SBIR Phase II: Inversion of Geophysical Measurements for Fracture Geometry

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This Small Business Innovation Research (SBIR) Phase II project considers an innovative method for detecting and quantifying natural fracture systems in rock. The geometry of the fracture system controls the permeability of many oil and gas reservoirs and aquifers. Both oil and gas and environmental applications require new tools and techniques to quantify the fracture geometry, thus allowing prediction of permeability. During the Phase I research an inverse method was developed for fracture geometry from diverse geophysical measurements. This was accomplished by combining forward models relating fracture geometry to various anisotropic, stress-dependent properties including permeability, electrical conductivity, and seismic velocity with a maximum entropy regularization criterion. It was demonstrated that a relatively small number of geophysical measurements could be used to invert for a statistical description of the fracture geometry with some predictive power. Following this proof of principle, in Phase II, this method will now be turned into an interactive tool for studying and understanding fracture system behavior for oil and gas and environmental applications. To accomplish this, the forward models will be refined, the inversion algorithm will be tuned for this specific problem, and the algorithms will be validated using case studies. This new capability will likely provide many improvements to exploration, development, and reservoir performance activities by defining realistic input parameters for reservoir fluid flow simulators. It is in our national interest to develop new innovative and cost effective exploration and reservoir simulation technologies which will extend the useful lifetime of oil and gas reservoirs and extending the period of time that competitively priced oil and natural gas can be produced in this country. l