Novel Green\nStrategy Based on Combination of CO<sub>2</sub>/Protic Poly(ionic\nliquids) for Enhancing Crude Oil Recovery

Carbon\ndioxide (CO<sub>2</sub>) contributes to erratic\nclimate\nchanges as a greenhouse gas in the atmosphere, highlighting the need\nfor effective carbon capture, storage, and conversion strategies.\nThis study introduces a green solvent approach using protic poly(ionic\nliquids) (PPILs) for CO<sub>2</sub> chemisorption to improve enhanced\noil recovery (EOR) methods through gas/polymer flooding. The PPILs\nwere synthesized by copolymerizing quaternized triethanolammonium\n2-acrylamido-2-methylpropanesulfonate (QAMPS) with an equimolar amount\nof triethanol ammonium acrylate (QAA) via radical polymerization,\nresulting in QAMPS/QAA copolymers. Similarly, QAMPS was copolymerized\nwith equimolar amounts of 2-hydroxyethyl methacrylate (HEMA) or <i>N</i>-vinylpyrrolidone (VP) to produce QAMPS/HEMA and QAMPS/VP\nprotic PILs. The study examined the chemical structure, thermal degradation\nstability, and transitions. The thermal degradation of QAMPS/QAA,\nQAMPS/HEMA, and QAMPS/VP was obtained at initial degradation temperatures\nof 210, 275, and 150 °C, respectively. The rheological properties\nof these PPILs to assess their effectiveness in CO<sub>2</sub> solubilization,\nabsorption, and desorption at both atmospheric and high pressures\n(800 psi) in formation water for potential application in EOR gas/polymer\nflooding strategies were examined. Additionally, the research explores\nthe dynamics of CO<sub>2</sub> uptake by PILs and the ensuing alterations\nin their viscosity, which are crucial for enhancing the performance\nand success of EOR processes. Flooding on a 1D sandstone model revealed\noil recovery rates of 38.9% for QAMPS/HEMA, 35.3% for QAMPS/VP, and\n35% for QAMPS/QAA, relevant to residual oil saturation (%<i>S</i><sub>or</sub>).