Quantitative Characterization of Blockage Patterns Based on Polymer Retention in Offshore Oil Fields

Bohai L Oilfield is the first early polymer injection oilfield in China, and some wells produce polymer blockage after polymer flooding, which seriously affects the oilfield’s polymer flooding effect and production capacity release. In order to improve the success rate of polymer blockage well treatment, quantitative research is conducted on the polymer blockage pattern. This article characterizes polymer blockage by the decrease in liquid volume after polymer injection. Based on the polymer formation retention model and mercury intrusion curve, the underground polymer distribution pattern was characterized by calculating four parameters: formation permeability, porosity, polymer formation retention concentration, and the decrease in liquid volume after polymer injection. A quantitative relationship was established between the change in liquid volume after polymer injection and the physical properties of the oilfield reservoir, and the law of polymer plugging was explored. The research results indicate that when the original permeability of Bohai L oilfield is less than 750 mD, polymer plugging occurs, and the decrease in liquid volume sharply increases, reaching 30% to 60%.This method provides a quantitative basis for the identification of aggregation and blockage patterns, guiding the prediction of aggregation and blockage patterns and carrying out targeted governance.