The FPSO Ikdam has been working in the Oudna field off Tunisia since 2006. Lundin Petroleum, a Swedish company, has been using the ship to store and process 20,000 barrels a day. (Lundin Petroleum AB)
With the growth in deep-water development by the oil industry in the Gulf of Mexico, a number of new production and delivery methods are being used. One is the floating production storage and offloading vessel, or FPSO.
An FPSO is a large tanker that processes and provides temporary storage for crude oil produced from nearby subsea wells. The ship periodically offloads the stored oil to a smaller vessel for delivery ashore. The FPSO receives fluids from a well via a turret-mounted swivel, and separates the fluid to oil, gas and water via the on-board production facilities.
Currently, there are no FPSOs operating in U.S. waters, but the first is expected to begin operating in the Gulf of Mexico within several years. Petrobras, the international energy giant of Brazil, has received approval from the U.S. Minerals Management Service for the development of the Cascade and Chinook fields in the Gulf of Mexico. Petrobras will use an FPSO to accept production from the two fields, a first for the Gulf. The fields are located in the Walker Ridge Block, over 180 miles from the Louisiana coast.
The FPSO will be anchored in 8,200 feet of water to accept and process oil and gas from at least two subsea wells in Cascade and one in Chinook. The two sites are approximately 20 miles apart. Wells will be drilled to a depth of 27,000 feet. Additional wells may be drilled, based on performance.
Tugs from Daewoo Shipping and Marine Engineering move the FPSO Agbami to its fitting out area. The $1.1 billion vessel will work in the Agbami field in offshore Nigeria in water depths to 4,500 feet by a Nigerian affiliate of Chevron Texaco. (Lundin Petroleum AB)
Petrobras will offer several technologies new to the Gulf including a disconnectable turret buoy to allow the FPSO to move during severe weather, crude transportation via a shuttle tanker, a polyester mooring system, and free-standing hybrid risers to transport oil and gas from the subsea flowline to the FPSO and from the FPSO to the export pipeline.
Petrobras has an extensive track record in operating FPSOs. The company has 15 units currently in operation and is building nine additional units.
Cesar Palagi, Walker Ridge Asset Manager for Petrobras America, said engineering studies are underway and construction should be finished in 2009.
For years, FPSOs have been used in international operations, especially the North Sea.
In Canada, FPSO use has already begun on two major oil fields. “We currently have two FPSOs working in the Newfoundland and Labrador offshore areas between 200 and 300 kilometers offshore,” said Sean Kelly, spokesperson for the Canada-Newfoundland and Labrador Offshore Petroleum Board.
Searose is working the White Rose field in offshore Newfoundland and Labrador.
“The (C-NLOPB) approved in April 2007 the application by Husky Oil for an increase in production from 100,000 barrels of oil per day to 125,000 barrels a day,” Kelly said. A further increase to 137,000 barrels per day is possible after a testing program.
Depiction of the subsea infrastructure of the Chinook and Cascade fields, which will be the first in the Gulf of Mexico to use an FPSO. (Petrobras)
The other Canadian FPSO is Terra Nova, owned by Petrocan, the state oil company. This FPSO has been working the Terra Nova field since 2002. The field is estimated to contain 410 million barrels of oil.
Before deep-water development in the Gulf of Mexico, there were no FPSOs in the area. A well-developed pipeline system was in place, and drillers seemed to prefer fixed-platform technology.
However, the relatively recent deep-water discoveries have renewed interest in FPSOs. Building pipelines 150 miles or more offshore is more expensive than using FPSOs and shuttle tankers to bring the oil to shore. FPSOs are also potentially attractive for smaller fields that have only marginal production — even those located closer to shore if a pipeline is not close by. Once the oil has been extracted, the FPSO can move to a new location.
At present there are 90 FPSOs in operation worldwide, 21 under construction and five available for deployment. Of the 90 in service, 22 are in the North Sea, 21 in Africa, 34 in Asia and Australia, and 13 in North and South America, according to Nortechs PTE Ltd. of Singapore, a leading builder of FPSOs.
The first FPSO in the Gulf of Mexico will be in Mexican waters at the Ku-Maloob-Zaap field offshore in Campeche. The ship will be operated by Bergesen Offshore under a 15-year agreement with Pemex, the state-owned oil and gas company.
|Petrobras 50, an FPSO working in the Campos Basin near Rio de Janeiro, Brazil. (Petrobras)|
Due to come on line in 2007, the ex-360,000-dwt tanker Berge Enterprise was converted to an FPSO by SembCorp Marine of Singapore. The conversion cost $54 million. It will be able to handle 600,000 barrels per day, including processing capacity of 200,000 barrels per day. The ship will also act as a gas export terminal. The new FPSO will rank third in production capacity and first in throughput capacity among existing FPSOs.
FPSOs typically operate with shuttle tankers to move the oil to shore. In U.S. waters, these tankers must meet Jones Act requirements and be coastwise qualified. If the FPSO is permanently moored, it does not have to be coastwise qualified. But if the FPSO is used to transport oil or natural gas to a U.S. port or a deep-water port on the Outer Continental Shelf, such as the Louisiana Offshore Oil Port, then it must be coastwise qualified.
With 73 percent of the new oil and gas finds in the Gulf located in deep water, FPSOs and their shuttle tankers will be a cost-effective way of transporting the hydrocarbons from the wellhead to the shore.