Optimization of Gas-Flooding Fracturing Development in Ultra-Low Permeability Reservoirs

Ultra-low permeability reservoirs are characterized by small pore throats and poor physical properties, which are at the root of well-known problems related to injection and production. In this study, a gas injection flooding approach is analyzed in the framework of numerical simulations. In particular, the sequence and timing of fracture channeling and the related impact on production are considered for horizontal wells with different fracture morphologies. Useful data and information are provided about the regulation of gas channeling and possible strategies to delay gas channeling and optimize the gas injection volume and fracture parameters. It is shown that in order to mitigate gas channeling and ensure high production, fracture length on the sides can be controlled and longer fractures can be created in the middle by which full gas flooding is obtained at the fracture location in the middle of the horizontal well. A Differential Evolution (DE) algorithm is provided by which the gas injection volume and the fracture parameters of gas injection flooding can be optimized. It is shown that an improved oil recovery factor as high as 6% can be obtained.