Effect of variable fracture permeability/matrix permeability ratios on three-dimensional fractured rock hydraulic conductivity

A sensitivity analysis is implemented using the boundary integral method to determine the relative contribution to total liquid flow through a rock block both by flow through the rock matrix and by flow through discrete fractures embedded within the rock matrix. Total liquid flow through a rock block with embedded fractures of arbitrary density, orientation, permeability, shape, and areal extent is simulated by discretizing the fracture-matrix boundary and the exterior surface of the rock sample using boundary elements. Steady liquid flow through fractures is computed by creating nodes along the outer rim of each fracture and then routing between nodes within the fracture plane using a two-dimensional boundary integral formulation. Flow between fractures is calculated by assigning boundary nodes along fracture intersections. Liquid flow through the rock matrix is calculated by employing a three-dimensional boundary integral formulation for nodes on fracture boundaries and on the exterior surfaces of the rock block. -from Authors