A NUMERICAL SIMULATION STUDY OF THE ALLISON UNIT CO_2-ECBM PILOT: THE IMPACT OF MATRIX SHRINKAGE AND SWELLING ON ECBM PRODUCTION AND CO_2 INJECTIVITY

摘要

The Allison CO_2-ECBM pilot, augmented by detailed reservoir-characterization work carried out in a recently completed DOE-sponsored research project, provides a unique benchmark test case for reservoir simulation of ECBM recovery and associated CO_2 storage. This paper presents the results of a reservoir-simulation study, focusing on the impact of matrix shrinkage and swelling on ECBM production and CO_2 injectivity. Using the field gas production and CO_2-injection rates as input to the Imperial College in-house ECBM/CO_2 storage simulator, METSIM2, with its newly implemented dynamic permeability model simulator, the injecting bottomhole pressures, produced-gas composition at the two wells experiencing noticeable CO_2 breakthrough, and the producing bottomhole pressures were satisfactorily history matched.