Enfield FPSO Operations, Australia

 

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 systems 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, until 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 Shuttle Pilot for first time a couple of weeks ago. I was very impressed with it , made the final 500 metres much less stressful especially with NG swinging 40 deg during approach.

- David Best, Woodside pilot

Woodside has since ordered four HarbourPilot sets for use at their shore facilities and a second ShuttlePilot for its new Vincent oilfield.

LNG SERVICE INDUSTRY

Hazira Port, India

The situation:  Hazira Port is a brand new Shell LNG import terminal on the West Coast of India, North of Mumbai. Purpose-built on a greenfield site, it does not yet show on any official charts, so the specially produced S-57 standard chart (generated from Shell's own survey data) provides the only charting reference. Ships entering the port must counter cross-currents of up to 2 Knots off the breakwaters, then stop and turn 180 degree as soon as they are through the entrance, before berthing bows-out at the discharge wharf.

The requirement:  Shell stated categorically that they were not prepared to bring ships in until they had a suitable precision piloting aid.

Implementation:  Navicom Dynamics supplied a HarbourPilot at very short notice in March 2005 and completed training the pilots two weeks before the 136,000 cubic metres LNG carrier Gemmata arrived with the first shipment - becoming the first ship other than the dredger to pass the breakwaters! The system uses MF Beacon DGPS from a very close reference station. The S-57 chart was specially created using Shell’s own survey data and engineering drawings.

Results:  The Operations Manager at Shell Hazira later commented… "Thanks to (Navicom Dynamics) for putting this tool on the market. (HarbourPilot) has reduced our risks tremendously."

 Shell Hazira took delivery of a second HarbourPilot unit in March 2007, reflecting the increased traffic through the port.