Evaluation of Natural Recharge of Chingshui Geothermal Reservoir in Taiwan

Abstract

Thermal water production in the liquid-dominated Chingshui geothermal field is largely from a fractured zone in the Jentse Member of the Miocene Lushan Formation. The age of Chingshui geothermal water was determined with tritium data. An interference test in Chingshui geothermal reservoir was analyzed to determine aquifer porosity-thickness product which was then used to calculate the fluid-in-place by volumetric method. The paper combined the use of both tracer and interference tests to evaluate the natural recharge of Chingshui geothermal reservoir. The annual natural recharge was estimated by combing the use of the mean residence-time of Chingshui geothermal water and the fluid-in-place of Chingshui geothermal reservoir. Estimates for fluid-in-place, mean residence time and natural recharge for Chingshui geothermal reservoir are 2?108 m3, 15 years, and 1.3?107 m3 / year, respectively.