Lifting Sub – High-Strength Design for Safe and Efficient Drilling Operations
Technical Overview
The Lifting Sub is a load-bearing handling tool used in drilling operations for lifting, suspending, and connecting drill collars and other tubular drilling tools. It is designed to withstand high axial loads, repeated lifting cycles, and severe operating conditions encountered in oil and gas drilling.
The tool is manufactured from high-strength alloy structural steel and processed through controlled heat treatment to achieve stable mechanical properties comparable to those of drill collars.
All connections are machined in strict compliance with API specifications, ensuring dimensional accuracy, load transfer efficiency, and safe compatibility with standard drilling equipment.
Material & Mechanical Properties
| Parameter | Specification |
|---|---|
| Material | High-strength alloy structural steel |
| Heat Treatment | Quenching & tempering |
| Yield Strength | ≥ Drill Collar standard |
| Tensile Strength | ≥ Drill Collar standard |
| Impact Toughness | Suitable for low-temperature drilling environments |
| Hardness | Controlled to prevent galling and thread damage |
Mechanical properties are designed to meet or exceed drill collar performance requirements.
Structural Design
| Feature | Description |
|---|---|
| Upper Shoulder Type | Straight Shoulder / Inclined Shoulder |
| Load Transfer | Shoulder-to-shoulder contact |
| Stress Distribution | Optimized to reduce stress concentration |
| Body Design | Heavy-wall structure for high load capacity |
Thread Connection
| Item | Specification |
|---|---|
| Thread Standard | API Specification |
| Thread Types | API REG, IF, FH (optional) |
| Thread Processing | CNC machined |
| Thread Inspection | API gauges applied |
| Connection Reliability | High torque resistance and repeatability |
Dimensional Range (Typical)
| Parameter | Range |
|---|---|
| Outside Diameter (OD) | Customized according to drill collar size |
| Length | Customized |
| Bore | Optional |
| Load Capacity | Designed based on working load requirements |
Custom dimensions and load ratings are available upon request.
Types of Lifting Sub
- Straight Shoulder Lifting Sub
Suitable for standard lifting operations with uniform load transfer. - Inclined Shoulder Lifting Sub
Designed to improve stress distribution and reduce localized shoulder wear under heavy lifting conditions.
Quality Control & Inspection
- Chemical composition analysis
- Mechanical property testing
- Heat treatment traceability
- Magnetic Particle Inspection (MPI)
- Dimensional inspection with API gauges
- Surface and thread visual inspection
Applications
- Lifting and handling of drill collars
- Tripping operations in drilling rigs
- Oil & gas drilling (onshore & offshore)
- High-load tubular handling operations
