求解双重孔隙介质油藏压力的一种新方法

求解双重孔隙介质油藏不稳定渗流压力要比单孔隙介质油藏不稳定渗流压力复杂得多，而对于复杂边界条件的双重孔隙介质油藏模型，很难求得其压力解。提出了将单孔隙介质不稳定渗流压力解转换为双重孔隙介质渗流不稳定压力解的方法，其步骤是：①单孔隙介质油藏不稳定渗流的拉氏空间压力解ｐＤ（ｚ）乘以拉氏变量ｚ；②用ｚｆ（ｚ）代替ｐＤ（ｚ）中的ｚ，得到一个表达式；③该表达式除以ｚ即得到双重孔隙介质油藏不稳定渗流的拉氏空间压力解ｐＤｆ（ｚ）；④采用数值拉氏反演Ｓｔｅｈｆｅｓｔ方法即可得到真实空间内的双重孔隙介质油藏不稳定渗流压力解。该方法求解过程简捷，计算结果正确

A NEW METHOD FOR SOLVING THE DIFFUSION EQUATION OF DUAL POROSITY RESERVOIR

The diffusion equation of dual porosity reservoir is more difficult to be solved than that of single porosity reservoir. Sometimes, the solution of diffusion equation of dual porosity reservoir with the complex boundary conditions is difficult to be derived. A new method to solve the diffusion equation of dual porosity reservoir is transformed from the solution of diffusion equation of single porosity reservoir. The derivative process is presented. The Laplace solution of the diffusion equation for the single porosity reservoir is multiplied by Laplace variable. Then the variable is replaced by another function, and an expression is obtained. The expression is divided by the Laplace variable, and the Laplace solution of diffusion equation for the dual porosity reservoir is transformed inversely by Stehfest numerical method. This new method avoids solving the diffusion equation with complex boundary conditions of dual porosity reservoir. The calculation indicates that this method is simple and practical.