A comprehensive reservoir simulation technique based on time-varying petro-physical parameters characterized by effective displacement flux

Key words:  water flooding  time-varying petro-physical properties  numerical simulation  displacement flux  remaining oil

Abstract:

During water flooding process, the physical properties of the reservoir can be changed due to high water erosion, which can affect the distribution of the remaining oil. In this study, in order to accurately simulate the distribution of the remaining oil under time-varying reservoir conditions, an effective displacement flux was used to quantitatively characterize the time-varying behavior of the petro-physical parameters based on laboratory experiments and mineral data of the reservoir rocks, and to form a new reservoir simulation technique based on a time-varying petro-physics model. A conceptual model was established using the time-varying model to analyze the impact of different time-varying parameters on the distribution of the remaining oil. The results show that, when the permeability changes with time, more water channeling can occur, inducing a negative effect on oil production. If the viscosity of the crude oil increases during water injection, the water-to-oil mobility ratio will decrease, resulting in viscosity fingering and poor displacement and sweeping efficiency. On the other hand, if the relative permeability of oil phase increases with time, the mobility of oil phase will increases, which is conducive to oil displacement. The results of a case study for an oil block indicate that the accuracy of history matching using the new model can be improved by over 7% after the time-varying petro-physical properties were considered. The new reservoir simulation technique can continuously characterize the dynamic changes of the important petro-physical properties during water flooding, which can increase the reliability of the simulation results on remaining oil distribution, and provide useful guidelines for further production optimization.