Using a Multilayer Reservoir Model To Describe a Hydraulically Fractured, Low-Permeability Shale Reservoir

This paper summarizes the development and application of a multi-layer reservoir description for the Gas Research Institute (GRI) Comprehensive Study Well 2 (CSW2), which is completed in the Devonian Shales and located in Calhoun Co., WV. We determined that a two-layer reservoir description best describes the complex reservoir and hydraulic fracture system of the CSW2. This reservoir description, determined using a numerical simulator, matched all the data collected, including preand post-fracture flow/buildup tests, multi-layer communication tests, individual-layer injectionlfalloff tests and preand post-fracture production data. The results of this study indicate that a multi-layer reservoir description provides better estimates of postfracture performance compared to a more conventional, single-layer reservoir description. This result also explains previous, optimistic estimates of post-fracture well performance which were based on single-layer interpretations of pre-fracture test data. This paper reviews and discusses briefly the many diagnostic tests performed on the CSW2, but focuses on the history match analysis and results determined with a two-layer reservoir model. The testing and analysis approach presented in this paper can be applied generally to other tight formations.