Permafrost, heat flow, and the geothermal regime at Prudhoe Bay, Alaska

Temperature measurements through permafrost in the oil field at Prudhoe Bay, Alaska, combined with laboratory measurements of the thermal conductivity of drill cuttings permit an evaluation of in situ thermal properties and an understanding of the general factors that control the geothermal regime.A sharp contrast in temperature gradient at approx.600 m represents a contrast in thermal conductivity caused by the downward change from interstitial ice to interstitial water at the base of permafrost under near steady state conditions. Interpretation of the gradient contrast in terms of a simple mode for the conductivity of an aggregate yields the mean ice content (approx.39%), and thermal conductivities for the frozen and thawed section (8.1 and 4.7 mcal/cm s /sup 0/C, respectively). These results yield a heat flow of approx.1.3 HFU, which is similar to other values on the Alaskan Arctic Coast; the anomalously deep permafrost is a result of the anomalously high conductivity of the siliceous ice-rich sediments. Curvature in the upper 160 m of the temperature profiles represents a warming of approx.1.8 /sup 0/C of the mean surface temperature and a net accumulation of 5--6 kcal/cm/sup 2/ by the solid earth surface during the last 100 years or so. Rising sea levelmore » and thawing of ice-rich sea cliffs probably caused the shoreline to advance tens of kilometers in the last 20,000 years, inundating a portion of the continental shelf that is presently the target of intensive oil exploration. A simple conduction model suggests that this recently inundated region is underlain by near-melting ice-rich permafrost to depths of 300--500 m; its presence is important to seismic interpretations in oil exploration and to engineering considerations in oil production. With confirmation of the permafrost configuration by offshore drilling, heat conduction models can yield reliable new information on the chronology of arctic shorelines.« less

[1]  J. C. Jaeger,et al.  Conduction of Heat in Solids , 1952 .

[2]  O. Johansen.  Thermal Conductivity of Soils , 1977 .

[3]  A. Lachenbruch,et al.  Thermal conductivity of rocks from measurements on fragments and its application to heat‐flow determinations , 1971 .

[4]  A. Lachenbruch,et al.  Thermal regime of permafrost at Prudhoe Bay, Alaska , 1982 .

[5]  T. Osterkamp,et al.  Heat and mass transport processes in subsea permafrost 1. An analysis of molecular diffusion and its consequences , 1978 .

[6]  A. Judge,et al.  Canadian Geothermal Data Collection - northern wells 1976-77 , 1975 .

[7]  M. C. Brewer,et al.  Dissipation of the temperature effect of drilling a well in Arctic Alaska , 1958 .

[8]  A. Lachenbruch.  THERMAL EFFECTS OF THE OCEAN ON PERMAFROST , 1957 .

[9]  Supplement to Canadian geothermal data collection : northern wells 1977-78 , 1979 .

[10]  R. H. Oppermann,et al.  Properties of ordinary water-substance: by N. Ernest Dorsey. 673 pages, illustrations, tables, 16 × 24 cms. New York, Reinhold Publishing Corporation, 1940.Price $15.00. , 1940 .

[11]  R. K. Haugen,et al.  Coastal-Inland Distributions of Summer Air Temperature and Precipitation in Northern Alaska , 1980, Arctic and Alpine Research.

[12]  H. Clark,et al.  The thermal conductivity of rocks and its dependence upon temperature and composition; Part II , 1940 .

[13]  A. Judge,et al.  Canadian Geothermal Data Collection - northern wells 1955 To February 1974 , 1974 .

[14]  D. Vries.  Thermal properties of soils , 1963 .

[15]  E. C. Bullard,et al.  The Time Necessary for a Bore Hole to Attain Temperature Equilibrium , 1947 .

[16]  D. Hopkins,et al.  Coastal morphology, coastal erosion, and barrier islands of the Beaufort Sea, Alaska , 1978 .

[17]  G. W. Greene,et al.  PERMAFROST AND THE GEOTHERMAL REGIMES , 1966 .

[18]  A. F. Birch.  The effects of Pleistocene climatic variations upon geothermal gradients , 1948 .

[19]  D. Hopkins.  1 – ASPECTS OF THE PALEOGEOGRAPHY OF BERINGIA DURING THE LATE PLEISTOCENE , 1982 .

[20]  J. B. Walsh,et al.  Effect of pressure and saturating fluid on the thermal conductivity of compact rock , 1966 .

[21]  W. Woodside,et al.  Thermal Conductivity of Porous Media. I. Unconsolidated Sands , 1961 .

[22]  E. Chamberlain,et al.  Permafrost Beneath the Beaufort Sea: Near Prudhoe Bay, Alaska , 1980 .

[23]  M. C. Brewer.  Some results of geothermal investigations of permafrost in northern Alaska , 1958 .

[24]  J. R. Mackay.  Offshore Permafrost and Ground Ice, Southern Beaufort Sea, Canada , 1972 .

[25]  G. W. Greene,et al.  Heat flow in the western United States , 1971 .