Methane hydrate gas production by thermal stimulation
Two models have been developed to bracket the expected gas production from a methane hydrate reservoir. The frontal-sweep model represents the upper bound on the gas production, and the fracture-flow model represents the lower bound. The in situ hydrate permeability is a major factor in estimating h...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1074.3993 http://pubs.aina.ucalgary.ca/cpc/CPC4-356.pdf |
| Summary: | Two models have been developed to bracket the expected gas production from a methane hydrate reservoir. The frontal-sweep model represents the upper bound on the gas production, and the fracture-flow model represents the lower bound. The in situ hydrate permeability is a major factor in estimating hydrate reservoir performance. A high-permeability reservoir may approach the high-efficiency performance of the frontal-sweep model. A low-permeability reservoir may have to be fracture-linked to establish injectivity, and will probably have low-efficiency performance that is similar to that of the fracture-flow model. Excess-gas reservoirs appear to be the most desirable; although excess-water hydrate reservoirs below the permafrost zone could also have reasonable permeabilities. In any case, drill stem testing and/or core analysis data should be used to evaluate the reservoir. Parametric studies were made to determine the importance of a number of variables, including porosity, bed thickness, injection temperature, and fracture length. These studies indicate that the hydrate-filled porosity should be at least 15 per cent, reservoir thickness should be about 25 ft or more, and well spacing should be fairly large (maybe 40 acres per well), if possible. Injection temperatures should probably be between 150 and 250°F to achieve an acceptable balance between high heat losses and unrealistically high injection rates. Deux modtles ont t t t mis au point pour encadrer la production prevue de gaz d'un rkservoir d'hydrates de mbhane. Le modtle a balayage frontal represente la limite superieure de production, alors que le modtle a tcoulement dans des fractures reprtsente la limite inferieure. La permeabilite in situ des hydrates est un probltme important de la prevision de la performance d'un rbervoir. Un reservoir a haute permeabilite peut avoir la performance trts efficace illustree par le modtle a balayage frontal. Un reservoir a faible permhbilite peut avoir a Etre fracture pour permettre I'injection, et meme alors il aura ... |
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