A Critical Review of Hydraulic Fracture Propagation in Shale Gas Reservoirs

Abstract

The successful exploration and development of unconventional shale gas reservoirs was possible with advances in hydraulic fracturing and horizontal drilling. Hydraulic fracture treatments open these natural fractures and create a fracture network in gas shales. However, the fracture propagation is not fully understood as of now. A critical review of hydraulic fracture propagation in shale gas formations is presented in this paper. Effects of pertinent factors on hydraulic fracture propagation are described and discussed. The factors are classified into three categories: well completion, fracture treatment, and formation properties. Well completion factors include casing roughness, perforation friction, tortuosity, fracture reorientation, and horizontal wells. Fracture treatment parameters include fluid property change, friction due to proppant, variable injection rate, multi-phase flow, proppant transport, and multi-stage treatment. Formation properties include rock toughness, temperature and pore pressure expansion, stress anisotropy, natural fractures, Young’s modulus, and formation permeability. This review gives engineers and researchers a better understanding of fracture propagation in shale gas reservoirs. Keywords: Hydraulic fracturing, fracture propagation, shale gas reservoirs, net pressure