Solubility and Residual Gas Trappings of CO_2 in Geological Storage

摘要

First, we experimentally evaluated the residual CO_2 saturation for typical conditions of aquifers at the depth from 700 m to 1,000 m. At least one thirds of CO_2 would be stored by residual gas trapping and solubility trapping as compared with the physical trapping by caprock. Next, we experimentally demonstrated that mass transfer form free CO_2 to water is high enough to assume the pore water coexists with free CO_2 is saturated with CO_2 even though the relatively high migration. Finally, we developed a non-invasive measurement technique that quantifies amount of CO_2 solved in water in porous rock by means of NMR. This technique could be applicable to monitoring of CO_2 around boreholes as well as laboratory experiments such as the diffusion and convection of CO_2 in water in porous rock.