Numerical Simulation of Pressure Distribution Changes in Porous Rocks under the Action of High Pressure Fluid

Abstract

The rock medium has the characteristics of heterogeneity, opacity and porosity. Fluid injection (such as hydraulic fracturing technology) can make the tight rock mass form a gas permeability enhancement zone near the borehole, which is conducive to unconventional natural gas extraction. Compared with experimental research, numerical simulation research has lower cost and higher efficiency, and has become an important method for research on fluid interaction and pore pressure. Based on this, this article mainly conducts a numerical simulation study on the changes in the internal pressure distribution of porous rocks under the action of high-pressure fluid (HPF). This article outlines the mechanism of quasi-static HPF fracturing coal and rock, and describes the classification of tensile fracture and shear fracture. In this paper, a numerical simulation method is used to construct a model of a porous rock sample, and a test of the internal pressure of the porous rock under the action of a HPF is carried out on the rock simulation sample. The experiment shows that when the intermediate principal stress σ2 is 20 MPa, the peak pressure of fluid is 12.5 MPa; when σ 2 is 25 MPa, the peak fluid pressure of is 12 MPa. This shows that the intermediate principal stress (or horizontal stress difference) is negatively related to the maximum fluid pressure.