A substantial hydrocarbon leak occurred on the production (P) installation on the Ula field at the southern end of the Norwegian continental shelf (NCS) on 12 September 2012.
The hydrocarbon quantities which flowed out in connection with the leak are estimated to have been 125 barrels (20 cubic metres) of oil and 1 600 kilograms of gas in all.
The PSA quickly resolved to initiate an investigation of the incident. See PSA to investigate hydrocarbon leak on Ula
Serious regulatory breaches were discovered at an early stage in the PSA investigation, which meant that BP had to adopt immediate physical measures on the installation. See Ula: swift action demanded
The investigation has revealed that the leak was caused by fracturing of the bolts holding together a valve in a separator outlet.
Seepage in the valve exposed the bolts to produced water with a high content of chlorides and a temperature of about 120°C. This resulted in chloride stress corrosion cracking which weakened the bolts until they finally fractured.
Major accident potential
Production was shut down for 67 days as a result of the leak. No people were injured in the incident.
The PSA has concluded that the incident had the potential to become a major accident, with the risk that a number of lives might have been lost and substantial material damage caused.
The investigation has identified a number of serious breaches of the regulations, related in part to BP’s management system for activities on the NCS.
Following the PSA’s earlier investigation of the fire on the Valhall PCP installation in 2011, operator BP was served with orders which included a review and assessment of the company’s systems for maintenance management on aging installations, and ensuring that maintenance programmes and the execution of such work were tailored to the age and condition of the installations and equipment.
The PSA’s investigation of the Ula incident shows that deficiencies still exist in the maintenance system.
On the basis of these findings, the PSA therefore gives notice of the following order:
Pursuant to section 69 of the framework regulations on administrative decisions, see sections 6 of the management regulations on management of health, safety and the environment, 21 on follow-up and 22 on handling of nonconformities, BP is ordered to:
Explanation of the terms “order” and “notification of order”
An order is an administrative decision made pursuant to the regulations. Before the PSA issues an order, it usually submits a notification of order to the companies involved.
A notification of order is neither a measure nor a warning of sanctions, but part of the PSA’s administrative process in accordance with the established rules of procedure. The notification is just a first step before an administrative decision is made.
An order is a powerful preventive measure and legally binding on the recipient.
Øyvind Midttun, press contact
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