Statoil ASA said a Feb. 18 condensate leak at its Gudrun platform in the North Sea could have been much worse, even fatal, if anyone would have been present at the time.
Results of a corporate investigation revealed a 2-mm wide crack extending 90% across the circumference of a 2-in. pipeline. Volume of the leak is estimated to be 4 cu m, with the leak rate calculated at 8 kg/sec.
The investigation team believed that “pure chance” prevented a full break on the line. In announcing the results on May 20, the company classified the incident to be “of the highest degree of seriousness.”
No one was injured as no personnel were in the area, but the outcome “could have been fatal if anybody had been exposed to the leak,” Statoil said. “A gas leak of this size represents a major incident potential if ignited.”
According to the investigation, noise and vibrations were reported on the morning of Feb. 18 and hydrocarbons were confirmed in the process module.
The company said the crack was the result of fatigue and overload. An “underdimensioned” level valve led to vibrations in the valve itself and in the surrounding piping system. The vibrations resulted in the loss of level valve control. The loss of valve control caused repeating powerful vibrations and strokes in the piping system that exceeded design capacity.
Gas detectors recorded the leak, ignition sources were disconnected, and the deluge system started automatically, as did the pressure relief system and the emergency shutdown system.
“Statoil is working systematically on gas leak prevention, and the learnings from this incident shall be translated into specific actions,” said Oystein Arvid Haland, a Statoil senior vice-president.
Production started at Gudrun in 2014 (OGJ Online, Apr. 7, 2014).