A Review-Dissolution and Mineralization Storage of CO2 Geological Storage in Saline Aquifers

Abstract

Saline aquifer has become the preferred storage location of carbon capture, and storage (CCS) technology because of its wide distribution, large storage capacity and high safety factor. According to IPCC statistics, the storage capacity of saline aquifers worldwide is 400 – 10000 Gt, which is dozens of times that of oil and gas reservoirs and hundreds of times that of coal seams. Therefore, the carbon storage in saline aquifer has the most potential for CO2 storage. Carbon sequestration in saline aquifers includes four trapping mechanisms: short-term geological and hydrodynamic capture and long-term geochemical (solubility and mineral) capture. Moreover, the solubility of CO2 in saline aquifer and the mechanism of mineral capture (salt precipitation) depends on the injected CO2 and the water-rock characteristics of saline aquifer. However, current knowledge on geochemical capture is still at an early stage compared to other capture theories. Recent researches indicate that although temperature, pressure, salinity of formation water and mineral composition of formation rocks are important factors affecting mineral storage, other reservoir parameters, such as reservoir thickness, dip angle, anisotropy, and bedding distribution, may also significantly affect salt precipitation, mineral storage, and geo-chemical storage. In this paper, we would like to present a comprehensive review on the solubility model of CO2 in saline aquifers, the phase permeability change of CO2 and saline aquifers, the mechanism of CO2-water -rock interaction, the dissolution and precipitation model of inorganic salt minerals, and the influencing factors for CO2 sequestration in saline aquifers. We believe that this review lays a foundation for future study of carbon storage technology in saline aquifer.