A new analysis model for heterogeneous shale gas reservoirs

Abstract

In this paper, a new analysis model (MNH), which considers the interactions of flow regimes in matrix, natural fractures and hydraulic fractures, is developed for heterogeneous shale gas reservoirs. In this model, the gas flow in shale matrix is described by non-Darcy law and gas desorption is also considered. Gas flow in discrete natural fractures follows the cubic law in each fracture and these natural fractures are described by a discrete fracture model. An equivalent method is put forward to describe the flow regime in hydraulic fractures. This model is used to analyse the flow regimes of shale gas flow within a multi-stage fractured horizontal well. It also investigates the influences of gas desorption, fracture aperture, spacing and number on the gas production rate. The results show that the MNH model can provide insights into flow mechanisms and production prediction for a multi-stage fractured horizontal well in shale gas reservoirs. [Received: November 2, 2017; Accepted: June 19, 2018]