A Study on CO2 Storage under Shale Reservoir at Nanometer Level

The greenhouse effect has brought about a series of ecological and environmental problems such as wind intensification, species extinction, acid rain, awful weather, sea-level rise, which are mainly caused by CO2 among all greenhouse gases. It is an effective way to alleviate the problem by injecting CO2 into shale reservoir. Such technology is the focus of attention of government and the public, and has been provided with well-established mathematical models and simulation software. While, compared to the mature development of this technology abroad, China is still on emerging state and studies on CO2 storage under shale reservoir was just launched. Given the current situation of domestic studies, this paper mainly probes into the mechanism of CO2 storage under shale reservoir, influencing factors, and provides the mathematical model for enhancing recovery of CO2 storage under shale reservoir based on dual medium hypothesis, in which, are viscous flow, molecular diffusion, coupling effect of Knudsen diffusion mechanism are taken into consideration. And then this paper develops the channeling equation with an eye to the coupling migration mechanism, provides source sink term model for production well and injection well, and gives research on numerical simulation. Finally, this paper discusses feasibility of enhancing recovery of CO2 storage under shale gas reservoir and analyzes the dynamic changes of CO2 storage volume and CH4 production volume during injection of CO2.