A multi-well interference pressure transient analysis method to determine the water source orientation of multi-fractured horizontal well

Key words:  multi-fractured horizontal well  unequal liquid-production rate  multi-well interference pressure transient analysis  well connectivity  water source orientation.

Abstract:

In order to determine the connectivity between injection wells and multi-fractured horizontal well (MFHW) accurately, a multi-well interference pressure transient analysis (MWIPTA) model was developed in this study, in which the effects of unequal liquid-production rate of fractures and the interferences from adjacent injection wells on pressure-transient behaviors were considered. The solutions of the model in terms of pressure drop were derived on the basis of the Green function and a Newman product method, and the characterization curves of bottomhole pressure were figured out along with a sensitivity analysis of important influencing factors. A typical MWIPTA curve can be divided into several flow regimes. In the interference flow regime, the pressure derivative curve will descend and higher injecting rate of the adjacent active wells can cause greater decline on the pressure derivative curve. When the total injection of the adjacent wells is smaller than the production of the MFHW, the pressure derivative curve will descend in a stepwise manner. When the total injection of the adjacent wells is bigger than the production of the MFHW, the pressure derivative curve will descend all the time. In addition, the closer distance between the MFHW and the adjacent injection wells, the longer interference flow regime will last. The results of a case study show that the model can be used to determine the connections between the injection wells and the MFHW and identify the water source orientation of the MFHW accurately, which can provide guidelines for increasing oil production of the MFHW.