Lessons learned from an incident where a crane lifting pin failed while pulling stuck casing during well abandonment, striking a worker.
A crane incident that caused a worker injury during well abandonment operations. A crew was using a lift boat crane and rigging to pull a seven-inch casing from the well.
They drilled holes in the casing, inserted a lifting pin, and attached it to the crane’s auxiliary hoist line with a two-part sling and D-rings. The crane lifted the casing until it got stuck. After setting the slips, the crew cut and removed a section, drilled new holes, and reinserted the lifting pin for another lift. They then used the crane’s main hoist to try to pull the stuck casing.
The lifting pin was attached to the main block, and two workers stood next to the casing, ready to remove the slips when the casing moved upward. When the crane operator raised the casing, the lifting pin failed, bent upward, and struck one worker in the face, causing him to fall.
He suffered a subdural hematoma, facial trauma, an open skull fracture and several facial bone fractures.
Incident findings
- Human errors led to the lifting pin failure and the worker’s injury.
- The crew installed a spool riser with an 11-inch inside diameter onto the wellhead, on top of a seal ring that was 11.44 inches in diameter. This stopped the casing from being pulled out.
- The crane operator lifted more than the approved safe lifting plan’s 24,255-pound limit and exceeded the lifting pin’s 60,000-pound safe working load. Tests suggest up to 102,000 pounds may have been applied to the pin during the incident.
- The crew did not place the D-rings of the sling right next to the casing; they were about 2 inches away. Procedures require the pull linkages to be as close as possible to reduce bending on the pin.
- The procedure used was meant for a drilling rig with a top drive and bails, not for a crane on a lifeboat. It also wrongly listed the lifting pin’s capacity as 67,000 pounds, when the safe limit is 60,000 pounds.
To help prevent similar incidents in the future, the Bureau of Safety and Environmental Enforcement recommends that operators and their contractors, where appropriate, do the following:
- Operators should always check that the load is free before starting crane operations to lift a work string during well abandonment. Never use a crane to pull or lift a load that is not free.
- Make sure the equipment used is clearly identified in procedures. Do not change procedures if they do not match the situation or equipment.
- Ensure the right equipment is available and installed during well abandonment. The lifting pin should be the correct length, since a pin that is too long can bend and fail early.
- Encourage workers to use stop work authority if they see or suspect unsafe conditions.
- Make sure proper rigging is used for all lifts and that it is installed as described in the lifting plan.
- Make sure that procedures for lifting operations properly cite safe working loads for all rigging and devices.
- Make sure everyone is aware of hazards and keeps a safe distance from equipment during lifts.