Investigation Report
Buoyant Riser Assembly Rose and Damaged Supports During Well Abandonment
02-24-2026 1715 G10380 AC 25 Other Lifting Device - Incident >$25K
- BSEE
- Investigation Report
- Unknown
- CorrosionMechanical failurePressure systems
- DecommissioningWell abandonment
- Operating and work proceduresRisk assessment
- Upstream oil and gas
- Offshore installation
Summary
Investigation of a riser-cutting incident during well abandonment at Hoover Spar. Positive buoyancy drove the stem/can assembly upwards, breaking deck stopper bolts and damaging support beams and nitrogen lines. Bolt analysis identified corrosion and section loss. Revised procedures removed buoyancy and landed the assembly before cutting; no injuries or pollution occurred.
Classifications: Corrosion; corrosion damage.
Classifications: Mechanical failure; equipment failure.
Classifications: Pressure systems; stored pressure; pressurised systems; pressurized systems.
Classifications: Decommissioning; facility dismantling.
Classifications: Well abandonment; plug and abandonment; P&A.
Classifications: Operating and work procedures.
Classifications: Risk assessment; hazard assessment.
Classifications: Upstream oil and gas; oil and gas extraction; upstream petroleum.
Classifications: Offshore installation; offshore platform; offshore rig.