Enhanced oil recovery and CO2 sequestration potential of Bi-polymer polyvinylpyrrolidone-polyvinyl alcohol

Abstract

In this study, the efficacy of blend, of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), was explored for enhanced CO2 absorption and thereafter, used polymer enhanced carbonated fluid for flow behaviour and oil recovery from synthetic porous media of sand, prepared by wet-ramming of sand in sand-pack. Initially, PVA-PVP blends of varying wt% (2–5 wt% PVA and 1–3 wt% PVP) were formulated and their stability along with potential for CO2 absorption were investigated via viscosity measurements and thermogravimetric analysis over varying pressure, temperature, and saline conditions. Thermal stability results indicated that the performance of PVA-PVP solutions was better (than pure PVA solution) even at 150 °C. Comparative viscosity tests indicated that the impact of adverse conditions was least on PVA-PVP solutions consequently, these solutions proved to be excellent CO2 carrier fluid after CO2 solvation experiments in an equilibrium cell. Rheological results indicate strong interactions between PVA and PVP which was understood by the formation of new bonds in solution causing an increase in the viscosity and solid like nature of solution. Finally, these solutions were used as EOR agents for oil recovery from a porous media. The oil recovery tests were performed at a temperature of 40 °C and reservoir salinity of 4 wt% NaCl and these results indicated that PVA-PVP solutions displayed enhanced oil mobilization in these conditions. As a result, oil recovery improved by 12–18% original oil in place (OOIP). Thus, based on the results of this study, it can be anticipated that newer polymer composites of PVA-PVP exhibited better synergy with CO2 and act as CO2 carrier fluid for improved oil recovery and enhanced carbon storage. In addition, they are viable candidates for use in elevated temperature and saline conditions of oil reservoirs.