Skip to Main Content
Book Chapter

Seismic and Thermal Characterization of a Bottom-simulating Reflection in the Northern Gulf of Mexico

By
Deborah R. Hutchinson
Deborah R. Hutchinson
U.S. Geological Survey, Woods Hole, Massachusetts, U.S.A.
Search for other works by this author on:
Patrick E. Hart
Patrick E. Hart
U.S. Geological Survey, Menlo Park, California, U.S.A.
Search for other works by this author on:
Carolyn D. Ruppel
Carolyn D. Ruppel
Georgia Tech, School of Earth and Atmospheric Sciences, Atlanta, Georgia, U.S.A.
Search for other works by this author on:
Fred Snyder
Fred Snyder
Schlumberger, Houston, Texas, U.S.A.
Search for other works by this author on:
Brandon Dugan
Brandon Dugan
Rice University, Department of Earth Sciences, Houston, Texas, U.S.A.
Search for other works by this author on:
Published:
January 01, 2009

Abstract

High-resolution multichannel seismic reflection data, exploration industry three-dimensional (3-D) seismic data, and heat-flow measurements collected on the southeast side of a mini basin (Casey basin) in the northern Gulf of Mexico continental slope have been used to characterize a bottom-simulating reflector (BSR). The BSR, which covers a small area of about 15 km2 (6 mi2), is identified by crosscutting relationships with seismic stratigraphy. Two mounds are identified. The larger Alpha mound is structurally formed at the junction of three arms of the structural high east of the mini basin. The smaller Beta mound may be a seep site. Conventional heat-flow measurements yield higher gradients (39–49 mK/m) to the northeast of the structural high and lower values (30–38 mK/m) to the south and west along the edge of the mini basin, which is separated from the structural high by the eastern Casey fault zone. When the near-sea-floor thermal gradients are extrapolated to the depth of the BSR, the resulting temperatures are generally too low if the BSR marks the base of the hydrate stability zone in a methane-only gas-hydrate system. Plausible changes in pore-water salinity or gas composition cannot account for this disparity, and thermal perturbations caused by fluid down welling, mass wasting, or depth-dependent thermal conductivity variations might best explain the low predicted BSR temperatures. The recognition of a BSR in the study area provides geophysical evidence that a hydrate stability zone with trapped free gas at its base exists in the northern Gulf and that minibasins can be locations for finding subsurface hydrate-associated free gas and probable gas hydrate.

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables

Contents

AAPG Memoir

Natural Gas Hydrates—Energy Resource Potential and Associated Geologic Hazards

T. Collett
T. Collett
Search for other works by this author on:
A. Johnson
A. Johnson
Search for other works by this author on:
C. Knapp
C. Knapp
Search for other works by this author on:
R. Boswell
R. Boswell
Search for other works by this author on:
American Association of Petroleum Geologists
Volume
89
ISBN electronic:
9781629810270
Publication date:
January 01, 2009

GeoRef

References

Related

A comprehensive resource of eBooks for researchers in the Earth Sciences

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

View Article Abstract & Purchase Options

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Subscribe Now