A comprehensive review of remediation strategies for mitigating salt precipitation and enhancing CO2 injectivity during CO2 injection into saline aquifers.

ABSTRACT

Geological CO2 sequestration is a proven method for mitigating climate change by reducing atmospheric CO2 levels. However, CO2 injection often induces salt precipitation, leading to decreased formation permeability, which in turn limits CO2 injectivity and storage capacity. Conventional approaches, such as freshwater and low-salinity water injection, have been employed to mitigate salt precipitation. Despite their widespread use, these methods provide only temporary improvement and can be ineffective in some scenarios, resulting in long-term issues such as salt recrystallization and clay swelling. Given the complexity and significance of this issue, a comprehensive review of salt precipitation mechanisms and remediation techniques is essential. This paper critically examines the processes of salt precipitation during CO2 injection in saline aquifers and evaluates various remediation techniques aimed at improving CO2 injectivity. The paper reviews the influence of CO2 flow dynamics, geochemical reactions, and fluid properties on salt precipitation and pore throat accumulation, assessing the efficacy and limitations of existing mitigation methods. Additionally, the paper explores alternative techniques with potential for long-term CO2 sequestration, analyzing their advantages and drawbacks. Based on insights from the reviewed sources, the paper recommends exploring alternative treatment measures and the integration of hybrid solutions to enhance CO2 injectivity. The findings presented serve as a valuable reference for advancing research and practice in this critical area, offering a deeper understanding of the challenges and potential solutions for effective CO2 sequestration in saline aquifers.