Non-magnetic drill collar is made of stainless steel with rather low magnetic permeability. The cross sections of the inside and outside pipe are both round. All threads are phosphated, copperized or cold worked. All connections are equipped with pressed steel thread protectors. Various thread connections are available. Customized sizes and non-mag steels with high strength and performance are also available.
Application
Non-magnetic drill collars are primarily used in MWD (Measurement While Drilling) and LWD (Logging While Drilling) operations, where magnetic interference from standard steel components would distort survey data. By placing non-magnetic drill collars directly above the measurement tools, the accuracy of downhole directional surveys is significantly improved, enabling precise wellbore placement in directional and horizontal drilling operations.
Key Features
- Low magnetic permeability — minimal interference with MWD/LWD instruments
- All threads phosphated, copperized or cold worked for enhanced durability
- Pressed steel thread protectors fitted on all connections
- Various thread connections available; customized sizes on request
- Size range: 3-1/8″ to 11″
Non-Magnetic Drill Collar Specifications
| Thread Type | OD (mm) | OD (in) | ID (mm) | ID (in) | Length (mm) | Chamfer (mm) | Bending Strength Ratio |
|---|---|---|---|---|---|---|---|
| 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 | 9150/9450 | 100.4 | 2.43:1 |
| NC35-47 | 120.7 | 4-3/4 | 50.8 | 2 | 9150/9450 | 114.7 | 2.58:1 |
| NC38-50 | 127 | 5 | 57.2 | 2-1/4 | 9150/9450 | 121 | 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 | 158.8 | 6-1/4 | 71.4 | 2-13/16 | 9150/9450 | 150 | 2.63:1 |
| NC46-65 | 165.1 | 6-1/2 | 57.2 | 2-1/4 | 9150/9450 | 154.8 | 2.76:1 |
| NC46-65 | 165.1 | 6-1/2 | 71.4 | 2-13/16 | 9150/9450 | 154.8 | 3.05:1 |
| NC46-67 | 171.4 | 6-3/4 | 57.2 | 2-1/4 | 9150/9450 | 159.5 | 3.18:1 |
| NC50-67 | 171.4 | 6-3/4 | 71.4 | 2-13/16 | 9150/9450 | 159.5 | 2.37:1 |
| NC50-70 | 177.8 | 7 | 57.2 | 2-1/4 | 9150/9450 | 164.7 | 2.54:1 |
| NC50-70 | 177.8 | 7 | 71.4 | 2-13/16 | 9150/9450 | 164.7 | 2.73:1 |
| NC50-72 | 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 | 208.6 | 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 | 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 |
Customized sizes and non-mag steels with high strength and performance are available.
