The geothermal potential of the IBM Plant Site Area, Tucson, Arizona, T15S, T16S, R15E

The IBM plant site south of Tucson, Arizona is favorably located for potential geothermal utilization using natural hot water. High temperatures were measured near the site during geophysical logging of a deep oil test drilled by Humble (Exxon) in 1972. The well, drilled to 12,556 feet 2.5 miles southwest of the IBM site, had measured temperatures of 114 degrees F at 2,969 feet and 296 degrees F at 12,001 feet (Schlumberger Well Services, 1972). These temperatures are minimum temperatures at those depths because they were measured only 10 and 20 hours after mud circulation was stopped. In other words, the well had not reached a stable temperature because rock adjacent to the hole had been cooled by circulating drilling mud introduced from the surface, and the rock was still reheating to its original undisturbed temperature prior to drilling. Figure (1) contains plots of temperature versus time after the last circulation of mud. The plots document the increase in temperature in the Humble (Exxon) well. The shallow temperature measurements from geophysical logging are shown in a temperature versus time plot and a temperature versus depth plot. It is evident that temperature changes with time and not with depth because the inferred temperature gradient, as a change of temperature with depth,is ridiculously high. (26 pages)Documents in the AZGS Documents Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu)