低渗非达西多相渗流的数值模拟分析

从低渗介质渗透率与压力梯度的关系出发建立数值模型,修正已有数值模拟器的渗透率项进行功能扩展,并给出计算实例.结果表明,在其他条件相同情况下,启动压力梯度越大,相同时间内的累积采油量、累积注水量越小,反之越大.启动压力梯度越大,渗流规律越偏离达西定律.本文建立的模型比传统模型更能准确反映低渗介质中的渗流特征.

Simulated analysis of low permeability of non-Darcy multi-phase seepage

In this paper, the author has given a non-Darcy flow numerical simulation model aimed to modify the Black Oil simulation model to characterize properly the special flow phenomenon in low permeability media. As is known, many researches show that the fluid flow in low permeability media may not obey the Darcy's law. However, the conventional numerical reservoir simulation theories based on the Darcy's law is very difficult to describe the characteristic of non-Darcy fluid flow in low permeability media. On the basis of the predecessors' research findings, we have developed a simulated model by taking into account the relation between the permeability of media and the pressure gradient. We have also provided an example for the simulation. The results indicate that under the same conditions and during the same time, the greater the start-up pressure gradient, the lower the cumulative oil products and the cumulative water injections. On the contrary, the less the start-up pressure gradient, the higher the cumulative oil products and the cumulative water injections; and the greater the start-up pressure gradient, the rule of the fluid flow the more different from the Darcy' law. Our analysis proves that the model developed in this paper could represent more properly the characteristics of non-Darcy fluid flow in low permeability media.