低渗透油藏渗流场与应力场耦合规律研究

基于岩石力学、渗流力学、地质力学、计算力学以及流-固耦合渗流的基本理论,考虑低渗透油藏渗流时的启动压力梯度和低渗透储层的流-固耦合特征,建立了低渗透油藏渗流场和应力场耦合的数学模型和数值模型。采用有限差分与有限元相结合的耦合数值计算方法进行了程序设计,研究了低渗透油藏渗流场和应力场的耦合规律。通过数值模拟方法对单井枯竭式开采过程中应力-应变随时间和空间的变化规律、岩石物性参数动态变化规律及开发指标变化规律进行了研究,并和刚性模型的计算结果进行了分析比较。可以看出,低渗透油藏的流-固耦合效应非常明显。

Study on the coupling of seepage and stress fields in low-permeability reservoirs

Mathematical and numerical coupling models of seepage and stress fields of low-permeability reservoirs are developed based on the basic theories of rock mechanics,fluid mechanics in porous medium,geologic mechanics,computational mechanics and fluid-solid coupling seepage,and etc,and by taking into consideration of their start-up pressure gradient of seepage flow and characters of fluid-solid coupling.A program is designed by using numerical computing method of coupling with finite difference and finite element integrated,and the coupling law of seepage and stress fields in low-permeability reservoirs is studied.The varying law of stress-strain with time and space,dynamic changing law of rock physical properties,changing pattern of development index in the process of natural depletion of single well are studied through numerical simulation and correlated with the calculation of rigidity model.It is revealed that the fluid-solid coupling effect in low permeability reservoirs is rather obvious.