DRILL COLLARS
Command Tubular’s drill collars are made of modified AISI 4145H chromium molybdenum alloy steel. These drill collar bars are full-length heat treated and water quenched to obtain mechanical properties as specified by API Spec 7-1.
Full mechanical and chemical mill test certifications are supplied with all drill collars. These mill test certifications guarantee a hardness range of 285 to 341 BHN and an impact value of 40 ft-lbs at room temperature, one inch below surface.
All drill collar bars are trepanned then drifted to API specifications to ensure close tolerance bores. Drill collars are also supplied with the outer surface either machined or rough peeled.
Full mechanical and chemical mill test certifications are supplied with all drill collars. These mill test certifications guarantee a hardness range of 285 to 341 BHN and an impact value of 40 ft-lbs at room temperature, one inch below surface.
All drill collar bars are trepanned then drifted to API specifications to ensure close tolerance bores. Drill collars are also supplied with the outer surface either machined or rough peeled.
- Drilling weight-on-bit (WOB)
- BHA directional control
- Hole size integrity
- Stiffness to maintain hole straightness
- Clearance for the drill string
- Compressive and torsional loads
- Mitigate differential sticking and stuck pipe thanks to spiraled grooves
Connections
All connections are precision-machined to API Spec 7-2 requirements. Thread roots are cold-worked to offer a greater resistance to fatigue. At Command Tubular all connections are phosphate coated to minimize galling during makeup and thread storage compound is applied. Thread protectors are installed to ensure adequate joint protection during shipment.
Product range and features
Standard:
- ODs from 2-7/8” to 11”
- API 7.1 & 7.2 specifications
- Slick or spiraled
- API & High-performance double shoulder connections
- Fatigue resistance features (threads cold rolled, API pin stress relief groove, and API box bore-back)
- Range 2 and 3 lengths
- Phosphate coated threads
- Slip and elevator recess
- A variety of steel grades: API, Sour Service, NS1, Low Temp, Non Magnetic
Options:
- Hardbanding
- Internal plastic coating for OD <6 1/2”
- Customized elevator and slip recess
- NS-1 or DS-1 or customers specifications
- Make and Break
Spiral Design + Slip & Elevator Recess
Spiral Design:
The spiral cut is added to a drill collar to prevent the likelihood of differential wall-sticking by reducing wall contact between the drill collar and the wall of the hole. The spiralling starts 22” from the bottom of the slip recess or 79” from the box end and ends 30” from the pin end. Adding spiralling to drill collars reduces the weight by approximately 4%.
Slip & Elevator Recess:
Command Tubular offers slip and elevator recesses to improve handling efficiency and safety. Unless otherwise specified, slip and elevator recesses are machined in compliance with API RP7G latest edition guidelines and can be provided together or separately.
The five options for slip and elevator recesses’ for Command Tubular are:
The five options for slip and elevator recesses’ for Command Tubular are:
- Slip Recess
- Slip and Elevator Recess
- API Configuration of 18” long slip recess
- Longer Elevator and Slip Recess with reduced OD’s
- One long recess with an 18 degree shoulder for use with drill pipe elevators
Hardbanding (flush or raised)
Type B hardbanding is recommended on drill collars with slip and elevator recesses and is applied in a 4” long wear pad above the elevator recess, a 1” long wear pad above the slip recess and a 10” long wear pad under the slip recess. For drill collars with a slip recess only, type C hardbanding is applied to a 10” long wear pad under the slip recess and a 4” long wear pad above the slip recess. For drill collars without any recess, type A hardbanding is applied in a 10” long wear pad located 30” from the end of the pin.
Operational Benefits
Our Drill Collars bars are trepanned in-house using specialty equipment to guarantee product performance and reliability. Our experience in material specification,mechanical properties, heat treatment, machining connections, and inspection are reflected in our product performance.
Our Drill Collars bars are trepanned in-house using specialty equipment to guarantee product performance and reliability. Our experience in material specification,mechanical properties, heat treatment, machining connections, and inspection are reflected in our product performance.
Drill Collar Specifications
| Drill Collar Number and Connection Label* | Outside Diameter (Inches) | Bore (Inches) | Length (Feet) | Approximate Weight (lb/ft) | Bevel Diameter (Inches) | Reference Bending Strength Ratio (BSR) |
|---|---|---|---|---|---|---|
| NC23-31 | 3 1/8 | 1 1/4 | 30 | 22 | 3 | 2.57:1 |
| NC26-35 | 3 1/2 | 1 1/2 | 30 | 26.7 | 3 21/64 | 2.42:1 |
| NC31-41 | 4.125 | 2 | 30 or 31 | 34.72 | 4 | 2.43:1 |
| NC35-47 | 4.375 | 2 | 30 or 31 | 44.51 | 4 33/64 | 2.58:1 |
| NC38-50 | 5 | 2 1/4 | 30 or 31 | 53.18 | 4 49/64 | 2.38:1 |
| NC44-60 | 6 | 2 1/4 | 30 or 31 | 82.61 | 5 11/16 | 2.49:1 |
| NC44-60 | 6 | 2 13/16 | 30 or 31 | 74.9 | 5 11/16 | 2.84:1 |
| NC44-62 | 6 1/4 | 2 1/4 | 30 or 31 | 90.52 | 5 7/8 | 2.91:1 |
| NC46-62 | 6 1/4 | 2 13/16 | 30 or 31 | 83.09 | 5 29/32 | 2.63:1 |
| NC46-65 | 6 1/2 | 2 1/4 | 30 or 31 | 99.19 | 6 3/32 | 2.76:1 |
| NC46-65 | 6 1/2 | 2 13/16 | 30 or 31 | 91.59 | 6 3/32 | 3.05:1 |
| NC46-67 | 6 3/4 | 2 1/4 | 30 or 31 | 108.02 | 6 9/32 | 3.18:1 |
| NC50-70 | 7 | 2 1/4 | 30 or 31 | 117.52 | 6 31/64 | 2.54:1 |
| NC50-70 | 7 | 2 13/16 | 30 or 31 | 109.6 | 6 31/64 | 2.73:1 |
| NC50-72 | 7 1/4 | 2 13/16 | 30 or 31 | 119.1 | 6 43/64 | 3.12:1 |
| NC56-77 | 7 3/4 | 2 13/16 | 30 or 31 | 139.1 | 7 19/64 | 2.70:1 |
| NC56-80 | 8 | 2 13/16 | 30 or 31 | 149.6 | 7 31/64 | 3.02:1 |
| 6 5/8 REG | 8 1/4 | 2 13/16 | 30 or 31 | 160.44 | 7 45/64 | 2.93:1 |
| NC61-90 | 9 | 2 13/16 | 30 or 31 | 194.95 | 8 3/8 | 3.17:1 |
| 7 5/8 REG | 9 1/2 | 3 | 30 or 31 | 217 | 8 13/16 | 2.81:1 |
| NC70-97 | 9 3/4 | 3 | 30 or 31 | 230 | 9 5/32 | 2.57:1 |
| NC70-100 | 10 | 3 | 30 or 31 | 242.97 | 9 11/32 | 2.81:1 |
| 8 5/8 REG | 11 | 3 | 30 or 31 | 299 | 10 1/2 | 2.84:1 |
*The first two digits of the (NC) Numbered Connections refer to the connection pitch diameter; the numbers to the right of the hyphen refers to the drill collar outside diameter in inches and tenths of an inch.
Drill Collar Features & Options
| Drill Collar OD | Elevator Recess OD (ER) (In) | Slip Recess OD (SR) (In) | Elevator Recess Radius (R) (In) |
|---|---|---|---|
| 4 3/4 | 4 1/4 | 4 3/8 | 1/8 |
| 5 | 4 1/2 | 4 5/8 | 1/8 |
| 6 1/4 | 5 5/8 | 5 3/4 | 1/8 |
| 6 1/2 | 5 7/8 | 6 | 1/8 |
| 6 3/4 | 6 | 6 1/4 | 3/16 |
| 8 | 7 1/4 | 7 1/2 | 3/16 |
| 8 1/4 | 7 1/2 | 7 3/4 | 3/16 |
| 9 1/2 | 8 5/8 | 9 | 1/4 |
| 11 | 10 1/8 | 10 1/2 | 1/4 |
These features are not recommended for collars with OD below 4-3/4″
Specifications – Non-Mag Drill Collars
| Drill Collar Conn. Size & Type | Min. OD (In) | Bore (In) | Length (Ft) | Bending Strength Ratio | Drill Collar Wt. Per 31 ft |
|---|---|---|---|---|---|
| NC 38 (3-1/2 IF) | 4 3/4 | 2 1/4 | 31 | 1.92:1 | 1448 |
| NC 38 (3-1/2 IF) | 4 3/4 | 2 11/16 | 31 | 2.32:1 | 1270 |
| NC 38 (3-1/2 IF) | 5 | 2 1/4 | 31 | 2.38:1 | 1650 |
| NC 38 (3-1/2 IF) | 5 | 2 11/16 | 31 | 2.89:1 | 1472 |
| NC 46 (4 IF) | 6 1/2 | 2 13/16 | 31 | 3.07:1 | 2842 |
| NC 46 (4 IF) | 6 1/2 | 3 1/4 | 31 | 3.59:1 | 2622 |
| NC 50 (4 1/2 IF) | 6 3/4 | 2 13/16 | 31 | 2.37:1 | 3115 |
| NC 50 (4 1/2 IF) | 6 3/4 | 3 1/4 | 31 | 2.62:1 | 2895 |
| 6-5/8 REG | 8 | 2 13/16 | 31 | 2.60:1 | 4640 |
| 6-5/8 REG | 8 | 3 1/4 | 31 | 2.75:1 | 4420 |
Note: Other sizes and connections are available as well as any other optional features listed below.