裂隙-孔隙介质等效渗透率的数值试验研究

Numerical Experimental Research of Equivalent Seepage Characteristic for Fractured Porous Media

摘要: 等效渗透率的影响因素一直是裂隙–孔隙双重介质渗透性研究中的难点。为了更好地研究裂隙–孔隙多孔介质的渗透特性，基于流体力学、渗流力学耦合作用原理，建立了裂隙–孔隙双重介质数学模型，得到了双重介质等效渗透率的计算公式。利用Comsol Multiphysics计算方法，研究了裂隙宽度、裂隙与压力梯度作用面角度及压力梯度对双重介质水平等效渗透率的影响规律。计算结果表明：1) 裂隙中的流速是孔隙中流速的104~107倍，裂隙宽度对水平等效渗透率的影响最大，起主导作用；2) 水平等效渗透率随裂隙与压力梯度作用面角度的增大而减小，从40?至45?之间减小的最为明显；3) 水平等效渗透率随压力梯度的增大而略有减小，压力梯度的大小对水平等效渗透率的影响不大。 The influencing factors of effective permeability have been a difficult point in studying seepage characteristic of pore-fissure media. In order to investigate the seepage characteristic for pore-fissure media, considering the coupling of fluid mechanics and seepage mechanics, the numerical experimental was made and solved for Comsol Multiphysics with FEM (finite element). Based on the numerical experimental results, the paper discussed the relationship among the horizontal effective permeability of pore-fissure media, the width and angle of the fracture. The results shown: 1) The velocity in fissures was 104 - 107 times faster than in pores. The width of the fracture played a leading role in horizontal effective permeability of pore-fissure media; 2) The angle between the fracture and the pressure gradient bigger, the horizontal effective permeabil-ity smaller. The decrease was the most obvious from 40? to 45?; 3) The pressure gradient had little impact on the horizontal effective permeability.