Liu Jianjun, Song Rui, Cui Mengmeng
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China ; School of Civil Engineering and Architecture, Southwest Petroleum University, Chengdu 610500, China.
School of Civil Engineering and Architecture, Southwest Petroleum University, Chengdu 610500, China.
ScientificWorldJournal. 2014;2014:140206. doi: 10.1155/2014/140206. Epub 2014 Apr 17.
A novel approach of simulating hydromechanical coupling in pore-scale models of porous media is presented in this paper. Parameters of the sandstone samples, such as the stress-strain curve, Poisson's ratio, and permeability under different pore pressure and confining pressure, are tested in laboratory scale. The micro-CT scanner is employed to scan the samples for three-dimensional images, as input to construct the model. Accordingly, four physical models possessing the same pore and rock matrix characteristics as the natural sandstones are developed. Based on the micro-CT images, the three-dimensional finite element models of both rock matrix and pore space are established by MIMICS and ICEM software platform. Navier-Stokes equation and elastic constitutive equation are used as the mathematical model for simulation. A hydromechanical coupling analysis in pore-scale finite element model of porous media is simulated by ANSYS and CFX software. Hereby, permeability of sandstone samples under different pore pressure and confining pressure has been predicted. The simulation results agree well with the benchmark data. Through reproducing its stress state underground, the prediction accuracy of the porous rock permeability in pore-scale simulation is promoted. Consequently, the effects of pore pressure and confining pressure on permeability are revealed from the microscopic view.
本文提出了一种在多孔介质孔隙尺度模型中模拟流固耦合的新方法。在实验室尺度下测试砂岩样品的参数，如应力应变曲线、泊松比以及在不同孔隙压力和围压下的渗透率。采用微型计算机断层扫描（micro-CT）扫描仪对样品进行扫描以获取三维图像，作为构建模型的输入。相应地，开发了四个具有与天然砂岩相同孔隙和岩石基质特征的物理模型。基于micro-CT图像，通过MIMICS和ICEM软件平台建立了岩石基质和孔隙空间的三维有限元模型。将纳维-斯托克斯方程和弹性本构方程用作模拟的数学模型。利用ANSYS和CFX软件对多孔介质孔隙尺度有限元模型进行流固耦合分析。据此，预测了砂岩样品在不同孔隙压力和围压下的渗透率。模拟结果与基准数据吻合良好。通过再现其地下应力状态，提高了孔隙尺度模拟中多孔岩石渗透率的预测精度。从而从微观角度揭示了孔隙压力和围压对渗透率的影响。
