Enhanced Oil Recovery and CO2 Storage by Enhanced Carbonated Water Injection: A Mini-Review

Carbonated water (CW) injection refers to a development method that involves dissolving CO2 in water under specific temperatures and pressures, followed by its injection into reservoirs for oil recovery. This technique can simultaneously enhance oil recovery and facilitate CO2 storage, although its effectiveness requires further improvement. To address this, an advanced approach known as enhanced carbonated water (ECW) injection has been proposed. This approach involves the addition of other fluids to CW, including polymers, nanofluids, surfactants, and low salinity water, to serve as displacement media during oil recovery. It aims to leverage the advantages of various technologies to further enhance oil recovery and CO2 storage effectiveness. Although ECW injection exhibits significant application potential, a systematic summary of its research progress is still lacking. Therefore, this article aims to fill this gap by systematically summarizing the latest research on ECW injection, detailing the mechanisms and performance in enhancing oil recovery and achieving CO2 storage. The method effectively exploits the synergistic benefits of CW and various displacement agents. Its primary mechanisms include increasing the dissolution of CO2 and prolonging the duration of CO2 retention in the water, reducing interfacial tension, and altering wettability. Both laboratory experiments and numerical simulations have demonstrated that ECW injection can significantly boost recovery and offer promising results in CO2 storage, presenting it as a highly prospective method for reservoir development. In addition, this paper discusses the main challenges facing this technology and explores potential future research directions, aiming to provide robust guidance for the research and application of this technology.