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Map showing the depth to the base of the deepest ice-bearing permafrost as determined from well logs, North Slope, Alaska

Oil and Gas Investigation Map 222

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Abstract

Because gas hydrates from within a limited temperature range, subsurface equilibrium temperature data are necessary to calculate the depth and thickness of the gas-hydrate stability field.  Acquiring these data is difficult because drilling activity often disrupts equilibrium temperatures in the subsurface, and a well mush lie undisturbed until thermal equilibrium is reestablished (Lachenbruch and Brewer, 1959).  On the North Slope if Akaska, a series of 46 oil and gas exploratory wells, which were considered to be near thermal equilibrium (Lachenbruch and others, 1982; 1987), were surveyed with high-resolution temperature devices (see table 1).  However, several thousand other exploratory and production wells have been drilled on the North Slope, and although they do not include temperature profiles, their geophysical logs often allow descrimination between ice-bearing and non-ice-bearing strata.  At the outset of this study, the coincidence of the base of ice-bearing strata being near the same depth as the 0°C isotherm at Prudhoe Bay (Lachenbruch and others, 1982) appeared to offer an opportunity to quickly and inexpensively expand the size of our subsurface temperature data base merely by using well logs to identify the base of the ice-bearing strata.

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Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Map showing the depth to the base of the deepest ice-bearing permafrost as determined from well logs, North Slope, Alaska
Series title:
Oil and Gas Investigation Map
Series number:
222
Year Published:
1989
Language:
English
Publisher:
U.S. Geological Survey
Description:
54.07 x 36.29 inches
Country:
United States
State:
Alaska
Scale:
1000000
Online Only (Y/N):
N
Additional Online Files (Y/N):
N