Effect of Density, Trace Length, Aperture, and Direction Angle on Permeability Performance of Fracture Networks

Abstract

A fractured rock mass was characterized by strong heterogeneity, discontinuity, and anisotropy. The study of flow in a fractured rock mass was a complex and challenging task. As the main seepage channels of a fractured rock mass, the fracture network was mainly affected by the fracture density, trace length, aperture, and direction angle. In this paper, the influence of fracture parameters on the permeability of the fracture network was studied by orthogonal experimental design and numerical modeling. A series of fracture networks were established to obtain seepage rules and permeability. The results showed that the increase in fracture density, trace length, and aperture increased the permeability of the model and that the fracture direction angle affected the pressure gradient and the anisotropy of the seepage in the model. The sensitivity of effective parameters on the discrete fracture network permeability performance was obtained. The influence factors of K1 were density, trace length, aperture, and direction angle in that order. The influence factors of K2 were direction angle, density, aperture, and trace length, in that order. The influence factors of K1/K2 were direction angle and density, aperture, and trace length in that order. These results could be used for parameter adjustment of fracture network modeling and determining the complex seepage characteristics in naturally fractured reservoirs.