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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 66 (1982)

Issue: 7. (July)

First Page: 972

Last Page: 972

Title: High Temperature Geothermal Well-Logging Techniques in Japan: ABSTRACT

Author(s): Toshinobu Itoh

Article Type: Meeting abstract

Abstract:

A high temperature geothermal well-logging system has been developed by Japan Petroleum Exploration Co., under the sponsorship of the Japanese government. The tools developed on this project are: Multi-Spacing Electrical-SP Log (equivalent to Lateral Log); Microspherical-Caliper Log; Side Wall Acoustic-Caliper Log (P-S Wave Sonic Log); Steering Tool (Azimuth, Hole Deviation and Inclination); Optical Borehole TV; Production Logging Tools (Temperature, Pressure, Continuous Flow and Caliper, and Borehole Sampler).

The maximum operating temperature of these tools is 325°C and they can withstand pressures of 500 kg/cm2, by the use of TFE teflon insulator armored cable. The tools have been subjected to field tests over 50 geothermal wells, since 1978, and all except the Optical Borehole TV were successfully operated where bottom-hole temperatures were as high as 210 to 275°C.

The side wall acoustic tool, which consists of P and S wave transducers, is very useful for the detection of formation fractures in volcanic rocks. The Optical Borehole TV could not be used where temperatures exceeded 150°C, because of heat radiation emitted from the mud and the holewall surrounding the down-hole probe, or when the tool was focused at the surface of the semiconductor imagesensor on the TV and the temperature of the image spot exceeded 120°C, even when placed in a Dewar bottle and heat sink assembly.

Super high temperature (450°C) production logging tools, using mineral insulation cable, are under construction and will be in operation by the end of August 1982. They are: Absolute and 1-meter spacing differential Temperature Survey; Continuous Pressure Measurement; Continuous Flow and Caliper Measurement; High Temperature Microphone and Accelometer, with a wall set mechanism.

The diameter of these tools is 2 inches and their maximum operating time is 30 hours at 450°C. They can withstand pressures of 500 kg/cm2.

The success of this system is apparent from the summary of field results and the technical report of the super high temperature production logging tools.

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Copyright 1997 American Association of Petroleum Geologists