The Spiral Drill Collar of Weigao is made from AISI 4145H modified alloy steel, and completely meets the requirement of API Spec 7-1 and SY/T5144 Standard. It is a kind of drill collar which adds three dextrogyrate spiral groove on the outer circle of ordinary drill collar when processing, and the purpose is to reduce the area of contact and friction with the well wall, which can effectively prevent the pressure sticking. The single weight of the spiral drill collar is round about 4% lighter than the ordinary drill collar with the same specification, and the shape and thread of the both ends are the same with the drill collar.
|
Connection #
|
OD
|
ID
|
L mm
|
DF
mm
|
Bending strength ratio
|
||
|
mm
|
in
|
mm
|
In
|
||||
|
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
|
127.0
|
5
|
57.2
|
2 1/4
|
9150 or 9450
|
121.0
|
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
|
150.0
|
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
|
254.0
|
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
|