* Leak at Heimdal was "serious" - safety watchdog
* 3.5 tonnes of gas leaked on the platform in 4 minutes
* Statoil says will reply to watchdog, has investigated leak
By Gwladys Fouche
OSLO, Feb 4 Norway's Statoil must
improve safety procedures at one of its North Sea platforms
after a gas leak occurred there in May, the Norwegian oil
industry safety watchdog said on Monday.
The Heimdal platform had to be evacuated last spring after
the testing of two emergency shutdown valves went wrong, leading
to some 3.5 tonnes (7,716 pounds) of gas leaking out onto the
platform in about four minutes.
Had there been a spark, the leak would have caused an
"The leak was one of the most serious gas leaks that
occurred off Norway for several years," the Petroleum Safety
Authority Norway said in a statement. "Gas was detected in a
large area of the facility."
In its order, the safety agency instructs Statoil to
investigate why improvements ordered after a gas leak at another
North Sea platform, Gullfaks B, in 2010 were not implemented at
It also asks the firm for a plan on how it will implement
the improvements at Heimdal, and that it should confirm a
similar incident cannot take place at any other installations
the company operates off Norway.
Statoil has until March 1 to reply to the authority.
At the time of the leak, Statoil described the situation as
"We take note of the order and we will use the time we have
until March 1 to come back to the safety authority with an
answer," Statoil spokesman Ola Anders Skauby said on Monday.
"Since the incident, we have worked on measures to avoid
this type of event from happening again."
Statoil holds a 39.44-percent stake in Heimdal, which is now
mainly a processing centre for other fields, including Huldra,
Skirne and Vale. Gas from the Oseberg field is also transported
Heimdal's own gas production is modest - an estimated 140
million standard cubic metres of gas was expected to be produced
in 2012, according to the Norwegian Petroleum Directorate.
Statoil's partners in the field are Centrica (23.80
percent), Total (16.76 percent) and Norwegian
state-owned firm Petoro (20 percent).