Stochastic optimization of hydraulic fracture and horizontal well parameters in shale gas reservoirs

Multistage hydraulic fracturing is one of the most important techniques in the successful exploitation and development of shale gas reservoirs. Most unconventional reservoirs rely on multistage hydraulic fracturing for commercial success. This success is accomplished by drilling horizontal well of appropriate length and creating transverse hydraulic fractures in stages across the well. Shale-gas reservoir's contact with the horizontal well bore is improved by using optimal well length, optimal fracture conductivity, optimum fracture length and optimum number of fracture stages. Because multistage fracturing of long horizontal wells increase the cost of field development, the economics of field development can be improved by using global optimization algorithms to estimate the optimum values of these operational parameters. In shale gas reservoirs, hydraulic fracture parameters such as fracture half-length, amount of proppant and fracture spacing should be optimized to maximize the net present value (NPV). In this work, differential evolution (DE) is implemented on a more realistic LGR-based shale gas reservoir simulation model. The objective is to maximize the net present value by optimizing hydraulic fracturing parameters and horizontal well length. Results obtained indicate that significant increase in NPV can be realized by using the optimization algorithm to estimate the operational parameters of hydraulic fracturing process in shale gas reservoirs.