The drill collars are made of 4145H modified chromium-molybdenum alloy steel acc. to API Spec.7. All threads can be phosphated, copperized or cold worked. All threads are machined with CNC Lathes-Double-Shouldered and a special thread, the max diameter of drill collar is 14 in. We can offer Slick Collars, Spiral Collars, Trigone Drill Collars, Non-magnetic Drill Collars.
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.
|
Connection #
|
OD
|
ID
|
L mm
|
DF
|
Bending strength ratio
|
||
|
mm
|
in
|
mm
|
In
|
mm
|
|||
|
NC23-31
|
79.4
|
3 1/8
|
31.8
|
1 1/4
|
9150
|
76.2
|
2.57:1
|
|
NC26-35
|
88.9
|
3 1/2
|
38.1
|
1 1/2
|
9150
|
82.9
|
2.42:1
|
|
NC31-41
|
104.8
|
4 1/8
|
50.8
|
2
|
9150 or 9450
|
100.4
|
2.43:1
|
|
NC35-47
|
120.7
|
4 3/4
|
50.8
|
2
|
9150 or 9450
|
114.7
|
2.58:1
|
|
NC38-50
|
127
|
5
|
57.2
|
2 1/4
|
9150 or 9450
|
121
|
2.38:1
|
|
NC44-60
|
152.4
|
6
|
57.2
|
2 1/4
|
9150 or 9450
|
144.5
|
2.49:1
|
|
NC44-60
|
152.4
|
6
|
71.4
|
2 13/16
|
9150 or 9450
|
144.5
|
2.84:1
|
|
NC44-62
|
158.8
|
6 1/4
|
57.2
|
2 1/4
|
9150 or 9450
|
149.2
|
2.91:1
|
|
NC46-62
|
158.8
|
6 1/4
|
71.4
|
2 13/16
|
9150 or 9450
|
150
|
2.63:1
|
|
NC46-65
|
165.1
|
6 1/2
|
57.2
|
2 1/4
|
9150 or 9450
|
154.8
|
2.76:1
|
|
NC46-65
|
165.1
|
6 1/2
|
71.4
|
2 13/16
|
9150 or 9450
|
154.8
|
3.05:1
|
|
NC46-47
|
171.4
|
6 3/4
|
57.2
|
2 1/4
|
9150 or 9450
|
159.5
|
3.18:1
|
|
NC50-67
|
171.4
|
6 3/4
|
71.4
|
2 13/16
|
9150 or 9450
|
159.5
|
2.37:1
|
|
NC50-70
|
177.8
|
7
|
57.2
|
2 1/4
|
9150 or 9450
|
164.7
|
2.54:1
|
|
NC50-70
|
177.8
|
7
|
71.4
|
2 13/16
|
9150 or 9450
|
164.7
|
2.73:1
|
|
NC50-72
|
184.2
|
7 1/4
|
71.4
|
2 13/16
|
9150 or 9450
|
169.5
|
3.12:1
|
|
NC56-77
|
196.8
|
7 3/4
|
71.4
|
2 13/16
|
9150 or 9450
|
185.3
|
2.70:1
|
|
NC56-80
|
203.2
|
8
|
71.4
|
2 13/16
|
9150 or 9450
|
190.1
|
3.02:1
|
|
6 5/8 REG
|
209.6
|
8 1/4
|
71.4
|
2 13/16
|
9150 or 9450
|
195.7
|
2.93:1
|
|
NC61-90
|
228.6
|
9
|
71.4
|
2 13/16
|
9150 or 9450
|
212.7
|
3.17:1
|
|
7 5/8 REG
|
241.3
|
9 1/2
|
76.2
|
3
|
9150 or 9450
|
223.8
|
2.81:1
|
|
NC70-97
|
247.6
|
9 3/4
|
76.2
|
3
|
9150 or 9450
|
232.6
|
2.57:1
|
|
NC70-100
|
254
|
10
|
76.2
|
3
|
9150 or 9450
|
237.3
|
2.81:1
|
|
8 5/8REG
|
279.4
|
11
|
76.2
|
3
|
9150 or 9450
|
266.7
|
2.84:1
|
|
8 5/8REG
|
355.6
|
14
|
76.2
|
3
|
9150 or 9450
|
266.7
|
2.84:1
|