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Gullfaks South multiphase compressor before load out. Photo by Harald Pettersen -

Statoil ASA was installed in 2000 at ExxonMobil’s

Subsea

Topacio feld in Equatorial Guinea, and has been in operation for more than 50,000 hours since.

The frst subsea water injection pump was installed at the Troll pilot, in the

Norwegian sector of the North Sea, in 2001, and the frst subsea seawater injec- tion system at Columba E, in the UK

North Sea, for CNR in 2006.

The deepest, longest tie back and high- est design pressure was installed in 2011, for the Chevron-operated, 2100m (7200ft) water depth Jack/St. Malo development in the US Gulf of Mexico. First oil from

Jack/St. Malo was last year. OneSubsea supplied the production and processing systems for the project, including 12, 15,000psi subsea wellhead trees, produc- tion controls, four manifolds and associ- ated connection systems, engineering

Boosting and project management. Through one of its predecessor companies, the frm also supplied three pump stations, three subsea pump control modules and asso- in the deep ciated and instrumentation equipment.

The pump systems, which are comprised of three megawatt single phase pumps,

The rewards on ofer from subsea boosting technology were are remarkable for their combination of spelled out at the MCE Deepwater Developmment Conference in 13,000psi design pressure and installed water depth.

London this spring by Arne B. Olsen, sales director, pumps and

OneSubsea also delivered the largest dif- subsea processing at OneSubsea. Meg Chesshyre reports.

ferential pressure systems to Total’s 1400m deep GirRI project (130 bar differential ubsea pumping improves feld a new technology, despite being around pressure) offshore Angola in 4Q 2014.

economics by reducing backpres- now for more than 20 years. The original One the key drivers for the technology

S sure on the reservoir, increasing vision for subsea multiphase pumps was has been increasing water depths, with well fow rates and total recoverable to create a technology that could extend projects, such as Jack/St. Malo, reaching reserves, explains Arne B. Olsen, sales satellite development from fxed plat- down to 3000m, with a design pressure director, pumps and subsea process- forms out to about 50km. Framo’s frst at 15,000psi, to meet requirements in the ing at OneSubsea. Boosting improves multiphase test rig was in place as early Gulf of Mexico and differential pressure fow assurance by increasing velocity in as 1987, at the company’s facility just evolution at 140 bar. pipelines, increasing temperature, and south of Bergen. Here, the frm selected

Wet gas compression stabilizing production. and tested the helicon-axial pump prin-

The most recent highlight for OneSubesa, “OneSubsea has been operating in the ciple to be used.

however, has been the delivery in March subsea processing arena longer than any The evolution of multiphase pumps this year of the world’s frst subsea other company in the world, and records from OneSubsea’s successful collabora- multiphase compressor to Statoil for today more than 15 years MTTF (mean tion with Shell on the Draugen feld in the Gullfaks South feld in the North time to failure) of our pumps,” he says, the Norwegian sector of the North Sea

Sea, Olsen says. The subsea multiphase with the frm’s technology development dates back to 1994. That marked the compressor enables boosting of unpro- facilitated by the company’s ability to delivery of the frst commercial subsea cessed wet gas production fuids, from invest in large realistic test infrastructure. multiphase pump (650 kW), in 270m 0-100% liquid phase, eliminating the

However, the subsea booster market water depth on a 9km tie back. This was need for an upstream separation facility has been slow to develop and there are followed by Statoil’s courageous deci- or an anti-surge system, and making it the a limited number of projects out there, sion to install subsea electrical pumps on industry’s only true wet gas compressor.

Olsen admits. the Lufeng feld in the South China Sea

It is expected to increase the recovery rate in 1997. These pumped some 42 MMbo

The vision for the Gullfaks South Brent reservoir by from 1997-2011.

Subsea boosting is still being described The frst true subsea multiphase pump 22 MMboe.

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