Logging technology for high-temperature geothermal boreholes
Research in materials, equipment, and instrument development was required in the Hot Dry Rock Energy Extraction Demonstration at Fenton Hill located in northern New Mexico. Results of this extensive development advanced the logging technology in geothermal boreholes to present state-of-the art. The new Phase II Energy Extraction System at the Fenton Hill Test Site will consist of two wellbores drilled to a depth of about 4570 m (15,000 ft) and then connected by a series of hydraulic-induced fractures. The first borehole (EE-2) was completed in May of 1980 at a depth of 4633 m (15,200 ft) of which approximately 3960 m (13,000 ft) is in Precambrian granitic rock. Starting at a depth of approximately 2930 m (9600 ft), the borehole was inclined up to 35/sup 0/ from vertical. Bottom-hole temperature in EE-2 is 320/sup 0/C. The EE-3 borehole was then drilled to a depth of 4236 m (13,900 ft). Its inclined part is positioned directly over the EE-2 wellbore with a vertical separation of about 450 m (1500 ft) between them. Many of the geophysical measurements needed to develop the hot dry rock concept are unique. Most of the routine instruments used in petroleum drilling fail in the hot and abrasive environment. New equipment developed includes not only the downhole sonde that houses the transducer and associated line driving electronics, but modifications also were needed on the entire data retrieval systems and associated data analysis technology. Successful performance of wellbore surveys in the EE-2 and EE-3 boreholes depended upon the capacity of the sensors, instrument sonde, cablehead, and armored logging cable to work in this severe environment. The major areas of materials development for surveying the boreholes in the high-temperature environment were on elastomeric seals, electrical insulation for logging cables, downhole sensors, and associated downhole electronic and electro-mechanical components.
- Research Organization:
- Los Alamos National Lab., NM (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6771110
- Report Number(s):
- LA-UR-84-1639; CONF-840572-2; ON: DE84012452
- Resource Relation:
- Conference: International symposium on observation of the continental crust through drilling, Tarrytown, NY, USA, 20 May 1984
- Country of Publication:
- United States
- Language:
- English
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Hot Dry Rock Geothermal Energy Development Program. Annual report, fiscal year 1983