Effect of flue-gas impurities on the process of injection and storage of CO2 in depleted gas reservoirs

Our previous coreflood experiments-injecting pure CO(2) into carbonate cores-showed that the process is a win-win technology, sequestrating CO(2) while recovering a significant amount of hitherto unrecoverable natural gas that could help defray the cost of CO(2) sequestration. In this paper we report our findings on the effect of "impurities" in flue gas-N(2), O(2), H(2)O, SO(2), NO(2), and CO-on the displacement of natural gas during CO(2) sequestration. Results show that injection of CO(2) with approximately less than 1 mole % impurities would result in practically the same volume of CO(2) being sequestered as injecting pure CO(2). This gas would have the advantage of being a cheaper separation process compared to pure CO(2) as not all the impurities are removed. Although separation of CO(2) out of flue gas is a costly process, it appears that this is necessary to maximize CO(2) sequestration volume, reduce compression costs of N(2) (approximately 80% of the stream), and improve sweep efficiency and gas recovery in the reservoir