Print this pageLithostratigraphic Analysis and Sedimentology of Cores from the Mount Elbert-01 Gas Hydrate Stratigraphic Well
In February, 2007, BP Exploration (Alaska), the U.S. Department of Energy and the U.S. Geological Survey completed the Mount Elbert-01 gas hydrate stratigraphic test well in the Milne Point Unit on the Alaska North Slope. A continuously cored section targeting two potential gas hydrate bearing reservoirs was taken between 1990 to 2494 feet. Coring was initiated below the base of permafrost and extended into the gas hydrate stability zone. Total core recovered was approximately 430 feet, or 85% of the total cored interval. Geochemistry, microbiology, physical properties and other subsamples were taken during field operations along with a basic field visual description of the core.
In April 2008, detailed lithostratigraphic description of the split core sections was completed. In addition, more than 500 sedimentological subsamples for select xrd/xrf, grain size, and petrographic analyses were taken. Lithostratigraphic analyses of the cores confirm that the major gas hydrate bearing reservoirs, Units “C” and “D," were comprised of individual coarsening upward, very fine to fine grained, quartz rich to quartz-feldspathic and chert-bearing sands in amalgamated, massively bedded or faintly subhorizontally laminated beds. The C and D Units each had sharp upper contacts capped by marine shales and silts which is consistent with descriptions of the marine facies in the Sagavanirktok Formation from other studies. The results of these and ongoing lithostratigraphic analyses are being integrated with the wealth of other data available from the Mount Elbert site, including wireline log measurements and results from other core analyses. Relationships between hydrate-rich, hydrate-poor, and non-hydrate bearing intervals will help refine numerical and conceptual models and improve understanding of the controls on hydrate occurrences in natural systems.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009