migration and accumulation of hydrocarbon commenced during Middle Jurassic and continues to the present time. Since the timing of main hydrocarbon generation varies spatially and has begun after trap formation, both early and late migration enhances the potential of the porous Upper Rotliegend (Upper Permian) reservoirs. Prospective hydrocarbon traps may occur in the southwestern regions of the basin due to shallower depth of burial.
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The Use of Gas Chimneys for Risk Mitigation in All Elements of a Petroleum System
Authors P. Nantais, M. McRae, B. Ritts and S. RoeGas chimneys and hydrocarbon seepage are well known from many offshore basins around the world with prolific petroleum systems. Also, there are many hydrocarbon accumulations with no observed gas chimneys. The presence of gas chimneys is often used to make inferences about source rocks and seal. The objective of this paper is to demonstrate that the application of a simple gas chimney classification scheme and critical thinking can also reveal significant information about reservoir, trap geometry, seal capacity, hydrocarbon phase and migration. Several examples from a number of basins will be used to demonstrate the concepts. Gas chimney is a poorly defined generic term that is typically used to describe areas of seismic data exhibiting a vertical diffuse, chaotic or degraded quality reflection character on 2D or 3D data. Gas chimneys can also be accompanied by velocity and amplitude anomalies or even complete wipeout zones. The perturbations on the seismic are thought to be caused by the presence of free gas in the section; although fracturing and overpressure might contribute to the deteriorated seismic response. Gas chimneys can generally be distinguished from other vertical seismic noise bands caused by near surface/seafloor effects, permafrost, hydrates or very shallow gas by the direction of propagation of the noise – top down or bottom-up. In-basin calibration organized by play-type is also an important element of this analysis and can be used to high-grade an exploration portfolio or play trend. The integration with basin modeling can further constrain interpretations and contribute to the understanding of geological risk. Characterization, classification and calibration of gas chimneys are a best practice for mitigating geological risk in an exploration basin. A gas chimney can be a positive sign for many exploration opportunities but the lack of a gas chimney cannot automatically be taken as negative evidence.
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Seismic Geomorphology and Seismic Stratigraphy from Shelf to Deepwater: Implications for Exploration and Development
More LessUnderstanding exploration and development risk associated with lithology prediction can greatly benefit from the interpretation of 3D seismic data. Such data can afford direct imaging of depositional elements, which can then be analyzed by applying seismic stratigraphic and seismic geomorphologic principles to yield predictions of lithologic distribution with respect to reservoir, source, and seal facies, insights to compartmentalization, and identification of stratigraphic trapping possibilities. Benefits can be direct, whereby depositional elements at exploration depths can be identified and interpreted, or they can be indirect, whereby shallow-buried depositional systems can be clearly imaged and provide analogs to deeper exploration or development targets. Numerous examples of imaged depositional elements from both shallow- and deeply-buried sections are presented. Deep-water deposits, in particular, have benefited greatly from analyses of 3D seismic data. The understanding of the stratigraphic and geomorphological evolution of these deposits has increased significantly as a direct result of 3D seismic-based analyses. In highcost deep-water exploration settings, insights derived from such analyses are critical to reduce risk with regard to reservoir presence and reservoir compartmentalization to ensure economic success. Depositional elements in settings such as shoreface, shelf, estuarine, and fluvial, as well as in carbonate environments also benefit greatly from 3D seismic analyses. Common techniques for geologic visualization include 1) visualizing and illuminating stratigraphic horizons, 2) time slicing and flattened time slicing, 3) interval attribute analysis (including seismic waveform analysis), 4) voxbody interpretation and mapping, 5) 3D perspective rendering, and 6) opacity rendering. The key to successful application of this approach lies in the correct interpretation of geologically meaningful patterns revealed by these techniques. Workflows in conjunction with numerous examples from a variety of geologic settings will be shown.
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Isotopic and Geochemical Records of the Middle Eocene Climatic Changes in Central Anatolia, Turkey
Authors F. Ocakoğlu, S. Açıkalın, İ.Ö. Yılmaz and C. ErayıkA 150 m thick lacustrine succession crops out in vicinity of Orhaniye and Güvenç villages in the 20 km north of Ankara (central Turkey). It is made of generally rhythmically bedded shalelimestone alternations. High resolution sedimentological logging and isotopic and geochemical investigation of the samples collected enabled the understanding of climatic and limnological conditions prevailed during the deposition of succession. Spectral analysis of bed thickness displayed statistically significant hidden cyclicities at 8.2 m and 16.1 m that would correspond precession and obliquity Milankovitch bands respectively. This finding, together with the previously published benthic foraminifera biozone data of overlying marine unit showed that the target lacustrine unit would have been deposited within 430 ka between 44.53 Ma and 44.1 Ma. Evaluation of the δ13C and δ18O concentrations indicates relatively high correlation between them. Carbonate intervals have higher δ18O (>-3 permil) and δ13C compared to shale levels. An overall negative shift in δ18O up in the section is typical. Proxy elements of Co, V, Ni, Mn and Zn, characteristic of reducing conditions are enriched in shale levels and more scarce in carbonates. The upper half of the section is evidently poor in these elements compared to lower half. Indicators of the weathering intensity in source area, the Na2O/Al2O3, Na2O/TiO2 and Na2O/K2O ratios are generally higher in carbonate intervals. Similarly, the upper part of the section has lower elemental ratios that may explain more humid and warm climate conditions. δ13C isotope stratigraphy having a positive shift (5.6 permil) in the lower part and then a negative shift towards up may support this interpretation. These briefly explained preliminary data proves that during the deposition of the Güvenç lacustrine sediments in the Middle Eocene climatic optimum, astronomic forcing may have been prime driver. Probably for this reason, δ18O stratigraphy of the area has very parallels with the previously published global pattern of this time. In this scheme, carbonate intervals of the Güvenç succession may have been formed during cold and dry periods while the shale intervals represent warm and hot period when the lake level and weathering intensity were higher.
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Sediment Properties and Geological Evolution of the Recent Lake Işıklı (Denizli, SW Turkey)
Authors S. Boyraz, N. Kazancı, M.T. İsmael, S. Öncel, Ö. İleri and Ö. MakaroğluLakes and lake sediments are the most reliable source of data for climate research. To obtain information about the Late Quaternary climate in SW Anatolia, Lake Işıklı were investigated and its findings are presented below. The Lake Işıklı is a shallow lake on the Büyük Menderes River in the Çivril town boundaries, located western margin of Dinar graben and about 65 km2 surface area. The six drillings which lengths from 1 to 5 meters have been done inside the lake using Livingstone samplers. As expected, the water content of the first 2 meter of cores is around %50, grey-green-black colored and contains abundant plant roots, rush pieces and gastropod shell. In the lower parts of cores, the water content gradually declining to %30 and colors are successive with brownish-black and gray tones. The lithological composition of lake sediments are characterized mostly silt, small quantity fine sand (11 -189 μm) and mean particle size is 55 μm. Due to the opening of lake to outside, suspended particles reduced. Lithological compositions are composed of predominantly calcite, quartz, feldispar and very small amount of dolomite and amorphous mineral. Based on its abundance, the clay content of lake sediments are illite, smectite and chlorite. These result suggest that the sediments of lake mostly originating by erosion from surrounding volcanic rocks. The magnetic susceptibility values of Lake Işıklı are not more interpretable. In general, it increases or decreases to the consistent with organic matter content. In lake sediments, total organic matter content ranges from %3,2 to %33.3. The total carbonate amount of lake, 165 cm intervals with the lowest amount of carbonate is %0.2, to the 355 cm depth lake has the highest amount with %14.2 and these values are vertically consistent with organic matter content. Lake sediments chronology based on AMS-14C measurements and according to this, the age of longest core (500 cm) is 5455±20 BP. The sedimentation rate calculated from measurements on cores obtained from different levels, for 0-200 cm interval is 0.88 – 1.26 mm/year, for 200-500 cm interval is 0.7 mm/year with average of 0.91 mm/year. In the light of these all analysis, lake sediments of the core could be distinguished three different level such as 0-140 cm, 140- 345 cm and 345-500 cm. It is interpreted that the first level corresponds to the stage of being swamp that has prevailed during the last 1260 years, and the second level corresponds to the stage of being dry that prevailed for 1740 years, while the third level corresponds to the stage of being lake and swamp that prevailed 2455 years.
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Study and Interpretation of Sedimentation Rates within Turkish Lakes
Authors N. Kazancı, K. Koç and S. BoyrazLakes are sensitive to environmental circumstances, thus it is accepted that these geographic elements are archives of climatic records for the relevant region. Some parameters, i.e dimensions of of both lake itself and drainage basin, local climate, lake system (open or closed), lithological variety of source rocks, active tectonism, altitudes play important roles on the lacustrine deposition and sediment thickness. In order to detect which parameters were prominent within Turkish lakes, sedimentation rates of twenty-two lakes were examined using original data together with results from literature. Authors were aware that deposition in lake margins should not be used for a proper sedimentation rates. Some of the studied lacustrine records (cores) were 0-2 m long formed within last 250 years (i.e lakes Ladik, Borabay, Aşağıtepecik, Yeniçağa, Sünnet, Sakarya Akgöl, Gravgaz), while others were 4-10 m long core covering a time span of 1000 to 7000 years (i.e lakes Manyas, Ulubat, Bafa, Burdur, Işıklı, Akgöl). Some lakes provided long cores and long deposition time i.e lakes Gölhisar, Elmalı Karagöl, Van, Konya, Tuzgölü, Pınarbaşı. Based on sediment thicknesses only, deposition rates of Turkish lakes were between 1.56 and 7.48 mm/year, mostly above 2.95 mm/year with an average of 3,5 mm/year during the last 250 years. It is worthy to note that recent lake sediments contain significant amount of pore water and it was not below 25 % even in the longest core. The sedimentation rates of Turkish lakes during the last 1250 years became 0.64 to 3.56 mm/year and their average was 1.98 mm/ year. In the last 5000 years it was between 0.30 and 0.91 mm/year with an average of 0.56 mm/ year. It is surprising that the value of the last 10 000 years (Holocene) is almost same (= 0.56 mm/year) with the previous one. Deposition rates of dead lakes (i.e dry lakes Konya, Sultaniye, Pınarbaşı) are between 0.05 and 0.39 mm/year. They are very close to watery but old lakes which are successors of old lakes, i.e lakes Tuz, Hotamış, Van). Overall, sedimentation rates of Turkish lakes are high significantly and average value of even old and dry lakes is around 0.22 mm/year. This is high four and ten times at least compared to values of modern and geological records in the world respectively. It may indicate that tectonism has been primary controlling factor on deposition in Turkish lakes since the late Quaternary.
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A Climate Record of the Last 1400 yrs from the Lake Çubuk (Göynük, Bolu, NW Anatolia) Based on Multi-Proxy Investigations
Authors F. Ocakoğlu, O. Kır, E.O. Dönmez, A. Akbulut, S. Açıkalın, C. Erayık, İ.Ö. Yılmaz and C. TunoğluA paleoclimatic study was carried out in the Lake Çubuk, 15 km to the east of Göynük town (Bolu, NW Anatolia). 3 m-thick core has been taken from the lake bottom and a trench has been opened at the lake margin. The core and trench samples were analyzed according to lithologic, stable isotope, geochemistry, pollen, ostracod and diatom components. Lithologically, the core consists of gray to green muds in the first 50 cm interval from the top. Alternation of fine sandy intervals and gray muds take place between 50-150 cm and dominantly greenish gray mudstones lie between 150-300 cm. Lamination and organic rich levels are almost absent through the core. According to the age model based on three 14C analysis, the base of the core goes back to 1400 yr BP. The sand rich interval was deposited within a very short time span (50 yrs) just after 1400 AD. Stable δ18O isotope data shows a general negative shift indicating a decrease in precipitation after 1450 AD. Certain geochemical proxies indicate the increase of biological productivity as well as oxidation in the lake water. Ratio of total tree and pinus pollens decreased significantly while shrub pollens considerably increased. Conformably, benthic/planktic diatom ratio slightly increases. The sandy event interval mentioned above is characterized by unique occurrence of certain diatom specious such as autocoseria sp. In the lower part of the core spanning between 1400 - 500 AD, isotopic proxies display two cold and dry periods peaked at 850 AD and 1250 AD respectively. During these century-lasting climate events stable isotopes (δ13C, δ18O) shift to more negative values, geochemical proxies for biological productivity and detrital input considerably decrease. These cold events are also characterized by enriched ostracod fauna and higher benthic/planktic diatom ratio indicative of lower lake levels. The Lake Çubuk climate record that comprises the global Little Ice Age and Medieval Warm Period was also compared with the previous regional/global patterns and discrepancies are discussed.
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Macondo: Anatomy of an Oil Disaster
By F. DemirmenThe oil disaster that took place on April 20, 2010 in the Gulf of Mexico (USA) left enduring marks on the history of oil industry. The loss of life, grave environmental impact, harm to health, and economic wounds from fisheries to tourism will long remain as key elements of the disaster in our memories. The disaster happened with explosion of the Macondo-1 exploratory well drilled by British Petroleum (BP) in deep-water Macondo prospect. The well was being drilled from a semi-submersible platform. At the well location the water depth was 1.522 m and the oilbearing horizons at approximately 5.500 m. The well had heralded an oil discovery. BP’s plan was to temporarily suspend the well and return at a later date for appraisal and production. After abandoning the well, the platform was to move to another location. At the time of explosion, the well was 43 days behind schedule. The explosion (blowout) happened on the night of April 20, 2010 during well abandonment when methane gas reaching the surface caught fire. The 33-ton platform tilted sideways and fell into water in flames. Crude oil and gas started to gush out into the sea. 11 rig workers died, 17 were wounded, and 115 personnel barely escaped. The giant platform was hurled 400 m away from the well. After frantic efforts that continued day and night, the oil spill was brought under control on July 15. But the permanent closure came about on September 19 when one of the two relief wells that were being drilled for backup intersected Macondo at 3.910 m vertical depth and heavy mud was pumped into the well. During the 3 months of spillage, 4.9 million barrels of oil flowed into the sea. It is estimated that some 75% of the spilled oil is still in the environment in one form or another. The New York Stock Exchange value of BP, its image severely damaged, dropped by 90 billion dollars by mid-June. Following various investigations conducted by the Congress and the federal government, it was concluded that the main cause of the accident was shortcuts taken during drilling shortly before explosion. The shortcuts, while reducing cost, also compromised well’s integrity. Most importantly, negative pressure tests were not given due attention. Delay in the completion of drilling meant 43 million dollars extra cost. In addition, the blowout preventer (BOP) had failed. The Macondo disaster spurred the filing of hundreds of lawsuits, more than 300 against BP alone, and seriously interrupted oil exploration and production in the Gulf of Mexico. It became evident that the oil industry was ill-prepared to deal with a major offshore accident. As a result, the industry is undergoing a major transformation. A “zero tolerance” policy that envisages no compromise in drilling safety is being embraced, and new regulations are in place. There are important lessons for Turkey to take.
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Black Sea Ultra Deepwater Drilling Operations and TPAO
Authors R. Atalay and S. KırbıyıkIn 2010, in the Turkish Black Sea Sector, 3 wells has been drilled with water depths more than 1800 m. Each can be classified as wildcat wells when their distances and uncertainties are considered.Turkish Petroleum Corporation (TPAO) has at least 50% share on these wells. TPAO was the operator of the two wells, where in the last one, Sürmene-1, was the sole ownser. World’s leading petroleum companies ExxonMobil, Chevron, Petrobras also involved in this project as either the operator or the partner. There has been a considerable increase in exploration and production facilities in the industry with the increasing oil prices since 2004. The only sector that was not affected by the 2008 worldwide economical crisis was the ultra deep water drilling operations. Operations in the Black Sea were held during the most active period of the industry. Therefore, it embraces its own challenges in various manners. It has taken 4 years to bring in a competent drilling unit to Black Sea, which can be considered as a remote area. It is even harder to sign a short-term contract to drill a couple of wells. Even though the idea of sharing the materials and services with partners seems logical and practical, it has its own management challenges. It needs significant importance and management that the offshore industry applied its new methodologies first in Turkey and for TPAO. The most important aspect of a project of this scale, is to form a project team that is capable of reaching the objectives of the project and is to provide a working environment that makes it easier to work in synergy. The purpose of this study to define how an ultra deep water drilling project is managed beginning from the planning phase, which has taken place in Black Sea with an inadequate infrastructure, challenging and complicated logistics environment, limited experienced and qualified human resources and an area that has inadequate and complicated rules, and share it with the industry, universities and interested audience.
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Applications of Fuzzy Set Theory for Risk Analysis in Maritime Industry: A Literature Survey
Authors A. Menteş and İ.H. HelvacıoğluOver the past decades the complexity of ship and offshore operations has increased rapidly. Therefore, efficient and sophisticated quantitative and qualitative safety analysis techniques have been widely developed and implemented for determination and analysis the risk limits of marine and offshore industries related problems. Most risk analysis models are based on quantitative solution techniques which require crisp data. However, in many cases, the available information related to risk factors is not numerical. Rather this information can be expressed as words or phrases in a natural language. In addition, imprecision and vagueness on failure rates may lead to uncertainty in results, thus causing underestimated or overestimated prediction risk levels. By allowing approximate analysis, fuzzy set theory is an effective tool for characterizing system safety for marine and offshore industries’ applications. The aim of this paper is to provide an in-depth presentation of the contributions of fuzzy set theory in the field of marine and offshore industries, focusing risk analysis for real-world applications. For this purpose, we review extensively the literature and consolidate the main results on the application of fuzzy set theory to marine and offshore industries safety problems. Throughout the course of this study, it has been observed that fuzzy set theory has been intensively applied to marine and offshore industries safety problems, and has been rapidly grown in the applications. Finally, recommendations on further studies in marine and offshore safety analysis are suggested.
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Pore Pressure Trends in Deepwater Operations and its Impact on the Casing Design
By A. ÖzkaleNational Oil Company TPAO has drilled 3 ultra deep wells in BlackSea as an operator and a partner in a joint venture. TPAO‘s Exploration efforts in BlackSea Ultra Deep Water will enlighten the future Exploration Campaigns in BlackSea. Exploration or Drilling Campaigns do not start with bit in the hole, it starts far before then. It starts with detailed planning and it ends not with bit out of the hole but capturing the lessons learned from the plans applied. In this paper; how pore pressure estimation and real time pore pressure affect the casing design in Black Sea and the future recommendations will be discussed.
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Managerial Performance in Ultra Deepwater Black Sea Operations
Authors S. Kırbıyık and A. MazlumWith increasing oil prices, one of the offshore regions that are being explored is the Black Sea. In 2010, there have been three wells drilled with at least 1800 m water depth. For the continuity and success of the projects, one thing that should not be disregarded is the importance of the managerial performance. Supplying equipment and services for such big operations in an environment that can be said to be a remote area like Black Sea may cause some struggle. Therefore, TPAO has taken over some of the contracts from their partners and developed a detailed costbook according to those. Authorization for Expenditure (AFE) is however needed to be finalized long before that, therefore built based on the quotations recieved from the third parties. Cost was tracked daily to analyze the Estimated Final Cost (EFC), Days Ahead/ Days Behind according to the planned days. It was also recorded what each activity consumed in terms of time and cost. One of the productivity measurements in the operations was nonproductive time (NPT) management. From the daily drilling reports, each activity is analyzed for its productivity and entered to the pre-built system for NPT. Thus, any unplanned activity could be determined by the incident, equipment and company. Realistic weekly reports are obtained through these studies for the time, cost, depth and productivity. Undoubtly, the most valuable asset of managerial performance is the human resource. During the execution of the project, people with different qualifications were assigned to different duties. An activity management scheme was carried out open for usage of everyone, which enabled tracking the project during its lifetime. In this study, in the field of project management of Black Sea drilling operations, evaluation of the performance in terms of the cost, human resource and time-based will be presented.
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Shale Gas Exploration and Production
By S.J. SunjayShale gas is natural gas from shale formations which acts as both the source and the reservoir for the natural gas. Each Shale gas reservoir has unique characteristics. Research work focus at bridging the gap between invariant characteristics at nano scale of sedimentary rocks and their macroscopic properties. 3D seismic is becoming successful because of the ability to identify fracutre and fault trends. Surface geochem cannot identify in the subsurface where the frac or fault systems will be intersected by the drill bit. This is why 3D is now being used aggressively and successfully. Unconventional reservoirs require some form of stimulation to obtain commercial production. Shale gas reservoirs require fracture stimulation to unlock gas from extremely lowpermeability formations. As fracture stimulation is an important aspect of well completions, production companies need to know basic information about fractures such as whether they will open, direction of fracture propagation, dimensions and type of fracture, and whether they will stay in zone. Increasingly, seismic is utilized to provide such information and guide drilling and completions. Three types of information extracted from seismic are useful in optimizing drilling locations: fracture characterization, geomechanical properties, and principle stress measurements (vertical maximum and minimum horizontal stresses). Given the target depth of formations in shale gas basins that are being exploited today, the maximum principle stress is vertical, giving rise to HTI (horizontal transverse isotropy). This means that the fracture system is comprised of vertical fractures which cause anisotropic effects on seismic waves as they pass through. These anisotropic effects are observed on 3D seismic data as changes in amplitude and travel time with azimuth. In multicomponent data shear wave splitting can be observed. The relationship between changes in P-wave amplitude with azimuth in anisotropic media to invert the observed seismic response and predict fracture orientation and intensity. Ultrasonic Measurements of Anisotropy of Shales: Laboratory measurements of ultrasonic velocities have confirmed that compressional waves travel faster in the direction of applied stress. The reason may be that all rocks contain some distribution of microcracks. As stress is applied, cracks oriented normal to the direction of greatest stress will close, while cracks aligned with the stress direction will open . In most cases, waves travel fastest when their particle motion is aligned in the direction of the opening cracks.A noticeable feature of acoustic anisotropy is shear wave splitting, or polarization, typically caused by fractures.
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The Impact of Global Energy Policies on Turkey and the Region
By N. PamirAchieving a secure (adequate, affordable, reliable, timely, clean and uninterrupted) supply of energy had always been a vital problem for consumers. However, for the suppliers, there is also a concern which can be called as “demand security”. They need long term committments from the demanding countries to justify their costly investments to develop hydrocarbon fields and thus enable long term supplies. Therefore the equation of energy security has more than a single parameter. We also have to consider the transit countries and their expectations to complete the picture.
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Organic Shale: A New Energy Source
By D. BentleyOrganic shale reservoirs have become an important source of Natural Gas Production in North America over the last 5 years. With this success Oil & Gas Operating Companies have started to look outside North America to understand if organic shale in other parts of the world could have similar impact on Natural Gas Production. This paper gives an overview of the following: 1) What is Organic Shale? 2) Where do we look for these rocks? 3) What is Reservoir Quality & Completion Quality 4) How to understand Reservoir Quality and what are the key rock attributes that control it. 5) Why do these rocks need to be Stimulated it be productive? 6) How to understand Completion Quality and what are the key rock attributes that control it. 7) Summary of current understanding. The stimulated fracture system is influenced by the extensive horizontal laminations that are pervasive in shale reservoirs. The laminations will strongly influence the hydraulic fracture height because of the difference in rock mechanical This overview is a current view of understand of this evolving source of energy. Organic shale has always been known as a source rock for oil and gas reservoirs; however the ability of this rock to actually be produced is a new challenge. Understanding the basics of these complex rocks is the starting point of this challenge, and this paper introduces a process to make this understanding much clearer.
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Evaluation Resource Play Potential: Developing an Integrated Solutions Toolkit
By W. KoolThe development of unconventional resource or ‘shale’ plays has dramatically changed the way in which reservoirs are evaluated and characterized. Mudstone facies that have been considered as seals and source intervals have become prolific reservoirs with the advent of horizontal drilling and multi-stage completions. Unlike conventional plays, resource plays have a greater degree of complexity and heterogeneity at a much smaller (pore) scale, yet these reservoirs are distributed basin-wide in many areas. While typical evaluation techniques common to conventional oil and gas reservoirs have been employed in the evaluation of resource plays, it is clear that these technologies are insufficient and that the tools used in characterizing finegrained rocks must improve. In North American basins the development of these plays has had the advantage of abundant well control, however, in the approach and an understanding of the scale of application and fidelity of each technology. In order to define areas of the greatest potential in new and existing basins, an integrated approach or ‘toolkit’ that contains multiple technologies at different scales of resolution will be a key innovation that may one day make resource plays conventional.
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