Choke management simulation for shale gas reservoirs with complex natural fractures using EDFM

Abstract

In this study, the non-intrusive EDFM (embedded discrete fracture model) method was presented to investigate the impact of different choke management strategies on well performance. Through the EDFM method, accurate simulation can be conducted to efficiently evaluate the fracture complexities. First, by implementing this powerful technology, a horizontal well with multi-stage hydraulic and natural fractures was set up, where the permeability can be distributed sequentially in each hydraulic fracture segment. Then various pressure drawdown scenarios from conservative to aggressive strategy were designed. The different levels of fracture closure can be properly modeled in each state. Additionally, pressure distribution for the matrix and fractures was depicted to provide straightforward insights for the choke management under two extreme strategies. Subsequently, a series of sensitivity studies were presented to evaluate the impacts of various factors on shale gas production, including fracture permeability modulus, fracture closure, and natural fractures network. The simulation results show that choke management can be simulated effectively by applying EDFM. After considering the fracture closure behavior and complex fracture networks, the conservative drawdown strategy can be addressed as the optimal strategy for the EUR, as it improves the cumulative gas production by maintaining the hydraulic fracture open through a steady pressure decline. The remained proppants enhance the fracture conductivity, thereby expanding its drainage influence towards larger zones of the reservoir. The influence of natural fractures, including the fracture length, fracture number, and fracture conductivity, are also studied. All these three variables play a significant impact on well performance. Consequently, the model becomes a valuable stencil to design fracture closure and complex fracture networks, which can be applied to optimize the choke management design for unconventional reservoirs.