Ensco 51 Blowout

Working offshore Louisiana, the crew of the Ensco 51 had just set casing when the well experienced an uncontrolled flow, causing a blowout and fire.

The 14-3/4" hole had been TD'd at 1700 ft and 10-3/4" casing run and circulated with no gas observed. The casing was then cemented and left to cure. In the early hours of 01 March, the casing was cut to length at surface and the slip-on wellhead positioned over the casing. Welding operations on the wellhead began, during which time a small blue flame was observed and extinguished. The source was thought to be grease. No gas was detected. Welding then continued and a second flame was observed, slightly larger than the previous flame. The area was again checked for gas resulting in the gas detector showing its maximum level. At 0130 hours, the driller observed flow from 10+ valve on the conductor below the platform.

Attempts were made to stem the increasing flow of gas and fluids from 10+ valve using sea water and weighted drilling mud but sufficient volume could not be added to slow the flow. The flow continued to increase and the decision was made to abandon both the rig and platform at 0300 hours. The 10+ valve was opened to divert the flow of gas away from the rig and platform, and all 43 personnel were then safely evacuated via two lifeboats to Platform B.

Specialist personnel from Wild Well Control were called in to help with capping and killing operations but the gas flow ignited in the early hours of 02 March, due to an unknown ignition source. The well partially bridged on 03 March, causing the fire to go out, and the well was subsequently killed. Production on the platform had been shut-in during drilling ops, which probably prevented a greater fire.

During the fire, the Ensco 51's derrick and substructure were completely destroyed, with the derrick collapsing onto the platform. The platform and its production equipment were also extensively damaged. In the 2nd quarter of 2002, Keppel FELS won the contract to upgrade and repair the Ensco 51 in Singapore for re-deployment in the Asia-Pacific region by November 2002.