双重介质系统液固耦合模型及其应用

在油气藏开发过程中,油气藏中孔隙—裂缝介质受渗流场和应力场的双重作用,这不是简单的线性叠加,而是彼此作用、相互影响,称为耦合作用。对双重介质而言,耦合作用可能导致油藏物性参数的变化,影响油气藏压力和流体的分布,因此有必要建立并利用液固耦合模型来模拟双重介质系统中流体的渗流特征。利用有效应力概念,可以建立双重介质渗流系统液固耦合的数学模型,并采用有限元方法,通过有限差分,获得数值解。通过实例模拟计算,获得了耦合效应对油气藏动态的影响:压力系数越高、储层物性越差,液固耦合效应越明显。但随着生产时间的延长,液固耦合效应对井底压力的综合影响会逐渐消失,并非所有的双重介质系统渗流都需要考虑液固耦合效应。 

STUDY AND APPLICATION OF LIQUID/SOLID COUPLE MODEL IN DOUBLE POROSITY MEDIA SYSTEMS

The 2 fields of fluid flowing and stress simultaneously play roles in the pore-fracture media(during) hydrocarbon exploration.The coupling effects may change the reservoir formation parameters and affect the liquid distribution.Therefore,it is necessary to utilize a liquid/solid couple model to analyze the fluid flowing behavior in double porosity media.This model has been made thanks to the concept of effective stress.Finite Element Method and limited difference are utilized to gain solutions.The influence of couple effect on accumulation is stated as follow: higher pressure coefficient,poorer formation nature,and more remarkable liquid/solid couple effects.The effect will gradually disappear as the development time prolongs,therefore,it is not necessary to take into account the liquid/solid couple effects in all double porosity media reservoirs.