温度-渗流-应力耦合作用下碎屑岩时效变形特性和渗透演化规律试验研究

As a common complex medium in oil and gas reservoirs, the study of clastic rock on time-dependent deformation and permeability evolution under thermo–hydro–mechanical(THM) coupling is one of the most challenging issue in petroleum engineering. This project focuses on the clastic rock in oil and gas reservoir engineering.Based upon the analyses of physical properties, short and long term behavior and permeability variation under HM coupling at room temperature (25℃).The short and long term tests of mechanical behavior and permeability properties under THM coupling are performed. Firstly, conventional compression and permeability tests under THM coupling are conducted to characterize the short term strength and deformation behavior. Secondly, the creep and permeability tests under various temperatures and stress levels(confining pressure, deviatoric stress and pore pressure) are performed to analyze long term deformation behavior and macro-micro failure mechanism. The permeability evolution and T-H-M-T(TIME) coupling mechanism during the process of stress and strain will be developed. Then the coupling relations among temperature, permeability coefficient, stress and strain will be proposed. Finally, the microscopic damage theory is introduced into the constitutive relation of porous media of non-associated plastic flow rule. The short and long term mechanical model of THM coupling will be established to take into account the damage and the permeability evolution. The results of this project will further deepen the experimental study of multi-field coupling and creep, and provide a theoretical basis for engineering safety evaluation.

碎屑岩作为油气储层常见复杂介质，温度-渗流-应力耦合作用下时效变形特性和渗透演化规律研究是石油工程中亟待解决的前沿科学问题。本项目以油气藏工程中碎屑岩为研究对象,常温（25℃）渗流-应力耦合条件下物理特性、短长期力学特性和渗透演化规律分析基础上，开展高温-渗流-应力耦合作用下短长期变形和渗透性试验研究。首先开展耦合条件下常规力学试验及渗透系数测定；其次开展不同温度和不同应力水平（围压、偏压和渗透压）下蠕变试验及渗透系数测定，分析短长期强度、变形特性及宏微观破坏力学机理，探讨渗透性演化规律和温度-渗流-应力-时间耦合机理，得到温度、渗透系数、应力和应变间耦合关系；最后基于试验成果，将微细观损伤理论引至非关联塑性流动法则的孔隙介质本构关系中，构建出考虑损伤和渗透性演化的温度-渗流-应力耦合短长期力学模型。相关成果可深化岩石多场耦合和流变试验研究，为工程安全性评价提供理论基础。

碎屑岩作为油气储层常见复杂介质，温度-渗流-应力耦合作用下时效变形特性和渗透演化规律研究是石油工程中亟待解决的前沿科学问题。本项目以油气藏工程中碎屑岩为研究对象,常温（25℃）渗流-应力耦合条件下物理特性、短长期力学特性和渗透演化规律分析基础上，开展高温-渗流-应力耦合作用下短长期变形和渗透性试验研究。首先开展了孔隙率、矿物成分等物理性能测试和高温（130℃）条件下常规力学试验；其次开展不同温度和不同应力水平（围压、偏压和渗透压）下蠕变试验及渗透系数测定，分析短长期强度、变形特性及宏微观破坏力学机理，探讨渗透性演化规律和温度-渗流-应力-时间耦合机理，得到温度、渗透系数、应力和应变间耦合关系；最后基于试验成果，将微细观损伤理论引至非关联塑性流动法则的孔隙介质本构关系中，构建出考虑损伤和渗透性演化的温度-渗流-应力耦合短长期力学模型。相关成果可深化岩石多场耦合和流变试验研究，为工程安全性评价提供理论基础。