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.

Jiajing Li, Zhe Liu, Chao Wang, Yingjie Dong, Fengying Guo. Numerical Simulation of Pressure Distribution Changes in Porous Rocks under the Action of High Pressure Fluid. Academic Journal of Engineering and Technology Science (2022) Vol. 5, Issue 1: 34-40. https://doi.org/10.25236/AJETS.2022.050107.

[1] Neupane B, Panthi K K , Vereide K . Effect of Power Plant Operation on Pore Pressure in Jointed Rock Mass of an Unlined Hydropower Tunnel: An Experimental Study[J]. Rock Mechanics and Rock Engineering, 2020, 53(7):3073-3092.

[2] Dakhelpour-Ghoveifel J , Shahverdi H . Prediction of gas-oil capillary pressure of carbonate rock using pore network modeling[J]. Journal of Petroleum Science and Engineering, 2020, 195(2):107861.

[3] Lei T , Yin X , Zong Z . Pore pressure prediction in orthotropic medium based on rock physics modeling of shale gas[J]. Journal of Natural Gas Science and Engineering, 2019, 74(11):103091.

[4] Braun P , Ghabezloo S , Delage P , et al. Theoretical Analysis of Pore Pressure Diffusion in Some Basic Rock Mechanics Experiments[J]. Rock Mechanics & Rock Engineering, 2018, 51(5):1-18.

[5] Garing C , Chalendar J D , Voltolini M , et al. Pore-scale capillary pressure analysis using multi-scale X-ray micromotography[J]. Advances in Water Resources, 2017, 104(jun.):223-241.

[6] De Carvalho T P , Morvan H P , Hargreaves D M , et al. Pore-Scale Numerical Investigation of Pressure Drop Behaviour Across Open-Cell Metal Foams[J]. Transport in Porous Media, 2017, 117(3):1-26.

[7] Zhou Z H , Ren Z , Wang K , et al. Effect of excess pore pressure on the long runout of debris flows over low gradient channels: A case study of the Dongyuege debris flow in Nu River, China[J]. Geomorphology, 2018, 308(MAY1):40-53.

[8] Wei C , Carcione J M , Picotti S , et al. Effect of pressure and fluid on pore geometry and anelasticity of dolomites[J]. Rheologica Acta, 2020, 59(11).

[9] Wang H T , Li X J , Liu P , et al. Prediction of roof supporting pressure for shallow tunnels in layered soils incorporating the effect of pore water pressure[J]. PLoS ONE, 2019, 14(6):e0217351.

[10] Song I H , Bae B S , Ha J H , et al. Effect of Hydraulic Pressure on Alumina Coating on Pore Characteristics of Flat-Sheet Ceramic Membrane[J]. Ceramics International, 2017, 43(13):10502-10507.

[11] Yi M , Cheng Y , Wang Z , et al. Effect of particle size and adsorption equilibrium time on pore structure characterization in low pressure N2 adsorption of coal: An experimental study[J]. Advanced Powder Technology, 2020, 31(10):4275-4281.

[12] Aliha M , Bahmani A . Rock Fracture Toughness Study Under Mixed Mode I/III Loading[J]. Rock Mechanics & Rock Engineering, 2017, 50(7):1-13.