Seismic evidence for an extensive gas-bearing layer at shallow depth, offshore from Prudhoe Bay, Alaska

Cold Regions Science and Technology
By: , and 

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Abstract

High-resolution seismic reflection data, recorded offshore from Prudhoe Bay, Alaska, were processed digitally to determine the reflectivity structure of the uppermost layers of the seafloor. A prominent reflector, found at 27 m below the mud line (water depths 7-9 m), has a negative reflection coefficient greater than 0.5. The large acoustic impedance contrast, coupled with a report of gas encountered at a corresponding depth in a nearby drillhole, shows that the reflector is the upper boundary of a zone containing gas. The gas exists in sandy gravel capped by stiff, silty clay. Analysis of unprocessed conventional high-resolution records from the region indicates that the gas-bearing layer may extend over an area of at least 50 km2 at a depth of 20-35 m below the mud line. Similar-appearing reflectors (Reimnitz, 1972), previously unexplained, occur in patches over wide regions of the shelf where offshore oil development is beginning at a rapid pace. This suggests the exercise of caution with respect to possible hazards from shallow gas pockets.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Seismic evidence for an extensive gas-bearing layer at shallow depth, offshore from Prudhoe Bay, Alaska
Series title Cold Regions Science and Technology
DOI 10.1016/0165-232X(81)90031-8
Volume 4
Issue 1
Year Published 1981
Language English
Publisher Elsevier
Publisher location Amsterdam, Netherlands
Contributing office(s) Energy Resources Program
Description 9 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Cold Regions Science and Technology
First page 63
Last page 71
Country United States
State Alaska
Other Geospatial Prudhoe Bay