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分析了20世纪50年代到目前有关低和特低渗透油田储集层非达西渗流理论及非达西渗流数值模拟的大量文献后指出:目前的非达西渗流方程存在一个负流量,不符合逻辑,不能作为渗流的基本方程,只能作为达西渗流和非达西渗流的判别式使用.对诸多低和特低渗透储集层的启动压力梯度的实验结果分析后发现,其数值过高,不符合实际情况.研究认为,1500 m深的低和特低渗透储集层油井中,合理的启动压力梯度值在0.006~0.04 MPa/m(储集层内泄油距离在500 m).同时,研究指出:当压力梯度达到一定值后,非达西渗流现象随之消失,启动压力梯度或非达西渗流等问题在产能预测和数值模拟过程中不用考虑,目前采用黑油模型(或双重介质模型)进行低和特低渗透油藏数值模拟是合适的.
After analyzing a great deal of literature about non-Darcy flow theory and non-Darcy flow numerical simulation of low and ultra low permeability oilfield reservoirs from the 1950s to the present, it is pointed out that there is a negative flow in the current non-Darcy flow equation, Logic can not be used as the basic equation of percolation but only as discriminant of Darcy percolation and non-Darcy percolation.Analysis of the experimental results of the start-up pressure gradient of many low and extra-low permeability reservoirs shows that the numerical value is too high , Which is not in line with the actual situation.The study suggests that a reasonable starting pressure gradient of 0.006-0.04 MPa / m (reservoirs with drainage distance of 500 m) in 1500 m deep low and extra low permeability reservoir wells. At the same time, the study shows that non-Darcy flow disappears when the pressure gradient reaches a certain value, and problems such as start-up pressure gradient or non-Darcy flow are not considered in productivity prediction and numerical simulation. At present, the black oil model Dual medium model) is suitable for numerical simulation of low and ultra-low permeability reservoirs.