Noble Denton providing naval architecture services on Sakhalin IIProjects and Operations // May 9, 2003
The Sakhalin II Project comprises two main platforms, Lunskoye A and Piltun-Astokhskoye B, plus a tanker loading unit. Piltun-Astokhskoye is primarily an oil producing field, with the platform located in 32m water depth. Lunskoye is a gas condensate field, with the platform located in a water depth of 45m. The platforms comprise a gravity based structure, with a large integrated topside. Construction of the substructures and topsides are likely to take place in the Far East. Mating of the topsides withthe substructure will take place, using the floatover concept. The tanker loading unit consists of a steel gravity based tower with a rotating head, to which an oil tanker connects to and offloads oil from. This is located in Aniva Bay, on the southerntip of Sakhalin island. Production start up for the Lunskoye A and Piltun-Askoye B platforms is currently planned for 2005 and 2006 respectively.
Noble Denton's scope has covered a range of naval architectural activities for the installation of the topsides. These activities included:
· Preliminary design of the topside transportation barge
· Topside loadout analysis
· Topside transportation analysis
· Topside mating analysis
Simulating the barge and topside motions during the floatover and mating operation as well as the calculation of impact loads on the pre-installed substructure presented a particular challenge. Time domain simulations modelling the dynamic interactions between the barge, topside and substructure were carried out for both platforms using the AQWA hydrodynamic software package.
Other specific activities included:
· Barge transportation stability and motions
· Comparative assessment of installation methodologies
· Installation procedure development
· Weather window assessment for mating operation
· Management and technical supervision of the topside transportation model testing
The work scope has drawn on the full range of in-house expertise, covering marine operations, design engineering and analysis and meteoceanography.