| Abstract |
In the year 2003, Korea Institute of Geoscience and Mineral Resources (KIGAM) have launched a project to develop the deep-seated geothermal water for large-scale space heating in Pohang city, located south-eastern part of Korean Peninsula, with the funding from KORP (Korea Research Council of Public Science and Technology). Various geologic and geophysical surveys including Landsat TM image analysis, gravity and magnetic surveys, magnetotelluric (MT) and self-potential (SP) surveys have been performed to delineate possible fractures that would serve as deeply connected geothermal water conduit. Based on the surveys, two test boreholes have been drilled; one for coring, 1.1 km deep, and the other for production test, 1.5 km deep. Pumping test from the test borehole reserves geothermal water of 51 °C with the production rate of 560 tons/day. With the promising results, a production well have been located roughly 1 km north from the test site and drilled down to 2.385 km deep, starting with 16 inch diameter and ending with 6 and a half inches. Drilling logs and geophysical logging indicates there are several permeable fractures intersecting the borehole and the bottom temperature is over 90 °C. From the production well, above 70 °C of geothermal water is expected to be produced and is to be used, for the first time in Korea, in a cascade manner such as district heating for apartments or public buildings nearby, green houses, and aquacultures |