REASSESSMENT OF GEOTHERMAL ENERGY POTENTIAL IN TATTAPANI GEOTHERMAL FIELD IN BALRAMPUR DISTRICT, CHHATTISGARH STATE, INDIA

Abstract

Tatapani geothermal field is one of the most important geothermal manifestations in Peninsular India, along Son-Narmada-Tapi (SONATA) rift zone. Earlier workers established feasibility of electric power generation of 300 kWe over the period of 20 years and inferred reservoir potential of 17 MWe.
The reassessment work involving collection of geological; and collation of these data with previous work were undertaken. The Magneto-Telluric survey (MT) indicated four conductor bodies right from 0.5km depth to 20km depth. The aqueous geothermometers indicated a temperature range of 160°C to 210°C. The maximum temperature is recorded 112.5oC in a borehole located at 23°41’16.4” N: 83°38’57.8” E.
The assessment is carried out on a shallow depth conductor body exist at 0.5km to 2km depth for which thermal log data of exploratory boreholes and hand pumps are available. The main geothermal zone extends over a length of 1380m from ENE to WSW with width varying from 270m in ENE to 345m in WSW at the depth of 250m. The average temperature surfaces at 500m interval has been used for constructing a 3D model to decipher vertical disposition of temperatures in the thermal reservoir. The geothermal reservoir shows elliptical shape with longer axis parallel to ENE-WSW trending Tatapani fault. The shape is also corroborated by the MT survey.
The available heat for power generation is calculated 42 MWe for 20 years from the volume of 4.4 x 109 m3 having depth of 1000m to 2000m. It is also attempted for 500m productive zone from 1500 m to 2000 m depth which is worked out 31 MWe for 20 years from the volume of 2.95 x 109 m3 having depth of 1500m to 2000m. The reassessment indicates that the Tatapani geothermal resource has high potential to generate electricity from shallow depth by binary cycle method.