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Shell Nigeria Bonga oil leak
After a leak of crude oil from the Bonga facility offshore Nigeria on December 20, and the launch of a full-scale response operation, Shell believes that no oil from the facility has made the 120 km journey to the Nigeria coast. (Bonga is operated by Shell Nigeria Exploration and Production Company Limited - SNEPCo – which is 100% Shell-owned.)
Recounting the incident
The Bonga field in OML118, which was discovered in 1995, lies in water depths of approximately 1,000 metres across an area of 60 square kilometers and is 120 kilometers offshore. Bonga has a nameplate oil production capacity of more than 200,000 barrels per day (bpd) – around 10 percent of total Nigerian output. It also produces approximately 150 million cubic feet of gas per day. SNEPCo, on behalf of the OML118 Contractor parties - Shell (55%), ExxonMobil (20%), Eni (12.5%), and Total (12.5%), operates the Bonga field with NNPC as license holder.
A full investigation into the Bonga oil leak is currently underway. The incident took place on December 20, when SNEPCo discovered a leak during a routine operation to transfer crude oil from Bonga’s floating production, storage and off-loading (FPSO) vessel to the waiting Suez Max tanker Northia.
As soon as it was aware of the leak, SNEPCo stopped the flow of crude to the tanker and isolated the export system. SNEPCo estimated that fewer than 40,000 barrels of oil had escaped in all.
SNEPCo’s oil spill response procedure and emergency response team were immediately activated to manage the situation, while the relevant Nigerian authorities were informed. International experts were also flown in to help in the response efforts. On December 21, as a precautionary measure, the Bonga field was completely shut in. Nigeria Country Chair Mutiu Sunmonu issued an apology on behalf of Shell.
Already by December 22, as a result of natural dissipation and evaporation as well as vessel dispersant applications, Shell estimated that the spill had reduced in size by about 50 %. Nevertheless, airborne dispersant operations began the next day with the arrival of a Bandeirante aircraft from Ghana and additional spill response materials were delivered with the services of two 747 aircraft. The oil sheen continued to further disperse and thin.
On Friday December 24, Shell’s Hercules C-130 aircraft arrived from Europe, flying four individual sorties with airborne dispersants. By the next day, the effectiveness of the emergency response was clear – that the oil leaked from Bonga had largely dispersed.
Surface sheen from the Bonga leak
Mutiu Sunmonu said: "I am very sorry the leak from Bonga happened in the first place, but am now happy to confirm the oil has dispersed. This could not have been done without the support of local and national government officials who enabled our teams to mobilise quickly and start to tackle the oil almost immediately.
“I also want to thank the teams that worked day and night to clean up the oil for their tireless efforts, and the communities along the western Delta shoreline for their support and understanding over recent days."
New spill detected
The successful effort to clean up the Bonga oil was challenged when a suspected third-party oil spill was detected in the area, revealed by a trail of oil approximately 100 km from the Bonga facility.
Shell decided to intervene to tackle this new spill, thought to be from a third-party vessel due to the different age, shape and color of the oil. Shell’s efforts, however, were not completely successful and the non-Bonga oil washed up on some parts of a sandy beach.
Shell is trying to gain access to the beach in order to carry out cleanup work, which is dependent on the co-operation of local community members.
The Bonga leak: understanding the origin
The Hercules C-130 delivers airborne dispersants to the area of the suspected third-party spill.
A remotely operated vehicle (ROV) confirmed on Thursday December 23 that the Bonga leak originated from one of the three loading lines linking the FPSO to an intermediate buoy, which in turn is linked to the loading tanker. The line in question was installed in December 2006 and had been tested as part of normal maintenance procedures. A full investigation into the cause is underway.