Statoil seeks to build huge subsea factories

HOUSTON — Norwegian oil and gas company Statoil wants to build huge, underwater “factories” that sit on the seabed as they produce and process gas offshore by 2020.

The effort would be the culmination of work the company has pursued since 1986, when it began using its first subsea wells that sit on the sea floor, said Ola Anders Skauby, Statoil’s vice president of communication, technology, projects and drilling. Today, it has nearly 500 of those subsea wells, and they account for half the company energy production. But it hopes to push the envelope further.

The idea is to put every component needed for offshore energy production underwater and out of sight, in part to insulate personnel and technology from difficult conditions.

The company says subsea factories are vital to its business opportunities in some parts of the world — particularly those that are furthest from shore in deep, cold, harsh environments. It’s touted the technique as an important part of future operations in the Arctic, Gulf of Mexico and Brazil.

Subsea gas compressors

One of the key components needed to make subsea factories a reality could soon come to fruition: large, undersea gas compressors that help increase production.

Next year, Statoil is set to deploy a pair of those devices off the coast of Norway  at a site called Åsgard.

“It’s as large as a soccer stadium — something you put on the sea floor,” Skauby said.

Testing of the compressors could begin this summer. It’s the culmination of 10 to 15 years of work, he said.

Compressors are usually on rigs. But building and installing the new underwater compressors could cost the equivalent of $2.7 billion. The move is expected to increase production of two offshore fields by at least 282 million barrels of oil equivalent, Statoil says.

The compressors, however, are just one piece of the subsea factory. The concept would also involve placing the machinery used to separate oil, gas and water onto the sea floor as well. That work is usually done atop a platform, but Statoil says it already operates the first commercial subsea processing plant in the world, dubbed Tordis, off the coast of Norway.

“We have that technology today,” Skauby said.

Subsea factories would also include a power source. Work remains to be done on that part of the undertaking.

“We’re starting to overcome that obstacle as well,” Skauby said. “You have to take steps to develop it.”

Costly endeavour

Still, Skauby said, subsea is costly and it’s not likely to be ever be widespread. Instead, it will take hold where the economics make the most sense. That’s likely to include deepwater plays and areas far from shore where transportation to and from a traditional rig would be a challenge. “It would allow us to go to areas that aren’t accessible by rigs,” Skauby said.

Different versions of subsea factories could be developed depending on the exact nature of the field they’re tapping, whether it’s a brownfield, greenfield, Arctic field or something else.

Still, the factories aren’t likely to be without controversy, since some environmental advocates have looked at Arctic offshore production with skepticism. That’s not lost on Skauby. “We’ll look at it step by step and only do as much as the technology allows us to do safely,” Skauby said.

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