A walk in Shell Park
  from: Offshore Engineer
  by: Jennifer Pallanich
  Wednesday, March 19, 2008

Looking to exploit the oil from its BC-10 field in deep waters offshore Brazil, Shell needed to find a way to produce the heavy crude from a low-energy reservoir. Jennifer Pallanich looks at the pioneering subsea oil and gas separation and pumping technology adopted for this Campos Basin field development.

Shell is relying on existing and extending technologies to produce the heavy oil in the low-energy reservoirs in Campos Basin block 10 (BC-10) field. ‘To make it viable, we had to put some energy into the reservoir production,’ explains Paul Dorgant, Shell’s venture manager for BC-10.

The operator is applying two electrical submersible pump (ESP) solutions to the matter: a caisson ESP and a separator caisson ESP. The caisson ESP will boost production in the reservoirs that have a low gas volume, such as Argonauta B West, Dorgant says. The other fields, Abalone and Ostra, which both have higher gas contents, call for separation to remove the gas from the liquids before the production hits the ESP, he says, because higher gas volumes decrease ESP efficiency.

Both caissons will be 42in with a 32in internal liner. One will have a tangential separator at the top, similar to the one Shell ordered for its Perdido development in the Gulf of Mexico. ‘They’re using the same separated ESP technology that we are,’ notes Dorgant.

Baker Hughes division Centrilift is supplying six enhanced run life ESP vertical booster stations, ESP equipment, engineering design, qualification and testing services. Four of the systems include liquid/gas separators. Two do not include separators, but employ Centrilift multi-phase fluid pumps.

Power delivery

The demands of increasing the energy from the reservoirs means Shell has to deliver power with high-powered umbilicals that can withstand fatigue in the deepwater environment, Dorgant says. Oceaneering is supplying 50km of steel tube production control and power umbilicals. Hybrid umbilicals provide electric power transmission to subsea pumps that increase as well as accelerate production from some fields, particularly those with heavy crude or in deepwater, according to Oceaneering.

Shell farmed into Petrobras’ BC-10 concession in 1999 and later took operatorship. In December 2005, the supermajor declared commerciality over the block’s Abalone, Argonauta, Nautilus and Ostra fields – all named after shells found along the Brazilian coastline. Locally the BC-10 complex has become known as Parque das Conchas (Portuguese for Shell Park).

One field, Nautilus, stretches over BC-10 and BC-60, home to Jubarte, and Shell and Petrobras are in unitization talks.

The first phase, the only one with contracts awarded so far, includes producing Abalone and Ostra as well as one of the Argonauta reservoirs. Shell has the first phase under construction and expects to drill another phase one appraisal well in the field early this year. The second phase – still in the planning stages – involves a second Argonauta reservoir, and a further phase could see development of Nautilus and a third Argonauta reservoir. Dorgant says the company is working to define how the third phase will look. The concession lease allows for a 27 year field life.

Contracts

Shell handed out phase one contracts beginning in November 2006 for the FPSO and equipment. First oil is expected by the end of the decade. Dorgant says Shell hopes to bring phase two onstream in 2013, so he anticipates contract awards around 2010 or 2011.

SBM landed the contract to design and convert the FSO XV Domy used at Total’s Amenam-Kpono project offshore Nigeria into an FPSO with an oil processing capacity of 100,000b/d and water injection capacity of 75,000b/d. The vessel will be equipped with turbines able to generate 60MW of electrical power for operating the facilities. Shell opted for a leased FPSO for BC-10. SBM will also own and operate the unit for 15 years plus options. The FPSO will be moored in 1780m of water, and field water depths range from 1500m to 2000m. The reserves themselves are fairly shallow below the mudline, reports Dorgant.

FMC has the contract for ten trees rated to 10,000psi, four manifolds, and six subsea boosting and separation systems. Subsea 7 is fabricating and installing the six steel lazy-wave risers. Dorgant says the solution makes sense because of the water depth, size of riser needed, and fatigue design. Subsea 7 is also due to install 109km of lines, transporting and installing three dynamic and two static umbilicals, installing the FMC manifolds, and fabricating and installing 25 rigid jumpers.

Shell’s history offshore Brazil includes the Bijupira-Salema project, which went onstream in 2003. Dorgant describes the BC-10 development as a significant step toward building a sustained presence in Brazil. ‘It’s a technical advancement and commercial advancement,’ he says. OE

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