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Analysis of Convective Heat Transfer in Deformed and Stratified Aquifers Associated with Frasch Thermal Mining
Author(s) -
Williams Daphne D.,
Lee MingKuo,
Crawford Joe E.,
Tyree Philip O.
Publication year - 1999
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1999.tb01137.x
Subject(s) - aquifer , convective heat transfer , convection , geology , thermal , heat transfer , mechanics , environmental science , groundwater , geotechnical engineering , meteorology , geography , physics
This paper presents numerical experiments designed to simulate heat transfer in deformed, stratified geologic formations during Frasch thermal mining operations in the Delaware Basin. In such operations, superheated water (163°C) is injected into permeable ore zones to melt and mobilize sulfur. The efficiency of Frasch mining depends largely on various aspects of hydrologic controls and geologic factors, such as directing heat flow toward target areas and minimizing heat dissipation through advection and conduction in ore zones. Numerical modeling techniques were used in the search of an optimum thermal mining strategy for maximum sulfur recovery in various geologic settings present at the Culberson Mine, west Texas. The sample calculations illustrate heat transfer patterns in inclined, folded, and fractured geologic formations. Important results presented include the controls of geologic structures on directions and rates of heat transfer and ground water flow, a display of field evidence for the occurrence of thermal convection in permeable ore zones, and a depiction of heat transfer during a thermal mining operation proceeding down‐dip along an inclined geologic unit. Modeling results and field data strongly support the hypothesis that thermal convection occurs and controls the heat transfer process in inclined ore zones. Simulations further suggest that the current thermal mining practice, which proceeds down‐slope along an inclined ore zone, may result in lowered ultimate sulfur recovery. In this mining approach most heat migrates up‐slope where the rock's permeability is enhanced by previous sulfur extraction, rather than down‐dip toward the target area.