Oil

Text size
- -A
- +A

Dalia, an offshore giant

Development plan for Dalia.

Location: Gulf of Guinea, offshore Angola

Partners: Six companies share the capital expenditure and profits. Angola's national oil company, Sonangol, is the titleholder. Total is the operator with a 40% interest, alongside StatoilHydro, 23.33%; Esso, 20%; and BP, 16.67%.

Dalia FPSO, Angola The floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field.
Dalia FPSO, Angola The floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field.
Dalia FPSO, Angola Catwalk on the floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field.
Dalia FPSO, Angola Logo on the floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field.
Pride Africa drillship Aerial view of Pride Africa, a dynamic positioning drillship purpose built in South Korea to develop deepwater fields in Angola’s Block 17, including Dalia and Girassol.
Pride Africa drillship Pride Africa, a dynamic positioning drillship purpose built in South Korea to develop deepwater fields in Angola’s Block 17, including Dalia and Girassol.
Dalia FPSO, Angola Workers on a catwalk on the floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field.
Dalia FPSO, Angola Power generation and gas compression unit on the floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field.
Dalia FPSO, Angola Transmission antenna/mast on the floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field.
Dalia FPSO, Angola A helicopter takes off from the helipad on the floating production, storage and offloading (FPSO) unit on Angola’s deep offshore Dalia field. In the foreground, a firefighter.

Lying in ultra-deep waters in the Gulf of Guinea, Dalia is one of the world's largest deepwater oil developments. Bringing it on stream was a colossal feat of engineering. With viscous oil, unconsolidated reservoirs and complex geological structures, Dalia keeps the challenges and innovations coming, as it breaks new technological ground.

Another "flower" in the Gulf of Guinea

Located 135 kilometers offshore Angola in the Gulf of Guinea, the field is part of Block 17, which specialists refer to as the "golden block" because of the succession of discoveries made there, including Girassol, Pazflor and Rosa.

Extreme conditions

Buried under more than 700 meters of unstable sediment, the Dalia field extends over an area of more than 200 square kilometers in a water depth of nearly 1,500 meters. The oil is trapped in a number of reservoirs formed some 20 million years ago. Swept along by the force of the Congo River, the sediment, rich in organic debris, deposited itself in broad channels on the seafloor. There the organic matter gradually decayed and was compressed into viscous, sour oil. These properties make it corrosive to installations and tough to extract today, especially in icy deepwater regions .

A high-tech floating factory

Some 71 wells averaging 3,500 meters in length, including 1,000 meters of horizontal wells, have been or will be drilled by 2013, including 37 production wells, 31 water injection wells and three gas injection wells. Each is equipped with automated wellheads that control the flow rate at all times and can shut a well down in an emergency.

Finally, the gigantic floating production, storage and offloading (FPSO) vessel is connected to the production equipment installed on the seabed by a web of flowlines for produced fluids and electro-hydraulic control cables known as umbilicals.

The crude oil is carried to the surface by eight enormous risers insulated from the cold and pressure of the ocean depths. Each weighs more than 800 metric tons.

Human beings cannot work at depths of 1,500 meters. Remote-controlled robots guided from the surface are used to perform tasks to within one meter. From the FPSO, 17,000 points across the subsea installations are monitored continuously via 75 kilometers of umbilicals.

A priority on safety and sustainable development

Safety and environmental protection are core focuses at the gigantic Dalia complex. Measures are taken to achieve optimal energy efficiency during production, gas and drilling water are reinjected, the first for future use and the second to curtail pollution, and the loading buoy is anchored more than two kilometers away from the FPSO to avoid any risk of fire or collision during ship maneuvers.

We train young Angolans at our industrial facilities, manufacture some items locally and allocate funds to rebuild infrastructure and finance social initiatives, thus helping to drive our partner country's development.

Dalia in Figures

Thought to contain up to a billion barrels of oil, the field extends over an area of 230 square kilometers, in water depths ranging from 1,200 to 1,500 meters. Brought on stream on December 13, 2006, it currently produces 250,000 barrels per day and has an estimated life of around 20 years.

The floating production, storage and offloading (FPSO) vessel is 300 meters long, 60 meters wide and 32 meters high. It weighs in at an equally impressive 416,000 metric tons, nearly 30,000 metric tons for the topsides alone. Its living quarters can accommodate up to 190 people.

Some 175 kilometers of lines and subsea cables snake across the ocean floor. Seventy-one wells are being or have been drilled, requiring close to 3,000 days of work.

The pieces of this giant jigsaw puzzle were made by nearly 1,000 different suppliers spanning the globe: the hull in South Korea, the wellheads in Norway, the insulated risers in France, and the anchor piles, subsea cables and loading buoy in Angola.