Simulation of Enhancing Efficiency for Low Permeability Coalbed with CO2 Injection
ProfessorState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Chengdu 610500, China; School of Civil Engineering and Architecture, Southwest Petroleum University, Chengdu 610500, China; e-mail: 39114028
CO2 flooding coal bed methane (CBM) not only stores the CO2 underground and reduces greenhouse gas emission, but also enhances gas production ratio. It is a coupling process of multiphase fluid flow and coal-rock deformation, which involves gas competitive adsorption, diffusion from coal matrix to fractures. A dual-porosity media which consists of matrix and fracture were built to simulate the flooding process, in which a mathematical model considered competitive adsorption, diffusion and seepage process and the interaction between flow and deformation was used. The results shown that: 1. The permeability ascending caused by matrix shrinkage is notable, should not be ignored. 2. A well group low gas injection scheme can obtain a higher recovery efficiency and CO2 storage.
Keywords: CO2 flooding coalbed methane, recovery efficiency, mathematical model
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