|
Connection
|
Drill Collar O.D.
|
Drill Collar I.D.
|
Length
|
Shoulder Taper O.D.
|
Bending Strength Ratio
|
|
mm
|
in
|
mm
|
in
|
mm
|
mm
|
|
NC23-31
|
79.4
|
3 1/8
|
31.8
|
1 1/4
|
9150
|
76.2
|
2.57:1
|
|
NC26-35(2 3/8IF)
|
88.9
|
3 1/2
|
38.1
|
1 1/2
|
9150
|
82.9
|
2.42:1
|
|
NC31-41(2 7/8IF)
|
104.8
|
4 1/8
|
50.8
|
2
|
9150/ 9450
|
100.4
|
2.43：1
|
|
NC35-47
|
120.7
|
4 3/4
|
50.8
|
2
|
9150/ 9450
|
114.7
|
2.58：1
|
|
NC38-50(3 1/2IF)
|
127.0
|
5
|
57.2
|
2 1/4
|
9150/ 9450
|
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
|
|
NC46-47（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
|
|
8 5/8REG
|
279.4
|
11
|
76.2
|
3
|
9150/ 9450
|
266.7
|
2.84：1
|
Comments:
Connection:IF- Internal Flush; FH- Full Hole; REG- Regular; NC- Numerical Connection
Product Description:
Drill collars are used to provide bit weight to drill bits so that drill pipes are in tension. Drill collars can keep drill bits centralized and hole track by large rigidity.
Our drill collars are made of modified AISI 4145H chromium molybdenum alloy steel. To ensure close tolerance bores, all drill collar bars are trepanned then drifted to API specifications.
Type:
Spiral Drill Collars
The spiral cut is added to a drill collar to prevent the likelihood of differential wall-sticking by reducing wall contact between the drill collar and the wall of the hole. The box end of the spiral collar is left uncut from 79 inches from box shoulder and the pin end is left uncut 30 inches from the pin shoulder.
Connection：
All connections are precision-machined to API specifications. API relief groove pin and bore back box stress relief are available on request. Thread roots are cold-worked to offer a greater resistance to fatigue. All connections are phosphated to minimize galling during makeup and applied with thread storage compound. Thread protectors are installed to ensure adequate joint protection during shipment.
Note:
When inquiring on drill collars, please specify info. below:
1) Outside diameter, bore and length;
2) Size and type of connection: each end of collar and special joint features;
3) Slick, Spiral or Non-Magnetic ;
4) Other special features: slip and elevator recesses and/or hard band type.