薛明宇等-中国石油大学（华东）-Numerical Study of Reservoir Stability in Depressurized Exploitation of Natural Gas

Session 2 - Oral 9

Numerical Study of Reservoir Stability in Depressurized Exploitation of Natural Gas Hydrate Reservoir

Mingyu Xue1, Yuanfang Cheng1*, Zhiyuan Wang1, Zhenhai Liu1, Bo Sun1, Xiangfu Shan

1 School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China

Abstract: Natural gas hydrate (NGH) is widely distributed in the South China Sea and has high exploitation potential. Aiming at the problems of reservoir compression and mudline settlement in the depressurized exploitation of NGH reservoirs. This paper proposed a 2D thermal-hydrologic-mechanical-chemical (THMC) coupling model by finite element simulation software. The effect of different production pressure difference on vertical displacement of reservoir top, reservoir bottom and mudline during production process was analyzed through numerical simulation. The results indicated: 1) The extraction of NGH will cause reservoir compression. In the early stage of production, both the sedimentation rate of reservoir top and uplift rate of reservoir bottom are large, and decreases gradually as production goes on; 2) With the increase of production pressure difference, the subsidence of reservoir top and uplift of reservoir bottom increase, and the difference of vertical displacement of mudline is not obvious. The simulation results show the effect of production pressure difference on the mechanical stability of NGH reservoir. In addition, the numerical simulation method of large-scale NGH reservoir is obtained, which provides a thought for large-scale numerical simulation of NGH reservoir under different exploitive modes.

Keywords: natural gas hydrate; reservoir settlement; multi-field coupling; numerical simulation