Cause & Consequence
- Uncontrolled release of a flammable gas or liquid
Specific Incident Equipment
Stem seal on double block and bleed
Presence of gas in a SSSV hydraulic control line and leakage out through the above valve stem leading to gradual accumulation of gas inside a sealed wellhead instrument cabinet:
• Gas migration to surface through the SSSV hydraulic control line tubing.
• Inadequate long term isolation of a pressurised Hc system.
• Inadequate risk assessment of the isolation following SSSV removal.
Investigate the adequacy of the well isolation for typically this situation of SSSV being removed.