Experimental Studies of Sulfonated Polymer Adsorption in Carbonates Under Challenging Conditions

This study investigates the dynamic adsorption behavior of an ATBS-rich hydrolyzed polyacrylamide (HPAM) polymer onto two different permeability carbonate rocks under varying salinity and high temperature conditions. The approach followed here is aimed at unraveling the complexities of polymer-rock interactions during enhanced oil recovery (EOR) operations and focuses on evaluating dynamic polymer retention in coreflooding experiments performed at 80°C. The analytical techniques used in this research include Ultraviolet-visible (UV-Vis) spectroscopy, Inductively Coupled Plasma (ICP), and Rheometry, which were employed to analyze the behavior of the polymers under these specific conditions. Notably, the results demonstrate that polymer retention levels are significantly influenced by the salinity of the brine and the permeability of the core. In the case of using diluted brine (5,767 ppm) and high permeability core (419 mD), polymer retention levels were substantially lowered, recorded at 37 µg/g-rock. Conversely, in the higher salinity seawater environment (57,670 ppm) combined with a lower permeability core plug (195 mD), retention levels were higher, reaching 57 µg/g-rock. This variation in polymer retention was further supported by the observed low residual resistance factor in conditions where lower polymer retention was recorded. Additionally, the study identified the occurrence of shear thickening behavior for the AMPS-based polymer during in-situ rheology characterization. These findings are crucial for understanding polymer behavior in different reservoir conditions, providing valuable insights for optimizing enhanced oil recovery processes.