Assessment of Tatapani Geothermal Field, Balarampur District, Chhattisgarh, State, India

Abstract

ABSTRACT Tatapani is the most promising geothermal field located on Son-Narmada lineament in Central India. Two types of lithounits comprising Proterozoic basement rocks viz. granite gneiss, biotite gneiss, phyllite, and Lower Gondwana Group consisting of carboniferous clays, siltstone, sandstone and shale are exposed in this area. The tectonic contact between Proterozoic and Gondwana rocks is marked by Tatapani fault trending ENE-WSW. Geological Survey of India has completed five borewells wells at Tatapani Geothermal field which discharge hot water of more than 100°C on surface. The silica geothermometry indicates an average reservoir temperature of around 157°C. The Na-K geothermometer indicates temperature in the range of 180°C to 200°C; hence, the deep reservoir temperature may be higher than 157°C as suggested by silica geo- thermometer. The hydrothermal alteration mineralogy supports the view that the reservoir temperature at deeper level may be in the range of 160-180°C or more. The production potential of 10.9 Mwe binary cycle electricity generation was estimated upto the depth of 1500m, for a period of 20 years, at the effluent temperature of 87°C. Considering the improvement in power generation technology, it is attempted in this article to refine the assessment of resource potential of geothermal field at Tatapani. The fair assessment of potential at Tatapani may help in planning deeper exploration for establishing geothermal power plant to generate energy commensurate with databse created during the course of field and laboratory studies.