Development of a Downhole Tri-axial magnetic field measuring system and its application to Subsurface Fracture Characterization
Grant-in-Aid for Scientific Research (A)
|Research Institution||Tohoku University|
SATO Motoyuki Center for Northeast Asian Studies, Tohoku University, Professor, 東北アジア研究センター, 教授 (40178778)
森谷 裕一 東北大学, 工学部, 助手 (60261591)
浅沼 宏 東北大学, 工学研究科, 助教授 (50250717)
新妻 弘明 東北大学, 工学研究科, 教授 (90108473)
中塚 勝人 東北大学, 工学研究科, 教授 (60005345)
小田 幸人 東北大学, 工学研究科, 助手 (40005369)
阿部 司 東北大学, 工学研究科, 助教授 (50005310)
EBIHARA Satoshi Center for Northeast Asian Studies, Tohoku University, Research Associate, 東北アジア研究センター, 助手 (20301046)
|Project Fiscal Year
1996 – 1998
Completed(Fiscal Year 1998)
|Budget Amount *help
¥18,500,000 (Direct Cost : ¥18,500,000)
Fiscal Year 1998 : ¥2,700,000 (Direct Cost : ¥2,700,000)
Fiscal Year 1997 : ¥5,100,000 (Direct Cost : ¥5,100,000)
Fiscal Year 1996 : ¥10,700,000 (Direct Cost : ¥10,700,000)
|Keywords||Magnetic field measurement / Induction logging / Directivity Measurement / Magnetic permeability measurement / Electrical Conductivity measurement / Tomography / 磁力計測 / インダクション検層 / 指向性計測 / 透磁率計測 / 導電率計測 / トモグラフィ / トモ グラフィ / 坑井内イメージング / 三軸磁力計測 / 異方性 / 三成分磁力計測 / 坑内磁力計測 / 岩石磁気特性|
This project was carried out in the three phases described below.
(1) Hardware development of the downhole tri-axial magnetic field measuring system was carried out. The basis of the system is the downhole tool developed by the NEDO under MITT, Japan. Fundamental experiment in air and in a borehole at Tohoku University experiment site at Higashi Hachimantai Geothermal field was achieved for understanding the tool characteristics. Theoretical tool response was calculated and directivity to electrical conductivity of the surround material was examined.
(2) Independent response of in-phase and quadrate - phase components was experimentally shown. Theoretical approach to the method of simultaneous electrical conductivity and magnetic permeability logging was studied. Also, we found this technique is sensitive to the thin layer detection and precise determination of geological boundary.
(3) A Cross-hole tomography technique was tested by using a low frequency downhole tool. The system use 2MHz-32MHz, which are intermediate frequency of conventional borehole radar and induction technique. We could show that this technique can be used in relatively conducting material.
Throughout this project, we showed experimentally and theoretically that the dowohole tri-axial magnetic field measuring system can be used for simultaneous electrical conductivity ad magnetic permeability logging, and that it is useful for characterization of subsurface fracture classification.
Research Output (9results)