PNNL

Simulations of methane production and supercritical carbon dioxide injection were developed that consider competitive adsorption of CH4 and CO2 on both organic matter and montmorillonite. The results were used to assess the potential for storage of CO2 in a hydraulically fractured shale gas reservoir and for enhanced recovery of CH4. Assuming equal volume fractions of organic matter and montmorillonite, amounts of CO2 adsorbed on both materials were comparable, while methane desorption was from clays was two times greater than desorption from organic material. The most successful strategy considered CO2 injection from a separate well and enhanced methane recovery by 73%, while storing 240 kmt of CO2.