API Spec 7-1 Drill Collar
- Grade: AISI 4145H
- Connection: API REG, NC
- Ends Process: Threading, Hardfacing, Phosphating, Inspection, Protective Coating
- Size: OD 3 1/8″ – 11″ x ID 1 1/4″ – 3″
- Length: 30FT – 31FT
- Type: Standard Drill Collars, Spiral Drill Collars, Non-Magnetic Drill Collars
API Spec 7-1 Drill Collar
API Spec 7-1 Drill Collars are crucial components in the drilling industry, designed to provide weight and stability to the drill string during oil and gas exploration. Manufactured to meet the stringent standards of API Spec 7-1, these drill collars ensure exceptional strength, durability, and reliability in demanding drilling environments. Their superior construction minimizes wear and tear, reducing maintenance costs and downtime. By selecting API Spec 7-1 compliant drill collars, you enhance the efficiency, safety, and overall performance of your drilling operations.
Chemical Composition of API Spec 7-1 Drill Collar
| Element | Composition (%) |
| Carbon (C) | 0.38 – 0.43 |
| Manganese (Mn) | 0.75 – 1.00 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.040 |
| Silicon (Si) | 0.15 – 0.35 |
| Chromium (Cr) | 0.80 – 1.10 |
| Molybdenum (Mo) | 0.15 – 0.25 |
Mechanical Properties of API Spec 7-1 Drill Collar
| Property | Value |
| Material | AISI 4145H modified steel |
| Hardness | 285-341 Brinell hardness |
| Impact Strength | Charpy “V” notch minimum impact strength of 40 ft-lb at 70°F (21°C) |
| Yield Strength | Minimum yield strength of 758 MPa (110,000 PSI) |
| Tensile Strength | Minimum tensile strength of 965 MPa (140,000 PSI) |
| Elongation | Minimum elongation of 13% |
Specifications
| Standard | API Spec 7-1 Drill Collar |
| Steel Grade | AISI 4145H |
| Ends Process | Threading, Hardfacing, Phosphating, Inspection, Protective Coating |
| Drill Collar Size | OD 3 1/8″ – 11″ x ID 1 1/4″ – 3″ |
| Drill Pipe Length | 30ft – 31ft |
| Ends Connections | API REG, NC |
| Packing | Drill collars are typically packed using conventional methods unless there are special requirements. The standard packing method involves bundling the drill collars with channel steel supports1. This ensures they are securely held together and protected during transportation and storage. |
| Types of Drill Collars | Standard Drill Collars: Solid cylindrical bars Spiral Drill Collars: Grooved to reduce differential sticking Non-Magnetic Drill Collars: Made from non-magnetic materials |
| Brand | Approved Manufacturer List (AML), or Country of Origin restrictions |
| Place of Origin | Made in China |
| MOQ | 1 Piece |
| Transportation | Land transportation by truck or train, sea transportation by container ship or bulk ship. |
Dimension of API Spec 7-1 Drill Collar
| Drill Collor Number | OD | ID | Length | Approximate Weight | Typical Bending |
| in. | in. | ft | lb/ft | Strength Ratio | |
| NC 23-31 | 3-1/8 | 1-1/4 | 30 | 22 | 2.57:1 |
| NC 26-35 (2-3/8 IF) | 3-1/2 | 1-1/2 | 30 | 27 | 2.42:1 |
| NC 31-41 (2-7/8 IF) | 4-1/8 | 2 | 30 or 31 | 34 | 2.43:1 |
| NC 35-47 | 4-3/4 | 2 | 30 or 31 | 47 | 2.58:1 |
| NC 38-50 (3-1/2 IF) | 5 | 2-1/4 | 30 or 31 | 54 | 2.38:1 |
| NC 44-60 | 6 | 2-1/4 | 30 or 31 | 83 | 2.49:1 |
| NC 44-60 | 6 | 2-13/16 | 30 or 31 | 76 | 2.84:1 |
| NC 44-62 | 6-1/4 | 2-1/4 | 30 or 31 | 91 | 2.91:1 |
| NC 46-62 (4 IF) | 6-1/4 | 2-13/16 | 30 or 31 | 84 | 2.63:1 |
| NC 46-65 (4 IF) | 6-1/2 | 2-1/4 | 30 or 31 | 100 | 2.76:1 |
| NC 46-65 (4 IF) | 6-1/2 | 2-13/16 | 30 or 31 | 93 | 3.05:1 |
| NC 46-67 (4 IF) | 6-3/4 | 2-1/4 | 30 or 31 | 109 | 3.18:1 |
| NC 50-70 (4-1/2 IF) | 7 | 2-1/4 | 30 or 31 | 118 | 2.54:1 |
| NC 50-70 (4-1/2 IF) | 7 | 2-13 /16 | 30 or 31 | 111 | 2.73:1 |
| NC 50-72 (4-1/2 IF) | 7-1/4 | 2-13/16 | 30 or 31 | 120 | 3.12:1 |
| NC 56-77 | 7-3 /4 | 2-13/16 | 30 or 31 | 140 | 2.70:1 |
| NC 56-80 | 8 | 2-13/16 | 30 or 31 | 151 | 3.02:1 |
| 6-5/8 API Reg | 8-1/4 | 2-13/16 | 30 or 31 | 162 | 2.93:1 |
| NC 61-90 | 9 | 2-13/16 | 30 or 31 | 196 | 3.17:1 |
| 7-5/8 API Reg | 9-1/2 | 3 | 30 or 31 | 217 | 2.81:1 |
| NC 70-97 | 9-3/4 | 3 | 30 or 31 | 230 | 2.57:1 |
| NC 70-100 | 10 | 3 | 30 or 31 | 243 | 2.81:1 |
| 8-5/8 API Reg | 11 | 3 | 30 or 31 | 300 | 2.84:1 |
| *The number connection (NC ) is an API connection with the V- .065 thread form with a V- .038R thread root radius. The first two digits are the pitch diameter of the thread and the last two digits are the outside diameter of the drill collar. | |||||
Applications of API Spec 7-1 Drill Collar
Weight on Bit (WOB): Drill collars provide the necessary weight to the drill bit, ensuring it can effectively penetrate the rock formations.
Directional Control: They help in maintaining the desired direction of the drilling operation, especially in directional and horizontal drilling.
Hole Size Integrity: Drill collars maintain the integrity of the hole size by preventing it from collapsing.
Stiffness and Stability: Their rigidity helps in maintaining the straightness of the wellbore, reducing the chances of deviation.
Mitigating Sticking: Spiral grooved drill collars reduce the risk of differential sticking and stuck pipe incidents.
Geothermal Drilling: They are used in geothermal drilling to access underground heat sources for electricity generation and heating.
Mining Exploration: Drill collars are also employed in mineral exploration within the mining industry.
