The FPSO Noble Seillean was a dynamically positioned floating oil production, storage and offloading vessel.

The vessel was designated as a single-well oil production ship (SWOPS) when constructed for BP by Harland and Wolff in 1986–1988.

The process plant, flare and the riser including subsea connection were designed and procured by Matthew Hall Engineering, which also provided construction assistance and commissioning of the oil production facilities.

Seallean was equipped with a flare, two cargo-handling cranes, a process plant inside the hull, a completion tower, and crew accommodation.

During the 1998 upgrade, an offtake reel system was installed which allows ship discharge of cargo to a dynamically positioned shuttle tanker.