Drill collar is a thick steel tube at the bottom of the drill string. It is an important component of the bottom hole assembly. Its main character is the thick wall (the wall thickness is generally from 38 mm to53 mm which is four or five times that of drill rod). This product has larger weight and rigidity. It has multiple shapes, such as round, square, triangle and spiral. Round and spiral type ones are commonly used. Drill collars are mainly used to supply drilling pressure to drill bit and make the bit remain the state of being tensioned.
Advantages1. Drill collars can be heated up quickly and the temperature is uniform. Hardenability of whole cross section is ensured. 2. This product is tested according to API standards. These tests include surface size measurement and ultrasonic and magnetic powder flaw detections on the whole pipe. 3. The tread root of the drill collar and the recess of elevator are all cold rolled. This method has improved its anti-fatigue property and lengthened its lifespan.
Application1. Drill collar adds pressure to drill bit in drilling process. 2. It ensures the necessary strength of the drill bit under compression. 3. This product also reduces the vibration, swing and bounces of the drill bit and makes it running steadily. 4. It is also used to control well deviation. 5. Drill collar straightens the drill bit with large rigidity and maintains the track of borehole.
Parameters| Specifications of Drill Collar | |||||||
| Thread Model | Outer Diameter (D) | Inner Diameter (d) | Length (mm) | DF (mm) | Ref. 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(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 | 100.4 | 2.43:1 |
| NC35-47 | 120.7 | 4 3/4 | 50.8 | 2 | 9150 | 114.7 | 2.58:1 |
| NC3850(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 or 9450 | 144.5 | 2.49:1 |
| NC44-62 | 158.8 | 6 1/4 | 57.2 | 2 1/4 | 9150 or 9450 | 149.2 | 2.91:1 |
| NC46-62(4IF) | 158.8 | 6 1/4 | 71.4 | 2 13/16 | 9150 or 9450 | 150.0 | 2.63:1 |
| NC46-65(4IF) | 165.1 | 6 1/2 | 57.2 | 2 1/4 | 9150 or 9450 | 154.8 | 2.76:1 |
| NC46-65(4IF) | 165.1 | 6 1/2 | 71.4 | 2 13/16 | 9150 or 9450 | 154.8 | 3.05:1 |
| NC46-67(4IF) | 171.4 | 6 3/4 | 57.2 | 2 1/4 | 9150 or 9450 | 159.5 | 3.18:1 |
| NC50-67(4 1/2IF) | 171.4 | 6 3/4 | 71.4 | 2 13/16 | 9150 or 9450 | 159.5 | 2.37:1 |
| NC50-70(4 1/2IF) | 177.8 | 7 | 57.2 | 2 1/4 | 9150 or 9450 | 164.7 | 2.54:1 |
| NC50-70(4 1/2IF) | 177.8 | 7 | 71.4 | 2 13/16 | 9150 or 9450 | 164.7 | 2.73:1 |
| NC50-72(4 1/2IF) | 184.2 | 7 1/4 | 71.4 | 2 13/16 | 9150 or 9450 | 169.5 | 3.12:1 |
| NC50-77 | 196.8 | 7 3/4 | 71.4 | 2 13/16 | 9150 or 9450 | 185.3 | 2.70:1 |
| NC50-80 | 203.2 | 8 | 71.4 | 2 13/16 | 9150 or 9450 | 190.1 | 3.02:1 |
| 6 5/8REG | 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 5/8REG | 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 |
Hebei Xinlian (Beijing) Petroleum Pipe Co., Ltd is a specialized drill collar supplier in China. Main products of our company include oil casing pipe, oil tube, casing coupling, tubing coupling, pup joint, seamless steel pipe and drill pipe. The production capacity is around 200000 t per year. With reliable product quality and trustable products, we have passed the ISO9001:2000 international quality management system certification and the API certificate of the American Petroleum Institute.
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