利用格子Boltzmann方法确定岩石孔隙空间中的气水分布

Determination of Gas-water Distribution in Reservoir Pore Using Lattice Boltzmann Method

基于三维数字岩心模拟岩石电阻率时,最关键的一步是获取不同含水饱和度的岩心,确定不同含水饱和度下岩石孔隙空间的流体分布,常用方法的数学形态只是一种数字图像处理技术,并未考虑流体自身的物理特性以及流体与岩石骨架、流体与流体之间的相互作用。采用格子Boltzmann方法模拟了气水分离过程,确定了储层岩石孔隙空间中的气水分布,能真实地再现表面张力、润湿性等基本界面现象。该数值模拟方法得到的气水分布规律与澳大利亚国立大学数字岩石物理实验室的X射线CT扫描实验结果基本吻合。为开展气岩石声电特性数值模拟研究奠定了基础。

The key step in the simulation of rock resistivity based on 3 D digital cores,is to obtain the cores with different water satura- tion and to determine the fluid distribution in the pore of the cores. The mathematical form of the commonly used method of completing this step is only a digital image processing technique,in which the physical properties of the fluid itself, as well as the interaction be- tween the fluid and the rock skeleton, the fluid and the fluid, are not considered. The gas-water separation process was simulated and the gas-water distribution in reservoir pore was determined using Lattice Bohzmann method, which can reproduce the basic interface phe- nomena such as surface tension and wettability. The gas-water distribution law in reservoir pore obtained using the numerical simulation method is consistent with the experimental result obtained by X ray CT scanning in the Digital Rock Physics Laboratory of Australian National University, which lays the foundation for the research on the numerical simulation of the acoustic and electrical properties of natural gas reservoirs.