Potential effective criteria for selection of polymer in enhanced oil recovery

Abstract

The major benefits of using polymers based EOR include an increase of viscosity of the injected water, increasing sweep efficiency, and reduction in mobility ratio. A variety of polymers are available in the market, yet every polymer is unusable for any field, thus posing selection and how to use challenges in novel EOR technology. This paper focuses on the screening of polymer based on filtration ratio and rheological tests. The Filtration Ratio (FR) test of the polymer solutions has been investigated to check the hydration properties of PHPA polymer by passing it through the nitrocellulose filter paper. The results indicated that FR less than 1.2 ensures proper hydration only if the proper size of filter paper is selected and the filter paper should withstand the pressure. Whereas the presence of monovalent ions slightly increases the FR thus causing the formation of early Filter Cake but can still be used only if FR is less than 1.2. These findings may help the industry to compare wide variety of polymers solutions for a specific well. Only those polymers would be used which passes FR test with little or no filter cake for further rheological tests, thus ensuring proper utilization of available time.

Keywords:

• enhanced oil recovery
• filter ratio test (FR test)
• partially hydrolyzed polyacrylamide (PHPA)
• rheology
• viscosity