Novel adsorption mechanisms identified for polymer retention in carbonate rocks

High molecular weight polymers are widely used in oilfield applications, such as chemical enhanced oil recovery (cEOR) technique for hydrocarbon recovery. However, during flow a porous rock, polymer retention is usually major challenge, it may result the decrease of concentration or lead to plugging pores with significant permeability reduction and injectivity loss. Hence, an understanding mechanisms will have profound effect optimizing process flooding, particular, carbonate rocks, which hold more than half world's reserves. Therefore, this study, hydrolysed polyacrylamide (HPAM) polymer, commonly EOR, investigated Estaillades rock. A novel approach investigating HPAM rock was carried out using Atomic force microscopy (AFM). Since ∼98% calcite, first characterised on cleaved flat calcite mineral surface after immersing solution. Afterwards, flooded observe dynamics mechanisms. We find that dominant mechanism fluid immersion adsorption, we believe driven by electrostatic interaction between The thickness adsorbed layer beyond 3 ​nm suggesting not only surface. Different types layers were formed representing trains, extended loops tails largest about 35 ​nm, longer tails. Layers begin impair Estaillades, thicker observed different regions ranging 50 350 ​nm. suggest due either mechanical entrapment and/or entanglement cause impairment rocks.