| Title | Preliminary Studies of Brine Reinjection a the Cerro Prieto Geothermal Field |
|---|---|
| Authors | J. Rivera R., S. Mercado G., C. F. Tsang |
| Year | 1978 |
| Conference | DOE-CFE Symposium on Cerro Prieto |
| Keywords | |
| Abstract | At the present time, Units I and 2 of the Cerro Prieto power plant generate 75 MW of power. For this purpose about 2200 tons/hr of fluids are produced, of this, 700 tons/hr of steam are sent to the plant and 1500 tons/hr of spent brine are discarded into an evaporation pond. The thermal energy extracted is estimated to be on the order of 723 x 109 cal/hr, of which about 260 x 109 cal/hr is lost with the discarded water to the atmosphere. If, instead of disposing this water, it were possible to recirculate it by sending it back into the reservoir, most of the energy presently dissipated into the atmosphere could be returned underground. Reinjection would also lengthen the productive life of the reservoir because it would constitute an additional source of fluid recharge. Furthermore, reinjection of separated brines would solve the problem of surface disposal. About 1500 tons/hr of brines are presently sent to the evaporation pond, and the problems will become more acute when Units 3 and 4, each with 37.5-MW capacity, go on line in mid-l979. At present, a number of studies are being conducted to evaluate alternative methods of injection. The methods being considered are: cold or hot injection with open, closed, or mixed systems. For each of these system, laboratory tests will be carried out using columns packed with different grain-sized sands. The sands used are from alluvial fans of the Cucapa range. The purpose of these tests is to establish the scale-forming tendencies of the water when injected under different conditions (Figures 1, 2 and 3). Later, similar tests will be made on models built with natural sandstones. Because of its favorable characteristics, well M-6 (see Figure 1) might be used in a pilot injection field test. The feasibility of reinjecting into two different levels, at 300 m and between 527 and 741 m depth, is being evaluated. Other possible wells for reinjection could be M-3 and M7. |