Impacts of T-type intersections on the connectivity and flow in Complex two-dimensional fracture networks

Abstract

Natural fractures usually form T-type intersections, but the impacts of T-type intersections on the connectivity and flow results (such as permeability and fluid production) in complex fracture networks are rarely investigated. Here, a stochastic discrete fracture network method is implemented to construct complex two-dimensional fracture networks, denoted as original fracture networks. By implementing the rule-based fracture growth algorithm, the corresponding kinematic fracture networks are generated with a substantial proportion of T-type intersections. The connectivity and flow results of both the single-phase and two-phase flow simulations in these two types of fracture networks are systematically investigated. The results show that kinematic fracture networks tend to connect more fractures with fewer intersections and yield better connectivity than the original ones. Most kinematic fracture networks have larger permeability in the single-phase flow simulation and higher cumulative gas production in the two-phase flow simulation than original fracture networks under the same boundary conditions. The proportions of permeability and production enhancement are 68% and 77%, respectively. Flow results have strong positive correlations with the connectivity of fracture networks, but they are nonequivalent and strongly impacted by the number of inlets and outlets.