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Shell Announces First Million Barrels of Oil from Ultra-deep Water off Brazil

Shell Production has now hit over one million barrels of oil at the Parque das Conchas fields 120 kilometres off the coast of Brazil, where ultra-deep water and a constant swell makes for tough operating conditions.

A series of technology firsts unlocked major new resources beneath water nearly two kilometres deep. Huge technical challenges had to be overcome to bring the fields to production. Remote-controlled submarines operating in massive pressures on the ice-cold sea floor installed the equipment needed to produce the oil from deep beneath the seabed.

A vast network of wells and pipelines connect reservoirs scattered up to 20 kilometres apart. In a double technical first, oil and gas are separated on the seabed before powerful electric pumps push the oil upwards from the low-pressure reservoirs to a specially converted production vessel on the surface that stores it for shipping to shore.

And kilometres-long umbilical cables stretching out from the vessel channel continuous power and chemicals - vital to prevent frozen solids forming in the oil - to the production machinery far below.

As long-term energy demand soars, accessing hard-to-reach resources such as those at Parque das Conchas will be increasingly vital. To develop the fields economically, the reservoirs of Parque das Conchas were connected through a single production process centred on the converted vessel.

Production from the fields - currently ramping up - is the latest step in Shell's strategy of delivering an additional 1 million barrels per day of oil and gas production in the coming years.

At the heart of the Parque das Conchas project - formerly known as BC-10 - is a floating production, storage and offloading vessel (FPSO) with the capacity to produce up to 100,000 barrels of oil and 50 million cubic feet of natural gas a day. Shell is the operator with a 50% share with partners Petroleo Brasileiro (Petrobras) holding 35% and India's ONGC Campos Ltda. 15%.

"Oil and gas will continue to play a major part in meeting the world's growing energy demands, and bringing Parque das Conchas production on-stream marks an important milestone for oil production in the region," says Shell Upstream Americas Director Marvin Odum. "This also reinforces Shell's presence in the country with a project that has created jobs and encouraged investments."

Pumping Up the Oil
To combat the low pressure in the reservoirs, Shell installed 1,500-horsepower electric submersible pumps on the seabed. Each pump uses the thrust of a Formula 1 car engine to drive the oil to the surface. The oil travels through specially-developed steel pipes that are flexible enough to move with the ocean's persistent swell.

Production comes from the Abalone, Ostra and Argonauta B-West fields lying at depths of between 950 to 2,500 metres below the seabed, south-east of the city of Vitória. Some 5,000 men and women worked together to overcome huge technical challenges to make Parque das Conchas a reality. The first phase of the project now on-stream involves nine producing wells. A second phase currently in planning will focus on the Argonauta O North field.

The pressure of water on the seabed is about 180 bar (2,600 pounds per square inch) - 180 times the average pressure at sea level - and too much for a human diver to bear. Temperatures are near-freezing and the sun's rays cannot penetrate. Remotely operated submarines steered by crews at sea level installed the pumps, well-head machinery and other equipment piece by piece.

Adding to the challenges, the resources lie in small to medium-sized reservoirs under a seabed terrain made unstable by shifting sands. To prevent sand, mud and shale from falling back into the well while drilling, Shell pumped in a mix of synthetic oil with additives under high pressure to hold the hole open. And the geological make-up of each reservoir varies, with the density of oil ranging from very heavy in the Ostra field to light in Abalone.

Some of the oil at Parque das Conchas has a high gas content. To prevent this gas from entering the pumps and damaging them, Shell installed machines to separate the oil from gas on the seabed, rather than on a surface platform or onshore. Instead of burning this gas off, it is being pumped back into the Ostra field for storage until construction of a gas export pipeline system is complete.

Round-the-clock Operations
The oil is pumped up to an FPSO because of the remote location of the fields, far from any pipelines, The vessel - a converted tanker - can store nearly 1.5 million barrels of oil for shipment to shore, enough to fill over 600 million soft drink cans. Laid end-to-end, the cans would circle the world twice. From there, tankers take it to markets.

In a further technical breakthrough, Shell developed huge steel umbilical cables to connect the FPSO to the seabed equipment in each of the reservoirs over a 270-square kilometre area. The electrical and hydraulic power they supply, along with the anti-freeze chemicals, is vital to keep operations running around the clock.

"Developing breakthrough technologies and being successful in Parque das Conchas will allow the development of other deep-water projects in Brazil and elsewhere," says Steven Grant, Subsea Team Lead of the project at Shell Brasil.

Posted 09/12/09

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