咸水层CO_(2)封存注入阶段盖层泄漏风险的数值模拟

Numerical simulation of leakage risk of CO_(2)storage caprock in saline water layer

为探究CO_(2)封存过程盖层封闭性变化,以某区块咸水层为研究背景,在数值模拟的基础上,以盖层密封性和力学完整性损伤研究为主线,基于两相渗流理论,建立了气-水-固多场耦合模型,通过改变注气速率和总量,对储层流体运移规律、盖层密封性和力学完整性变化进行研究。结果表明:随着与注入井径向距离的增加,CO_(2)-盐水界面形状逐渐垂向增加,泄漏量与注气总量和注气速率相关;通常在盖层力学失效前,盖层密封性就已经受到破坏,拉伤区通常先发生在注射孔周围。

This paper describes the exploration of the closure change property of the caprock in sealing of CO_(2).By taking a block of saline water layer as the research background,on the basis of numerical simulation,the study focuses on the closure property of the caprock and mechanical integrity damage.Based on the two-phase seepage theory,the study consists of estabulishing a gas-water-solid multi-field coupling model to study the fluid migration law of the reservoir,and the changes of the sealing properties of the caprock and the mechanical integrity by changing the gas injection rate and total amount.The results show that with the increase of radial distance from injection well,the shape of CO_(2)-salt water interface gradually increases vertically.The leakage is related to the total amount and rate of gas injection.Generally,before the mechanical failure of the caprock,the sealing properties of the caprock have been destroyed.The tensile damage usually occurs firstly around the injection borehole.