Gas-lift reverse circulation drilling rigs are widely used in deephole drilling due to their high efficiency and energy-saving features. Mastering the correct operating techniques not only improves drilling efficiency, but also extends equipment life and reduces construction costs.
1. Properly Configuring Air-Water Parameters
The core of gas-lift reverse circulation is the removal of slag through a mixture of compressed air and flushing fluid. During operation, the air and water pressures must be adjusted according to the drilling depth and formation characteristics. Generally, the air pressure is controlled between 0.5 and 0.7 MPa, and the air volume is appropriate to maintain a stable bubble flow. If slag removal is not smooth, increase the air pressure or check the air supply line for blockages. Furthermore, the flushing fluid flow rate must be matched to the drilling speed to avoid hole wall collapse or drill bit overheating due to insufficient flow.
2. Optimizing the Drill Tool Assembly
The drill bit type should be selected based on the hardness of the rock formation. For example, a roller bit should be used for hard rock formations, while a scraper bit should be used for soft soil formations. Ensure that the drill pipe joints are properly sealed to prevent air leaks that affect the circulation efficiency. When lowering the drill string, proceed slowly and evenly to avoid impact that could cause hole deflection or damage to the equipment.
III. Standardized Operating Procedures
Before starting, check the air compressor, circulation system, and piping for tightness. During drilling, closely monitor the return of slag. If a sudden decrease in slag discharge or gas leakage is detected, immediately stop the machine for investigation. When stopping drilling, first shut off the gas supply, then gradually stop the water supply to prevent water hammer damage to the piping.
IV. Maintenance and Troubleshooting
Regularly clean the drill bit and slag discharge pipe of sediment, inspect wear-resistant parts for wear, and replace them promptly. Common faults, such as circulation interruption, are often caused by air line blockage or water seal failure, requiring targeted repair.
By scientifically controlling parameters, standardized operation, and regular maintenance, the operational efficiency of gas-lift reverse circulation drilling rigs can be significantly improved, ensuring the safe and efficient progress of drilling operations.
