Hydrocarbon Leak from Prover Loop Sphere Door

Cause & Consequence

• Uncontrolled release of a flammable gas or liquid

Incident Location

Fixed Installation

Incident Activity

Production operations

Specific Incident Equipment

Meter Proving System

Lessons Identified

• The master prover procedure is a standard procedure that gives general instruction to calibrate a pipe prover but does not state a specific timescale for the operation; nor does it specify door seal replacement requirements
• Although a stock of the seals is maintained on-board as part of the export streams prover critical spares, the manufacturing date and shelf life of seals is not clear
• The leak was detected manually with no actuation of the fixed gas detection system
• Although the leak on the prover door was manually isolated without incident it is not good practice for the operations team to be exposed to any hydrocarbon leak in view of escalation potential

Incident Recommendations

• The master prover procedure to be revised to state that the door seals must be removed and replaced and this along with the reinstatement of the door is to be carried out by a competent technician
• Storage requirements and shelf life of seals to be confirmed by the manufacturer.
• Module G fixed gas detection system to be reassessed by the onshore TA team.
• Although the prover door seals are pressure-rated and fit for purpose, consideration should be given to isolating the prover loop on completion of any prover activity, in order to minimise the exposure time to a potential leak path. Procedure to be amended to reflect any operational change
• Formal recording of when prover door seals are replaced to be instigated and should include recording of the manufacture date and batch number of seals for audit purposes.