Pipework on Shell UK’s Brent Charlie platform in the North Sea deteriorated to such an extent that contained hydrocarbon fluids escaped, forming a potentially catastrophic explosive and flammable mixture that could have ignited.
In addition to the release, ventilation fans designed to prevent, control or mitigate the effects of escaped hydrocarbon gas did not function properly as they were not suitably maintained. This led to a release of mixed phase crude oil and gas from the corroded pipework. The probability of ignition was assessed to be less than 1%.
Aberdeen Sheriff Court heard there was an uncontrolled hydrocarbon release incident from a Return Oil Line (ROL) pipework inside concrete leg Column 4 of the Brent Charlie offshore installation. The release involved 200kg of gas and 1,550kg of crude oil – the largest uncontrolled hydrocarbon release on the UK Continental Shelf reported to HSE in 2017.
The release placed over 170 platform personnel at risk from a potentially catastrophic fire and explosion had the escaping hydrocarbon gas ignited inside the concrete leg.
HSE noted that the platform manager, and the various emergency teams, deserve praise for their decision making and actions taken that assisted with preventing the incident from escalating. Their sound judgement and decision making ensured the situation was eventually brought under control.
An HSE investigation found that deficiencies in Shell’s safety management system led to the release. The ROL pipework in Column 4 was not properly maintained for several years. The pipework was installed for short-term use and was due to be removed in 2010 but remained in place for seven years, during which time it suffered corrosion damage. It failed on 19 May 2017 and a large volume of gas was uncontrollably released into the leg. Ventilation extract and supply fans designed to prevent and mitigate this major accident hazard were also inadequately maintained, which exacerbated the risk to the 176 people on the platform.
Shell UK Limited pleaded guilty and was fined £560,000.
This case highlights the importance of reviewing their current management of change processes, strengthening inspection regimes to identify potential internal corrosion within pipework, and ensuring that inspection frequency of safety-critical equipment considers full analysis of the equipment’s maintenance history.
