This investigation report refers to an accident that took place during an attempt to weld the casing head of a slip-on wellhead, gas flow was noticed coming from the +10 valve. Later, unsuccessful attempts were made to stop the flow, which was then coming from the drive pipe/surface casing annular region. The gas flow eventually ignited and caused extensive damage to the platform. The well bridged over and kill operations were completed successfully and fortunately there were no injuries.
This investigation report refers to a hydrocarbon leak which occurred from a well flexible riser during a planned shutdown on Visund on 9 April 2011. Oil film and gas bubbles were observed in the sea near the production risers on the east side of the facility.
A blowout occurred on a Well during the period from May 9 to May 18, 2001, after the 13⅜–inch surface casing was cemented. The mobile offshore drilling unit (MODU) was cantilevered over “Platform A.” The plan called for the well to be directionally drilled with a drift angle of approximately 55 degrees. On May 8, 2001, after the 13⅜-inch surface casing was cemented, a slight flow was noted coming from the annulus between the surface casing and the 18⅝-inch conductor casing. The diverter was closed and pressure started increasing on the annulus. Valves and piping were rigged up to the 18⅝-inch A section to permit monitoring of pressure and transport of fluids to and from the annulus. Throughout the night of May 8 and through 0730 hrs on May 10, unsuccessful attempts were made to bleed off the annular pressure.
At approximately 1740 hours on February 14, 2008, a seal ring on the bottom flange below the master valve began to leak and dry gas was released into the atmosphere. Since the SCSSV was not operable and the leak was below the master valve, it was not possible to prevent the escape of natural gas. The South Pelto No. 10 platform was evacuated shortly after the loss of well control without injury. The Well was secured on February 17, 2008.
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Officer of the Watch 