Recent Developments in Geothermal Drilling Fluids
In the past, standard drilling muds have been used to drill most geothermal wells. However, the harsh thermal and chemical environment and the unique geothermal formations have led to such problems as excessive thickening of the fluid, formation damage, and lost circulation. This paper describes three recent development efforts aimed at solving some of these drilling fluid problems. Each of the efforts is at a different stage of development. The Sandia aqueous foam studies are still in the laboratory phase, NL Baroid's polymeric deflocculant is soon to be field tested, and the Mudtech high-temperature mud was field tested several months ago. Low density and the capability to suspend particles at low relative velocities are two factors which make foam an attractive drilling fluid. The stability of these foams and their material properties at high temperatures are presently unknown and this lack of information has precluded their use as a geothermal drilling fluid. The aqueous foam studies being conducted at Sandia are aimed at screening available surfactants for temperature and chemical stability. Approximately 100 surfactants have been tested at temperatures of 260 and 310 C (500 and 590 F), and several of these candidates appear very promising. NL Baroid has developed a polymeric deflocculant for water-based muds which shows promise in retarding thermal degradation effects and associated gelation. Formulations containing this new polymer have shown good rheological properties up to 260 C (500 F) in laboratory testing. A high-temperature mud consisting primarily of sepiolite, bentonite, and brown coal has been developed by Mudtech, Inc. A field test of this mud was conducted in a geothermal well in the Imperial Valley of California in May 1980. The fluid exhibited good hole-cleaning characteristics and good rheological properties throughout the test.
- Research Organization:
- DOEEEGTP (USDOE Office of Energy Efficiency and Renewable Energy Geothermal Tech Pgm)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 886126
- Report Number(s):
- SAND-81-0036C; CONF-810105-25; TRN: US200616%%1003
- Resource Relation:
- Conference: International Geothermal Drilling and Completions Technology Conference, Albuquerque, NM, USA, 21 Jan 1981
- Country of Publication:
- United States
- Language:
- English
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