Four Common Drill Pipe Accidents and Their Solutions-2

Four Common Drill Pipe Accidents and Their Solutions

Drill pipe accidents are an unfortunate but manageable aspect of rotary drilling operations. The four most common types are pipe dropping, pipe sticking, pipe jamming, and pipe burial. Below, we outline these scenarios and practical solutions to address them.

1. Pipe Dropping

Description: During deep foundation drilling, especially when using the final section of the drill pipe, there is a rare chance of pipe breakage. This can result in the remaining drill pipe and bucket being left in the borehole. Causes may include poor drill pipe quality, geological strength, or operational errors.

Solutions:

1.  Diving: If the borehole diameter is large enough and conditions permit, divers can be sent down to attach a steel wire rope to the broken pipe. This method is effective but can be expensive.

2.  Casing: Create a steel skeleton using rebar, then secure a steel wire rope with a snare mechanism. Use ropes to stabilize the framework at three points to ensure balance during lowering. Once prepared, insert the framework and wire rope into the borehole.

3.  Inspection: Before deploying the casing, identify the depth of the breakage within the borehole. Use measurement ropes to detect the inclination of the broken drill pipe, determine whether it is in contact with the borehole wall, and assess sediment conditions inside the borehole. These factors are critical; without proper preparation, the framework may not reach the intended position, and sediment may prevent retrieval even if the pipe is secured.

2. Pipe Sticking

Description: Pipe sticking occurs when using double-bottom sand or rock drilling buckets. The bucket bottom may open and become stuck against the borehole wall, causing the drill pipe to become immobile. This issue is rare but can result from geological conditions, bucket wear, or operator errors.

Causes:

1.  Drilling Bucket: Excessive wear, lack of maintenance, large gaps in the bucket mechanism, insufficient spring tension, or unstable hooks can cause the bucket bottom to open unexpectedly during drilling, especially in vibrating geological conditions.

2.  Geology: Hard geological formations such as compacted sand layers, gravel, mudstone, sandstone, weathered rock, or cobble layers increase the likelihood of sticking as borehole walls resist reaming or compression.

3.  Operator Errors: Inexperienced operators, insufficient geological knowledge, negligence in bucket maintenance, or failure to detect load changes can increase the risk of pipe sticking. Forcing operations under high load further escalates the issue.

4.  Narrow Boreholes: The harder the geology, the smaller the borehole diameter. If the bucket bottom opens in such conditions, sticking is likely.

Prevention and Solutions:

1.  Routine Maintenance: Regularly inspect and maintain the drilling bucket, especially the gaps between the bucket bottom and hooks. Ensure hooks are secure and not easily dislodged by sediment or vibrations.

2.  Test Bucket Stability: After closing the bucket bottom, use the main winch to shake or rotate the bucket slightly. If the bottom frequently opens, investigate and repair hook stability promptly.

3.  Controlled Drilling: In vibrating layers, use low rotation speeds and light pressure to reduce vibrations. Replace worn bucket teeth in hard formations to avoid narrowing the borehole.

4.  Monitor Load Changes: Pay attention to winch sound, lifting speed changes, and drill rod sinking to detect load variations. Adjust operations promptly when changes occur.

5.  Load Assessment: If lifting load increases, reduce or stop winch operation. Use depth instruments to assess the bucket’s position and geological conditions. Rotate the drill pipe slowly to determine if the bucket bottom is open.

6.  Controlled Expansion: If the bucket bottom is open, lower engine speed and output minimal torque to expand the borehole carefully. Stop lifting immediately if load increases. Rotate the pipe to expand further if needed, or reverse and lower the winch to prevent sticking.

7.  Geological Awareness: Determine geological conditions at the depth where the bucket bottom opens. For example, if the bottom opens at 35 meters in a cobble layer but mud layers are present above 30 meters, lifting 5 meters can resolve the issue.

8.  Shock Prevention: Avoid dropping drill rods abruptly, as the impact can open bucket bottoms unexpectedly, causing sticking.

9.  Post-Sticking Assessment: Determine the bucket’s condition—whether it contains sediment and if the bottom is open. If the bottom is closed, the issue may be jamming instead.

10.  Avoid Forced Lifting: Do not force winch operations under high load. This can break the winch wire or twist drill rods, leading to further damage.

11.  Maintain Fluid Pressure: During pipe sticking, maintain mud and water pressure to prevent borehole collapse and protect equipment.

12.  Seek Expertise: If unsure of the cause or lacking experience, avoid rash actions. Wait for experienced personnel to assess and resolve the issue.

3. Pipe Jamming

Description: Drill pipe jamming occurs when the pipe becomes trapped in narrow sections of the borehole, often due to deformation or excess material.

Solutions:

undefined Borehole Enlargement: Use reaming tools to enlarge the borehole and free the jammed pipe.

undefined Vibration: Apply mechanical or hydraulic vibration to loosen the jammed pipe.

undefined Lubrication: Introduce lubricating agents to reduce friction and aid in retrieval.

4. Pipe Burial

Description: Drill pipes can become buried due to sediment collapse or sudden geological changes. This is especially challenging in unstable formations.

Solutions:

undefined Sediment Removal: Use suction pumps or drilling fluid circulation to remove sediment around the buried pipe.

undefined Progressive Extraction: Gradually extract the pipe while maintaining fluid balance in the borehole to prevent further sediment collapse.

Why Choose Us?

Our company specializes in high-quality drilling tools designed to minimize accidents and enhance efficiency. With robust materials, precision engineering, and customized solutions, our products are ideal for challenging drilling environments.

If you have any questions or need assistance, feel free to contact us at renee@welongpost.com. Our team is committed to providing expert guidance and superior products for all your drilling needs.