变形多孔介质温度-渗流-应力完全耦合模型及有限元分析

FULLY COUPLED THERMAL-HYDRAULIC-MECHANICAL MODEL AND FINITE ELEMENT ANALYSIS FOR DEFORMATION POROUS MEDIA

根据多孔介质中温度、渗流及应力之间复杂的耦合关系,基于连续介质力学和混合物理论,导出变形多孔介质热–流–固三场耦合模型及其控制方程,探讨有限元法的求解过程,以ABAQUS软件为求解器,在MATLAB语言环境下编制相应的计算程序,并通过典型算例考证程序的正确性。然后研究石油钻井过程中的热–流–固耦合作用过程,详细分析场耦合作用对井壁孔隙压力、温度和应力的影响,计算结果表明,热–流–固耦合作用对井壁稳定有重要的影响,应全面考虑各物理场之间的耦合作用。研究成果为分析岩土介质多场耦合过程提供一条有效的途径,从而为进一步研究温度–渗流–应力–化学(THMC)耦合问题奠定基础。

With the application of continuum mechanics and mixture theory,a coupled mathematical model and governing equations of full coupled relation between temperature,seepage and stress fields for porous media are established.The solution process for coupled problem of three fields is studied by using finite element method and the corresponding computer code is developed with MATLAB with the ABAQUS solver.A typical example of application is presented to verify the validity of the code.Then,the coupled process of wellbore is studied and the influence laws of pore pressure,temperature and stress are discussed between different coupled fields.The results show that the coupled processes have significant effects on wellbore stability.The presented method can provide references for the influence of multi-field coupling on geological environment and coupled thermal-hydraulicmechanical-chemical process analysis of underground engineering.