有界封闭地层中煤层气渗流问题

Flow Problems of Coalbed Methane through Bounded Confining Stratum

本文研究了有界封闭地层中煤层气渗流问题的压力动态特征,引入渗透率模数建立了变形双重介质拟稳态和非稳态渗流模型。对于双重介质拟稳态渗流的数学模型采用直接隐式差分法和Newton迭代法进行求解,对于非稳态渗流模型采用正则摄动法和Laplace变换进行求解,并通过拉氏数值反演得到零阶摄动解。本文还对变形参数和双重介质参数变化时压力的变化规律进行了讨论,给出了几种情况下的典型压力曲线图,这些结果为油田开发提供了理论依据和试井方法。

In this paper, pressure behavior characteristics for the flow problems of coalbed methane in bounded confining stratum are studied. The new mathematical models of the pseudo-steady and unsteady state flow problems with deformed double porosities are built by introducing the permeability module. The numerical solutions for pseudo-steady state flow models are obtained by the direct implicit differential method and Newtonian iterative method, while the numerical solutions for unsteady state flow models are obtained by the regular perturbation method and Laplace transform with the zero order perturbation solutions obtained by the Laplace numerical inversion. The rules of pressure change are discussed when the deformation parameters and double porosities parameters change in the models,and the typical pressure curves under several different conditions are plotted,which provide theoretical bases and well testing methods for oilfield development.