The structure of methane gas hydrate bearing sediments from the Krishna-Godavari Basin as seen from micro-CT scanning
The structure of methane gas hydrate bearing sediments from the Krishna-Godavari Basin as seen from micro-CT scanning
The Indian National Gas Hydrate Program (NGHP) Expedition 1, of 2006, cored through several methane gas hydrate deposits on the continental shelf around the coast of India. The pressure coring techniques utilized during the expedition (HYACINTH and PCS) enabled recovery of gas hydrate bearing, fine-grained, sediment cores to the surface. After initial characterization core sections were rapidly depressurized and submerged in liquid nitrogen, preserving the structure and form of the hydrate within the host sediment. Once on shore, high resolution X-ray CT scanning was employed to obtain detailed three-dimensional images of the internal structure of the gas hydrate. Using a resolution of 80 ?m the detailed structure of the hydrate veins present in each core could be observed, and allowed for an in depth analysis of orientation, width and persistence of each vein. Hydrate saturation estimates could also be made and saturations of 20–30% were found to be the average across the core section with some portions showing highs of almost 60% saturation. The majority of hydrate veins in each core section were found to be orientated between 50 and 80° to the horizontal. Analysis of the strikes of the veins suggested a slight preferential orientation in individual sample sections, although correlation between individual sections was not possible due to the initial orientation of the sections being lost during the sampling stage. The preferred vein orientation within sample sections coupled with several geometric features identified in individual veins, suggest that hydraulic fracturing by upward advecting pore fluids is the main formation mechanism for the veined hydrate deposits in the K–G Basin.
1283-1293
Rees, E. V. L.
bf4268ba-b6e7-42d6-bc39-98e7c11c4986
Priest, J. A.
e1acfbf6-3099-41e1-be51-da92e1fdb1a5
Clayton, C. R. I.
8397d691-b35b-4d3f-a6d8-40678f233869
July 2011
Rees, E. V. L.
bf4268ba-b6e7-42d6-bc39-98e7c11c4986
Priest, J. A.
e1acfbf6-3099-41e1-be51-da92e1fdb1a5
Clayton, C. R. I.
8397d691-b35b-4d3f-a6d8-40678f233869
Rees, E. V. L., Priest, J. A. and Clayton, C. R. I.
(2011)
The structure of methane gas hydrate bearing sediments from the Krishna-Godavari Basin as seen from micro-CT scanning.
Marine and Petroleum Geology, 28 (7), .
(doi:10.1016/j.marpetgeo.2011.03.015).
Abstract
The Indian National Gas Hydrate Program (NGHP) Expedition 1, of 2006, cored through several methane gas hydrate deposits on the continental shelf around the coast of India. The pressure coring techniques utilized during the expedition (HYACINTH and PCS) enabled recovery of gas hydrate bearing, fine-grained, sediment cores to the surface. After initial characterization core sections were rapidly depressurized and submerged in liquid nitrogen, preserving the structure and form of the hydrate within the host sediment. Once on shore, high resolution X-ray CT scanning was employed to obtain detailed three-dimensional images of the internal structure of the gas hydrate. Using a resolution of 80 ?m the detailed structure of the hydrate veins present in each core could be observed, and allowed for an in depth analysis of orientation, width and persistence of each vein. Hydrate saturation estimates could also be made and saturations of 20–30% were found to be the average across the core section with some portions showing highs of almost 60% saturation. The majority of hydrate veins in each core section were found to be orientated between 50 and 80° to the horizontal. Analysis of the strikes of the veins suggested a slight preferential orientation in individual sample sections, although correlation between individual sections was not possible due to the initial orientation of the sections being lost during the sampling stage. The preferred vein orientation within sample sections coupled with several geometric features identified in individual veins, suggest that hydraulic fracturing by upward advecting pore fluids is the main formation mechanism for the veined hydrate deposits in the K–G Basin.
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Published date: July 2011
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Infrastructure Group
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Local EPrints ID: 360566
URI: http://eprints.soton.ac.uk/id/eprint/360566
ISSN: 0264-8172
PURE UUID: c3071d89-6998-4d89-96aa-b209706871d5
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Date deposited: 17 Dec 2013 14:44
Last modified: 15 Mar 2024 03:04
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E. V. L. Rees
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J. A. Priest
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