The Simulation of Viscous Fingering by Diffusion-Limited-Aggregation Model Based on Pressure-Oriented Rule

摘要

Viscous fingering phenomenon happens during CO_2 flooding because of viscosity differences between CO_2 and crude oil. It leads to premature breakthrough of displacement fluid and decrease of sweep efficiency. In this paper, a three dimensional Diffusion-Limited-Aggregation model based on pressure-oriented rule is presented to account for the effect of viscosity ratio, injection rate on viscous fingering. Furthermore, Digital cores in our simulation are obtained by CT experiment from real rocks. The results show that viscosity difference is the dominating factor that influences viscous fingering. With the increase of viscosity difference between the two displacement fluids, sweep efficiency decreases dramatically. At appropriate injection rate, the effect of viscous fingering can be decreased.