基于格子气自动机的岩心数值实验新方法

A New Method for Numerical Experiments on Porous Rocks with Lattice Gas Automata

具有复杂孔隙结构的非均质油气藏岩石物理参数的实验测量一直是花费高昂而又困难的工作。在细胞自动机基础上发展起来的格子气自动机从模拟多孔介质微观结构入手,用大量简单规则的局域作用来表现整个多孔介质中流体流动的宏观复杂性,提供了一种研究多孔岩石微观孔隙结构对宏观特性影响的新方法。利用2D格子气自动机分别计算了两相和三相多孔介质的电导率,数值计算结果与油田岩心实验测量结果具有相同的变化规律,揭示了储层岩石微观孔隙结构复杂性在宏观电性上的表现,同时数值实验具有可观测多孔介质微观孔隙结构和流体分布状态,且不受孔隙度和饱和度大小限制的优点,可为复杂非均质油气藏的开发提供重要的岩石物理信息,是一种有应用前景的岩心数值实验新方法。

Petrophysical experiments have been run into difficulties in accurately measuring petrophysical parameters of inhomogeneous reservoir rocks with complex pore structure. The Lattice Gas Automata (LGA) developed from cellular automata, which is based on knowledge of the microscopic scale of porous media, is capable of modeling the rich complexity of macroscopic porous fluid flow with simple local interactions rules. It provides a new method for studying the effects of microstructure on the effective macroscopic properties of porous rocks. In this paper, 2D LGA is used to calculate the effective electrical conductivity of two phases and three phases media respectively. Numerical experimental results agree well with the results from rock sample testing. It is capable of exhibiting macroscopic properties of porous media origined from microstructure complexity. In addition, numerical simulations have the advantage of visualizing microstructures and fluid distributions in porous media with no restriction on the porosity and fluid saturation ranges. It can provide important petrophysical information for development of complex inhomogeneous reservoir. It is a new method for numerical experiments on porous rocks with better application prospect.