--> ABSTRACT: Heat Flow Through and Around Salt Sheets, by John J. O'Brien and Ian Lerche; #91030 (2010)
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Heat Flow Through and Around Salt Sheets

John J. O'Brien, Ian Lerche

Using a numerical modeling approach, we investigate the characteristics of conductive heat flow and the temperature distribution around a highly conductive salt sheet embedded in a lower conductivity host rock. At large distances from any major lateral variations in conductivity, the solution to the Previous HitoneNext Hit-Previous HitdimensionalNext Hit heat flow equation provides an excellent approximation of the full numerical solution. Lateral variability is generally significant, however, and the Previous HitoneNext Hit-Previous HitdimensionalTop model should be used carefully. Where lateral changes occur in conductivity, heat flux lines converge to exploit the high-conductivity pathway through the salt.

The surface heat flux profile over a low-dip laterally extensive salt sheet of uniform thickness shows a broad asymmetric peak/trough structure centered over the edge of the salt. The magnitude of this effect depends on the thickness and depth of the salt sheet, the contrast in conductivity between salt and the surrounding rocks, the heat flux across basement, and the dip of the salt sheet. At increasing dip angles the surface heat flux assumes a more symmetric form, becoming more like the profile associated with salt diapir.

For a flat salt sheet, temperatures in the underlying formation are lowest underneath the central portion of the sheet, increasing progressively toward the edge. Dip of the salt sheet imparts a horizontal component to the flow of heat, resulting in enhanced heating of the updip edge of the salt as well as the enhanced cooling of the downdip salt. Burial depth of the salt impacts significantly only on shallow isotherms.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.