| Abstract: | Oceanic methane hydrates are mineral deposits formed from a crystalline ‘ice‘ of methane and water in sea-floor sediments (buried to less than about 1 km) in water depths greater than about 500 m; economic hydrate deposits are probably restricted to water depths of between 1.5 km and 4 km. Gas hydrates increase a sediment‘s strength both by ‘freezing‘ the sediment and by filling the pore spaces in a manner similar to water-ice in permafrost. Concentrated hydrate deposits may be underlain by significant volumes of methane gas, and these localities are the most favourable sites for methane gas extraction operations. Seismic reflection records indicate that trapped gas may blow-out naturally, causing large-scale seafloor collapse. In this paper, we consider both the physical properties and the structural integrity of the hydrate stability zone and the associated free gas deposits, with special reference to the Blake Ridge area, SE US offshore, in order to help establish a suitable framework for the safe, efficient, and economic recovery of methane from oceanic gas hydrates. We also consider the potential effects of the extraction of methane from hydrate (such as induced sea-floor faulting, gas venting, and gas-pocket collapse). We assess the ambient pressure effect on the production of methane by hydrate dissociation, and attempt to predict the likelihood of spontaneous gas flow in a production situation.Oceanic methane hydrates are mineral sits formed from a crystalline `ice‘ of methane and water in sea-floor sediments (buried to less than about 1 km) in water depths greater than about 500 m; economic hydrate deposits are probably restricted to water depths of between 1.5 km and 4 km. Gas hydrates increase a sediment‘s strength both by `freezing‘ the sediment and by filling the pore spaces in a manner similar to water-ice in permafrost. Concentrated hydrate deposits may be underlain by significant volumes of methane gas, and these localities are the most favourable sites for methane gas extraction operations. Seismic reflection records indicate that trapped gas may blow-out naturally, causing large-scale seafloor collapse. In this paper, we consider both the physical properties and the structural integrity of the hydrate stability zone and the associated free gas deposits, with special reference to the Blake Ridge area, SE US offshore, in order to help establish a suitable framework for the safe, efficient, and economic recovery of methane from oceanic gas hydrates. We also consider the potential effects of the extraction of methane from hydrate (such as induced sea-floor faulting, gas venting, and gas-pocket collapse). We assess the ambient pressure effect on the production of methane by hydrate dissociation, and attempt to predict the likelihood of spontaneous gas flow in a production situation. |
| Genre: | Article |
| ProdID: | 70020459 |
| Citation Author: | Max, M. D.; Dillon, W. P. |
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| Citation End Page: | 357 |
| Citation Issue: | 3 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Petroleum Geology |
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| Citation Number Of Pages: | 15 |
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| Citation Publisher: | Sci Surv Ltd |
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| Citation Search Results Text: | Oceanic methane hydrate: the character of the Blake Ridge hydrate stability zone, and the potential for methane extraction; 1998; Article; Journal; Journal of Petroleum Geology; Max, M. D.; Dillon, W. P. |
| Citation Start Page: | 343 |
| Citation Volume: | 21 |
| Citation Year: | 1998 |
| Type: | citation/reference |
| Text: | Oceanic methane hydrate: the character of the Blake Ridge hydrate stability zone, and the potential for methane extraction; 1998; Article; Journal; Journal of Petroleum Geology; Max, M. D.; Dillon, W. P. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1111/j.1747-5457.1998.tb00786.x |
| Date Other: | Thu, 1 Jan 1998 00:00 -0600 |
| Publisher: | Sci Surv Ltd |
