Investigation of CO2 Enhanced Gas Recovery in Shale Plays

摘要

Shale gas production gets a tremendous breakthrough with the advent of horizontal well and massive hydraulic fracturing. There is still extensive gas stored in a reservoir after primary production so gas injection has a possibility to improve gas recovery for a shale play. In shale gas reservoirs, the gas can be in a free or absorbed state. In addition, there is a difference in the adsorption capacity between hydrocarbon and non-hydrocarbon components, therefore, it may cause gas recovery variation by hydrocarbon and non-hydrocarbon gas injection. In this paper, a Montney shale gas reservoir is modeled by Petrel based on data from Accumap. CH4/CO2 flooding performances are simulated by CMG GEM. Results have shown that CO2 has a good potential of gas production improvement in shale gas reservoirs. Furthermore, the higher the total organic content (TOC) of a shale reservoir, the better CO2 enhanced gas recovery (EGR) performance.