Evaluation of Salt Dissolvers for CO2 Injectivity Improvement

Abstract This study addresses the critical challenge of salt precipitation during carbon dioxide (CO2) sequestration in saline aquifers and its detrimental impact on injectivity. Focusing on the evaluation of potential salt dissolvers, the research evaluates the efficacy of 1-ethyl-3-methylimidazolium chloride ([EMIM][Cl]) and Zinc Chloride-Urea Deep Eutectic Solvents (DES) in improving CO2 injectivity through the dissolution of precipitated halite. Employing Berea sandstone as a representative porous medium, this study adopts a comprehensive experimental approach, including relative injectivity change (RIC), porosity change, and weight change to assess permeability improvement post-treatment and halite dissolution. The results highlight the superior performance of [EMIM][Cl] in dissolving precipitated halite. However, the Zinc Chloride-Urea DES used in this study was reactive to water, dissolving into its constituent ions and causing more precipitations inside the core sample. The best RIC value obtained is from 10% v/v concentration of DES used for 24 hours which is -0.511 while the second-best RIC value obtained is from a 2000 ppm concentration of EMIM[CL] used for 24 hours which is -0.356. From this project, the best duration for using the treatment solution is 24 hours and the best treatment solution is EMIM[CL] with 2000 ppm concentrations. Future directions should focus on DES with non-metal Hydrogen Bond acceptors (HBA) such as chlorine chloride, further investigating their effectiveness in dissolving precipitated halite, paving the way for more sustainable and accessible solutions for carbon capture and storage (CCS).