AN ACOUSTIC IMPEDANCE INVERSION APPROACH TO DETECT AND CHARACTERIZE GAS HYDRATE ACCUMULATIONS WITH SEISMIC METHODS: AN EXAMPLE FROM THE MALLIK GAS HYDRATE FIELD, NWT, CANADA ...

• Main Authors: Bellefleur, Gilles, Riedel, Michael, Mair, Stephanie, Brent, Tom
• Format: Text
• Language: English
• Published: The University of British Columbia 2008
• Subjects: Mackenzie Delta
• Online Access: https://dx.doi.org/10.14288/1.0041051; https://doi.library.ubc.ca/10.14288/1.0041051

Two internationally-partnered research well programs, in 1998 and 2002, studied the Mallik gas hydrate accumulation in the Mackenzie Delta, Canada. Gas hydrate bearing intervals were cored, logged and production tested thus establishing Mallik as an excellent site for testing geophysical imaging techniques. Here, we apply a model-based acoustic impedance inversion technique to 3D seismic reflection data acquired over the Mallik area to characterize gas hydrate occurrences and to help define their spatial extent away from well control. Sonic logs in Mallik research wells show that P-wave velocity of sediments increases with hydrate saturation, enough to produce detectable reflections for the lower two of three known gas hydrate zones. The inversion method converts these reflections into acoustic impedances from which velocity and hydrate saturation can be estimated. Acoustic impedance inversion results indicate that the deepest gas hydrate zone covers an area of approximately 900,000 m2. With some assumptions ...