关键词: 低渗透, 各向异性, 启动压力梯度, 应力敏感, 数学模型

Abstract: Eolotropy, threshold pressure gradient and stress sensitivity are unique feature of low permeability reservoir. The authors of this paper build mathematical model of low velocity non Darcy flow through porous media, which takes three factors above mentioned into consideration. Because of nonlinear for equations, approximate solution is used to solve steady flow and unsteady flow. Meanwhile, under the condition of fixed production and variable production as well as fixed BHP, movement rule of dynamic boundary, reservoir pressure characteristic and production change rule are solved by means of material balance mechanism. The results show that stimulative region boundary of eolotropy reservoir extends outward in the pattern of ellipse, which changes reasonable well row spacing; the factors of threshold pressure gradient and stress sensitivity make productivity decline, and the speed of boundary movement becomes slower, and single well control size reduces. It becomes more and more difficult to develop this kind of reservoir.

Key words: low permeability, eolotropy, threshold pressure gradient, stress sensitivity, mathematical model