Study on the channeling limit of polymer flooding in the conglomerate reservoir

The conglomerate reservoirs are known for their high degree of heterogeneity, which poses a challenge during polymer injection. Fluids tend to channel along dominant paths leading to premature appearance of polymer in the oil well. This phenomenon results in a rapid increase in water cut, leading to wastage of the polymer. Currently, there is no reliable method for identifying polymer channeling in such conglomerate reservoirs. To address this issue, this paper conducts physical simulation experiments on parallel cores under varying heterogeneous conditions based on the geological characteristics of the reservoir. The study analyzed and statistically evaluated the distribution ratio, water cut, and polymer concentration in the output under varying heterogeneous conditions. This analysis identified the distribution ratio and polymer concentration as key indicators of polymer channeling. Based on these findings, a comprehensive discriminant diagram of polymer channeling was established. The study found that the coefficient of permeability variation (CV) was the primary factor contributing to channeling. This diagram can be used to understand the underlying principles of polymer channeling and provide technical guidance for developing effective profile control schemes and optimizing site construction strategies.