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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
81 - 100 of 163 results
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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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