NUMERICAL SIMULATION OF THE INFLUENCE OF FRACTURES ON SEEPAGE IN MATRIX^1)

A steady state seepage model of fractures in homogeneous matrix is established and velocity and pressure distribution are obtained by numerical simulation. It is found that fractures cause source and confluence effects in matrix and thus the influence on matrix seepage by parallel and cross fractures of different distributions is analyzed. Furthermore possible consequences of different fractures are evaluated in view of oil and gas exploitation and displacement. The results show that at the fracture ends pressure changed suddenly and correspondingly the velocities changed sharply. For the matrix the fracture inlet is equal to confluence and the outlet equal to source. The symmetric fracture distribution leads to decrease of the flow in the surrounding matrix and the fracture flow is the main part in the cross section, however the asymmetric fracture distribution is conducive to increase flow in the matrix.