| Abstract |
Cerro Prieto, located 20 miles SE of Mexicali in Baja California, is the world's largest producing hot-water geothermal field (620 MWe capacity). In the mid 1950's The Comision Federal de Electricidad de Mexico (CFE) began geological and geochemical surveys of the area of natural manifestations near the Cerro Prieto volcano; in 1959 they started exploratory drilling. The early wells were successful and the best, well M-5, produced large quantities of fluid hotter than 300·C from 1100 m to 1300 m depth. New wells were drilled near M-5 and by 1968 nearly all wells that were used for initial electrical generation had been drilled and tested, and their produced fluids analyzed. The field went on line with 75 MWe in 1973-74 and drilling continued in preparation for field expansion. In 1977 an agreement was signed by CFE and the U.S. Department of Energy (DOE) for a 5 year cooperative study of the field, which has resulted in extens.ive geological, geophysical, geochemical, and reservoir studies reported in the Cerro Prieto Symposium volumes I-IV (CFE-DOE, 1978-82). These studies were reviewed by Lippmann (1983); the geochemical component of the CFE-DOE and earlier CFE studies will be discussed here. The geochemistry of Cerro Prieto was previously reviewed by Truesdell et al. (1984a). |