Author: Thomas Flynn

Publisher:

Published: 1982

Total Pages: 57

ISBN-13:

Two geothermal test wells were drilled in January, 1983, in Antelope Canyon to access the potential for resource utilization by the City of Caliente's proposed space heating district. Both holes, drilled into bedrock at 220 feet, encountered hot water in the upper part of the hole (40 to 100 feet) and cooler water below (100 to 210 feet). Temperature-depth profiles measured in the two holes are nearly identical, and are similar to profiles measured in existing nearby wells. Lithologic logs constructed from drill chip samples reveal that a clay layer, in the vicinity of the temperature reversal, represents an aquiclude that limits fluid mixing. The diameter of well CD-l was subsequently increased from 6 inches to 14 inches to a depth of 100 feet. The well was cased with 40 feet of 8 5/8 inch diameter screen in the production zone. Well completion consisted of gravel packing, swabbing and jetting with Barafos solution to remove entrapped drilling fluids, installation of a gravel-fill tube, and cementing the upper 42 feet of the blank-cased hole. A series of pumping tests were completed in February, 1983, including pump-efficiency tests, stepped draw-down tests, and 1-, 2-, and 3-day sustained pumping tests. The test results indicated that the transmissivity of the thermal aquifer is very, very high. A pumping rate of 255 gallons per minute at 80°C (178°F) may be considered a minimum. Drawdowns of 3 to 6 feet were recovered instantly after pumping was stopped. Pumping of this well had no apparent effect on the water levels of two nearby observation wells. Significant temperature increases were recorded in both observation wells during the last few days of the tests. Five water samples were collected for chemical analyses during the course of CD-l pump tests. The samples were collected to determine the water quality for the proposed space heating district and possible reinjection, and to establish a water chemistry base-line for comparative analysis of fluid chemistry during the course of the pumping and from subsequent development. In addition, the chemical data were compared to existing analyses of thermal and non-thermal waters in Caliente. The results of these analyses indicate little or no change in composition over the period of pump testing, and demonstrate a high degree of correlation with nearby thermal fluids. The water quality meets state health standards for all chemical constituents and may be used as a source of potable water. Chemical geothermometers indicated that the maximum temperatures from this resource range from 120 to 140°C. The highest temperature measured in this resource is 96°C.