3-D basin-scale reconstruction of natural gas hydrate system of the Green Canyon, Gulf of Mexico.

Burwicz, Ewa B., Reichel, Thomas, Wallmann, Klaus, Rottke, Wolf, Haeckel, Matthias and Hensen, Christian (2017) 3-D basin-scale reconstruction of natural gas hydrate system of the Green Canyon, Gulf of Mexico. Geochemistry, Geophysics, Geosystems, 18 (5). pp. 1959-1985. DOI 10.1002/2017GC006876.

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Abstract

Our study presents a basin-scale 3D modeling solution, quantifying and exploring gas hydrate accumulations in the marine environment around the Green Canyon (GC955) area, Gulf of Mexico. It is the first modeling study that considers the full complexity of gas hydrate formation in a natural geological system. Overall, it comprises a comprehensive basin re-construction, accounting for depositional and transient thermal history of the basin, source rock maturation, petroleum components generation, expulsion and migration, salt tectonics and associated multi-stage fault development. The resulting 3D gas hydrate distribution in the Green Canyon area is consistent with independent borehole observations. An important mechanism identified in this study and leading to high gas hydrate saturation (> 80 vol. %) at the base of the gas hydrate stability zone (GHSZ), is the recycling of gas hydrate and free gas enhanced by high Neogene sedimentation rates in the region. Our model predicts the rapid development of secondary intra-salt mini-basins situated on top of the allochthonous salt deposits which leads to significant sediment subsidence and an ensuing dislocation of the lower GHSZ boundary. Consequently, large amounts of gas hydrates located in the deepest parts of the basin dissociate and the released free methane gas migrates upwards to recharge the GHSZ. In total, we have predicted the gas hydrate budget for the Green Canyon area that amounts to ∼3,256 Mt of gas hydrate which is equivalent to ∼340 Mt of carbon (∼7 x 1011 m3 of CH4 at STP conditions), and consists mostly of biogenic hydrates.

Document Type: Article
Keywords: numerical modeling; gas hydrate; basin modeling ;3D modeling; Green Canyon; Gulf of Mexico
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2017GC006876
ISSN: 1525-2027
Projects: SUGAR
Date Deposited: 02 May 2017 08:55
Last Modified: 07 Jul 2017 08:48
URI: http://oceanrep.geomar.de/id/eprint/37750

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