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Shell Oil Spill, Nigeria: FPSOs Coming to the US

Shell’s big oil spill off Nigeria yesterday reportedly occurred during the transfer of oil to a tanker in their Bonga offshore field.  Oil is produced in the Bonga Field using an FPSO – basically, a modified oil tanker anchored in place.  Oil collected from wells on the seafloor flows up through riser pipes connected to the FPSO.  Shuttle tankers take crude oil out of the FPSO’s storage tanks and carry it to coastal refineries. Here’s a schematic diagram showing the Bonga Field layout:

FPSO operation at Bonga Field off Nigeria. Image courtesy Offshore Technology.

In March 2011, federal regulators approved the first-time-ever use of FPSOs to develop an offshore field in the US Gulf of Mexico.  Petrobras got the nod for their Cascade-Chinook development in water 8,200′ deep, 160 miles off the Louisiana coast.  Their FPSO, a converted tanker called the BW Pioneer, holds 600,000 barrels of oil (25.2 million gallons). BOEMRE and Coast Guard divvied up oversight responsibility for this vessel / production facility with an MOU in 2009. This project got off to a very poor start when 8,500′ of riser pipe went crashing  to the Gulf seafloor back in early April.

Our main concern is that FPSOs are potentially sources of massive oil spills:  a serious blowout, fire or explosion, collision with another vessel, intentional attack, rogue wave or storm damage, or other incident could result in a near-instantaneous release of millions of gallons. And as we’ve said here before, despite the underwhelming oil cleanup results during last year’s BP / Deepwater Horizon spill, we’ve made no significant progress in our ability to handle big spills.

Shelling out the Oil in Waters off Nigeria: Radar Satellite Image December 21, 2011

Envisat ASAR satellite radar image showing large slick (black) from major Shell oil spill off Niger Delta.  Image taken December 21, 2011 at 9:30am local time.  Image courtesy European Space Agency.

Royal Dutch Shell’s Nigerian drilling operations in the highly productive Bonga Field were officially brought to a halt yesterday after “less than 40,000 barrels of oil” (1.7 million gallons) were reportedly leaked during a transfer of crude to a tanker. We’ve just processed a radar satellite image taken this morning (December 21, 2011) of the field, with the spill clearly visible.  Here it is showing the slick outlined in yellow; it is about 70 km (45 miles) long, 17 km (10 miles) wide at it’s widest, and covers 923 square kilometers (356 square miles) of ocean:

Another, much smaller oil slick appears at lower right; this looks like a bilge dump from a passing vessel, not related to the Shell spill.

Located 120 km off the the Nigerian coast, the Bonga Field is the first deepwater oil exploration and production project for the country since Shell began offshore drilling there in 2005. Shell’s onshore operations in the Delta have a long history of spills.

 

Map showing location of Bonga Field off Nigeria. Courtesy Marcel De Jong, Shell Deepwater Services Regional Study Team.