Oceanic Hydrates: More Questions Than Answers
From an oil industry standpoint, methane hydrate is known as a major problem because it plugs casing and pipelines. From a media standpoint, hydrates provide an almost inexhaustible supply of articles concerning greenhouse effects, landslides, global warming and mysterious events such as the loss of...
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crsagepubl:10.1260/0144598001492175 2024-09-09T19:52:12+00:00 Oceanic Hydrates: More Questions Than Answers Laherrere, Jean 2000 http://dx.doi.org/10.1260/0144598001492175 http://journals.sagepub.com/doi/pdf/10.1260/0144598001492175 en eng SAGE Publications http://journals.sagepub.com/page/policies/text-and-data-mining-license Energy Exploration & Exploitation volume 18, issue 4, page 349-383 ISSN 0144-5987 2048-4054 journal-article 2000 crsagepubl https://doi.org/10.1260/0144598001492175 2024-07-29T04:25:23Z From an oil industry standpoint, methane hydrate is known as a major problem because it plugs casing and pipelines. From a media standpoint, hydrates provide an almost inexhaustible supply of articles concerning greenhouse effects, landslides, global warming and mysterious events such as the loss of aircraft in the “Bermuda Triangle”. From a scientific standpoint, they provide much scope for academic research projects. Oceanic hydrates have been recovered in some of the thousands of ODP/Joides boreholes, from which a total of over 250 km of core have been taken. Unfortunately, hydrates dissociate when brought on deck, and few samples were preserved for further analysis. Most of the oceanic hydrates are reported to be of biogenic origin, except where they overlie petroleum reservoirs, as in the Caspian Sea and Gulf of Mexico. The hydrates in the cores are found mostly as dispersed grains or thin laminae. Massive pieces of hydrate, greater than 10cm thick, have been found only at three sites. Downhole logs are unreliable indicators of hydrates due to cave-ins, and in many instances the inferred presence of hydrates depends on indirect evidence, such as seismic reflectors (BSR) or chlorinity changes in pore waters. The oil industry requires much better evidence than this before attributing reserve status to a resource, yet in the case of hydrates, enormous deposits (such as recently declared in New Caledonia) are reported on the strength of no more than uncertain seismic information. The gas hydrate stability zone (GHSZ) occurs in oceanic sediments over the first few hundred meters below the seabed. In this zone, any methane from organic material, including any seepages from below, is converted into solid hydrate, and is locked in place in the sediments. The origin of the methane is poorly understood, with even its biogenic origin being challenged. Dissolved methane or free gas may precipitate at geological discontinuities such as faults, fractures and lithological boundaries, as well as at water salinity, ... Article in Journal/Newspaper Methane hydrate SAGE Publications Energy Exploration & Exploitation 18 4 349 383 |
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English |
description |
From an oil industry standpoint, methane hydrate is known as a major problem because it plugs casing and pipelines. From a media standpoint, hydrates provide an almost inexhaustible supply of articles concerning greenhouse effects, landslides, global warming and mysterious events such as the loss of aircraft in the “Bermuda Triangle”. From a scientific standpoint, they provide much scope for academic research projects. Oceanic hydrates have been recovered in some of the thousands of ODP/Joides boreholes, from which a total of over 250 km of core have been taken. Unfortunately, hydrates dissociate when brought on deck, and few samples were preserved for further analysis. Most of the oceanic hydrates are reported to be of biogenic origin, except where they overlie petroleum reservoirs, as in the Caspian Sea and Gulf of Mexico. The hydrates in the cores are found mostly as dispersed grains or thin laminae. Massive pieces of hydrate, greater than 10cm thick, have been found only at three sites. Downhole logs are unreliable indicators of hydrates due to cave-ins, and in many instances the inferred presence of hydrates depends on indirect evidence, such as seismic reflectors (BSR) or chlorinity changes in pore waters. The oil industry requires much better evidence than this before attributing reserve status to a resource, yet in the case of hydrates, enormous deposits (such as recently declared in New Caledonia) are reported on the strength of no more than uncertain seismic information. The gas hydrate stability zone (GHSZ) occurs in oceanic sediments over the first few hundred meters below the seabed. In this zone, any methane from organic material, including any seepages from below, is converted into solid hydrate, and is locked in place in the sediments. The origin of the methane is poorly understood, with even its biogenic origin being challenged. Dissolved methane or free gas may precipitate at geological discontinuities such as faults, fractures and lithological boundaries, as well as at water salinity, ... |
format |
Article in Journal/Newspaper |
author |
Laherrere, Jean |
spellingShingle |
Laherrere, Jean Oceanic Hydrates: More Questions Than Answers |
author_facet |
Laherrere, Jean |
author_sort |
Laherrere, Jean |
title |
Oceanic Hydrates: More Questions Than Answers |
title_short |
Oceanic Hydrates: More Questions Than Answers |
title_full |
Oceanic Hydrates: More Questions Than Answers |
title_fullStr |
Oceanic Hydrates: More Questions Than Answers |
title_full_unstemmed |
Oceanic Hydrates: More Questions Than Answers |
title_sort |
oceanic hydrates: more questions than answers |
publisher |
SAGE Publications |
publishDate |
2000 |
url |
http://dx.doi.org/10.1260/0144598001492175 http://journals.sagepub.com/doi/pdf/10.1260/0144598001492175 |
genre |
Methane hydrate |
genre_facet |
Methane hydrate |
op_source |
Energy Exploration & Exploitation volume 18, issue 4, page 349-383 ISSN 0144-5987 2048-4054 |
op_rights |
http://journals.sagepub.com/page/policies/text-and-data-mining-license |
op_doi |
https://doi.org/10.1260/0144598001492175 |
container_title |
Energy Exploration & Exploitation |
container_volume |
18 |
container_issue |
4 |
container_start_page |
349 |
op_container_end_page |
383 |
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1809921550060617728 |