Experimental study of rock/water/CO2 interaction at temperatures of 100-350°C

In order to reduce the amount of CO2 emitted to the atmosphere, injection of CO2 into underground is considered one of the useful approaches. Although all reservoirs under investigation to date for CO2 disposal have temperatures below 100 degreesC and most are in sedimentary rocks, existing data of CO2 solubility in water suggests that hotter and deeper rock masses may also be candidates for underground CO2 injection due to enhanced CO2 solubility under high pressures even at high temperatures. We conducted some experimental studies of rock/water/CO2 interaction on granite and sandstone at temperatures of 100-350 degreesC using a batch type autoclave. It was shown that the presence of CO2 promoted dissolution of the rocks, especially alkali metals and alkaline-earth metals, and deposition of some kinds of aluminosilicate, compared with those in experiments without CO2.