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TitrePreliminary assessment of the geological potential for sequestration of CO2 as gas hydrate in the Alberta portion of the Western Canada Sedimentary Basin
AuteurCôté, M M; Wright, J F
SourceCommission géologique du Canada, Dossier public 6582, 2013, 57 pages, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
Mediaen ligne; numérique
SNRC72E; 72L; 72M; 73D; 73E; 73L; 73M; 74D; 74E; 74L; 74M; 82A; 82H; 82I; 82J; 82O; 82P; 83; 84
Lat/Long OENS-120.0000 -110.0000 60.0000 49.0000
Sujetshydrocarbures; capacité de production d'hydrocarbures; hydrate; gaz; gaz carbonique; températures au sol; températures géothermiques; roches sédimentaires; reservoirs; conditions de pression-température; pressions interstitielles; porosité; perméabilité; Bassin sédimentaire de l'ouest canadien; Changement climatique; combustibles fossiles; stratigraphie; tectonique; Nature et environnement; Cénozoïque; Tertiaire; Mésozoïque; Crétacé; Jurassique; Trias; Paléozoïque; Permien; Carbonifère; Mississippien; Pennsylvanien; Dévonien; Silurien; Ordovicien; Cambrien
Illustrationslocation maps; diagrams; profiles; plots; cross-sections; stratigraphic columns; pie charts
Bibliothèque de Ressources naturelles Canada - Ottawa (Sciences de la Terre)
ProgrammeProduction des Hydrates de gaz, Hydrates de gaz
Diffusé2013 04 23
Résumé(Sommaire disponible en anglais seulement)
Worldwide concern regarding the role of increasing atmospheric CO2 concentrations in exacerbating global warming has led to a variety of proposals for the capture and longterm storage of anthropogenic CO2. The injection and subsequent sequestration of large volumes of CO2 gas within porous geological formations (e.g. depleted oil/gas reservoirs; deep saline aquifers) has been suggested as an effective means for the long-term sequestration of CO2 from industrial sources. However, a serious concern with this CO2 sequestration option is that the injected CO2 is typically stored as a relatively mobile fluid (gas or liquid), with the attendant risk that the injected gas may migrate beyond the confines of the storage reservoir. In such a situation the long-term storage integrity of the reservoir may be compromised, possibly leading to the contamination of domestic freshwater aquifers, or other potential health hazards associated with an uncontained
volume of gaseous CO2. The Geological Survey of Canada (GSC), with funding support from Canada's Climate Change Action Plan (CCAP 2000), has conducted a preliminary assessment of options for the geological sequestration of CO2 as a as a relatively immobile solid-phase gas hydrate within suitable sedimentary formations in Canada. Clearly, the sequestration of CO2 as a solid phase has distinct advantages over CO2 storage as a mobile fluid, in that the sequestered CO2 can be expected to remain in place more or less indefinitely, as ong as temperature and pressure conditions within the storage reservoir remain reasonably stable. An initial study, published in 2006 as GSC Open File 4596, identified a number of sandstone and limestone formations underlying the deeper portions of the Canadian Great lakes, for which very large for CO2 storage as gas hydrate capacities (perhaps in excess of 100 Gt) were indicated.
The present study investigates opportunities for CO2 sequestration as gas hydrates within the Alberta portion of the Western Canadian sedimentary basin. Based on a regional-scale geothermal analysis, industry borehole data and precise ground temperature logs, a significant land area north of Cold Lake and south/southwest of Fort McMurray has been characterized as having geological conditions (in terms of ground temperature and pressure, porosity and permeability) favorable for the in situ formation and long-term maintenance of stable CO2 hydrate. Preliminary estimates indicate that as much as 61 Gt of CO2 (or more) could potentially be sequestered as solid-hase gas hydrate in Alberta reservoirs, at target depths of roughly 300-400 m below surface. Finite-element numerical ground thermal modeling was employed to evaluate the possible impacts of continued climate warming on the stability of sequestered CO2 hydrate over the longer term. The premise being tested assumes that the presence of a substantial sedimentary overburden in areas targeted for sequestration provides an effective buffer against the propagation of warmer surface temperatures (anticipated as a consequence of progressive lobal warming) into the ground at depth. The modeling indicates that a time frame of between 1000-2000 years is required for a 3°C increase in surface air temperature to cause an increase in ground temperature of 1°C at 300 m depth.
This preliminary assessment offers a potential new strategy for the geological sequestration of CO2 in Alberta, however considerable additional work is required to advance this idea from concept to practice. Specifically, the acquisition of more reliable site-specific data including ground surface temperatures and local geothermal gradients, pore water geochemistry, porosity and permeability, would be a pre-requisite to the implementation of a small-scale demonstration project in a readily accessible region of northeastern Alberta.
Résumé(Résumé en langage clair et simple, non publié)
Les préoccupations à l'échelle mondiale concernant l'augmentation des concentrations de dioxyde de carbone dans l'atmosphère ont donné lieu à diverses propositions visant le captage et le stockage à long terme du dioxyde de carbone produit par les installations industrielles. La présente étude examine les possibilités de séquestrer le CO2 sous forme d'un hydrate de gaz solide relativement immobile dans la partie albertaine du bassin sédimentaire de l'Ouest canadien. Selon les analyses géothermiques effectuées à l'échelle régionale, les données de forage de l'industrie et les enregistrements précis de la température du sol, les conditions géologiques dans une vaste étendue située entre Cold Lake et Fort McMurray sont favorables à la formation in situ et à la formation et au maintien à long terme d'hydrate de CO2 stable. Les estimations provisoires indiquent qu'on pourrait séquestrer jusqu'à 61 Gt de CO2 sous forme d'hydrate de gaz en phase solide, à des profondeurs cibles de 300 à 400 m. Des travaux supplémentaires doivent être exécutés pour faire progresser cette idée et la faire passer de concept à la pratique : en particulier, l'acquisition de données propres au site plus fiables, notamment la température du sol, la géochimie, la porosité et la perméabilité de l'eau interstitielle.