Flange leak investigation

Several leaking flanges were discovered on an operational subsea gas pipeline, resulting in the line being shut down at a great cost to the operator. Jee was asked to investigate the cause of these leaks and to provide recommendations for the rectification of the problem to allow production to resume as quickly as possible.

This project involved:

• The analysis of the pipeline during installation, hydrotest and operation, in order to determine if the flanges or studbolts had been overstressed, if the bolt tensions were sufficient to seal the flanges and if the pipeline would be fit for service once the repairs had been completed
• Providing recommendations for the subsea inspection of the leaking flanges and for their repair based on this information
• The review of installation and pre-commissioning records to identify any factors that may have led to the leaking flanges and to check if procedures were followed
• The review of the client’s installation procedures to identify any changes that could be made in order to prevent problems during future installations
• The identification of further investigative activities

The cause of the leaking flanges was identified, the repair process was carried out successfully and the pipeline was deemed to be fit for service.  This allowed operations to resume, at great relief to the client.