Early Geothermal Exploration of Southern Dixie Valley: A Case Study

Abstract

During geothermal exploration of Southern Dixie Valley and the southeastern corner of the Carson Sink, Hunt Energy Corporation identified two thermal gradient/heat flow anomalies. These anomalies were each explored by drilling a series of shallow, intermediate, and deep wells. After each stage of drilling, the next series of wells were targeted in the areas of highest gradient. This technique proved unsuccessful because the observed high gradients tended to become isothermal or negative at depth. A number of developed Basin and Range geothermal systems have been drilled with similar information and similar results in the initial stages of exploration (Desert Peak, for example). This “overturn” of gradients is an effect produced by lateral flow of geothermal fluids. With present knowledge of Basin and Range geothermal systems, exploration of these prospects would be carried out much differently, with a more detailed study of the thermal regime, fluid flow patterns, and structural setting before further drilling. This sort of thermal and structural modeling is currently being carried out in conjunction with exploration of these prospects by the U.S. Navy Geothermal Program Office.