Operational Experiences With The Offshore Loading Units Auk-ELSBM And Brent-SPAR

Buyzen, J.P.M., Shell Expro UK Ltd. Scotland Introduction Shell Expro operates in the British sector of the North Sea on behalf of Shell and Exxon. The company has three operating locations: London, (Head Office), Lowesoft (Southern Gas fields) and Aberdeen (Middle and Northern North Sea). This paper deals with the operation of the Auk-ELSBM (Middle North Sea) and Brent-SPAR (Northern North Sea), activities which are controlled from Aberdeen (Fig. 1). DESCRIPTION OF THE INSTALLATIONS General The hostile environment of the North Sea demands a major effort with respect to the design and effective operation of the offshore loading facilities. Although designs show significant differences, each of these installations is a variation of the Single Point Mooring theme, in that they all incorporate some form of mooring turntable and fluid swivel, which permits the tanker, while remaining moored, to weathervane around the SPM in response to the prevailing weather and sea conditions. THE AUK-ELSBM (Exposed Location Single Buoy Mooring) Location The ELSBM is located 2,000 m from the Auk platform and moored to the seabed by 8 anchors, each weighing 15 tons, which are set around the buoy in a circle with a 460 m radius. Each anchor is attached to the ELSBM by a 3 in. diameter stud link chain and is pretensioned (Fig. 2). The water depth in the Auk field is 84 m.