Drill Collar is mainly used to provide bit weight to drill bit so that drill pipe is in tension. Especially drill collar can keep drill bit centralized and hole track by large rigidity
Drill Collar Number O.D. I.D. Length
(mm) Bevel Diameter Ref bend g Strength ratio
(mm) (in) (mm) (in)
NC23-31 79.4 3 1/8 31.8 1 1/2 9150 76.2 2.57:1
NC26-35(2 3/8 IF) 88.9 3 1/2 38.1 1 1/2 9150 82.9 2.42:1
NC31-41(2 7/8 IF) 104.8 4 1/8 50.8 2 9150 100.4 2.43:1
NC35-47 120.6 4 3/4 50.8 2 9150 114.7 2.58:1
NC38-50(3 1/2 IF) 127.0 5 57.2 2 1/4 9150 121.0 2.38:1
Drill Collar,Drill Collars,Drilling String