Author(s)

Takashi Fujii, Kaori Endo, Satomi Nakagawa, Yoshiyuki Sato, Hiroshi Inomata, Shinsuke Nakao, Toshiyuki Hashida

Fracture and Reliability Research Institute, Tohoku University, Sendai, Japan.
Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
Research Center of Supercritical Fluid Technology, Tohoku University, Sendai, Japan.
Research Center of Supercritical Fluid Technology, Tohoku University, Sendai, Japan..

For the assessment of the carbon dioxide (CO₂) storage potential of water-filled reservoir rocks (i.e., saline aquifers), it should be first important step for a thorough understanding of the effect of water content on CO₂/water/rock interactions during CO₂ injection. The purpose of this study is to examine the CO₂ sorption amount for Kimachi sandstone and Berea sandstone at different water content using the manometric method at temperature of 50?C and pressures of up to 20 MPa. Our results document that a significant quantity of CO₂ was sorbed on the two types of sandstone on all water-saturated bases, which corresponded to the amount adsorbed on the air-dry basis. Also, all the wet samples had significantly higher sorption capacity than the theoretical values calculated from the solubility model based on dissolution of CO₂ in pore water and the pore-filling model, which assumes that the pore volume unoccupied by water is filled with CO₂. Furthermore, the observations indicated a certain degree of correlation between the sorbed amount and the water content, except at pressures below the critical point for Berea sandstone. This investigation points out that CO₂ sorption is a possible mechanism in CO₂ geological storage even under water-saturated conditions and that the mechanism of sorption on silica and silicate minerals plays an essential role in the reliable and accurate estimation of the CO₂ storage capacity of water-saturated reservoirs.

CO₂; Water Saturation; Sorption Potential; Sandstones

T. Fujii, K. Endo, S. Nakagawa, Y. Sato, H. Inomata, S. Nakao and T. Hashida, "Water Saturation Dependence on CO₂ Sorption Potential of Sandstones," Natural Resources, Vol. 3 No. 2, 2012, pp. 48-55. doi: 10.4236/nr.2012.32008.