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Achieve Long-Term Caprock Integrity
I
n Canadian oil sands, in situ production can be technically challenging. Subsurface injection processes such as steam assisted gravity drainage (SAGD) and cyclic steam stimulation (CSS) expose the formation to changes in pressure and temperature, enhancing recovery and altering rock stresses but potentially threatening caprock integrity. Therefore, understanding enhanced oil recovery (EOR) effects on the formation is crucial to project performance, especially in light of impending government legislation which requires operators to secure long-term caprock integrity.
For more information email: heavyoil@calgary.oilfield.slb.com
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Š 2010 Schlumberger. 10-ho-0006
GeoloGICal ChallenGes
Alberta’s oil sands contain immobile bitumen, effectively a solid at reservoir conditions. Resources are found in a variety of environments, and production mechanisms that prove successful in one region will not necessarily succeed in another. In Canada, SAGD and CSS are the two most common EOR methods used; both processes cause reservoir volume to expand. And although steam injection shears the reservoir to enhance performance, it can also fracture boundary layers, risking containment breach of the caprock or fault reactivation. sChlumberGer solutIons
Integrated reservoir engineering and geomechanical analysis are the keys to optimizing oil sands in situ projects. Geomechanics helps predict alterations in formation rock properties and caprock integrity, based on well logs, well tests, and core, surface, or seismic data. The information is used by Schlumberger in reservoir and geomechanical modeling and monitoring to provide a robust, predictive system. This integrated approach includes advanced measurements obtained with the Sonic Scanner* acoustic scanning
platform, mini-frac testing with the MDT* modular formation dynamics tester tool, multidisciplinary expertise in geosciences and engineering from the TerraTek* Geomechanics Laboratory Center of Excellence, VISAGE* reservoir geomechanics modeling software, and ECLIPSE* reservoir simulation software. The result is a complete set of solutions to simulate and predict the dynamic behavior of heavy oil reservoirs. optImum results
Reservoir modeling and geomechanical analysis can enhance project design and operating parameters to reduce project costs. Without fully understanding the formation, expensive setbacks can occur. Characterizing the geology, understanding reservoir geomechanics, field monitoring, and integrated analysis enables operators to understand the risks and benefits associated with higher injection pressures and steam/oil ratios. Production mechanisms can then be optimized to suit the environment, and long-term caprock integrity can be achieved.