| Abstract | Storage of CO<inf>2</inf> in depleted natural gas reservoirs is considered an attractive option to mitigate climate change concerns arising from the emissions of CO<inf>2</inf> from sources such as thermal power plants. A number of depleted gas reservoirs located in Northern Alberta with the pressure and temperature conditions of 2-5 MPa and 1-10°C, respectively, are identified as potential sites for CO<inf>2</inf> storage in gas hydrate form. CO<inf>2</inf> hydrate is ice-like crystalline compound consisting of hydrogen-bonded water molecules and CO<inf>2</inf> molecules. The water molecules build a network with hydrogen bonds to stabilize CO<inf>2</inf> molecules in it. Equilibrium pressures of CO<inf>2</inf> hydrate corresponding to 1 and 10°C are 1.41 and 4.29 MPa, respectively. Therefore, the pressure and temperature conditions of depleted gas reservoirs in Northern Alberta are within CO<inf>2</inf> hydrate formation region. There are several computer simulations that have demonstrated the possibility of storing CO<inf>2</inf> as solid hydrate in these depleted natural gas pools. However, there has not any laboratory demonstration of CO<inf>2</inf> injection and storage in a simulated depleted gas reservoir. We are investigating the injection of CO<inf>2</inf> in a bed of silica sand partially saturated with water (wet sand) at pressure and temperature conditions similar to those in a typical depleted gas reservoir in Northern Alberta. Through the pressure drop measurements, the CO<inf>2</inf> gas consumption is determined and also the amount of water converted to hydate is calculated. The results indicate that most CO<inf>2</inf> gas is consumed in a Semi-batch gas injection experiment, and 35-40%,40-45%, and 45-50% of water formed hydrate in Batch, Series-batch, and Semibatch gas injection experiments, respectively. |
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