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Second EAGE Workshop on Geosteering & Well Placement
- Conference date: 22 Sep 2013 - 25 Sep 2013
- Location: Dubai, United Arab Emirates
- ISBN: 978-90-73834-54-5
- Published: 22 September 2013
33 results
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Geosteering: Selecting the Right Technology to Optimize Well Placement
More LessDrilling horizontal wells successfully required to address various challenges, and accurate well position monitoring and trajectory adjustment are certainly ones highly affecting future production and recovery. Due to the versatility and the uncertainty attached to the precise location and description of the reservoir targeted, it is often necessary, to minimize risk on the overall project, to adopt a fit for purpose strategy to geosteer horizontal wells.
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Advancement in Slim LWD Tool Measurement Improves Precision in Geosteering for Complex Lithology Reservoirs
Authors M.A. Ibrahim, N. Musharfi, A.R. Belowi, A.B. Abdelkader, H. Elmasry and A. AbbasThe challenge in the industry today is to maximize recovery from existing assets that require drilling and geosteering in complex clastic reservoirs. Consequently, optimization of the well trajectories while drilling this type of formation is vitally important to achieve the maximum production from each drainage point. Therefore,sophisticated geosteering capabilities coupled with technical support is important, especially when the lateral is planned to be drilled in the direction of the minimum stress. The borehole is normally slim with horizontal section exceeding 3,000 ft. In response to the above challenge a slim azimuthal spectral gamma ray tool (4.75 inches) has been used as a solution for proactive geosteering which provides real time petrophysical evaluation in the complex clastic reservoirs. The ability to measure uranium (U), potassium (K), and thorium (Th) in combined with resistivity, density, and neutron and sonic successfully optimized the path through the sweet spot in the reservoir thus avoiding the tight non-reservoirs sandstones. This paper shares the results of wells geosteered using LWD Spectral Gamma combined with quad-combo data and the real time petrophysical model for shaly-sand evaluation using Multimin models. In addition, this paper discusses the advantages of real time geo-mechanics evaluation which leads to successful geosteering.
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Maximizing Value Through Use of an Optimized Landing and Geosteering Strategy on Draugen Late-Life Development Wells
Authors V.M. Barrón, M. Ecclestone, J.W. Goedbloed, T. Carlson, C. Dupuis and H. WangDraugen is a low structural relief oil field with a sandstone reservoir and, at production start-up, a 50m vertical oil column above the free water level. Reservoir quality is excellent with an average porosity of 29% and multi-Darcy permeability. Draugen started producing light oil in 1993 and had a planned development life of 20 years. After reviewing options for improving recovery from the field, an additional 20 years of production has been planned, with the target to raise the recovery factor above 70%. As part of this project, infill drilling to target un-swept attic oil plays an important role. The infill 2013/14 campaign comprises four infill wells. The first well has been drilled and landed during the summer of 2013; its final reservoir section and completion are scheduled for autumn 2013. The other wells will be drilled and completed in 2014. This presentation will focus on the results of the first well.
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Seismic Inversion and Resistivity Inversion While Drilling Methods Application for Reservoir Geometry Characterization
Authors Y. Wismoyo, A. Setiawan, F. Maula and F. FardhuThe challenge of construction horizontal well is reservoir geometry especially in the clastic environment such as fluvial distributary channel which has multiple uncertainties such as geological structure and geometry uncertainty exist in the form of channels with variable continuity, thickness and depth. The key for having a successful horizontal well is reducing uncertainties of geometry. Through modeling of seismic inversion, multiple geological and drilling scenarios can be explored prior to drilling, and the reservoir geometry model is updated in real time while drilling by inversion of resistivity. The paper only defines the geometry/reservoir architecture by making a model of seismic and resistivity inversion quantitatively and accurately before drilling,and will be updated during the process of drilling and after drilling. This application is used in the horizontal well construction with complex geological structure and challenging stratigraphy environment such as delta or thin reservoir so that the geo-model is lack of confidence and low accuracy although it has the adequate amount of offset well around it or pilot well. This condition will cause the high geometry uncertainty in the well construction. This combination technique has been used and proved in Niru field.
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Successful Reservoir Navigation in Horizontal Wells in Carbonate Reservoirs with a Reversed Resistivity Signature
Authors S.M. Ghnia, M. Elhouni, K. Elgayed, F. Breviglieri and P. OdiaseAbstract Bahi is one of a series of large oil fields located in Sirte Basin, Libya. A horizontal drilling campaign was initiated in 2013 to maximize reservoir performance and increase oil production. Azimuthal Resistivity technology was used to place and maintain the well within the zone of maximum interest, about 3 to 7ft TVD from the roof. The main challenge in wellbore placement based on resistivity is the reversed resistivity contrast that in this field exists between the roof (10 ohm.m) and the reservoir (1.5 ohm.m). The reversal results in a reduced maximum depth of bed detection. The applied Azimuthal Resistivity and Closed Loop Rotary Steerable System technologies, coupled with Reservoir Navigation services provided real-time deep azimuthal resistivity images that enabled successful borehole navigation through the horizontal section, following the structural complexity with 100% reservoir exposure in the 1816ft lateral hole section.
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Geosteering Impact on Developing Oil and Gas Fields, Saudi Arabia
By S.I. HumaidDuring the past few decades, drilling technologies have evolved from drilling vertical wells to complex horizontal wells. Although vertical wells are still being used in the industry as observation, evaluation or pilot wells. When it comes to developing oil and gas fields and maximizing reservoir contact to enhance production, the industry relies on horizontal wells. With the advancement in drilling tools and formation evaluation technologies, well placement industry has also flourished. With these advance tools, well placement (Geosteering) entered a new spectrum where thin reservoirs can be targeted for extended lateral section with a very high percentage of reservoir contact in the best fluid saturation horizon. The objective of this extended abstract is to highlight the geosteering impact on developing oil and gas fields Saudi Aramco.
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Adding a New Piece in the Puzzle Between Well Placement and Surface Seismic
Authors M. G. Viandante, G. Skinner, L. Pontarelli, A. Nagel, G. Morgan, G. Freeston-Smith and C. Matthewstical role in optimizing the placement of the producer well using its unique depth-of-investigation and multilayer-detection capability to map several layers, in real time, both above and below the drilled trajectory—to a distance of approximately 115 ft [35 m] TVD. The tool delineated the shape of different sand progrades. The distance-to-boundary information provided by the tool were used to update the reservoir and geological model in real time, allowing the wellbore to be geosteered with certainty while connecting different progrades and, ultimately, exceeding the client KPIs.
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Geosteering Beyond Seismic Resolution: A North Sea Case Study
Authors T. W. Kui, N. Stevenson, P.I. Espedal, L. Yearron, F. Perna and H. WangThe combination of planning, personnel and technology enabled achievement of the well results. Geosteering techniques proved and accessed 600m md of additional pay zone which conventional technologies and techniques would not have accessed. Analysis of deep directional resistivity data raised confidence of seismic inversion data during and after drilling.
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Landing in Carbonates - Challenges and Experiences in Brazil
Authors M. Mendes, M. Ribeiro, C. Pontes, V. Costa, A. Ghizi, J. Seydoux, R. Samaroo, I. Hernandez, D. Salim and C. SantosPlanning the most efficient trajectory in horizontal section requires landing the well at the right inclination and location with respect to the reservoir structure. In heterogeneous and faulted carbonate reservoir, landing is significantly improved with the use of a Deep Directional Resistivity mapping LWD tool. Examples from landing in offshore Brazil successfully demonstrate the value of such a measurement to improve the correlation while drilling of key formation markets with respect to seismic features and to delineate and detect intrinsic bedding previously unknown from the seismic data. Deeper depth of investigation provide a significant improvement in the landing process in carbonate environments by reducing the seismic uncertainty and understanding the reservoir structure better and on a larger scale while at the same time offers the opportunity to avoid drilling a costly pilot well.
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New Way to Landing Improves Reservoir Seismic Understanding
Authors A. Meira, P. Netto, A. Mainieri, G. Schmitt, J. Seydoux, R. Samaroo, D. Salim and C. SantosSuccessful placement of horizontal wells requires accurate landing of the well at a desired position in the reservoir. The current industry practice is to drill exploration wells and pilot wells to improve the knowledge of the reservoir structure and at the same time to obtain a better correlation with seismic to refine the overall reservoir geological structure. A new 8.25-in. Deep Directional electromagnetic (EM) LWD service with a radial depth of investigation in excess of 30 m has been introduced in Brazil for landing applications that allows remote detection of the approaching reservoir with sharper resolution than obtained with seismic measurements. Because of its depth of investigation, a more accurate correlation with the seismic model structure could be reached in real-time allowing for optimization of the landing trajectory without the need of a costly pilot well. Based on this new information, improvements in seismic reprocessing are expected to further enhance the knowledge of the reservoir.
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Accessing More Reserves with Proactive Geosteering on the Odoptu-More Sakhalin ERD Project
Authors V. Filimonov, A. Shirshov and K. KudashovThe Odoptu-more field has a very complex geology and the main challenge for geosteering is asymmetric anticline structure which gives significant increase in structural uncertainty with increasing length of horizontal section. In the area of western anticline slope (more remote from the shore) formation dip can vary from 0 to 7 deg. Such challenging environment limits the length of horizontal section on the project by 500 m. In spite of such complicated drilling and geological condition Rosneft took the challenge – planed 7100 m long horizontal well with longest drain in the field – 1000m. This paper describes how this task was successfully executed utilizing “Model-Compare-Update” and “Distance to boundary” geosteering methods and compares the weight of each method in decision making process in different geological environments.
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Application of New Deep Directional Resistivity Tool to Fully Define Reservoir
Authors M. Viandante, M.S. Spotkaeff, S. Jenkins, A. Simms, E. Oldham, S. Silcock, M. Seaton, E. Mirto, A. Nath, S. Chow, R. Lepp and T. BlasdaleA large challenge in drilling a horizontal well is that they are planned using a seismic visualisation of the reservoir, but are drilled using a visualisation of borehole scale, which is much smaller. This results in only a vague structural outline which can be trusted from the seismic data, which in turn necessitates the geosteering process. Furthermore, even the deepest reading bed boundary mapping tool currently available can only visualise one or two boundaries in anything other than a relatively thin reservoir for referencing back to the seismic data. Additionally, evaluating a horizontal reservoir must be carried out using devices which only see a limited distance into the formation. With current commercially available technology, there is no measurement which can detect a range of reservoir variation vertically away from the wellbore. A new generation deep directional EM tool, has a greatly enhanced depth of investigation which is capable of detecting formation boundaries exceeding 80-ft from the borehole, coupled with the ability to detect multiple boundaries in any direction. As well as being able to tie the borehole directly to the seismic scale, this combination of measurements allows for the evaluation of the reservoir over the entire formation thickness.
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Achieving Increased Net Reservoir Contact Using High Resolution LWD Resistivity Imaging
Authors S.M. Dama, O. Al Mutwali, S. Al Hassani, H. Aboujmeih, B. Al Dhafari, S. Al Jabri, A.S. Al Mansoori, A. Lotfy and O. Abel RazekA dual horizontal oil producer completed in offshore Abu Dhabi faced unplanned faults while drilling the 8.5” pilot hole, resulting in complete losses. Based on this event, deployment of radioactive sources in the horizontal section presented highly risky geosteering operations, potentially leading to extensive fishing operations in case of a stuck pipe. The alternative technology adopted was to utilize a high resolution LWD resistivity imaging tool for wellplacement applications and reservoir characterization in a water based mud system. The case study achieved increased production due to maximizing reservoir contact by utilizing accurate realtime dip picking and together with qualitative at-bit resistivity measurements.
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Geosteering From Remote Operational Centers: A Necessity
By A.K. ThorsenDuring development of the geosteering service and business, there has been an ongoing debate of the most effective work process and where the value and impact will be the largest. Initially, all geosteering was completed at the wellsite, and very often by an experienced LWD engineer with a variety of geological background and knowledge. As resistivity technology develops, and the change from “simple” omnidirectional resistivity (through the use of multiple frequencies and continuous development of frequencies penetrating larger volumes of rock) the need for interpretation knowledge is increasing. To ensure necessary expertise is available, remote operations and data transmission from rigsite to SMEs are a necessity. The goal is to generate trust in interpretations of increasingly complex data among the personnel and drillers responsible for the delivery of the well. Short decision times and accepted methodology as standard work processes are essential for increased efficiency and optimizing wellbore placement in the real-time domain. Definitions of the changing value of the operations based on of well trajectory changes, and understanding of the process that has led to increased optimum placement and overall efficiency in field productivity, will be discussed.
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The Technological Evolution of Geosteering and its Impact on Formation Evaluation
More LessPrior to the global oilfield boom and its effect on technological development, wellbores were restricted to simple vertical drilling and basic wireline logging. However, technological developments in line with increased global energy demand, has resulted in commercially viable development efforts for previously untapped unconventional reservoirs. The challenges associated with unlocking the potential of these highly heterogeneous and thin reservoirs has encouraged a fresh approach for reservoir development and management strategy, including increased utilization of deviated and horizontal well drilling in order to maximize reservoir exposure, hence flow area for hydrocarbons. This brought on the introduction of steerable and logging while drilling systems, consequently the industry began its step change in its outlook towards drilling and logging operations.
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Well Placement Enabling Deep 3D Petrophysics
Authors A. Meira, J. Seydoux, A. Neto, P. Netto, J. Denichou and D. OmeragicRecent development in well placement have allowed mapping of the nearby resistivity boundaries and evaluating reservoir structure up to 30m away The new deeper resistivity measurements allow integration of measurement of different scales to propagate the structure with petrophysics parameters far deeper away from the borehole and to provide the best possible geological model populated with properties that can be used to estimate production and completion design. A method is presented that includes the interpretation of a formation structure from the deep directional resistivity tool, correction of petrophysical logs using this structure, refinement of the resistivity model, and propagation of the petrophysical properties. As a results, accessing a more accurate deep formation structure model with a tighter integration with petrophysics provide a more accurate estimation of reserves and production process.
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Formation Evaluation in Carbonates with LWD Logs in High Angle Wells in Presence of Heavy Hydrocarbons
By P. FerrarisComplex carbonate reservoirs present unique challenges for measuring porosity, deriving permeability, and assessing producibility. While drilling a complex carbonate reservoir offshore Brazil, to be developed using horizontal , geosteered wells, an operator required a Logging while Drilling (LWD) analysis to characterize producible zones. The operator used magnetic resonance service to obtain real-time LWD measurements in a several challenging horizontal wells. The NMR LWD measurements evaluate pore-size distribution to estimate formation properties and consequently determine the best stimulation treatment and completion optimization. A multi-sensor LWD collar is also run in conjunction to evaluate rock and fluid properties and obtain accurate lithology description, porosity and continuous permeability. Presence of relatively heavy hydrocarbon type (18-20 API with viscosity of 12 cP) represented a special challenge, affecting the traditional NMR interpretation approach. Utilizing a sequential multi-mineral application methodology together with NMR data, fluids were split into five categories: clay bound water, capillary irreducible water, un-flushed formation oil, filtrate and movable water. An integrated permeability thickness profile was computed allowing classification of each zone potential and size accordingly the stimulation plan. The predictions were confirmed by stimulation execution, resulting in very fast pressure decays over the intervals characterized to have the highest permeability.
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Proactive Well Placement and ICD Completion Enhance Productivity in Al-Khafji Complex Fluvial Reservoir
Authors U. Obot, A.M. Al-Dhafeeri, T.A. Ismail, T.I. Moh and S.Y.A. SuleimanAn LWD directional electromagnetic (EM) bed boundary mapping tool in the BHA enabled KJO and Schlumberger geoscientists and engineers to precisely geosteer and place wellbore trajectory within thin target reservoir. After successful proactive well placement a completion design that included field-adjustable nozzles on the ICDs resulted in production with significantly less water cut compared to other wells in the field that were completed conventionally. The complimentary effect of optimal well placement with pressure compensated ICD completion design has improved production from Khafji sand stringers with marked decrease in water production.
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Integrating Technology and Resources - Optimizing Clastic Reservoir Exploitation
Authors J.C.L. Kok, Y.H. Shim, M. Bouchard and R. NeuschaeferEarly clastic-reservoir field-development practices involve commingled production across several stacked reservoir units. This commonly leads to early high water production as clean sandstone reservoirs generally exhibit strong bottomwater drive. In most cases, the wells are prematurely shut-in leaving behind valuable reserves. Today, horizontal wells are a well-recognized methodology to improve hydrocarbon recovery by maximizing reservoir contact. However, water breakthrough is not isolated in horizontal wells due to water coning from imbalanced lateral fluid drawdown. In practice, flow rate are increased to maintain production economics. Along with high water handling and correspondingly low hydrocarbon recovery, operators are oftentimes discouraged from pursuing such ventures. It becomes apparent that for effective exploitation, horizontal wells must be placed as far as possible from the OWC. Developments in logging-while-drilling technology have enabled accurate well placement below the reservoir trap while mapping OWCs. Completion technologies can be introduced to delay or to regulate water breakthrough. While these technologies individually adds value to horizontal well production, in combination, they can be customized to enhance recovery and prolong the life span of a well; effectively achieved by strategic planning with simulations, realtime geosteering well designs and integrating postjob well-placement results to completion-optimization workflows.
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Future Deep Directional Resistivity Answer Products Challenges Established Interactions Between the Operator and the Service Company
Authors F. Antonsen, P.A. Olsen and M.V. ConstableThe new deep directional resistivity tool developed by Schlumberger has a depth of investigation of factor 5-10 deeper than the standard type of directional bed-boundary mapping tools. The deep EM-measurement is clearly a very central puzzle piece in bridging the gap between standard LWD-measurements, reservoir scale geologic features and surface seismic. There will be a strong push from operators to use this new data not only for well placement challenges, but also for reservoir characterization (Constable et al. 2012). However, we must remember that deep EM-measurements are relatively new in the industry. Still, we already discuss how to push the envelope beyond the challenge of optimizing well placement. There is a high risk of over-interpretation when we start to push the envelope based on limited knowledge.
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Enriching the Static Earth Model through a Near-wellbore Structural Modeling Workflow Combining all Horizontal Well Data
The static earth model is the centrepiece of field development, from initial reserves evaluation to well planning to production and recovery optimization. Also, the static model is most often the main source of information into the well placement pre-job model. However, while it was always agreed that the findings of a well placement job should be used to refine the original model, up until now, enriching the static model was not offered as a mature service by the providers of geosteering solutions and interpretation. This paper and presentation introduces a new workflow combining LWD information from borehole images and deep boundary mapping services (possibly from several wells in an area) into a near-wellbore 3D structural model supporting all available data. The 3D near-wellbore structural model workflow is an important contribution to workflows closing the loop from horizontal logging and well placement back to the reservoir model update.
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Biosteering in Margham Field, Onshore Dubai - A Case Study on Significant Updating of the Static Model During a UBCTD Campaign
Authors A. Henderson and P.R. MarshallFollowing successful introduction to the Middle East of underbalanced, coil tubing drilling, with biosteering (use of microfossils from cuttings samples to identify individual layers within the reservoir succession by reference to field-specific zonation schemes) as the geosteering method of choice, a campaign was planned for 2006 in the Margham Field, onshore Dubai. The field, discovered in 1982, had been developed by means of conventional drilling of 17 vertical and 2 deviated wells into Lower Cretaceous carbonate reservoirs over a period of more than 20 years. From the outset, it had been understood that the field was tectonically and structurally complex, forming part of the arc of thrustaffected structures that occur to the west of the Oman Mountains. Conventional biostratigraphy had assisted in early interpretation of major faulting in the Tertiary and Upper Cretaceous sections above the reservoirs, but seismic resolution was unable to clarify any degree of faulting within the Lower Cretaceous.
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New Technologies for Well Placement in Complex 3D Scenarios and Full Integration with Geo-models
Authors D. Omeragic, V. Polyakov, C. Dupuis, Y. Chen, B. Brot, S. Shetty, T. Habashy, T.L. Flugsrud and T.L. FlugsrudWe present enabling technologies for well placement in 3D scenarios: advanced modelling and inversion framework needed to interpret the data in complex scenarios, ran on demand as a service on Grid computing infrastructure and fully integrated with reservoir geo-models.
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Advanced Geosteering on Example South Tambey Field
Authors M. Sharov, E. Bondarev and O. LeontyevaNow possibilities of new approaches in geosteering application for drilling horizontal wells are studied. As it is widely known already, the modern technological instruments allows to carry out azimuthally three-dimensional measurements in a well, being focused on definition of structural elements of a bedding of layers and measurement of distances to layer boundaries in real time. Information received during drilling together with its structural and petrophysical interpretation allows trying new approach which can possible to call three-dimensional geosteering.
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Multiple Approaches of Geosteering and Well Placement
By M. SarrajOptimum development plans for major oil and gas fields require solid integrated subsurface description. Defining geological, petrophysical, reservoir engineering, and drilling uncertainties is essential to select the optimal development concept for reservoir depletion plan. Hence, well placement and geosteering of injector/producer horizontal wells has a significant impact on maximizing reservoir contact and thus exploit productivity and sustainability of new delivered wells.
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LWD and “DTB” Technology Pushing Subsurface Understanding beyond Conventional Limits in a Heavy Oil Belt, India
Authors C.J. Keot, P.K. Dubey, N. Sanjay Kumar, A. Walia, N.S. Rao, A.K. Singh and R.R. KumarThe northern part of Cambay basin, western India, is characterized by a heavy oil belt. A thermal EOR method widely known as In-situ Combustion (ISC) was adopted in this belt to enhance oil recovery. To capture EOR displaced oil and also to improve primary recovery, horizontal wells are being planned and drilled for last 8 years in this belt. Initially horizontals were drilled with MWD technology only but in 2011, LWD technology was introduced. A primary driving force for this technology switch was to use LWD data in real time to understand the nature of flue gas distribution and complex structural features in these fields. Additionally for drain hole sections, “Distance to Boundary” (DTB) technology was adopted for proactive navigation. LWD data from 7 infill horizontal wells drilled in this belt provided important information on flue gas saturation and distribution across these fields. This information was used to place drainholes sufficiently below the flue gas saturation level to avoid premature gassing out of wells.The use of “DTB” technology in drainhole improved well productivity owing to better controlled placement in the sweet zone. The gamut of information provided by LWD and DTB technology has comprehensively helped in better planning and recovery.
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Horizontal Well Placement in Thin Shallow Reservoir Sands for Heavy Oil Fields Development
Authors E. Rojas, J. Velasco, A. Salamanca, D. Romero and A. LeguizamonAfter a successful development campaign of Girasol heavy oil field through horizontal wells with more than 90 wells drilled and completed, the efforts and experience of the operator was directed to the development of other assets like Abarco and Under River fields. The fields are located in Colombia Middle Magdalena Valley basin and share a sequence of sandstone channels which were deposited in a fluvial environment associated to braided and meandering streams. The main target sands are located at 1,100 to 1,600 ft true vertical depth, their thicknesses range from 10 to 30 ft. and contain 11 to 13 °API oil. To maximize production, horizontal trajectories of up to 2,600 ft long, equally spaced and laterally parallel have been placed in up to five target sands from a clusters arrangement to minimize environmental impact and to develop the reservoir below the Magdalena River. Well placement under this geologically complex scenario is, in general, difficult to achieve with the use of conventional geosteering techniques, as they generally fail to identify unexpected changes in the reservoir geometry. This risk is minimized by using deep, directional electromagnetic measurements while drilling, allowing a reservoir geometry mapping in real- time, several feet from the borehole.
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Potential Improvements for Geosteering
By H.M. BandahGeosteering pioneers started with basic technologies for well placement. In the early days, several challenges were handled individually without integrating different sources of data, which reflected negatively on the final results. Today, there have been many improvements with geosteering technologies. Yet these technologies that are being used for geosteering have some technical limitations. For example, some tools are positioned behind the bit by more than 40 feet. Besides that, integrating these technologies remains a major challenge. Also, available computer applications are limited in their capabilities to incorporate real-time subsurface data into a 3D geological model. In this paper, four ideas will be considered as potential improvements for geosteering in the future.
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Successful Approach to Push ERD Limit, Enhance Production, and Optimize Reserve Recovery of an Extended Reach Oil Field
Authors S.B. Amarjit, Z. Xiaoping, H. Yingshi, T.B. Tran, P. Halomoan and J. DenichouAn operator in offshore South China planned to develop a new field comprising multiple thin oil-bearing zones. It was decided to develop the field by upgrading an existing drilling rig on a platform rig 6 km away to drill extended reach horizontal wells. The objective was to place long lateral drains in a thin-pay reservoir. However, the foreseen high drilling torque risk within the backdrop of the drilling rig that has maximum 42,000 llbf drilling torque capacity may limit this option. In addition, subsurface challenges may highly constrain the ability to access the target reservoir optimally for production and reserve recovery optimization. This paper features successful approach using the latest Logging-While-Drilling (LWD) technology and Geosteering technique to overcome extended reach horizontal wells drilling challenges – executed under limited drilling rig capacity and highly subsurface uncertainties. The efforts described are performed in real-time while drilling and aim to place the well optimally along the thin pay zone by delineating and mapping the top and bottom pay zone boundaries simultaneously. With this ability, the lateral can be placed accurately without making unnecessary trajectory adjustment that can result in additional drilling torque.
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Proactive DTB Geosteering Technique Deliver Excellent Result in Lower Burgan Thin Channel Sand Reservoir-North Kuwait
Authors H. Haddou, S. Chowdhuri, N. Abbas, A. Khan, A.G. Tarek, M. Juyal, M. Wenang, S. Noreldeen and P. ChakrabortyDrilling of development wells in the Burgan sands involves very thin and sinuous targets. These targets are the channel sand stringers and contain a substantial amount of hydrocarbons. Optimal well placement is required to drain them in a cost effective manner. Conventional well placement has met with limited success in stringers and thus resulted in low production figures. This led to the introduction of Schlumberger’s distance to boundary mapping tool in Kuwait which has proven consistently that a proactive well placement technology can be translated into maximum reservoir contact, minimum well-bore tortuosity and a facilitator for optimal production. Due to the uncertainty that is inherently present in the distribution of the channel sands, the prediction of the azimuth of channel meander can now be confidently solidified with new deep and directional electromagnetic measurements. By detecting the upper and lower conductive shale boundaries the wells can be steered in this very challenging environment of channel sands. This well was successfully drilled using the distance to boundary mapping tool and the production test resulted above 5700 BOPD which is almost 100% above the expected production rate. This paper has also been submitted for the forthcoming SPE, KOGS conference during October, 2013, in Kuwait.
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ONGKM Field Development with Well Placement by High Resolution Data at Carbonate Environment
Authors G.P. Grebenyuk, D.M. Eremeev and A. BelyaevGeosteering of the first wells in this field was based on basic methods, neverthelesschangescamewith experience. At the end of 2012, in addition to the induction resistivity and gamma ray, was used Well Placement service based on Azimuthal Density Neutron tool& density image interpretation. Final result was significantly improved. However, this experience has allowed to allocate another shadedpoint– definition of fracturing & cavernous zones, related to filtration properties of the productive layer.In 2013 under pilot industrial activities in this field forfracture zones identificationswhile drilling one of the best service company introduced a well-placement& borehole geologyinterpretationusinglaterolog system that provides both high resolution resistivity and images. This service perfectly accomplished the task in carbonate environment of ONGKM. Post well interpretation of resistivity images allow to update static model with sub seismic faults & fracture development.
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Real Time Stratigraphy: Improving Placement of High Angle Wells using INPEFA Log Transform Correlation in Carbonates
Authors J.G. Koopmans, S.D. Nio, H. Abdul Aziz, J. Hall and M. JasserWe present a real time log processing workflow that allows confident placement of wells, especially in complex carbonate depositional sequences, by exploiting a wealth of stratigraphic information present in conventional logging data. The workflow is based on the spectral analysis of data logs that identifies a hierarchy of sedimentary cycles, controlled by orbitally forced climate change. The INPEFA Log Transform (INPEFA), which is the key process in this workflow, mathematically analyses composite waveforms consisting of various amplitudes, phases and frequencies. Geologically, INPEFA is able to predict lithofacies variability, stratigraphic discontinuities and genetic relationship of depositional sequences. Application of the INPEFA workflow to real time stratigraphy provides a framework to interpret stratigraphic sequences while drilling. The benefits of this workflow includes optimal well placement and drilling operations by using a simplified Bottom Hole Assembly (BHA) solution permitted by minimalised logging requirements. This enables operators to make fast decisions during geosteering, save costs on logging equipment and obtain a higher Dogleg Severity (DLS).
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Using Inversion of Extra-deep Resistivity Data in High-angle Wells
More LessThe ability to look deeper around the well-bore using EM induction measurements is very beneficial for proactive geosteering and optimal well placement. A deeper reading tool leads to an increase in complexity of the data and models involved. Inversion becomes a necessity in resolving multi-layer formation parameters from multi-component LWD resistivity measurements. In this paper we consider the application of advanced inversion software to common tasks in geosteering and while drilling formation evaluation with an extra-deep resistivity tool. A field case study is presented.
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