Updated: Elevator Guide Roller Drops to Deck Below

Description of Incident

A derrick elevator guide roller weighing 0.6kg was discovered on the drill floor in front of the drilling control room (DCR).

The roller is normally attached to the derrick elevator. The elevator was parked at its lowest position of 10.5m at the time the object was found. The elevator can operate to a maximum height of 57.1m.

Findings:

Severe corrosion of the elevator guide roller bearing allowed it to drop free of the assembly.

A 100% close visual inspection was carried out on the elevator roller assemblies by the rig crew, which included rotating the rollers to feel for bearing ‘rumbling’ which would indicate signs of corrosion or wear.

Following this inspection and replacement, the elevator was put back into service.

Recommendations:

Planned maintenance recommendations:

• Arrange a 100% change out of roller bearings for elevator, creating a base line for future maintenance.

• 6 monthly planned maintenance to de-load and inspect roller assemblies, including mechanic oversight of OEM roller inspections to verify bearing condition.

• OEM Inspection criteria and reports to contain adequate detail on inspection completed.

• Establish a 60-month life span for roller bearings which may be adjusted based on 6 monthly inspections.

• OEM to review design for secondary retention (consider all failure modes).

• Review maintenance learnings for other roller bearing assemblies (e.g. pipe handling, v door, bop trolley).