Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
A Comprehensive Theoretical and Experimental Study on Fluid Displacement for Oilwell-Cementing Operations
Aranha, Pedro Esteves (Petrobras) | de Miranda, Cristiane Richard (Petrobras) | Cardoso, Walter F. (Petrobras) | Campos, Gilson (Petrobras) | Martins, Andrรฉ Leibsohn (Petrobras) | Gomes, Frederico C. (Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio)) | de Araujo, Simone Bochner (Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio)) | Carvalho, Marcio S. (Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio))
Summary Displacing fluids in downhole conditions and for long distances is a complex task, affecting several steps of well construction. Cementing gains relevance the moment that fluid contamination compromises cement-sheath integrity and consequently zonal isolation. Density and rheology design for all the fluids involved is essential to achieve operational success. Properties hierarchy and preferred flow regimes have been empirically defined and tend to provide reasonable generic results. Challenging operations, including ultradeep waters and their narrow operational-window scenario, require further knowledge of the physics involved to prevent undesirable events. This paper presents the in-house development of software for annular miscible fluid displacement that analyzes fluid displacement in typical vertical and directional offshore wells, for Newtonian and non-Newtonian liquids and laminar- and turbulent-flow regimes. The formulation proposed provides accurate results for a wide range of input parameters, including the cases in which the ratio of the inner radious to the outer radius of the annulus is small. The computational work is validated by unique results obtained from an experimental test rig where detailed displacement tests were conducted. Contamination degrees were measured after the displacement of a sequence of fluids through 1192 m of vertical well. Effect of fluid-density and rheology hierarchy, flow regimes, and displacement concepts was investigated. The results provide relevant information for the industry and fundamental understanding on displacement of Newtonian and non-Newtonian liquids through annular sections.
- North America > United States (1.00)
- South America > Brazil (0.96)
- Research Report > New Finding (0.40)
- Research Report > Experimental Study (0.40)
- Reservoir Description and Dynamics (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (0.93)
- Well Drilling > Casing and Cementing > Cement formulation (chemistry, properties) (0.88)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (0.70)
Summary For multistage hydraulic fracturing of horizontal wells with cased-hole completion, multiple perforation clusters are used typically to create multiple fractures in any single stage. How to place these perforation clusters is a critical issue because the number of perforation clusters to be used and the space between them significantly impact how effectively the fractures can be created in the formation. To optimize the spacing of perforation clusters, stress distributions and fracture mechanics need to be well understood. In this study, the displacement-discontinuity method is used to construct a boundary-element model, which is able to analyze the stress distributions around multiple transverse fractures and the geometries of those fractures. With the boundary-element model, multiple cases are investigated for a different number of fractures and fracture spacings. Changes of both minimum and maximum stresses and shear stress around these fractures are illustrated first. It is found that for the cases with more than two parallel fractures, there is a strong stress concentration around the center fractures. The calculated displacements indicate that the created fractures are no longer elliptic-like, and the widths of the center fractures are reduced significantly compared with those of a single fracture. For the case of two parallel fractures, the stress concentration between two fractures also results in asymmetrical fracture shape, but the fracture widths are not reduced significantly. This study indicates that the number and spacing of the fractures need to be selected carefully to create effective fractures with appropriate fracture geometries. The boundary-element model provides a useful tool to relate rock geomechanic properties to stress distribution and fracture geometries for multiple fractures in hydraulic fracturing of horizontal wells, which can be used as a guide to space the perforation clusters.
- Europe (1.00)
- North America > United States > Texas (0.28)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.41)
- North America > United States > Oklahoma > Anadarko Basin > Cana Woodford Shale Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > Central Graben > PL 018 > Block 2/4 > Greater Ekofisk Field > Ekofisk Field > Tor Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > Central Graben > PL 018 > Block 2/4 > Greater Ekofisk Field > Ekofisk Field > Ekofisk Formation (0.99)
- North America > United States > Texas > Permian Basin > Martin Field > Ellenburger Formation (0.93)
SEAM Phase I RPSEA is progressing on schedule toward a completion date of the end of June 2013. Several activities are ongoing as multiple data sets are simulated, compiled, or contracted for simulation. This report is an update on the status of the simulations being conducted on the SEAM Phase I Deepwater Model. A complete listing of the parameters for all simulations on the SEAM Phase I Deepwater model was given in the May 2012 issue of The Leading Edge. Funding for the expanded simulations is provided by the Research Partnership to Secure Energy for America (RPSEA subcontract No. 07121โ2001).
With high-permeability hydrocarbon reservoirs exhausting their potential, developing low-permeability reservoirs is becoming of increasing importance. In order to be produced economically, these reservoirs need to be stimulated to increase their permeability. Hydraulic fracturing is a technique used to do this. A mixture of water, additives, and proppants is injected under high pressure into the subsurface; this fluid fractures the rock, creating additional pathways for the oil or gas. Understanding the nature of the resulting fracture system, including the geometry, size, and orientation of individual fractures, as well as the distance from one fracture to the next, is key to answering important practical questions such as: What is the affected reservoir volume? Where should we fracture next? What are the optimal locations for future production wells?
Impact and Lessons of Using High Permeability Streaks in History Matching a Giant Offshore Middle East Carbonate Reservoir
Brantferger, K. M. (Zakum Development Company (ZADCO)) | Kompanik, G. S. (Zakum Development Company (ZADCO)) | Al-Jenaibi, H. M. (Zakum Development Company (ZADCO)) | Dodge, W. S. (Zakum Development Company (ZADCO)) | Patel, H.. (Zakum Development Company (ZADCO))
Abstract A new generation geologic model for a giant Middle East carbonate reservoir was constructed and history matched with the objectives of creating a model suitable for full field prediction and sector level drill well planning. Several key performance drivers were recognized as important factors in the history match; 1) unique carbonate fluid displacement; 2) data validation and horizontal well trajectory issues; and 3) distribution of high permeability streaks. Ultimately a full field history match consisting of more than 1000 well strings and several decades of history was achieved using detailed distribution of the high permeability streaks, while honoring measured core poro-perm relationships, lab-validated displacement curves, and well test data. This paper discusses the role of the geometry and the vertical distribution of the high-permeability streaks in the history matching of a giant offshore carbonate reservoir. Specifically, the modeling of the high-permeability streaks โ which consist of thin rudist and algal rudstone, floatstone, and peloidal grainstone, with abundant, well-connected inter-particle porosity - became possible after extensive revamping of the reservoir rock type model, updating well descriptions, and a detailed zonal mapping of the high permeability streaks and dolomitic zones. The areal and vertical model resolution was doubled over the previous models to accommodate the internal sub-layering of the upper four reservoir zones in order to capture the thin (~1.4 ft) high-permeability streaks. During the history match, local modifications of the high-permeability streaks were the integral part of the feedback loop between the simulation engineers and geoscientists that kept the common-scale simulation model and geologic model synchronized. The final history match was validated by extensive analysis of the modelsโ vertical conformance as compared to production logs. This approach made it possible to construct a more heterogeneous model than previous models; while honoring both field KH and matrix poro-permeability without local permeability multipliers. The combination of these features provides a higher confidence model of long term well injectivity/productivity.
Abstract Some of the most active and high profile hydrocarbon plays currently being explored and developed around the world lie below a salt canopy. Drilling through a thick salt canopy has the potential to provide a faster route to reach a sub-salt objective rather than drilling through the overpressured sedimentary section in a supra-salt mini-basin. Unfortunately, numerous geological factors can complicate the drilling leading to expensive sidetracking or casing operations. Wellbore stability problems, such as unexpected low fracture gradient, are relatively common while drilling close and out of salt structures. Significant savings on drilling costs can be made if potential wellbore stability problems could be identified and avoided in the well planning process. In this paper we present a workflow to improve wellbore stability predictions for drilling through and near salt structures. Common assumptions in wellbore stability studies on stress magnitude and orientation are not valid while drilling close to a salt body as salt structures create, due to their shape and rheological behavior, a perturbation of the stress field with strong spatial variation of the principal stress magnitudes and orientations. To provide realistic stress input data for wellbore stability predictions, the stress fields around salt structures are simulated using non-linear materials and realistic 3D geometries. The workflow presented in this paper provides an efficient way to create realistic 3D finite-element based geomechanical simulations from these complicated structural data. The workflow allows for a detailed simulation of the stress field around salt bodies that is new to the hydrocarbon industry and helps to significantly reduce the risk for wellbore failures of increasingly costly wells drilled to exploit, e.g., sub-salt plays in the Gulf of Mexico and offshore Brazil.
- Europe (0.95)
- North America > United States (0.67)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.48)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (1.00)
- Geophysics > Borehole Geophysics (1.00)
- South America > Brazil > Campos Basin (0.99)
- South America > Brazil > Brazil > South Atlantic Ocean (0.89)
- North America > Cuba > Gulf of Mexico (0.89)
Abstract Ocean Bottom Cable (OBC) seismic survey has several technical advantages over conventional towed streamer technique. However, its usage is still limited as requirement of relatively large operational efforts likely results in more survey cost and duration. Moreover, OBC seismic operations could affect other field activities and multi-vessel operations required for OBC survey and longer survey duration potentially increase HSE risks in fields. Consequently, enhancement and optimization of OBC survey productivity is essential particularly in specific situations such as shallow water, congested producing oil/ gas fields (e.g. Offshore Abu Dhabi) and in environmentally restricted areas. Although several studies have been carried out to establish key parameters, designs and geometries for high OBC survey productivity, the current developments in the seismic industry technology and equipment are enabling to establish a variety of survey designs and geometries which were not feasible previously. Therefore, our study was conducted with the aim to analyze the impact of OBC Survey Designs / Geometries on productivity considering the current available equipment and technology and meeting the established geophysical survey objectives. Applications of dual source operations were also discussed by using two cases: (1) Distanced Separated Simultaneous Shooting (DS3); and (2) Dual Source Vessel Flip-Flop Shooting (DSVFFS). Dual source operations for both marine streamer and land cases have been well described whereas few examples of its applicability to OBC survey have been presented. In this paper, we described the impact of dual source operations on OBC survey efficiency and technical challenges determined from the relationship between OBC Survey Geometries/Designs and interference noise wave fields which have to be considered as more complex scenario than other types of surveys. We believe that the established new approach will assist to acquire future OBC survey with high productivity and in a very cost effective manner.
Abstract Chronostratigraphic seismic interpretation provides insights into basinal evolution. By mapping the internal stratigraphic architecture, this method has been widely used for well placement optimization and reservoir model building. Over many years of research at TOTAL, the Sismage team has created GeoTimeโข, a software tool for automatic chronostratigraphic analysis of seismic data, particularly in complex geological settings. This tool can be used to automatically or semi-automatically track the chronostratigraphic surfaces. The output is a 3D cube of stratigraphic surfaces (iso-geological time) which can be used to build the frame work for geomodels. A 3D cube of "Wheeler Diagram" is also obtained by segmenting the seismic volume into different depositional or non-depositional packages. This diagram provides better understanding on the spatial distribution of deposition through the geological time. In this paper, we will firstly introduce the GeoTimeโข methodology, and then demonstrate two application examples. The first example is taken at a regional scale, where GeoTimeโข was used to automatically track the major stratigraphic surfaces within a first order progradation system. The seismic volume was then segmented into sub order sequences bounded by the automatically tracked surfaces. 3D Wheeler diagram was also constructed to understand the depositional history. The second example is taken at reservoir scale from a producing field with more than 800 borehole penetration. In this example, we imposed geological constraint into the GeoTimeโข workflow, and improved the previous interpretation of higher order prograding clinoforms for placing new development wells.
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Interpretation (1.00)
Conceptual Structural Model of an Onshore Carbonate Hydrocarbon Field in Abu Dhabi: Constraints and Implications
Sirat, Manhal (Abu Dhabi Company for Onshore Oil Operation (ADCO), UAE) | Mahmoud, Sabry L. (Abu Dhabi Company for Onshore Oil Operation (ADCO), UAE) | Popa, Desdemona Magdalena (Abu Dhabi Company for Onshore Oil Operation (ADCO), UAE) | Koyi, Hemin (Uppsala University, Sweden)
Abstract A carbonate field in Onshore Abu Dhabi is characterized by its complicated structural setting, which involves basement tectonics. A new seismic attributes analysis has been conducted to reveal the structural style, and to identify significant lineaments representing possible major and minor faults. Based on this analysis, a conceptual model is presented, which reveals the development mechanism of the major structure and associated faults. Structural constraints such as lineaments length, faults throw and displacements are strongly related to the seismic resolution constraint. Whereas timing of the structural development events represents a challenge and needs to be linked to sedimentation and sequence stratigraphic framework and thus needs further study. In total, six fracture sets have been identified including the N75W, N45W, NS, EW, NE-SW and N70E. The Conceptual structural model shows that the contractional structure has been modified as a giant positive flower structure-like associated with a basement strike slip fault. At least two major longitudinal faults bound the structure parallel to its fold axis (NE-SW), which pose sigmoidal map geometry. There are numerous transverse faults linking and/or cross cutting those longitudinal faults creating andulations that may define new minor plays. Significant implications of this study include better understanding of the regional structural geology of Abu Dhabi, and define new plays within the studied structure. In addition, the new identified fracture system provides essential information for the ongoing and future development plans for this field and for other fields in the region with similar structural settings.
- Phanerozoic > Cenozoic (0.93)
- Phanerozoic > Mesozoic > Cretaceous > Upper Cretaceous (0.71)
- Phanerozoic > Mesozoic > Cretaceous > Lower Cretaceous (0.68)
- Phanerozoic > Paleozoic > Permian (0.68)
- Geology > Structural Geology > Tectonics > Plate Tectonics (1.00)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (1.00)
- Geology > Structural Geology > Fault (1.00)
- Geology > Geological Subdiscipline (1.00)
- Geophysics > Seismic Surveying > Seismic Interpretation (0.89)
- Geophysics > Seismic Surveying > Seismic Processing (0.70)
- Asia > Middle East > Iraq > Zagros Basin (0.99)
- Asia > Middle East > Iran > Zagros Basin (0.99)
- Asia > Middle East > UAE > Abu Dhabi > Arabian Gulf > Rub' al Khali Basin > Abu Dhabi Field (0.97)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Faults and fracture characterization (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Copyright 2012, Society of Petroleum Engineers This paper was prepared for presentation at the Abu Dhabi International Petroleum Exhibition & Conference held in Abu Dhabi, UAE, 11-14 November 2012. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright. Abstract We introduce a 3D ocean bottom cable (OBC) seismic survey design flow with the so-called focal beam method for finding the optimum acquisition geometry to satisfy geophysical requirements. This method is based on the so-called common focus point (CFP) technology, and it is a subsurface oriented and target oriented approach, making it possible to quantitatively analyze sought-after attributes, such as potential resolution and pre-stack amplitude fidelity, for one or more gridpoints in the subsurface of a given acquisition geometry.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)