Performance of Shale Gas Reservoirs with Nonuniform Multiple Hydraulic Fractures

Abstract

Unconventional shale gas resource has become a very significant base throughout the world. Potential shale gas resource is huge and production has increased over the last few years. In this study, extensive numerical simulations were conducted to compare productivity of shale gas reservoirs with nonuniform configuration of hydraulic fractures. Nonuniform multiple hydraulic fractures are characterized by various fracture spacing and half-length. A dual permeability model with logarithmically spaced local grid refinement technique is applied to represent a system of natural fractures, shale matrix, and a hydraulically fractured horizontal well in shale gas reservoirs. Nonuniform fracture spacing leads to the overlap of gas drainage areas and lower productivity. Nonuniform fracture half-length also affects decline of cumulative gas production because pressure drop does not reach tips of long fractures at early time. For best productivity, equally-spaced fractures of uniform half-length are recommended.