CAJ | 학술논문

目前国内关于 CO2咸水层封存尚处于先导性和试验性研究阶段，对超临界 CO2注入过程中岩层力学响应和流体运移的理论与技术方面的认识还不完善。为研究CO2注入下岩层变形和流体运移，基于两相流动数学模型，给出了超临界CO2和咸水质量守恒方程；采用毛细压力和有效饱和度的关系式，将质量守恒方程变换成以毛细压力为变量的表达式，以便于考虑流体压力对岩层的影响。提出了无流体压力影响下的岩层力学本构模型，该模型能够同时考虑岩层的塑性变形和损伤。分析了两相流体-岩层相互作用机制：一方面，采用有效应力原理，考虑流体压力对岩层的力学影响；另一方面，通过岩层固有渗透率变化考虑岩层变形对流体运移的影响。
목전국내관우 CO2함수층봉존상처우선도성화시험성연구계단，대초림계 CO2주입과정중암층역학향응화류체운이적이론여기술방면적인식환불완선。위연구CO2주입하암층변형화류체운이，기우량상류동수학모형，급출료초림계CO2화함수질량수항방정；채용모세압력화유효포화도적관계식，장질량수항방정변환성이모세압력위변량적표체식，이편우고필류체압력대암층적영향。제출료무류체압력영향하적암층역학본구모형，해모형능구동시고필암층적소성변형화손상。분석료량상류체-암층상호작용궤제：일방면，채용유효응력원리，고필류체압력대암층적역학영향；령일방면，통과암층고유삼투솔변화고필암층변형대류체운이적영향。
Deep underground injection of carbon dioxide (CO2) into saline reservoir in China is in the stage of pilot project and field validation.The mechanical response of reservoir and fluid transportation induced by injection of supercritical CO2 are imperfect in theory and technology. In order to study the reservoir deformation and fluid transportation, the mass balance equations for both supercritical CO2 and saline are firstly presented based on two-phase flow model. The capillary pressure is introduced and served as the argument in the mass balance equations after some equation manipulations, with the help of relation between capillary pressure and saturation degree, which can facilitate consideration of the influence of fluid pressure on the reservoir formation. Secondly, a constitutive model is proposed to describe the mechanical behavior of dry rock of reservoir formation without fluid pressure, both the plastic deformation and damage mechanism can be considered. The coupling mechanism of fluid and reservoir formation is analyzed;the effective stress concept is used to consider the effect of fluid pressure on the reservoir formation, while the influence of reservoir deformation on fluid transportation is described by the variation of permeability of reservoir formation.