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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
1 - 20 of 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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