Interpretation of Geophysical Well Logs from Deep Geothermal Borehole in Pohang

포항 심부 지열 시추공에 대한 물리검층 자료해석

  • Hwang, Se-Ho (Groundwater & Geothermal Resource Division, Korea Institute of Geoscience & Mineral Resources) ;
  • Park, In-Hwa (Groundwater & Geothermal Resource Division, Korea Institute of Geoscience & Mineral Resources) ;
  • Song, Yoon-Ho (Groundwater & Geothermal Resource Division, Korea Institute of Geoscience & Mineral Resources)
  • 황세호 (한국지질자원연구원 지하수지열연구부) ;
  • 박인화 (한국지질자원연구원 지하수지열연구부) ;
  • 송윤호 (한국지질자원연구원 지하수지열연구부)
  • Published : 2007.11.30


Various geophysical well logs have been made along the four deep wells in Pohang, Gyeongbuk. The primary focus of geophysical well loggings was to improve understanding the subsurface geologic structure, to evaluate in situ physical properties, and to estimate aquifer production zones using fluid temperature and conductivity gradient logs. Especially natural gamma logs interpreted with core logs of borehole BH-1 were useful to discriminate the lithology and to determine the lithologic sequences and boundaries consisting of semi-consolidated Tertiary sediments and intrusive rocks such as basic dyke and Cretaceous sediments. Cross-plot of physical properties inferred from geophysical well logs were used to identify rock types such as Cretaceous sandstone and mudstone, Tertiary sediments, rhyolite, and basic dyke. The temperature log indicated $82.51^{\circ}C$ at the depth of 1,981.3 meters in borehole BH-4. However, considering the temperature of borehole BH-2 measured under stable condition, we expect the temperature at the depth in borehole BH-4, if it is measured in stable condition, to be about 5 or $6^{\circ}C$ higher. Several permeable fractures also have been identified from temperature and conductivity gradient logs, and cutting logs.


  1. 송윤호, 정승환, 이상규, 김정호, 황세호, 황학수, 이성곤, 조성준, 이명종, 설순지, 박인화, 2000, 지반 물리탐사 연구, 한국지질 자원연구원 연구보고서 1999-R-TI02-P-01, p111
  2. 송윤호, 이창범, 박덕원, 김형찬, 이철우, 이성곤, 이종철, 이병대, 박인화, 이태종, 조병욱, 염병우, 이승구, 이봉주, 기원서, 박노 욱, 박영수, 임무택, 현혜자, 손정술, 임형래, 황세호, 오재호, 김세준, 이윤수, 김민규, 박 찬, 정용복, 천대성, 김통권, 이진수, 임성근, 서정희, 2004, 심부지 열에너지 개발 사업, 한국지질자 원연구원 연구보고서 일반-04(연차)-01, p226
  3. 송윤호, 이창범, 박덕원, 김형찬, 이철우, 이성곤, 박인화, 이태종, 심병완, 조병욱, 염병우, 이승구, 황세호, 이상규, 이윤수, 김통 권, 이진수, 안은영, 윤 욱, 김연기, 임현철, 이병대, 서정희, 2006, 심부 지열에너지 개발사업, 한국지질자원연구원 연구보 고서 OAA2003001-2006(4), p190
  4. 신제현, 황세호, 김현태, 이상규, 양승진, 2002, 소구경 시추공에서 물리검층을 이용한 공극 측정, 한국자원공학회 추계학술발표회 논문집, 123-128
  5. 이상규, 황세호, 황학수, 박인화, 1998, 지하물성의 정보화를 위 한 물리검층 품질관리 연구, 한국자원연구소 KR-98(C)-10, p65
  6. 황세호, 박찬, 이상규, 신희순, 2000, 소구경 시추공에서의 밀도 검층, 한국자원공학회, 대한자원환경지질학회, 한국지구물리 탐사학회 춘계공동학술발표회 논문집, 298-300
  7. Keys, W. S., and Sullivan, K., 1979, Role of borehole geophysics in defining the physical characteristics of the Raft River geothermal reservoir, Idaho, Geophysics, 26, 1116-1141
  8. Keys, W. S., 1982, Borehole geophysics in geothermal exploration, in Developments in Geophysical Exploration Method -3, Fitch, A. A., eds, Applied Science Publishers
  9. Lee, D. S., 1977, Chemical composition of petrographic assemblages of igneous and related rocks in south Korea, J. Korea. Inst. Mining Geol., 10, 75-92