| Title | Drilling Confirmation of the Casita Indicated Geothermal Resource, Nicaragua |
|---|---|
| Authors | P. White, K. Mackenzie, J. Brotheridge, J. Seastres, B. Lovelock and M. Gomez |
| Year | 2012 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Casita, Nicaragua, slimhole, Indicated resource |
| Abstract | Following on from previous geological, geochemical and geophysical exploration activities, a vertical slimhole well (CSS-01) on the mid slopes of Casita volcano was completed to a depth of 842 m in November 2011 by Cerro Colorado Power (CCP). Wireline logging and flow testing of this well has confirmed the existence of a vapourdominated reservoir at Casita, with a temperature of 230- 250¢XC, and a total gas content of about 0.7 wt%. Based on the results from CSS-01, MT geophysics, and the distribution of surface thermal activity, the Indicated geothermal resource within the CCP concession covers an area of up to 6 km2 as per the definition of the Canadian Geothermal Reporting Code. There is likely to be a liquid reservoir below the vapour zone around an upflow under Casita volcano, although this has yet to be proven by drilling. Well CSS-01 (which has provided temperature and chemistry data) and the surrounding area with thermal activity constitutes an Indicated Resource. Prospective areas outside the Indicated Resource area, including La Pelona caldera and the lower flanks of Casita, are classified as Inferred Resource, based on the MT geophysical data. A resource assessment prepared by SKM for CCP produced the following estimates: - Indicated Resource: Based on a probabilistic stored heat estimate and considering the direct measurements of the well CSS-01, the indicated resource within the CCP concession is 85 MWe (gross) for 20 years (at P90). - Inferred Resource: Based on a probabilistic stored heat estimate, the Inferred Resource within the CCP concession area has a capacity of 68 MWe (gross) for 20 years (at P90). |