Fate and Transport of Sulfonated Polymeric Inhibitors in the Reservoir: Studied by Column Experiments With Calcite Media

Sulfonated polymers are frequently used in the oil and gas industry to prevent inorganic scale damage, but studying their fate and transport in reservoirs has been difficult due to the challenges in analyzing them at effective concentrations. Recycling inhibitors in reservoirs necessitates inhibitors that do not adhere strongly to mineral surfaces, making polymeric inhibitors a promising option. This research aims to examine the sorption and transport of sulfonated polymeric inhibitors in calcite-packed columns using the Brine Chemistry Inhibitor (BCIn) technique, with the goal of recycling the inhibitors, specifically in the Permian basin. The BCIn method was used in this study to determine concentrations of sulfonated inhibitors, which had been shown to be reliable for measuring polymeric inhibitors at near ppm levels. The study began with conducting batch experiments on barite and calcite salts to gain initial insights into the adsorption properties of inhibitors. Next, flow-through experiments were performed where sulfonated inhibitors were injected into a column packed with calcite, followed by a flow-back test. Different sulfonated polymeric inhibitors were tested under various temperatures in the lab’s synthetic brine matrices. The concentrations of sulfonates versus injected time were plotted to assess the retention of inhibitors on rock surfaces. A commonly used phosphonate scale inhibitor (DTPMP) was included for comparison of adsorption characteristics. The experimental findings suggest that sulfonated polymeric inhibitors exhibit limited adsorption capacity but strong binding between inhibitor molecules and mineral surfaces. An inhibitor treatment scenario is proposed, where the first injection is used to saturate the surfaces of rocks, and subsequently, produced water containing low-concentration inhibitors can be recycled. The research expands our understanding of sulfonated polymeric scale inhibitors’ fate and transport in reservoirs, overcoming the challenge of analyzing polymeric inhibitors at low concentrations. The results provide evidence supporting the potential of applying polymeric inhibitors via injection wells for safeguarding production.