The Case of the Hardband Tungsten Particles
In the old days, when onshore oilfield wells were about 5000 feet and nearly straight down, well casing wall wear was not a major concern. A common practice for extending drill pipe life was hardbanding welds on the box joint of each drill pipe. During the hardbanding, tungsten carbide particles were included in the soft, steel weld-wire overlayed on the box joint. The tungsten carbide particles created a raised hardened-surface on the box joint that could greatly increase the life of the drill pipe before the drill pipe became worn too thin for the drill-string requirements.
During the past 50 years or so, oilfield wells have become much deeper and highly deviated to nearly horizontal. It was determined that drill pipe with hardband tungsten particles could cause as much as 25% or more wear on the well casing wall and likely resulted in blowouts for deep, deviated wells.
Drill pipes with hardbanding tungsten carbide particles were found intermixed with other drill-string pipe that had “casing friendly” hardbanding on box joints. At the well-site, WJMG used nondestructive methods for alloy analysis with a portable instrument to identify box joints that contained hardbanding with tungsten carbide particles. Drill pipe with tungsten carbide hardbanding was eliminated from the drill-string inventory and not allowed for drilling the well.
Nowadays, “casing friendly“ hardbanding can protect the well casing wall more than the pipe in the drill string. Without tungsten particles in the hardbanding, there was less friction during contact with the well casing, less heat and less wear on the well casing. Hardbanding of drill pipe box ends only reduces the amount of wear on the well casing and other components during well drilling operations.
The Lesson Learned:
Drill-string damage to the well casing while drilling deep wells and deviated wells increases the owner’s overall drilling costs, operating costs and risks for a blowout. The owner should take precautions that increase the profitable life of the well. Drill pipe with tungsten carbide particle hardbanding should be removed from the drill-string before drilling the well. WJMG material Identification techniques can spot tungsten carbide particles in hardbanding for removal of the drill pipe with tungsten carbide particle hardbanding before damaging the well casing wall and reduce the potential for well blowouts.