Study of heat transfer characteristics during dissociation of gas hydrates in porous media
An experimental technique was developed to measure the rate of formation and dissociation of hydrates in porous media. In the first phase of the work, hydrates of propane and methane were studied. Propane hydrate cores were formed by contacting liquid propane with compacted porous ice cores at 274 K for 24 to 100 hours, whereas the formation of methane hydrates was achieved by contacting ice cores with gaseous methane at about 7000 kPa and 274 K, for 24 to 200 hours. These hydrate cores were dissociated by circulating warm water over the top of the core, under controlled temperatures and pressures. The major findings of these experiments are as follows: 1) the phenomena of dissociation of hydrates to liquid water and gas is similar to nucleate boiling of liquids; 2) the rate of dissociation of hydrates at constant ..delta..T, is directly proportional to the area of hydrates exposed to the warm fluid or the composition of hydrates in the core; and 3) the rate of heat transfer and dissociation increase with increase in pressure and the rate of circulation of the warm fluid. Unified correlations for heat transfer and dissociation rates were successfully obtained for both methane and propane hydrate dissociation. These correlations will be useful to predict the rate of dissociation and gas production in hydrate reservoirs. In the second phase of his work, in order to simulate the conditions of hydrate dissociation in the earth, methane hydrates were formed and dissociated in unconsolidated cores of sand. The results of these experiments have demonstrated that the heat transfer resistance of the media (rock) plays an important role in dissociation of hydrates in earth.
- Research Organization:
- Pittsburgh Univ., PA (USA)
- OSTI ID:
- 5753228
- Country of Publication:
- United States
- Language:
- English
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