API Spec 7 Oilfield Drill Collar, Drilling Threaded Collar with competitive price for Sale
1) Standard: API Spec 7
2) API and ISO certified
3) Specification: 3-1/8'', 3-1/2'', 4-1/8'', 4", 4-3/4'', 5'', 6" 6-1/4", 6-3/4", 7", 7-1/4", 7-3/4", 8", 8-1/4", 9", 9-1/2", 9-3/4", 10", 11"
4) Material: Plain Carbon Steel, Alloy Steel
5) Description
A drill collar is a device used in the drilling of oil wells for weighting the drill bit, enabling it to drill through rock. It is a bar made of solid steel, either plain carbon steel or a non-magnetic steel alloy, drilled lengthwise to permit the passage of drilling fluids. A drill collar forms the lowest element of a drill string, which encompasses all the elements of a down-hole process from the surface to the rock bit.
6) Structure
These devices are typically 31 feet (about 9.45 m) long and threaded at both ends, male at one end and female at the other, to allow multiple drill collars to be joined above the bit assembly.
The number of drill collars attached to a drill string will depend upon the material composition of the strata at the drill site and the likely depth of the well. A relatively shallow well with less dense geologic structure through which the bit must pass will require fewer drill collars than a deep shaft through dense material.
Typically, drill collars will be consistent in length but may vary in diameter, and their outside configuration may be slick or spiral. The outside diameter may vary from about 3-1/2 inches (8.89 cm) to 11 inches (27.9 cm) and greater. The reference to slick or spiral outer configuration refers to the machining of the outside surface of the collar.
7) Parameter
| Type | OD(mm) | ID(mm) | L(m) ±152.4mm d | DF(mm) ±0.4 |
| NC23-31 | 79.4 | 31.8 | 9.14 | 76.2 |
| NC26-35 | 88.9 | 38.1 | 9.14 | 82.9 |
| NC31-41 | 104.8 | 50.8 | 9.14or9.45 | 100.4 |
| NC35-47 | 120.6 | 50.8 | 9.14or9.45 | 114.7 |
| NC38-50 | 127 | 57.2 | 9.14or9.45 | 121 |
| NC44-60 | 152.4 | 57.2 | 9.14or9.45 | 144.5 |
| NC44-60 | 152.4 | 71.4 | 9.14or9.45 | 144.5 |
| NC46-62 | 158.8 | 57.2 | 9.14or9.45 | 149.2 |
| NC46-62 | 158.8 | 71.4 | 9.14or9.45 | 150 |
| NC46-65 | 165.1 | 57.2 | 9.14or9.45 | 154.8 |
| NC46-65 | 165.1 | 71.4 | 9.14or9.45 | 154.8 |
| NC46-67 | 171.4 | 57.2 | 9.14or9.45 | 159.5 |
| NC50-70 | 177.8 | 57.2 | 9.14or9.45 | 164.7 |
| NC50-70 | 177.8 | 71.4 | 9.14or9.45 | 164.7 |
| NC50-72 | 184.2 | 71.4 | 9.14or9.45 | 169.5 |
| NC56-77 | 196.8 | 71.4 | 9.14or9.45 | 185.3 |
| NC56-80 | 203.2 | 71.4 | 9.14or9.45 | 190.1 |
| 6-5/8REG | 209.6 | 71.4 | 9.14or9.45 | 195.6 |
| NC61-90 | 228.6 | 71.4 | 9.14or9.45 | 212.7 |
| 7-5/8REG | 241.3 | 76.2 | 9.14or9.45 | 223.8 |
| NC70-97 | 247.6 | 76.2 | 9.14or9.45 | 232.6 |
| NC70-100 | 254 | 76.2 | 9.14or9.45 | 237.3 |
| 8-5/8REG | 279.4 | 76.2 | 9.14or9.45 | 266.7 |
| NC50-67 | 171.5 | 71.4 | 9.14or9.45 | 159.5 |
8) Mechanical Property
| OD Size | Yield Strength | Tensile Strength σb | Elongation | Reduction of area | Reduction of area |
| 3-1/8~6-3/4 | ≥758 -110,000 | ≥827 -120,000 | ≥18 | 50 | ≥50 |
| 7~10 | ≥689 -100,000 | ≥758 -110,000 | ≥20 |
Puyang Zhongshi Group Co., Ltd is a professional manufacturer of various oilfield equipments and cementing accessories since 1997, restructured enterprise of SINOPEC.
We have the certificates of API 5CT, API 10D, API 11E, API 6A, API 11AX, ISO 9001 and ISO 14001, etc..
Our products mainly include:
1. Casing Centralizer 2. Float Collar & Float Shoe
3. Cementing Plug 4. Cementing Head
5. Cement Basket 6. Tubing Pump / Rod Pump
7. Valve Ball & seat 8. Casing / Tubing Pipe and Coupling
9. Stage Collar 10. Pumping Unit
11. Air Blaster 12. Sucker Rod
Our group have more than 10 years export experience and 9 subsidiary factories, more than 500 employees. We are the first-class supplier of resources market of SINOPEC and CNPC. Our foreign customers are mainly from America, Central Asia, Russia, Southeast Asia, Middle East, etc.