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TitreAcoustic impedance inversion and seismic reflection continuity analysis for delineating gas hydrate resources near the Mallik research sites, Mackenzie Delta, Northwest Territories, Canada
AuteurRiedel, M; Bellefleur, G; Mair, S; Brent, T A; Dallimore, S R
SourceGeophysics vol. 74, no. 5, 2009 p. B125-B137,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20060132
ÉditeurSociety of Exploration Geophysicists
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceTerritoires du Nord-Ouest
Lat/Long OENS-135.0000 -134.0000 69.5000 69.0000
Sujetslevés sismiques; données sismiques; hydrate; analyses de diagrammes de sondage; estimation des ressources; géologie économique; géophysique
Illustrationslocation maps; seismic reflection profiles; graphs; geophysical images
Résumé(disponible en anglais seulement)
We combine acoustic impedance inversion of 3D seismic data, log-to-seismic correlation, and seismic attribute analyses to delineate
gas-hydrate zones at the Mallik site, Mackenzie Delta, Northwest Territories, Canada. Well-log data define three distinct hydrate zones over a depth range of 890 - 1100 m. Synthetic seismic modeling indicates the base of the two deeper hydrate zones are prominent reflectors. The uppermost gas-hydrate zone correlates to seismic data with a lower degree of confidence. The extent and geometry of the two lower hydrate zones suggest that local geology plays a significant role in the lateral and vertical distribution of gas hydrate at Mallik. The reliability of the hydrate concentrations calculated from the inverted impedances is qualified by the match between original and synthetic seismic data to produce confidence maps for the two lower gas-hydratebearing intervals. A total in-place volume estimate of solid gas hydrate for an area of 1.44 km2 around well 5L-38 yields a value of approximately 45 x 106 m3 (equivalently, 6.6 x 109 m3 of gas). We further qualify our mapping of gas hydrates by some amount of continuous resource, defined as lateral continuity measured by seismic attribute similarity and sand-dominated rock. Using these attributes, the continuous amount of hydrate at Mallik is about half the in-place volume (i.e., 25 x 106 m3). Elsewhere within the 3D seismic cube, the seismic impedance inversion yields evidence of potential gas-hydrate deposits near wells A-06 and P-59 at levels near the predicted base of the hydrate stability zone.