Article: CO2 hydrates as a climate change mitigation strategy: definition of stability zones in the Portuguese deep offshore Journal: International Journal of Global Warming (IJGW) 2013 Vol.5 No.2 pp.135 - 151 Abstract: Storage of CO2 as hydrates in sub-seabed sediments has been indicated as an alternative solution for the geological storage of CO2, suitable for offshore areas where large ocean depths and low temperatures exist at short distance from the shore. This paper presents the works conducted to identify the CO2 hydrates stability zone, i.e., the areas where CO2 hydrates may form and remain stable, in the deep offshore of Portugal. The methodology involved building maps of geothermal gradient, seabed temperature, detailed bathymetry and conversion to hydrostatic pressure, and maps of sediment thickness. These data were integrated in a GIS environment and a Fortran code was implemented to compute the thickness of the hydrate stability zone, based on the pressure and the temperature conditions in the sub-seabed sediments. Preferential areas, where further studies should be conducted, are delineated. Inderscience Publishers - linking academia, business and industry through research

Title: CO₂ hydrates as a climate change mitigation strategy: definition of stability zones in the Portuguese deep offshore

Authors: Luis Félix Bernardes; Júlio Carneiro; Manuel Pinto De Abreu

Addresses: EMEPC – Estrutura de Missão para a Extensão da Plataforma Continental, Rua Costa Pinto, 165, 2770-047 Paço de Arcos, Portugal ' Centro de Geofísica de Évora e Departamento de Geociências, Rua Romão Ramalho, 59, 7000 Évora, Portugal ' EMEPC – Estrutura de Missão para a Extensão da Plataforma Continental, Rua Costa Pinto, 165, 2770-047 Paço de Arcos, Portugal

Abstract: Storage of CO₂ as hydrates in sub-seabed sediments has been indicated as an alternative solution for the geological storage of CO₂, suitable for offshore areas where large ocean depths and low temperatures exist at short distance from the shore. This paper presents the works conducted to identify the CO₂ hydrates stability zone, i.e., the areas where CO₂ hydrates may form and remain stable, in the deep offshore of Portugal. The methodology involved building maps of geothermal gradient, seabed temperature, detailed bathymetry and conversion to hydrostatic pressure, and maps of sediment thickness. These data were integrated in a GIS environment and a Fortran code was implemented to compute the thickness of the hydrate stability zone, based on the pressure and the temperature conditions in the sub-seabed sediments. Preferential areas, where further studies should be conducted, are delineated.

Keywords: CO2 hydrates; carbon dioxide; carbon storage; Portugal; sub-seabed sediments; global warming; climate change mitigation strategy; stability zones; deep offshore; geothermal gradient; seabed temperature; bathymetry; hydrostatic pressure; sediment thickness; GIS; geographic information systems.

DOI: 10.1504/IJGW.2013.053495

International Journal of Global Warming, 2013 Vol.5 No.2, pp.135 - 151

Received: 10 Nov 2011
Accepted: 24 Sep 2012
Published online: 28 Feb 2014 *

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Title: CO2 hydrates as a climate change mitigation strategy: definition of stability zones in the Portuguese deep offshore

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Title: CO₂ hydrates as a climate change mitigation strategy: definition of stability zones in the Portuguese deep offshore