二维裂隙密度及其渗透率的逾渗关系研究

Study of the Percolation Relationship between Fracture Density and Permeability of 2-D Facture Networks

摘要: 在低渗透介质储存中，裂隙是石油运移的主要通道。因而裂隙介质的渗透率是石油勘探的一个重要参数。应用连续逾渗模型分析，把低渗透储存的裂隙网络合理简化，能够对深层复杂介质的渗透规律进行研究。使用排除体积对裂隙密度进行无量纲化，从而使裂隙的宏观性与裂隙的形状无关。使用Monte Carlo方法模拟得到不同裂隙密度时的裂隙网络图，然后基于连续逾渗模型，采用有限元方法利用COMSOL Multiphysics求解器解，数值模拟得到裂隙的渗透率与无量纲化密度成乘幂关系。该模拟结果可能为裂隙网络渗透率的定量评价提供一个简单而又实用的方法。这一规则的发现也增强了逾渗理论在油气田勘探中的应用。

Abstract: Fracture networks strongly influence oil migration in reservoirs, especially in low-permeability reservoirs. So the parameter of fracture permeability plays an important role during the exploration of oil and gas fields. Simplifying the fracture network of reservoirs, and continuum percolation theory are successfully applied for studying the fracture permeability in deep and complex media. By using excluded area to dimensionless the fracture density, macroscopic properties of fracture networks become independent of fracture shape. Using Monte Carlo simulation, the facture net-work with different fracture density is obtained, and then based on continuum percolation theory and finite element analysis software, called COMSOL Multiphysics, we get the relationship between dimensionless density and macro-scopic permeability, which is scaling law. The simulated results may offer a simple and practical method to evaluate frac-ture permeability quantitatively and enhance the applications of percolation theory in the exploration of oil and gas fields.