ABSTRACT
The geothermal energy of the earth is diffuse, diverse, and by any measure immense. Geothermal resources are generally classed in three main categories: hydrothermal systems, including both vapor-and-liquid-dominated systems, hot dry rock systems, and geopressured systems. In many deposits, water temperatures are too low for efficient flash separation. In such instances a different geothermal power process—the vapors turbine or binary system has been developed. The largest volume of geothermal water is too cool for power production. Past and future use is largely limited to local space heating and certain agricultural uses. In 1975, the US Geological Survey published an assessment of the Gulf Basin geopressured-geothermal resources as a part of their overall assessment of geothermal resources throughout the US The U.S.G.S. assessed about 145,000 square kilometers or a little less than one-half the area they consider underlain by geopressured zones.
