Gas migration from compressor wash line to water tank

Cause & Consequence

• Uncontrolled release of a flammable gas or liquid

Incident Location

Fixed Installation

Incident Activity

Production operations

Specific Incident Equipment

Non Return Valve/Water wash tank

Lessons Identified

Gas had migrated back from the compressor casing into the water wash tank via two block valves, two non return valves and pump. One valve was partially open (a 1/3 of a turn off its seat) the other may have been “passing”. The 2 non return valves cannot be guaranteed to be tight shut off and may “pass”.

Incident Recommendations

Replace all NRV's and associated block valves in the compressor wash systems

Conduct a risk assessment to ensure the safe operation / running of both the compressor and compressor wash skid until the NRV’s and block valves are replaced.