Research on profile inversion pattern of polymer flooding

Abstract Polymer flooding is becoming more common and more successful, and has made a great contribution to EOR. However, the statistical analysis of water injection profile data shows that the injection profile easily inverses during the process of single slug polymer flooding in heterogeneous reservoir. It is unfavorable for enhancing oil recovery. According to seepage mechanics theory, the cognition is determined that the injection rate distribution in high and low permeability layers depends on reservoir heterogeneity and physicochemical property of polymer. The basic reason of profile inversion lies in the different dynamic variation of resistance factors in the high and low permeability layers. In order to use existing reservoir simulation software to accurately describe the profile inversion characteristics, a processing method is submitted which is that different polymer characteristic parameters and relative permeability curves are assigned to different regions according to the distributions of reservoir characteristics during polymer flooding. Then, this processing method is used for systematically studying the profile inversion laws of different permeability ratio, polymer concentration and injecting-polymer occasion. The results show that these factors have great influence on the profile inversion. This provides a technical support for studying the profile inversion rules and corresponding improvement method.