基于全微分表示的组分模拟新方法

首先把多组分数学模型表示成关于各求解变量的全微分形式,然后用全微分量表示了它的数值模型。该方法先微分、再离散,并且保留了二阶微分量,在累积项的处理上严格地区别于全隐式方法,因而是一种全新的组分模拟方法。这一方法的基本出发点是,把各求解变量的微分视为称做基本微分单元的新变量,于是所有变量的微分都可以表示成基本微分单元的代数和形式。变量的微分量是该变量的一个微分改变量,它由于各求解变量的共同作用而引起。求解差分方程组的过程就是通过求取基本微分单元的不同取值逐步地改进各求解变量。

A NEW APPROACH TO COMPOSITIONL SIMULATION FORMULATIONED BY FULLY DIFFERENTIAL METHOD

The paper describes a new approach to reservoir simula-tion, the formulations in multi-component reservoir simulation model are firstly expressed as fully differential form on unknown variables, then are dispersed as numerical difference equations on these variables. The basic viewpoint is that all unknown variables’differences are regarded as new variables of singulardifferences cells, and then all variables’differences can be expressed as the algebra sum of the cells.The differential variables of the variables are the differentially changing variables of the variables, which is derived from common solution of the variables. The iteration procedure of solving these difference equations will be improved on all unknown variables through using value of the cells step by step.