Deep Geothermal Resources Survey Program- Igneous, Metamorphic And Hydrothermal Processes In A Well Encountering 500Degreesc At 3729 M Depth, Kakkonda, Japan

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Journal Article: Deep Geothermal Resources Survey Program- Igneous, Metamorphic And Hydrothermal Processes In A Well Encountering 500Degreesc At 3729 M Depth, Kakkonda, Japan

Abstract
The exploration well WD-1a was drilled to a depth of 3729 m in the Kakkonda geothermal field, northeast Japan, using efficient borehole cooling techniques. The well penetrated an entire shallow hydrothermal convection zone, an entire contact metamorphic aureole and part of a neo-granitic pluton. The recovered temperature of the well indicates a boiling point-controlled profile up to 380°C to a depth of 3100 m, and a conduction-controlled profile with a very high gradient from 3100 m to the bottom of the hole, where the temperature is 500°C. WD-1a may be the first geothermal well that encountered 500°C, which exceeds the conventional hydrostatic boiling-point curve. An inflection point of the temperature-depth profile at 3100 m and about 380°C reflects the brittle-plastic boundary. The brittle-plastic boundary constrains the maximum depth of fracture formation, and the fracture distribution constrains the maximum depth of hydrothermal convection.

Authors 
Hirofumi Muraoka, Toshihiro Uchida, Masakatsu Sasada, Masahiko Yagi, Kohei Akaku, Munetake Sasaki, Kasumi Yasukawa, Shin-ichi Miyazaki, Nobuo Doi, Seiji Saito, Ko Sato and Shoichi Tanaka








Published Journal 
Geothermics, 1998





DOI 
10.1016/S0375-6505(98)00031-5


 

Citation

Hirofumi Muraoka,Toshihiro Uchida,Masakatsu Sasada,Masahiko Yagi,Kohei Akaku,Munetake Sasaki,Kasumi Yasukawa,Shin-ichi Miyazaki,Nobuo Doi,Seiji Saito,Ko Sato,Shoichi Tanaka. 1998. Deep Geothermal Resources Survey Program- Igneous, Metamorphic And Hydrothermal Processes In A Well Encountering 500Degreesc At 3729 M Depth, Kakkonda, Japan. Geothermics. (!) .