| Abstract |
Tatapani Geothermal Field, is located on the Son Narmada lineament, 100 km NE of Ambikapur, district Surguja. Downhole well testing of the borewells at TGF was ompleted by Geological Survey of India and Oil and Natural Gas Corporation, in 1995 to decipher the sub surface characters of shallow reservoir. The well testing data was published in 1999. Based on the investigations done by GSI during the last two decades, a 300 kWe pilot geothermal power plant is proposed at Tatapani. The borewells were not in use since 1995 hence the testing of these wells was repeated in 1999 to verify the temperature and pressure parameters. The second phase of well testing data indicated that the temperatures are consistent while the discharge is reduced which may be attributed to caving in the boreholes. Maximum temperature of 112?C is recorded in the borewell. Inversion of temperature from 112 to 109?C is observed below the depth of 200m, indicating incursion of cold water in the borewell. The borewells need cleaning and proper casing programme before commencing the production. The flowing pressure observed in the wells is 32.6 bars at the depth of 340m. The pressure gradient varies from 0.093 to 0.0958 bars / m which is near hydrostatic. The pressure parameters are found to be in conformity with the results of previous well testing data. A continuous discharge of bore wells over 7 days showed pressure drop of 0.22 bars at the bottom hole, indicating moderate productivity. The well testing has confirmed that the borewells are free flowing and interconnected. The results of two well testing show consistent temperature and pressure parameters over a period of 4 years. Thus, it may be surmised that the wells may sustain regular production. |