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为了解有效围压对低渗透砂岩渗流性能的影响规律,利用高精度的FDES-641三轴驱替评价系统,以盐水作为渗流流体,分别采用恒速法和恒压法进行低渗透饱和砂岩在有围压耦合作用下的稳定渗流实验。结果表明:岩石渗透率随着有效围压的增加而下降,呈现非线性关系。结论为:1)当流速或压力梯度保持恒定时,随着有效围压升高,渗透率下降速率逐渐降低,渗透率比与有效围压近似呈反比关系。2)当有效围压下降时,岩石渗透率回升,但回升路径低于原始路径。3)恒速法比恒压法操作方便、精度高,有利于围压作用下的稳定渗流实验。
In order to understand the effect of effective confining pressure on the seepage performance of low permeability sandstone, a high precision FDES-641 triaxial displacement evaluation system was used. Using saline as the seepage fluid, constant velocity and constant pressure A steady seepage experiment under confining pressure. The results show that the rock permeability decreases with the increase of effective confining pressure, showing a nonlinear relationship. The conclusions are: 1) When the velocity or pressure gradient remains constant, with the increase of effective confining pressure, the rate of decrease of permeability decreases gradually, and the permeability ratio is approximately inversely proportional to the effective confining pressure. 2) As the effective confining pressure decreases, the rock permeability rises, but the recovery path is lower than the original one. 3) constant speed method than the constant pressure method easy to operate, high precision, is conducive to the role of confining pressure steady seepage experiment.