The End of Frade

The Brazilian National Petroleum Agency (ANP) is examining a scenario where a series of seabed leaks may occur in a 7km radius around the Frade oil field in the Campos Basin, due to sagging of the seabed in the area and fissures in the rocks surrounding the Frade oil reservoir. The Frade well is located 130km off the city of Macaé in Northeast Rio de Janeiro at a depth of 1,200 meters (3,996 ft). Although it is still unclear if Chevron, the main field operator is responsible for this due to having exceeded the pressure limits of the well, there is evidence that the super-major operator did exceed the well wall pressure limit. Transocean´s chief driller at the site, Brain Mara, claims that while drilling, a mud pressure of 9,5 pounds per gallon was not enough to contain a kick from the reservoir, therefore the drillers increased this pressure to 13,9 pounds per gallon in order to push the oil back down and control the kick. He also claimed to know that the maximum pressure the walls of the well could take would be up to 10,57 pounds per gallon, but continued with the risky operation as he was following orders. The rupture of the well wall if mud pressures over 10,57 was applied was forecast in the wells Leak Off Test (LOT). However Chevron´s president in Brazil, George Buck, claims that the mud pressure was only increased 6 days after the initial spill in November 7th which was comprised of a 300 meter fissure which spilled a total of 2,400 barrels. On March 4th another fissure 800 meters long was discovered around 3 km from the original spill location and that´s when the sagging of the seabed was positively identified. This spill was much smaller than the original spill as the wellhead was already sealed off but geologists in Brazil are claiming that the reservoir pressure is still forcing out small quantities of oil through the fissures in the rocks surrounding the deepwater well. They also claim that these fissures and the seabed sagging were caused by the overpressure applied to the well walls before the first spill in November. Chevron denies that the two spills have any relation. Nothing is proven either way at this point, but the fact is that the seabed sagging along with the fissures on the rocks surrounding the reservoir may well force the premature ending of any operations in the Frade field, which before the November accident had other wells producing a total of 61,500 barrels/day. Chevron has already suspended production and it is increasingly likely that Chevron may have its operations license in Brazil revoked due to the accident. Claudio Paschoa