A Study On Optimization of Water-Viscosity Reducer-Polymer Combination Injection in Ordinary Heavy Oil Reservoirs

Abstract

According to the characteristics of extremely high viscosity and poor fluidity of heavy oil in Chenjiazhuang 25 block of Shengli Hekou Oil Production Plant, a sand filling pipe model was made, based on the results of simulated displacement test, the chemical agents such as viscosity reducer and polymer provided by Shengli were used to explore and evaluate the chemical agent dosage, injection mode and chemical agent combination displacement mode with the recovery rate and cumulative water cut as indicators. The final experimental results showed that the optimal injection amount of viscosity reducer was 0.3 PV. The final recovery ratio could be effectively improved by mixing polymer with viscosity reducer, and the final recovery ratio of the mixed injection of polymer and viscosity reducer was 10 percentage points higher than that of the separate injection of polymer and viscosity reducer. Through conversion injection and alternate injection experiments, it was finally determined that the best combination injection mode of chemical agent was to mix polymer and low interfacial tension oil displacement agent first and then to change into mixing polymer and viscosity reducer. The injection volume of the two slugs before and after the conversion was 0.15 PV respectively, and the total injection volume of the chemical agent was 0.3 PV. The injection timing of the chemical agent was selected after 1 PV of water flooding.