Pressure transient behaviors for horizontal wells with well interferences, complex fractures and two-phase flow

Abstract

During the production of multi-stage, multi-well pads in shale reservoirs, there are common phenomena of well interferences, complex fracture generation, and multi-phase flow for the multi-well pad. However, there still lacks an understanding on the pressure transient behaviors with those phenomena. To narrow this gap, the pressure transient behaviors of oil-water two-phase flow of fractured horizontal wells with complex fractures and well interferences are studied by a numerical pad-well model, based on PEBI grids and discrete fracture model (DFM).The pressure transient solutions of fractured horizontal wells with complex fractures and well interferences have been demonstrated by model verifications and field applications. The results show that the flow regime of interference effects is stronger when the child well has a larger production rate, a smaller well spacing, more secondary fractures, longer secondary fractures, and higher fracture conductivity. It is also found that the formation pressure loss increases with increasing oil phase viscosity and oil volume factor when the viscosity of water is constant. The oil/water volume factor mainly affect the well testing interpretation of parameters such as wellbore reservoir coefficient. What's more, the field application shows that the well testing data are interpreted and the fracture parameters are evaluated successfully with well interferences, while the single-well testing model without considering well interference cannot match with field data at the late stage and the estimation errors will occur. This work is meaningful to understand the well interference and to evaluate the fracture parameters in multi-stage, multi-well pad with multi-phase flow.