BP Exploration is seeking British government approval to develop Donan field in North Sea Block 15/20 using its new Seillean floating production vessel.
The 10 million ($170 million) ship is taking on its second cargo of crude from Cyrus field in North Sea Block 16/28.
Seillean, the world's first production vessel to hold station using only dynamic positioning, began operations in April.
Its dynamic positioning capability and specially designed system that allows easy connection and disconnection of the wellhead, lets the vessel load a cargo from the twin wellheads in Cyrus field, then steam to a Northwest European port, discharge the cargo, and begin the cycle again.
The Seillean crew reports the vessel's seven thrusters and the dynamic positioning system have performed above expectations. The vessel is designed to continue loading in winds of force 8 or 9 and seas of 15 ft. It has not been tested by weather that rough.
Commissioning of the final systems on the vessel is in progress. Overall, the main systems have worked well.
BP drilled two horizontal wells into the Cyrus reservoir, which holds reserves estimated at 13 million bbl. The two wells are capable of producing as much as 18,000 b/d, although normal production will not exceed 15,000 b/d.
At that flow rate, Seillean's storage space takes about 3 weeks to fill. Another week is required for the roundtrip discharge operation.
Donan, the new target for Seillean, holds 25-30 million bbl of reserves. In anticipation of a development permit from the U.K. Department of Energy, BP installed the first of two wellheads, with work in progress on the second.
WHAT'S NEXT
Operations in Donan field will enable BP to fulfill the original concept of a mobile production vessel. Seillean's mobility is designed to give small fields, where reservoir pressures have started to decline, a chance for pressure buildup while the ship takes a cargo or two from another reservoir.
BP is investigating the possibility of modifying that concept to allow Seillean to offload its cargo into a shuttle tanker during the early part of a field's life, when reservoir pressure is still good. This will require a dedicated shuttle tanker. The company is considering the logistics of adapting the tanker that will service its Wytch Farm oil trade from Southampton on the south coast of England.
Seillean's start-up has kindled interest from other U.K. operators, which have recognized its well test potential. BP says the most likely use for the vessel in this area might be a long term test of Clare field, west of the Shetland Islands, where a group of companies with interests in large heavy oil reservoirs are starting a new series of studies of the field.
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