Optimization for Jacket Buoyancy Tank on Launching and Upending Stage

摘要

This paper presents the CPP jacket launching, self-upending analysis and lowering as a part of the Field Development project during FV stage. The analyses have been performed to simulate the behavior of the jacket for different phases of the launching and self-upending process and to ensure that the jacket structure can be launched from the barge with sufficient mudline clearance during its dive. CPP jacket strength during launching and lowering phases has also been carefully reviewed. The jacket will be launched into the open sea from a generic barge of 198.12m length x 51.82m/42.06m breadth x 12.20m depth. The analyses have been accomplished with assumption of being in a calm environment with no presence of significant wind, wave and current. Design water depth for assessment of the bottom clearance is considered as 75.90m(Launching) and 76.0m(Lowering). An optimization study to determine the number and size of buoyancy tanks, which initially proposed by four (4) tanks with 4,600mm OD x 25mm Thickness x 52.00m. In addition, the capacity of derrick crane barge and the installation cost are investigated as per the capacity of buoyancy tanks as well as adjustment of sling length. The barge stability and strength checks and the effect of the environment during the jacket launching and self-upending will not be discussed in this paper.