| Abstract |
Unconventional geothermal reservoirs play an important role in supplying fuel for a growing energy demand in the U.S. Development of such reservoirs relies on creating a fracture network to provide flow and transport conduits.{, #49;Narr, 2006 #49} The fractures represent the main channels for the movement of the underground fluid during injection and production operations. Geomechanical interactions among all fractures (natural and hydraulically induced one) change the initial stress distribution of the rock and then impacts fracture initialization, and propagation processes. As the later governs the flow pattern and total heat and fluid recovery in the reservoir, having such stress variations at high-resolution level could be potentially useful for a realistic representation and geomechanical characterization of those largescale unconventional reservoirs, as well as, for instance, during a massive fracture prediction analysis, and the proper design of exploitation strategies. The displacement discontinuity method (DDM) is frequently used for modeling the behavior of fractures embedded in linearelastic rocks. However, DDM is not computational efficient for very large systems of cracks, often limiting its application to small-scale problems. Fast summation techniques such as the Fast Multipole Method (FMM) can speed up the analysis of fracture problems, even using personal computers with modest computational resources. This work presents a novel approach for the efficient post-processing computation of regional stress variations in large-scale fractured reservoirs combining DDM and FMM. Several case studies involving naturally fractured reservoirs are treated and the effect of several geomechanical aspects such as non-linear joint deformation and fracture fluid pressure, are evaluated. Results of the approach show a good agreement with conventional solutions, demonstrating its efficiency and accuracy for large-scale situations, as well as its usefulness for the geomechanical characterization of unconventional reservoirs. |