Pressure Transient Analysis of Wells in Shale Oil Reservoirs with ComplexHydraulic Fracture Networks Based on Numerical Approach

摘要

Due to the complexity of shale reservoir geology,hydraulic and micro-fractures can be coupled into anextremely complex symmetrical or asymmetrical fracture network around vertically fractured wells(VFW)after fracturing.The important and useful work is to analyze the transient pressure response of the VFW,tomore accurately predict the productivity of VFW.In this paper,a numerical method to accurately simulatethe complex fracture network geometry and analyze the transient pressure responses of the VFW,due tothe complexity of the fracture network geometry.The results show a longer fracture length on one sidecauses a smaller pressure depletion,a shorter bilinear flow,and a deeper and longer the degree of"dip".Themore fractures on one side can lead to a greater degree of"dip"and a smaller pressure depletion.With thefracture conductivity on the right side increases,while that in other side remains constant value,it results ina shorter bilinear flow,a deeper and longer the degree of"dip",a smaller pressure depletion,and a weakerbi-radial flow(BRF).In addition,it is found that flow regimes affected by magnitude of fracture networksare mainly bi-linear flow(BLF),"dip"and BRF.The pressure behaviors between asymmetrical fracturenetworks and symmetrical fracture networks are mainly in the periods of BLF,"dip",and BRF.Throughanalyzing the transient pressure responses of the VFW,the parameters of the complex fracture network canbe well predicted,so that the productivity of the VFW can be estimated more accurately.