Field drilling tests on improved geothermal unsealed roller-cone bits. Final report

Technical Report · Thu May 01 04:00:00 EDT 1980

DOI:https://doi.org/10.2172/5414712· OSTI ID:5414712

Hendrickson, R R; Jones, A H; Winzenried, R W; Maish, A B

The development and field testing of a 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bit are described. Increased performance was gained by substituting improved materials in critical bit components. These materials were selected on bases of their high temperature properties, machinability and heat treatment response. Program objectives required that both machining and heat treating could be accomplished with existing rock bit production equipment. Six of the experimental bits were subjected to air drilling at 240/sup 0/C (460/sup 0/F) in Franciscan graywacke at the Geysers (California). Performances compared directly to conventional bits indicate that in-gage drilling time was increased by 70%. All bits at the Geysers are subjected to reaming out-of-gage hole prior to drilling. Under these conditions the experimental bits showed a 30% increase in usable hole drilled, compared with the conventional bits. The materials selected improved roller wear by 200%, friction per wear by 150%, and lug wear by 150%. These tests indicate a potential well cost savings of 4 to 8%. Savings of 12% are considered possible with drilling procedures optimized for the experimental bits.

• Research Organization: Terra Tek, Inc., Salt Lake City, UT (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5414712
• Report Number(s): SAND-80-7079
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150901* -- Geothermal Engineering-- Drilling Technology & Well Hardware
BEARINGS
DRILL BITS
DRILLING
DRILLING EQUIPMENT
EQUIPMENT
FIELD TESTS
GEOTHERMAL FIELDS
GEOTHERMAL WELLS
GEYSERS GEOTHERMAL FIELD
GRAYWACKE
Geothermal Legacy
PERFORMANCE
ROCK DRILLING
ROCKS
SEDIMENTARY ROCKS
TESTING
WELL DRILLING
WELLS