Institute of Petroleum Engineering

Centre for Gas Hydrate Research Publications



Abstract 120
Preliminary Experimental Investigation on Replacing Methane in Hydrate Structure with Carbon Dioxide in Porous Media
Jadhawar, P., Yang, J., Jadhawar, J., and Tohidi, B.
The 5th International Conference on Gas Hydrates, Trondheim, Norway, June 13-16 (2005).
Reducing the emission of greenhouse gases in atmosphere is a great challenge for minimizing major climate changes in the 21st century. Although the ideal solution could be non-carbon energy resources, it is widely believed that the fossil fuels will continue to play a major role in meeting our energy demands for foreseeable future. Natural gas (methane) is the best low carbon energy source that can supply energy for the most part of this century. Therefore, the best option seems to be producing energy from low carbon energy sources by sequestering the industrially produced CO2 into subsurface formations. Huge sedimentary deposits of naturally occurring gas hydrates in permafrost regions and beneath the sea in outer continental margins are being regarded as a huge storehouse of potential energy source. Injecting CO2 in these reservoirs could produce CH4 gas by a replacement mechanism. Methane entrapped in the crystal lattice of hydrates could be selectively replaced by the injected CO2. Preliminary thermodynamic feasibility studies and the experiments conducted in porous medium in this laboratory, shown that the slow conversion of CH4 hydrate into CO2 hydrates (and release of methane) by replacement mechanism is achievable under excess gas conditions. Rate of methane recovery, and hence the conversion from CH4 hydrates to CO2 hydrates almost doubled when the test carried out at 10.8 C and a pressure above the saturation pressure of CO2, compared to the test results at 2 C with a pressure below CO2 saturation pressure. The tests were carried out while keeping operating pressures just above the methane hydrate dissociation pressures, within the range of 50 psia.

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