Norway’s Petroleum Safety Authority Norway, PSA, has notified Statoil of an order after its investigation of a hydrocarbon leak on Heimdal on 26 May 2012. The leak is described as among the most serious for several years on the Norwegian Continental Shelf.
The report identifies serious non-conformities from the regulations which are significant for safety. PSA wants Statoil to confirm that “a lack of effect” is not present on other Statoil platforms.
The hydrocarbon leak occurred in connection with the testing of two emergency shutdown valves (ESDVs) on Heimdal’s HMP1 production, drilling and quarters platform.
To prepare for the test, a pipeline was to be depressurised to the flare. This contained a ball valve with a 16-bar pressure class as the final barrier against the flare. Because it was closed, the valve experienced a pressure of 129 bar.
The pressure caused the seal in the valve flange to fail, resulting in a gas leak estimated at 3 500 kilograms. The initial leak rate was 16.9 kilograms per second (k/s). Gas was detected across a large area of the installation.
This leak ranks among the most serious gas emissions on the Norwegian continental shelf (NCS) for several years. See the RNNP reports on trends in risk level in the petroleum activity for 2001-11.