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Collaborating Authors
Oklahoma
Special Considerations in the Design Optimization of the Production Casing in High-Rate, Multistage-Fractured Shale Wells
Sugden, C.. (Blade Energy Partners) | Johnson, J.. (Exco Resources) | Chambers, M.. (Exco Resources) | Ring, G.. (Blade Energy Partners) | Suryanarayana, P.V.. V. (Blade Energy Partners)
Summary Typical shale well completions involve massive, multistage fracturing in horizontal wells. Aggressive trajectories (with up to 20°/ 100 ft doglegs), multistage high-rate fracturing (up to 20 stages, 100 bbl/min), and increasing temperature and pressure of shale reservoirs result in large thermal and bending stresses that are critical in the design of production casing. In addition, when cement voids are present and the production casing is not restrained during fracturing, thermal effects can result in magnified load conditions. The resulting loads can be well in excess of those deemed allowable by regular casing design techniques. These loads are often ignored in standard well design, exposing casing to the risk of failure during multistage fracturing. In this work, the major factors influencing normal and special loads on production casing in shale wells are discussed. A method for optimization of shale well production casing design is then introduced. The constraints on the applicability of different design options are discussed. Load-magnification effects of cement voids are described, and a method for their evaluation is developed. Thermal effects during cooling are shown to create both bending stress magnification and annular pressure reduction caused by fluid contraction in trapped cement voids. This can result in significant loads and new modes of failure that must be considered in design. The performance of connections under these loads is also discussed. Examples are provided to illustrate the key concepts described. Finally, acceptable design options for shale well production casing are discussed. The results presented here are expected to improve the reliability of shale well designs. They provide operators with insight into load effects that must be considered in the design of production casing for such wells. By understanding the causes and magnitude of load-augmentation effects, operators can manage their design and practices to ensure well integrity.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Petroleum Play Type (1.00)
- North America > United States > Texas > Haynesville Shale Formation (0.99)
- North America > United States > Texas > Fort Worth Basin > Barnett Shale Formation (0.99)
- North America > United States > Oklahoma > Arkoma Basin > Cana Woodford Shale Formation (0.99)
- (5 more...)
- Well Drilling > Casing and Cementing > Casing design (1.00)
- Well Completion > Hydraulic Fracturing > Multistage fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale oil (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale gas (1.00)
An Innovative Approach for Pore Pressure Prediction and Drilling Optimization in an Abnormally Subpressured Basin
Contreras, Oscar (Schulich School of Engineering, University of Calgary) | Hareland, Geir (Schulich School of Engineering, University of Calgary) | Aguilera, Roberto (Schulich School of Engineering, University of Calgary)
Summary Thus far, an indirect generalized method to predict pore pressure under subpressured conditions has not been reported in the literature. In this work, an innovative procedure is presented for estimation of pore pressure and optimization of wells drilled in the abnormally subpressured Deep Basin of the Western Canada Sedimentary Basin (WCSB). The procedure starts with detailed evaluation of five wells drilled in a township that covers the study area. Pore pressure was calculated from sonic logs and the modified D exponent by the use of Eaton's method (Eaton 1975), which proved to be the most effective approach for abnormally subpressured conditions over a variety of methods tested (Contreras et al. 2011). The optimization procedure was carried out by use of the apparent-rock-strength log (ARSL), which is an effective indicator of formation drillability and is very sensitive to the pore pressure. Next, optimization of individual sections in each well was carried out to determine the optimum types of bits and operational parameters for the lowest cost of drilling. An artificial-intelligence function was implemented to set up the optimum combination of parameters in such a way that the rate of penetration (ROP) (m/h) was increased after a number of simulation runs while controlling the bit wear. Special attention was focused on tight gas reservoirs for selection of the most suitable parameters that increase the quality of drill cuttings. It was concluded that the roller-cone bit IADC 547 (with at least 0.73 hp in the bit per square inch) provides the best-quality cuttings for the Nikanassin Group. This is of paramount importance for increasing accuracy in the quantitative determination of permeability and porosity from cuttings particularly in those tight gas reservoirs where the amount of cores is very limited. It is concluded that wells in the Deep Basin of the WCSB can be drilled efficiently with seven bit runs while maintaining the cuttings quality, bit-wear level, and well stability at a significantly high average ROP of 13 m/h. Another conclusion is that the normal trend methods from sonic logs are the most effective approach when dealing with an abnormally subpressured basin.
- North America > Canada > British Columbia (1.00)
- North America > Canada > Alberta (1.00)
- North America > United States > Oklahoma > Anadarko Basin > M Formation (0.99)
- North America > Canada > British Columbia > Western Canada Sedimentary Basin > Alberta Basin > Deep Basin (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Deep Basin (0.99)
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)
Abstract In iceberg prone regions, subsea substructures placed on the seabed are atrisk of impacts from free-floating and scouring iceberg keels. Here themethodology for assessing iceberg loads and two mitigation strategies aredescribed. The iceberg load model was an extension of previous work forestimating iceberg impact loads on offshore surface-piercing structures. Components of the algorithms were modified such that global design loads fromkeel contacts account for the change in contact location (i.e., longer leverarm in the vertical direction resulting in greater rotation effects). Theiceberg eccentricity model and the relationship between contact area andpenetration distance were also modified to account for iceberg keel contactswith a generic low profile structure on the seabed. One concept considered wasa single wellhead structure fitted with a special weak shear link incorporatedinto the design at the expected scour level. The shear link, or failure joint, would act as a mechanical fuse designed to fail in a combination of shear, tension and buckling during keel loading. The failure joint minimizes downholestructural response during iceberg keel loading on the production tree. Thedesigned failure mechanism would allow the well to be re-entered by protectingthe well casing from damage. Another concept considered was a steel truncatedcone structure installed over the well installation and fixed to the seabed byone of several identified foundation concepts. The protection structure absorbsenergy through crushing of the ice keel and encourages the iceberg to deflectaround and over the structure. The steel structure would be designed accordingto ultimate limit states accounting for energy absorption through elastic andplastic deformation of the structure. Design loads would correspond to anAbnormal Level Ice Event (ALIE) with an annual exceedance probability of 10–4. The size of the frame is governed by the size of the wellhead and tree system, Remotely Operated Vehicle (ROV) access requirements, and slope to encourageiceberg keel deflection. Piles may be the best option for securing a protectionstructure to the seabed, especially if a local vessel can be sourced to performthe installation. As an alternative to piles, using a drill rig to install wellcasings may be an option; however, market conditions for drilling rigs maydictate economic feasibility.
- North America > United States (1.00)
- North America > Canada > Newfoundland and Labrador > Newfoundland (0.29)
- North America > Canada > Newfoundland and Labrador > Newfoundland > North Atlantic Ocean > Atlantic Margin Basin > Grand Banks Basin > Jeanne d'Arc Basin (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Carter Field (0.93)
- North America > Canada > Newfoundland and Labrador > Newfoundland > North Atlantic Ocean > Labrador Shelf Basin (0.89)
- North America > Canada > Newfoundland and Labrador > Newfoundland > North Atlantic Ocean > Grand Banks Basin (0.89)
Welcome to the second half of TLE's two-part special section on passive seismic and microseismic. This month, we focus again on monitoring hydraulic fracturing with microseismic with five articles, but also expand beyond “micro” seismicity, to include unintended “induced” seismicity that may occur during injection. Five articles in this special section focus on induced-seismicity topics. In this introduction, we will highlight various issues related to undesired induced seismicity which may be caused by hydraulic fracturing and deep, underground salt water disposal.
- North America > United States > Texas (0.49)
- North America > United States > Oklahoma (0.47)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Texas > Fort Worth Basin > Barnett Shale Formation (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Eola Field (0.99)
- North America > United States > Colorado > Raton Basin (0.99)
- (12 more...)
The potential for induced seismicity in energy technologies
Shemeta, Julie E., Eide, Elizabeth A., Hitzman, Murray W., Clarke, Donald D., Detournay, Emmanuel, Dieterich, James H., Dillon, David K., Green, Sidney J., Habiger, Robert M., McGuire, Robin K., Mitchell, James K., Smith, John L. (Bill), Ortego, Jason R., Gibbs, Courtney R.
The great majority of earthquakes that occur each year around the world have natural causes. A small number of lesser-magnitude seismic events have been related to human activities and are called “induced seismic events” or “induced earthquakes” (NRC, 2012). Of concern are induced events that are large enough to be noticed by the public, typically events larger than magnitude 3 (note the range earthquake sizes that are felt can widely vary depending on project location and site characteristics). Induced seismic activity has been described since at least the 1920s and attributed to various human activities including the impoundment of water reservoirs, controlled explosions related to mining and construction, underground nuclear tests, and energy technology developments that involve injection or withdrawal of fluids from the subsurface. Historically known induced seismicity has generally been small in both magnitude and intensity of ground shaking.
- North America > United States > Texas (0.94)
- Europe (0.68)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.69)
- North America > United States > Texas > Permian Basin > Cogdell Field > Fuller Sand Formation (0.99)
- North America > United States > Texas > Permian Basin > Cogdell Field > Area Formation (0.99)
- North America > United States > Texas > Fort Worth Basin > Barnett Shale Formation (0.99)
- (6 more...)
China's Early Stage Marine Shale Play Exploration: A Deep Asia Pacific Region Horizontal Multiple-Stage Frac: Case History, Operation, and Execution
Lv, Zonggang (PetroChina Southwest Oilfield Southern-Sichuan Branch) | Wang, Lin (PetroChina Southwest Oilfield Southern-Sichuan Branch) | Deng, Sufen (PetroChina Southwest Oilfield Southern-Sichuan Branch) | Chong, King Kwee (Halliburton) | Wooley, James S. (Halliburton) | Wang, Qiang (Halliburton) | Ji, Peng (Marks) (Halliburton)
Abstract During the past five years, shale gas developments have changed the game for the US natural gas industry. Globally, shale exploration activities are also increasing. China is in the early stages of exploiting the world's largest reserves of shale gas resources while attempting to cope with increasing energy demands. This paper presents a case history of applicable technology currently used in North America for initial attempts at shale gas exploration in China. This case study is the first Cambrian age marine shale well in the Qiongzhusi formation located in the shale-gas-rich Sichuan province. Many technologies were brought from North American shale gas applications for this well (Chong et al. 2010). This study describes the technologies used to drill and complete the targeted shale gas formation and guide the completion and stimulation design. The target formation was drilled horizontally and the casing was cemented. The formation was then stimulated with multiple stages after full integration of data from geologic, geomechanical, petrophysical, and core analysis, which aided in the fluid and proppant selection, proppant concentration, and the designed injection rate. A diagnostic fracture injection test (DFIT) was performed before the main treatment to confirm fracture gradient, closure, pore pressure, system permeability, and leakoff. Microseismic mapping was also used, which proved to be valuable when planning and assessing the fracturing results. Currently, the well is flowing gas at rates comparable to early production time in a typical North American shale gas well with a similar type of completion. This case study serves as an example of successful implementation of proven technology outside of the North America shale gas market. Continued projects such as this one are the predecessor to full-scale development of shale gas and have helped shape the abundant gas supply currently in the United States. Additionally, these types of projects are necessary to help China improve their future outlook on gas supply.
- Asia > China > Sichuan Province (0.89)
- North America > United States > Texas (0.68)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Microseismic Surveying (0.68)
- North America > United States > Texas > Haynesville Shale Formation (0.99)
- North America > United States > Texas > Fort Worth Basin > Barnett Shale Formation (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Cana Woodford Shale Formation (0.99)
- (6 more...)
Abstract During the past six years, the technology for shale gas/oil developments in North America has seen many improvements and optimizations as the industry experiences a sharp rise in the contribution of hydrocarbons from these resources. More recently, Europe and Australia have joined the US in expanding recoverable hydrocarbons from these unconventional resources, and initial activities are on the rise in Latin America, China, Saudi Arabia and India. Despite such improvements and optimizations, a closer look at the performance reveals that not all wells are producing commercially. In addition, the hydraulic fracture stages are not all contributing within the producing wells. This scenario potentially suggests that it is important to target the field's sweet spots while dealing with shale resources (like most other hydrocarbon-bearing formations). Hence, resource development based on the current concepts of geometric placement of hydraulic fracture stages (e.g., using fixed well/fracture spacing) may not be appropriate to develop such heterogeneous unconventional resource basins. In the discussion we illustrate certain well-defined criteria that can identify the sweet spot locations within a field/basin for the optimal well placement. We further document the vital formation/zone characteristics that define the locations for hydraulic fracture stages and thus move away from the arbitrary geometric placement. The paper will discuss the well-placement optimization process and identify the required combination of proposed special petrophysical, geochemical, and geomechanical investigations (wireline, Logging While Drilling and cores). The hydraulic fracture stage placement analysis as presented, shoulders on the need to understand the existing natural fracture system. This understanding is achieved through geophysical log measurements and comprehensive analysis of the hydraulic fracture development pattern, as well as interaction of hydraulic fractures at each stage with the natural fractures. A naturally fractured reservoir can be drained more efficiently if a complex fracture network can be created by the hydraulic fracture stimulation. This begins by drilling the well in the direction of minimum principle horizontal stress in the area. The paper concludes by presenting examples demonstrating the practical application of some of the specific aspects of the methodology discussed and with a number of specific conclusions. In summary, the three key points to Proper Placement of Wells and Hydraulic Fracture Stages, in order to maximize the net value of an operator's asset are: Begin With a Complete Understanding of the Reservoir Use a Multidiscipline and Integrated Approach Across Each Phase of the Life Cycle Effectively Use Modern Technology
- North America > United States > Texas (1.00)
- Asia > Middle East (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.96)
- Geology > Petroleum Play Type > Unconventional Play > Shale Play (0.94)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Microseismic Surveying (0.68)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Maverick Basin > Eagle Ford Shale Formation (0.99)
- (10 more...)
Copyright 2012, Society of Petroleum Engineers This paper was prepared for presentation at the SPE Middle East Health, Safety, Security, and Environment Conference and Exhibition held in Abu Dhabi, UAE, 2-4 April 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 Accurate prediction of individual well potential and estimation of field capacity are the key for managing Coal Seam Gas (CSG) wells and its deliverability to Liquefied Natural Gas (LNG) plant. Because there are no downhole gauges in these wells there is limited reservoir data. The associated uncertainty, the absence of fast predictive wellbore models and challenges in generating accurate well performance predictions add to the deliverability challenge. This paper presents a method used to estimate CSG well performance for Australian CSG assets using neural network (NN) and proxy modeling. Traditional methods for prediction of well potential, such as numerical simulation or statistical techniques, have significant limitations. Numerical prediction is traditionally accurate but very complex in setup and computation; statistical techniques have the advantage of being fast but often lack accuracy. The approach starts with the automatic acquisition, validation, and quality control of static and dynamic production parameters in proxy modeling.
- Oceania > Australia (1.00)
- Asia > Middle East > UAE > Abu Dhabi Emirate > Abu Dhabi (0.54)
- North America > United States > Oklahoma (0.46)
- Overview > Innovation (0.50)
- Research Report (0.46)
- North America > United States > Texas > Anadarko Basin (0.99)
- North America > United States > Oklahoma > Red Fork Channel Sand Formation (0.99)
- North America > United States > Oklahoma > Anadarko Basin (0.99)
- (2 more...)
Abstract The Lower and Middle Ordovician paleocave systems form an important type of reservoirs in the Tarim basin, China. To better understand the impact of fractures on the paleocave reservoir development, with acquired wide azimuth 3D seismic data, both post-stack volumetric geometric attributes and P-wave azimuthal AVO analysis are applied to characterize multiscale fracture distributions. In this study, volumetric seismic attributes including dip, discontinuity and curvature are used to identify sub-seismic faults and associated fracture corridors and to describe subtle folds and flexures within the reservoirs. P-wave azimuthal AVO analysis is applied to detecting high angle fractures. Six azimuth-sectored stacks are used to compute P-wave seismic anisotropy from which fracture density and orientation are estimated. Two major sets of conductive fractures trending northeast and northwest, associated with different tectonic events, are identified using imaging logs from seven wells in the study area. Fractures predicted from geometric attributes and from the P-wave azimuthal AVO analysis are compared. The feasibility of two approaches for characterizing and mapping various types of fractures is investigated. Our results show that geometric attributes can better allow detecting and imaging subseismic faults and fracture corridors. The azimuthal AVO analysis allows detecting zones associated with both large scale fracture corridors and small scale diffuse fractures. However, the poor quality data and local geological structures may prevent from using obtained fracture predictions in a quantitative way. Integrating geometric attributes and azimuthal AVO analysis allows obtaining a comprehensive fracture distribution from fracture networks on the corridor scale to diffuse fracture distributions on the small scale. In this paper, case studies are used to illustrate how these two approaches can be integrated to provide a comprehensive multi-scale fracture distributions calibrated with well data and validated against the conceptual fracture models.
- Asia > China (0.70)
- North America > United States > Texas (0.46)
- Geology > Structural Geology > Fault (1.00)
- Geology > Geological Subdiscipline (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.46)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin (0.99)
- Oceania > Australia > Victoria > Bass Strait > Gippsland Basin (0.98)
- North America > United States > Texas > Meramec Formation > Meramec Formation > Mississippi Chat > Mississippi Lime > St. Louis Formation (0.98)
- (23 more...)