Abstract

Two geoengineering activities, i.e. CCS demonstration project and coal mining, occur in the same location is a very challenging problem in the Ordos basin, China. However, the interaction between CO2 geological storage and coal mining is barely studied all over the world. In this combination, a complicated thermo-hydro-mechano-chemical (THMC) analysis is required to ensure caprock integrity as well as the utmost coal production. As known, large amounts of CO2 that needs to be injected into deep saline aquifers in a CCS project may cause stress redistribution around CO2 injection point. Similarly, stress redistribution could also emerge below mined area due to floor heave of coal mining. Therefore, the aforementioned two redistribution areas will meet each other, and stress variation and related changes in the overlapping region is studied in this paper. Firstly, an intelligent linker program is developed for coupling of ABAQUS (stress analysis) and ECLIPSE (reservoir simulation), and it is executed to solve the combination problem. After that, an industrial example analysis of Ordos basin is carried out for THMC simulation. According to the numerical results, tensile and shear zones exist in the overlapping region and caprock, and they may be easier to damage.

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