岩石随机孔隙结构的三维重构模型与细观渗流分析

3-dimensional reconstruction model of rock with random pore structure and microscopic seepage analysis

将多孔岩石介质的孔隙视为具有毫米量级的随机细观结构,重构岩石三维随机孔隙结构模型,在细观力学的层面上研究孔隙结构对多孔岩石渗流的影响。引入微管渗流模型,利用统计学原理和FLAC3D软件研究多孔岩石介质随机孔隙结构的重构技术和细观渗流数值模拟方法。研究结果表明:多孔岩石孔隙率越大,流体由非稳定流过渡到稳定流的时间愈短,渗透系数和孔隙率具精度很高的线性关系,岩石介质透水性的孔隙率阈值nλ=4.05%,峰前多孔岩石介质的渗透系数主要受体积应力控制,且两者之间具有负指数关系。重构毫米量级的孔隙结构单元,其数值稳定性可以得到保证。

Taking porous rock medium as random microscopic structure with range of millimeters, rock model with 3-dimensional random pores was reconstructed, and the influence of pore structure to porous rock seepage was studied on the level of meso mechanics. By introducing microtubule seepage model, statistics principle and FLAC3D software were used to develop the reconstruction technology of porous rock medium with random pore structure produced and numerical simulation method of meso seepage. The results show that the time from unsteady flow to steady flow is shortened with the increase of porosity. There exists high accuracy linear relationship between seepage parameters and porosity, and the porosity threshold （nλ） of permeability of porous rock medium is 4.05%. The permeability of porous rock medium is mainly effected by volumetric stress. Furthermore, during pre-peak process the negative exponential relationship between the permeability and the volumetric stress is also shown. The numerical simulation stability of porous structure unit with range of millimeters can be guaranteed.