MULTIFIELD COUPLED NUMERICAL MODELING IN THE EXPLOITATION OF UNCONVENTIONAL GAS RESERVOIRS

The development of unconventional oil and gas resources,along with carbon sequestration,plays a vital role in ensuring energy security and achieving the"dual carbon" goals. However,these processes involve complex multi-physics coupling effects that are challenging to accurately characterize using conventional numerical models. To address this issue,this study introduces a self-developed multi-physics coupled numerical simulator. Designed with a modular architecture,the simulator enables efficient thermo-hydro-mechanical-chemical(THMC)coupled computations. This paper outlines the fundamental principles of the simulator and reviews its applications in several areas. In the context of natural gas hydrate extraction,the simulator reveals the production potential of a novel"in-situ thermal compensation,depressurization,and filling" method,identifies dominant dissociation mechanisms in reservoirs with different physical properties,and proposes an optimized thermal injection-depressurization co-production strategy. In studies on synergistic methane hydrate extraction and CO₂ sequestration,results demonstrate a"production-assisted storage" mechanism,which enhances both sequestration efficiency and long-term security through the formation of an"umbrella-shaped self-sealing structure." Additionally,the simulator has been used to evaluate the long-term heat extraction performance of deep geothermal systems using"clustered U-shaped multilateral wells" and to investigate multi-stage evolution patterns during in-situ shale oil conversion. These findings deepen the scientific understanding of multi-physics coupling mechanisms in unconventional resource development and offer theoretical and technical support for the sustainable utilization of unconventional energy.