Publications

North Belut CPP Topsides contains facilities for gas compression, condensate extract, gas and liquid export, utilities and living quarter units. The Topsides, an integrated deck which weighs approx. 14,000MT, was installed employing a floatover method in June 2009. This paper describes aspects related to the floatover method. Various studies performed during FEL stages concluded that the floatover was the most efficient method of installation. The 5000MT jacket was designed with a large opening in the middle to allow the entrance of the floatover barge. Key elements of the floatover are a flat top barge (tight fit vs. loose fit), engineering, which involves aparticular analysis called mating analysis, a set ofinstruments called LMU (Leg Mating Unit) and a rapid ballast system. Mating analysis comprised time and frequency domain analyses which were performed to predict forces during pre-mating, mating (entry, alignment, initial contact and load transfer) and post mating (separation and exit) at three sea states. LMU is a layer of elastomers which were installed to ease load transfer. There are four units of LMU installed on 4 legs. The LMU was designed based on the weight and the C.o.G. of the Topsides. It was predicted that at 70% of load transfer, a maximum LMU stroke of 500mm would be achieved. Testing of LMU was done by the manufacturer to ensure each LMU had correct stiffness. The rapid ballast system was required to fit the tide conditions on site. A ballast speed of 1m in 20 minutes was achievable with the rapid ballast system. Mating analysis predicted that the maximum lateral force in all stages of operation would still be less than the maximum force the jacket was designed for (900MT). Maximum LMU stroke was achieved on all 4 legs. Pre-mating, mating and post mating were performed in a total of 15 hours of operation. No technical problems occurred during the floatover operation.