Drill Collar Specs

Specifications – Standard

Sizes, Bores, and Connections

Drill Collar Conn.
Size & Type
Min. OD Bore Length Bending Strength
Ratio***
Drill Collar Wt.
(in.) (in.) (ft.) (lb.)
2 3/8 REG 3 1/8 1 1/4 31 2.75:1 653
2 7/8 PAC 3 1/8 1 1/4 31 2.16:1 653
NC 26 (2-3/8 IF) 3 1/2 1 1/2 31 2.42:1 828
NC 31 (2-7/8 IF) 4 1/8 2 31 2.43:1 1077
NC 38 (3-1/2 IF) 4 3/4 2 1/4 31 1.91:1 1448
NC 38 (3-1/2 IF) 5 2 1/4 31 2.38:1 1650
NC 46 (4 IF) 6 1/4 2 1/4 31 2.38:1 2811
NC 46 (4 IF) 6 1/2 2 1/4 31 2.76:1 3077
NC 46 (4 IF) 6 1/2 2 13/16 31 3.07:1 2842
NC 50 (4-1/2 IF) 6 1/2 2 1/4 31 1.89:1 3077
NC 50 (4-1/2 IF) 6 1/2 2 13/16 31 2.03:1 2842
NC 50 (4-1/2 IF) 6 3/4 2 1/4 31 2.20:1 3350
NC 50 (4-1/2 IF) 6 3/4 2 13/16 31 2.54:1 3115
NC 56 8 2 13/16 31 3.02:1 4640
6-5/8 REG 8 2 13/16 31 2.60:1 4640
6-5/8 REG 8 1/4 3 31 2.99:1 4888
7 5/8 REG 9 1/2 3 31 2.82:1 6723
7-5/8 REG.** 9 1/2 3 31 2.82:1 6723
8-5/8 REG.** 11 3 31 2.84:1 9272
** Low torque face
*** Ratio of box to pin section modulus – See API RP7G for details
Note: Other sizes and connections are available as well as any other optional features listed below

Drill Collar Features & Options

Drill Collar OD Elevator Recess
OD (ER)
(in)
Slip Recess
OD (SR)
(in)
Elevator Recess Radius (R)
(in)
4 3/4 4 1/4 4 3/8 1/8
5 4 1/2 4 5/8 1/8
6 1/4 5 5/8 5 3/4 1/8
6 1/2 5 7/8 6 1/8
6 3/4 6 6 1/4 3/16
8 7 1/4 7 1/2 3/16
8 1/4 7 1/2 7 3/4 3/16
9 1/2 8 5/8 9 1/4
11 10 1/8 10 1/2 1/4
These features are not recommended for collars with OD below 4-3/4″

Specifications – Non-Mag

Sizes, Bores, and Connections

Drill Collar Conn.
Size & Type
Min. OD Bore Length Bending Strength
Ratio***
Drill Collar Wt.
(in.) (in.) (ft.) Per 31 ft
NC 38 (3-1/2 IF) 4 3/4 2 1/4 31 1.92:1 1448
NC 38 (3-1/2 IF) 4 3/4 2 11/16 31 2.32:1 1270
NC 38 (3-1/2 IF) 5 2 1/4 31 2.38:1 1650
NC 38 (3-1/2 IF) 5 2 11/16 31 2.89:1 1472
NC 46 (4 IF) 6 1/2 2 13/16 31 3.07:1 2842
NC 46 (4 IF) 6 1/2 3 1/4 31 3.59:1 2622
NC 50 (4 1/2 IF) 6 3/4 2 13/16 31 2.37:1 3115
NC 50 (4 1/2 IF) 6 3/4 3 1/4 31 2.62:1 2895
6-5/8 REG 8 2 13/16 31 2.60:1 4640
6 5/8 REG 8 3 1/4 31 2.75:1 4420
Note: Other sizes and connections are available as well as any other optional features listed below.

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