低速非达西渗流的全隐式模拟模型

许多研究表明，低渗透介质中的流体渗流需要启动压力梯度，并不遵循达西定律；而传统的油藏数值模拟理论都是建立在达西定律之上的，因而它很难反映低渗介质中的流体渗流特征，为了让油藏模型能正确描述低渗介质中这种特殊的渗流现象，基于前人的研究成果，建立了一种非达西渗汉的全隐式数据模拟模型，并给出了该数学模型的有限差分 相应的全隐式处理方法，完成了已有模拟器的功能改造。最后给出了计算实例，结果表明，在其它条件相同的情况下，启动压力梯度越大，则在相同时间内的采出程度越低，累计注水量越少；相反，启动压力梯度越小，则在相同时间内的采出程度越高，累计注水量越多。分析表明，算例的模拟结果是合理的，此模型能够反映低渗介质中流体的低速大西渗流特征。

Fully implicit simulation model for low-velocity non-Darcy flow

Many researches show that the fluid flow in low permeability media doesn't obey the Darcy's law, and needs a start-up pressure gradient. It is very difficult for the conventional numerical reservoir simulation theories to describe the characteristic of fluid flow in low permeability media, because they are all based on the Darcy's law. On the basis of the predecessors' research findings, a non-Darcy flow fully implicit numerical simulation model is presented in this paper to characterize properly the special flow phenomenon in low permeability media. Besides, the finite difference expression of this model and the responding fully implicit process for the model is given in this paper, and the function modifications of the existing simulator has been done. Finally, an example is given in the paper. The results indicate that under the same other conditions and during the same time, the greater the start-up pressure gradient, the lower the oil recovery and the smaller the cumulative water injection quantity; on the contrary, the less the start-up pressure gradient, the higher the oil recovery and the more the cumulative water injection quantity. The analyses demonstrate that the results of the example are reasonable and the model developed in this paper could represent the characteristic of low velocity non-Darcy fluid flow in low permeability media.