Petrobras Platform P-36 Explosions, Brazil.
Location: Rio de Janeiro offshore, Brazil
Damage: The platform sank into the sea.
Construction Type: Steel.
Fire Resistance: No information available.
Function: Semi-submersible processing platform.
Dimensions: Length = 112.8 m; Width = 77 m
Maximum height = 119.1 m
Weight = 34,600 tons
The Petrobras Platform 36 (P-36) was located in the deepwater Roncador Field in the northern Campos Basin area, some 125 km off the coast of Brazil. Campos Basin is the largest oil reserve in Brazil, covering an area of over 100,000 km2 and was discovered in 1976. The Roncador Field, discovered in 1996, covers an area of 111 km2 and has a sea depth varying from 1,500 to 1,900 m.
The P-36 was transformed from a drilling rig, known as Spirit of Columbus, into a floating production facility with a processing capacity of 180,000 barrels per day. It was a moderately sized semi-submersible platform with two submerged pontoons supporting four large columns which in turn supported the main deck housing the production facility.
As typical for semi-submersible platforms, the P-36 was floating on the sea by buoyancy and had no physical support to the seabed. It was positioned on the surface of the sea by an anchoring system.
The P-36 had been in production since May 2000 and had an oil production rate of around 80,000 barrels at the time of the incident.
Fire Protection System:
No information is currently available in the public domain.
The Explosion and Fire:
In the first hour of 15 March 2001, three explosions occurred in the starboard aft column of the Petrobras Platform P-36, causing the fire and flooding of the platform.
The platform sank into the water of approximately 1360 m deep on 20 March 2001.
The incident was initiated by the rupture of the Emergency Drain Tank (EDT) in the starboard aft column due to excessive pressure at 00:22 on 15 March 2001. The rupture caused damage to various equipment and installations, leading to the flooding of water, oil and gas into the column. Emergency Firefighting Service was sent to the area. After 17 minutes, the dispersed gas caused fire, causing a major explosion which killed 11 crew. The explosion also resulted in serious physical damage to the platform.
Of the 175 people on board, 165 were successfully evacuated including a person who was seriously burned and died 1 week later. The continuous flooding finally destabilised the P-36 and it sank five days later.
A brief account of the incident is given as follows:
The P-36 sank into the deep water after the explosions in March 2001.
The investigation showed that the deficient procedures and training to deal with emergency situations were the major factors leading to the catastrophic disaster. The watertight compartments, providing the buoyancy to the platform, were not sealed which allowed excessive flooding.
The loss of the 11 crew highlighted that emergency response teams should be properly trained and equipped with portable equipment such as gas detectors for continuous monitoring the situation. This is particularly important in cases of possible concentration of flammable, explosive and toxic gases.
Sources of Information:
1.BBC News Online / World / Americas – UK Edition
2.Petrobras (2001). Inquiry Commission P-36 Accident, Final Report.
3.The United States Environmental Protectio Agency (2001). “Giant oil rig sinks.” Oil Drop, 5(1), pp 1-3.