Common Problems with Rotary Drilling Rigs and How to Fix Them

Rotary drilling rigs are essential equipment in modern foundation construction, widely used for their high drilling efficiency and adaptability. However, during construction, rotary drilling rigs often encounter problems that affect quality and progress. To ensure smooth construction, it is necessary to summarize common problems and propose corresponding solutions.

I. Pre-construction Quality Control

Before commencing construction, the construction company should conduct a comprehensive inspection of the equipment's performance. For used rotary drilling rigs, particular attention should be paid to testing the power and hydraulic systems to ensure stable operation after extended use. Test drilling can also provide insights into the penetration rate and mud density in different formations, providing a reliable basis for formal construction. 

II. Key Control Points During Construction 

During drilling, precise measurement and proper casing placement are essential to ensure alignment and stability, while maintaining the mud level above the groundwater prevents wall collapse. Crawler rotary drilling rigs provide strong maneuverability for complex sites but still require regular system calibration to avoid drill bit deviation and hole diameter changes.

III. Common Problems and Solutions

1. Hole Collapse

• Cause: 

This is often caused by insufficient mud performance, unbalanced water levels, or external vibrations. This manifests as a sudden drop in the mud level within the hole, accompanied by the emission of bubbles or abnormal drill cuttings.

• Solution: 

Immediately increase the mud density to maintain adequate head pressure; deepen the casing to enhance stability. Minor collapses can be cleared with a sludge pump; severe collapses require backfilling with sand, gravel, or clay to stabilize the hole wall before re-drilling.

2. Hole Deflection

Cause: 

This is usually caused by uneven drill bit force, uneven ground conditions, or improper operation, resulting in the hole axis gradually deviating from the designed position.

Solution: 

Minor deviations can be corrected by sweeping the hole. Severe deviations should be backfilled with clay for compaction and re-drilling. During drilling, ensure that verticality is monitored in real time to ensure a stable drill bit force.

3. Shrinkage and Hole Enlargement

Causes:

Shrinkage is often caused by high mud loss or severe drill bit wear; enlargement is caused by excessive drill bit swing or mud erosion of the hole wall.

Solution: 

When shrinking, the drill bit should be promptly replaced or repaired, and the mud wall protection should be improved. When enlarging, the drilling tool's trajectory should be controlled to maintain a stable mud viscosity and reduce erosion of the hole wall.

4. Drill Burial and Drill Stuck

Causes: 

The drill bit becomes trapped in the hole due to inadequate cleaning of drill cuttings or excessive friction between the drill tool and the hole wall.

Solution: 

Avoid blind and forced lifting. Gently lift the drill tool and rotate it repeatedly while flushing with clean water or mud. If necessary, use a small impact drill to loosen and gradually unblock the jam.

5. Dropped Objects

Causes: 

Drill tool components or foreign objects may fall off and sink to the bottom of the hole, potentially blocking or disrupting drilling progress. 

Solution: 

Immediately remove the foreign object using specialized salvage tools. If the foreign object is covered by mud, clean the drill cuttings from the bottom of the hole before salvaging. Direct entry into the hole is strictly prohibited; the drilling must be carried out under casing and with adequate safety precautions.

Conclusion

With the increasing popularity of rotary drilling rigs, the requirements for equipment and expertise are becoming increasingly demanding. Through proper pre-construction inspections, careful operation, and timely problem resolution, both new and existing drilling rigs can ensure quality and safety. The continued adoption of various types of equipment, such as crawler rotary drilling rigs, will make construction even more efficient and reliable.