Failure mechanisms of polycrystalline diamond compact drill bits in geothermal environments

Technical Report · Tue Sep 01 00:00:00 EDT 1981

DOI:https://doi.org/10.2172/5167331· OSTI ID:5167331

Hoover, E R; Pope, L E

Over the past few years the interest in polycrystalline diamond compact (PDC) drill bits has grown proportionately with their successful use in drilling oil and gas wells in the North Sea and the United States. This keen interest led to a research program at Sandia to develop PDC drill bits suitable for the severe drilling conditions encountered in geothermal fields. Recently, three different PDC drill bits were tested using either air or mud drilling fluids: one in the laboratory with hot air, one in the Geysers field with air, and one in the Geysers field with mud. All three tests were unsuccessful due to failure of the braze joint used to attach the PDC drill blanks to the tungsten carbide studs. A post-mortem failure analysis of the defective cutters identified three major failure mechanisms: peripheral nonbonding caused by braze oxidation during the brazing step, nonbonding between PDC drill blanks and the braze due to contamination prior to brazing, and hot shortness. No evidence was found to suggest that the braze failures in the Geysers field tests were caused by frictional heating. In addition, inspection of the PDC/stud cutter assemblies using ultrasonic techniques was found to be ineffective for detecting the presence of hot shortness in the braze joint.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5167331
• Report Number(s): SAND-81-1404; ON: DE82006965
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
DRILL BITS
FAILURES
TESTING
BRAZED JOINTS
BRAZING
DIAMONDS
GEOTHERMAL FLUIDS
GEOTHERMAL WELLS
GEYSERS GEOTHERMAL FIELD
TUNGSTEN CARBIDES
CARBIDES
CARBON
CARBON COMPOUNDS
DRILLING EQUIPMENT
ELEMENTAL MINERALS
ELEMENTS
EQUIPMENT
FABRICATION
FLUIDS
GEOTHERMAL FIELDS
JOINING
JOINTS
MINERALS
NONMETALS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
WELDED JOINTS
WELDING
WELLS
Geothermal Legacy
150901* - Geothermal Engineering- Drilling Technology & Well Hardware