三维三相达西流法及其在库车坳陷的应用

3-D 3-phase Darcy flow method and its application to the Kuqa Depression

多相达西流法是油气二次运移模拟技术中最复杂的方法,存在三大技术难点:①模型十分复杂,求解比油藏模拟的难度大得多;②收敛性、稳定性不易保证,导致计算结果精度低、计算中途异常停止;③计算机耗时量巨大,在微机上算完一个大型盆地要花几天时间。为此,采用了基于PEBI(直交平分)网的有限体积法、基于牛顿迭代的全隐式法及ORTH-MIN(正交极小化)法,摸索出了"正确地选取一个模拟工区的最大允许时间步长"是解决上述三大技术难点的最大关键点,从而攻克了这三大技术难点。研发了三维三相达西流软件,并应用于库车坳陷,获得了较好的油气运聚史模拟结果。

The multi-phase Darcy flow method is the most complicated among all the modeling methods for se- condary hydrocarbon migration. It has three major technical problems ： （ 1 ） its model is too complicated to easily generate a solution, at least much difficult than that in reservoir simulation; （2） it is not easy to ensure the con- vergence and stability of the model and thus rendering a calculation of low accuracy or causing abnormal shut- down ; and （3） it is very time-consuming as the calculation of a larger basin may take several days to complete. To tackle these problems, we tried the finite volume method based on PEBI （perpendicular and bisection） cells, the fully implicit solution based on the Newton iteration, and the ORTHMIN （orthogonal minimum） algorithm, and came to a conclusion that the key to deal with the problems is to correctly select the allowable maximum time step for a simulated block. Finally, we developed a program of 3D 3-phase Darcy Flow. An application of the software to the Kuqa Depression had gained positive results.