Hybrid Self-adaptive Polymer: A Novel EOR Technique to Maximize Oil Recovery

Abstract

A significant amount of remaining oil is left behind in candidate consolidated sandstone reservoir region and has the potential to be recovered. However, the fluid incompatibility under harsh reservoir conditions hinders EOR performance of polymer flooding, leading to degradation of polymer solution and formation damage. Polymer flooding is a widely applied chemical enhanced oil recovery (EOR) method designed for recovering bypassed oil by improving viscosity of displacing fluid. This research proposed a comprehensive polymer flooding strategy to diminish the degradation of polymer solution and minimize the formation damage in reservoir condition by integrating rock characterization, polymer screening studies, formation damage investigation, and oil displacement efficiency experiments. A self-adaptive polymer (SAP) with shear-thickening feature was systematically tested and studied for the first time. The factors affecting bulk rheology, polymer retention, and oil displacement efficiency were experimentally investigated and compared with regular partially hydrolyzed polyacrylamide (HPAM) polymer, including polymer concentration, polymer type, solution brine salinity, solution brine hardness, formation brine salinity, and formation brine hardness. Bulk rheology test was conducted to compare bulk viscosity of each polymer solution at different temperature and shear rate. Formation damage test was conducted through coreflood experiments to investigate mobility control ability and formation damage of candidate polymer solutions. Drainage and displacement efficiency experiments were also conducted to investigate the performance of candidate polymer solution on oil recovery efficiency. The novelty of this integrated study lays the foundation for a thorough and bespoke screening EOR study, which is currently under development for an offshore candidate field. Preliminary screenings were also conducted through core flooding with representative outcrops. An understanding of the integration of various reservoirs and fluid properties is essential in determining the characteristics of the entirety of the candidate reservoir. Incorporating these complex zones in an integrated reservoir characterization study is fundamental in achieving successful EOR deployment and optimizing oil production.

Date of Award	Jul 2022
Original language	American English