UK-based Subsea 7 has recently completed the VIC/P44 Stage 2 Development (Henry) Project, offshore Australia, which involved the installation of a 21.7km-long 30.5cm rigid pipeline to connect the subsea production trees at the Henry-2 and Netherby locations, together with four rigid spool pieces.
The project also included the installation of a 22km-long electro-hydraulic umbilical from Casino-4 to Pecten East locations.
Awarded to Subsea 7 in August 2009 by Santos, the work scope required the Henry and Netherby fields to be tied back to the existing Casino field, located offshore Victoria in the Otway Basin.
The engineering was completed by a dedicated project team with offshore operations commencing in December 2009. One of Subsea 7's rigid reeled pipelay vessels, the 'Seven Navica', arrived in Singapore in late November 2009 before commencing its journey to the project's spoolbase in Crib Point, Victoria.
The 'Seven Navica' successfully installed the 21.7km of 30.5cm rigid pipe complete with two in-line tee skids, over two trips returning to the spoolbase in the interim. The 'Seven Navica' was supported by Subsea 7's Dive Support Vessel, 'Rockwater 2', which installed four sections of umbilical, electrical and hydraulic flying leads, three pipeline end manifolds, associated subsea infrastructure and 650 stabilisation mattresses to complete the tie-ins and freespan rectification.
Over 2000 lifts were performed by the 'Rockwater 2's' 300-tonne active heave compensated crane. The umbilicals ranged from 3.3km to 6.5km in length and were installed utilising an in-line tensioner and a reel drive system.
The vessel also installed rigid spools; performed the associated metrology and assisted Santos with field commissioning and start-up activities.
The Henry and Netherby fields, located in 56 to 72 metres of water, are operated by Santos on behalf of a joint venture it has with AWE and Mitsui E&P Australia.
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