Enfield FPSO Operations, Australia

21°29'S, 114°00'E

 

 

 

The situation:  Woodside Energy Ltd operates the FPSO Nganhurra at the Enfield site off
Western Australia. The area is susceptible to tropical cyclones and any FPSO needs to be able
to rapidly and safely disconnect from its riser turret mooring, and connect up again as early as
possible after the danger has passed.  Winds and currents which are often opposed mean
that the natural attitude of the FPSO (laden) and a shuttle tanker (in ballast) can be very different –
complicating the approach for offtakes. There is also a high risk of a jackknife situation
developing during an offtake.

The requirement:  Build specifications for the company’s new FPSO, Nganhurra, included
positioning for use while connecting to their riser turret mooring (RTM) and while offloading to
a shuttle tanker.

The solution:  ShuttlePilot

ShuttlePilot improves safety and effectiveness of both operations by simultaneously showing
both units concerned (RTM & FPSO or FPSO and Offtake tanker) in their correct relative positions
and automatically measuring ranges and closing speeds. Once connected any misalignment
between the headings of the two vessels is constantly measured, and alarms raised if the
difference exceeds the selected limit. The ability to record and replay manoeuvres has proved
invaluable for analysis and training purposes.

Implementation:  The prototype ShuttlePilot was proved ashore using receivers mounted on
cars. Its first sea trial was during Nganhurra’s maiden RTM connection. The system worked
exactly as expected during that operation and no further testing or modification of the system
was required. Woodside is also using the ShuttlePilot sensor aboard the FPSO to monitor the
integrity of the RTM buoy mooring.

Results:  “In the past, the distance has been measured from the stern of the FPSO to the bow
of the shuttle tanker using a laser gun, and the information relayed to the pilot by radio. The
Navicom allows for immediate and continuous synopsis of the situation by the pilot without
communication”.

- Peter Wright, Woodside pilot    

 “This is my first stint as pilot on Nganhurra and I used ShuttlePilot for the first time a couple of
weeks ago. I was very impressed with it, it,made the final 500 metres much less stressful,
especially with NG swinging 40 deg during approach.

- David Best, Woodside pilot

Woodside has since purchased four HarbourPilot sets for use at their shore facilities and a
second ShuttlePilot for its new Vincent oilfield.  A third ShuttlePilot has just been ordered for the
facility that is to replace the Cossack Pioneer.