Abstract: Exploration for Nonelectric Geothermal Resources in Colorado

Jay D. Dick, Richard Howard Pearl

The Colorado Geological Survey, with funding from ERDA under contract EG-77-S-07-1678, is evaluating the low-temperature geothermal resources of Pagosa Springs and Glenwood Springs, Colorado, with the purpose of developing these fluids for nonelectric uses.

Both regions are characterized by abundant hot saline springs and wells. The thermal waters in Pagosa Springs range in temperature from 54 to 58°C and Glenwood Springs averages 50°C. The discharge of the springs in the two areas ranges from a low of a few gallons per minute to 2,263 gal/minute at the Big Spring in Glenwood Springs.

Detailed geophysical surveys are being conducted using dipole-dipole and dipole-bipole resistivity, time domain electromagnetics, Vibroseis, and active seismic. Preliminary interpretation of the electric resistivity surveys indicates that the reservoirs may be small (1 to 2 sq mi or 2.6 to 5.2 sq km) and confined to the immediate hot springs areas. The reservoir at Pagosa Springs is at an average depth of 400 ft (120 m) and at Glenwood Springs the reservoir appears to be associated with the Leadville Limestone.

Geothermometer modeling gives estimated reservoir temperatures at Pagosa Springs of 75 to 125°C, and 55 to 80°C at Glenwood Springs.

Field work to have been completed during the fall and winter of 1977-78 includes completion and interpretation of geophysical surveys, drilling of geothermal-gradient holes, and a detailed aquifer-testing program.

AAPG Search and Discovery Article #90964©1978 AAPG Rocky Mountain Section Meeting, Salt Lake City, Utah