双重孔隙介质非线性流固耦合渗流

Flow through Fissured Media with Dual Porosity and Nonlinear Elastic Behavior

本文给出了考虑双孔双渗介质弹性变形的流固耦合渗流模型。不仅考虑了固结对渗流的影响,同时也考虑了固体变形对渗流参数(孔隙度和渗透率)的影响。这样,渗流就成了双孔双渗介质中非线性流固耦合渗流。在此基础上,本文还推导了双重孔隙介质非线性流固耦合渗流有限元计算格式,编制了计算机程序,并可模拟单孔隙,双重孔隙,常系数线性和变系数非线性等流固耦合渗流计算。给出了算例并作了对比。结果表明,固体变形引起的介质参数变化对流体渗流早中期过程有重要的影响,对渗流后期影响并不大。这对于石油开采有重要的参考价值。

Based on the double porosity concept and taken into account the media deformation, this paper to derives a set of nonlinear governing equations which describe the fluid behavior flowing through the naturally fissured media with deformable matrix. When the coefficients vary with fluid pressures (or time), the equations are nonlinear. In this model, the media deformation has an effect not only on the properties of media, such as the permeability and porosity, also on the fluid seepage in the media. In addition, a computer program (based on finite element method) has been developed. The program is capable of simulating problems associated with single and double porosity, having two options of constant or variable coefficients in governing equations. In the variable coefficient option, at each time step, the values of coefficients are updated using the set of constitutive relations. An example is pressented here also. The results of the simulation show that the influence on the seepage due to media deformation focus on the early stage and middle stage.