We have a sting of 5 7/8" Grant Prideco Drillpipe with a XT57 thread.
We are having major problems with the tool joints not breaking.We now
have had to purchase a set of HT200 rig tongs. As it can take up to
110k to break the joints.
The drillpipe has the treads cleaned, and pin and box re-dopped on
each trip. A drilling break of the string is done off bottom on every
trip. The max TQ seen on the string is 30kft/lbs, downhole temp is
105 deg C. The drillpipe is made up to 50kft/lbs and Koper-Kote dope
Is there anyone out there who have this string and DO not have this
We had the same problems back in 2004 where breaking took an average
of >60 k ft.lb with some breaking > 100 k ftlb. MU was 43 k ft.lb.
Again there were no signs of downhole make up. Upon discussing the
problem with a colleague who had the same problem, his solution was
to throw out the copper base compound and replace it with a zinc
based compound. He claimed the problems dissapeared after changing to
zinc compound. You can find the specification of this zinc based
compound in Grant Prodeco's brochure for XT59 drillpipe.
Edwin Damasena -
Posted from - 2007-12-03 03:32:51replyResponse