Drill collar is made of rolled or forged AISI 4145H chrome molybdenum alloy steel for effective control of chemical composition and trace element content.
Drill collar is at the lowest part of the drill string and is the main component of the lower drill assembly. Its main feature is the wall thickness (usually 38 ~ 53mm, equivalent to the drill pipe wall thickness of 4 to 6 times), with greater gravity and stiffness.
|
Nominal size |
D |
d |
Lmm |
DF(mm) |
Bending Strength ratio |
||
|
mm |
In |
mm |
in |
||||
|
NC31-41(2-7/8IF) |
104.8 |
4-1/8 |
50.8 |
2 |
9150 |
100.4 |
2.43:1 |
|
NC35-47 |
120.7 |
4-3/4 |
50.8 |
2 |
9150 |
114.7 |
2.58:1 |
|
NC38-50(3-1/2IF) |
127.0 |
5 |
57.2 |
2-1/4 |
9150 |
121.0 |
2.38:1 |
|
NC44-60 |
152.4 |
6 |
57.2 |
2-1/4 |
9150/9450 |
144.5 |
2.49:1 |
|
NC44-60 |
152.4 |
6 |
71.4 |
2-13/16 |
9150/9450 |
144.5 |
2.84:1 |
|
NC44-62 |
158.8 |
6-1/4 |
57.2 |
2-1/4 |
9150/9450 |
149.2 |
2.91:1 |
|
NC46-62(4IF) |
158.8 |
6-1/4 |
71.4 |
2-13/16 |
9150/9450 |
150.0 |
2.63:1 |
|
NC46-65(4IF) |
165.1 |
6-1/2 |
57.2 |
2-1/4 |
9150/9450 |
154.8 |
2.76:1 |
|
NC46-65(4IF) |
165.1 |
6-1/2 |
71.4 |
2-13/16 |
9150/9450 |
154.8 |
3.05:1 |
|
NC46-67(4IF) |
171.4 |
6-3/4 |
57.2 |
2-1/4 |
9150/9450 |
159.5 |
3.18:1 |
|
NC50-67(4-1/2IF) |
171.4 |
6-3/4 |
71.4 |
2-13/16 |
9150/9450 |
159.5 |
2.37:1 |
|
NC50-70(4-1/2IF) |
177.8 |
7 |
57.2 |
2-1/4 |
9150/9450 |
164.7 |
2.54:1 |
|
NC50-70(4-1/2IF) |
177.8 |
7 |
71.4 |
2-13/16 |
9150/9450 |
164.7 |
2.73:1 |
|
NC50-72(4-1/2IF) |
184.2 |
7-1/4 |
71.4 |
2-13/16 |
9150/9450 |
169.5 |
3.12:1 |
|
NC56-77 |
196.8 |
7-3/4 |
71.4 |
2-13/16 |
9150/9450 |
185.3 |
2.70:1 |
|
NC56-80 |
203.2 |
8 |
71.4 |
2-13/16 |
9150/9450 |
190.1 |
3.02:1 |
|
6-5/8REG |
209.6 |
8-1/4 |
71.4 |
2-13/16 |
9150/9450 |
195.7 |
2.93:1 |
|
NC61-90 |
228.6 |
9 |
71.4 |
2-13/16 |
9150/9450 |
212.7 |
3.17:1 |
|
7-5/8REG |
241.3 |
9-1/2 |
76.2 |
3 |
9150/9450 |
223.8 |
2.81:1 |
|
NC70-97 |
247.6 |
9-3/4 |
76.2 |
3 |
9150/9450 |
232.6 |
2.57:1 |
|
NC70-100 |
254.0 |
10 |
76.2 |
3 |
9150/9450 |
237.3 |
2.81:1 |
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