Oil-displacement Efficiency Evaluation on Polymer Alternative Injection in Heterogeneous Conditions

摘要

We used 6 parallel homogenous cores to simulate heterogeneous reservoir and made laboratory experiments of polymer flooding after water flooding. Then we compared such indexes as shunt fraction, water cut and recovery efficiency of different alternative injection cycles in polymer flooding stage. The results show that, profile reversal in polymer flooding can be better restrained and postponed with 0.2PV alternative cycle, the fluid entry proportion of low-permeability reservoir is bigger, low point water cut duration is longer, and the recovery efficiency is higher. We also analyzed the cause of profile reversal in polymer flooding incorporating resistance coefficient, and we think profile reversal takes place when resistance coefficient changing rates between high and low permeability reservoir are equal.