A Numerical Model for Pressure Transient Analysis in Fractured Reservoirs with Poorly Connected Fractures

Abstract

Given that some fractured reservoirs have poorly connected natural fractures, the conventional Warren and Root model (1963) may not applicable. To narrow this gap, we introduce a numerical method to build a dual-porosity model for those reservoirs. To verify this numerical model, we perform a case study with a semianalytical model (SPE-187290-MS) for a discretely fractured reservoir. During the model verification, the pressure response from this numerical model are compared to the semianalytical results for fractured reservoirs with poorly connected fractures. It is found that the difference between the pressure responses obtained by these two models is negligible. Results show that pressure transient behaviors of wells with intersecting fracture exhibit completely different flow regimes with those without intersecting fracture. Bilinear flow, linear flow, transient flow, and pseudo-radial flow may progressively occur for intersecting fracture. A radial flow in matrix occurs for discrete fractures, before the impacts of nature fractures exhibit. Once these impacts are detected, the pressure derivatives show a dual-porosity feature "V-shape", which is virtually quite different from that in Warren and Root's dual-porosity model.