Perforation cluster spacing optimization with hydraulic fracturing-reservoir simulation modeling in shale gas reservoir

Understanding the hydraulic fracture propagation behavior of numerous clusters and its effects on final gas production is crucial for the successful development of shale gas reservoirs. This study introduces a methodology that combines hydraulic fracturing with the modeling of the production of a shale gas reservoir. A loose coupling approach is used to solve independent governing equations in the fracture and reservoir domains of two discretized separate domains. Complex fracture propagation paths are captured using the XFEM (extended finite element method) program. The simulation of shale gas production is also made more realistic by considering the Langmuir isotherm effect and non-Darcy flow. According to numerical models of hydraulic fracture propagation and shale gas production, the eventual shale gas output is sensitive to the actual hydraulic fracture path. Comparing the fracture geometry shows that the simultaneous fracturing design scheme has more complex fracture propagation than the sequential hydraulic fracturing design scheme. For the simultaneous fracturing design scheme, more intense stress interaction can result in stronger deflection. Whereas, in the sequential hydraulic fracturing design scheme, fracture deflection mainly occurs at the fracture tip area. Additionally, an increase in perforation may result in more fractures with deviating trajectories. Thus, it is more desirable to couple the curved hydraulic fracture stimulation and shale gas reservoir production modeling for the simultaneous fracturing design scheme. Because of the competition of closed hydraulic fracture, the final gas production is not positive with perforation number in both different fracturing schemes. The application submitted utilizing this approach shows that, in this particular scenario, gas generation using curved fracture geometry can provide greater performance than the typical straight fracture geometry assumption. Field operators may gain additional knowledge in choosing the best well completion scenario for a given set of geological parameters from the optimization fracture clusters along the horizontal well concerning production.