酸性环境下砂岩腐蚀的渗流特性

为拓展酸性介质与砂岩之间的细观特性研究，基于数字岩心模型和格子Boltzmann方程，开展砂岩受酸腐蚀过程的加速模拟试验，分析不同酸性环境下受酸腐蚀砂岩的渗流特性。通过CT扫描设备探究受酸腐蚀砂岩内部矿物组成的结构变化；利用Image J和Avizo可视化图像处理软件建立了受酸腐蚀砂岩的数字岩心，结合格子Boltzmann方程构建出砂岩受酸腐蚀过程中的渗流模型，分析砂岩受酸腐蚀过程中内部孔隙结构和渗流特性的变化规律。研究结果表明：CT扫描试验可展示砂岩内部的矿物组成及孔隙分布，反映酸性溶液对砂岩的腐蚀程度；渗透深度随孔隙率的增大而增大，变化速率先快后慢，最后趋于稳定，说明基于Boltzmann方程构建的渗流模型对模拟砂岩受酸腐蚀过程具有较好的适用性。

Seepage characteristics of sandstone subjected to acid corrosion

In order to investigate the microscopic characteristics between the acid medium and the sandstone, based on the digital core model and the lattice Boltzmann equation, this paper carried out an simulation test of the acid corrosion process of the sandstone, and analyzed the seepage characteristics of the sandstone under different acidic environmental circumstances. Firstly, the structural changes of the internal mineral components of the acid-corroded sandstone were studied by CT scanning equipment. Then, the seepage model of the sandstone subjected to acid corrosion was constructed by combining the digital core of acid-corroded sandstone which is established by the visual image processing software Image J, Avizo and the lattice Boltzmann theoretical equation. The change rules of the internal pore structure and seepage characteristics of sandstone in the process of acid corrosion were analyzed. Results show that the mineral composition and pore distribution of sandstone and the corrosion degree of the sandstone by acidic solution could be revealed by CT scan tests. The penetration depth increases with the increase of porosity. The rate of increase is first fast and then slow when the porosity is large, and finally tends to be stable. It indicates that the seepage model based on Boltzmann equation has good applicability for simulating the acid corrosion process of sandstone.