In March 2001 the Petrobras 36 Oil Platform (P-36) was the world’s largest floating oil production platform, operating 130 km (80 mi) off the Brazilian coast in the Roncador Field. Tragically, by the end of the month it was floating no more.
The platform had started life as the drilling rig Spirit of Columbus, before being reflated as a production platform. It was a semi-submersible with two pontoons that supported four large columns. They in turn carried the main deck with its production facility. Although capable of processing 180,000 barrels of oil per day, P-36 was operating at less than half capacity.
Just after midnight on March 15, less than a year after production had begun, an emergency drain tank in the starboard aft column ruptured due to excessive pressure. Water, oil and gas flooded in. The emergency firefighting team rushed to the scene, but 17 minutes later dispersed gas caught fire, causing a major explosion that killed ten crew members.
P-36 had become a dangerous place to be and a full-scale evacuation began almost immediately. By 06.00 all 165 surviving crew members had been lifted off, two hours before the stricken rig suddenly tilted by more than 15 degrees. But the owners weren’t about to abandon their valuable baby without a fight, and attempts were made to stabilize the damaged platform. Salvage teams pumped nitrogen and compressed air into the submerged pontoon, but bad weather hampered their operations.
On March 20 one final effort was made, but it was all in vain. At 05.30 that morning the inclination reached 31 degrees and P-36 continued to topple. By 09.00 the angle was 45 degrees and at 10.45 34,600 tons of metal worth $350 million – plus 1,500 tons of crude oil – started the 1,375 m (4,500 ft) journey to the bottom of the Atlantic Ocean.
When: March 20 2001
Where: Campos Basin, Atlantic Ocean
Death toll: 11 of the rig’s crew of 175 were killed – ten in the explosion and one who died of severe burn injuries after being evacuated.
You should know: The accident enquiry showed that P-36’s emergency response teams were not properly trained – or equipped – to deal with any eventuality. They didn’t have the portable gas detectors that would have enabled them to monitor the threat… and perhaps prevent any loss of life.