The Kizomba A FPSO, which achieved first oil in August, is using mooring and tethering components supplied by Moorlink. In July, the Gothenburg-based company also completed delivery of components for the Kizomba B FPSO. Both developments are operated by Esso Exploration Angola. Success on these projects marks Moorlink's breakthrough into the floating production market.
Kizomba A's mooring components – four installation swivels – were ordered by Hyundai/FMC, the main contractor for the FPSO. The latter is moored in 1,200 m of water. Moorlink was responsible for the de-sign and manufacture of the swivels, which also needed to be capable of passing through the chain stopper assembly. The components had to undergo a rigorous testing program to gain approval from classification society DNV. This included side-load testing and torsion testing in addition to the usual in-line pull tests.
Moorlink MD Björn Palmquist with one of the Kizomba A tether components.
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A full-scale test program was performed in the presence of DNV representatives. For the measurement of breakout torque values, a method of installing the two swivels back-to-back in the test bed was adopted. Side-load testing simulated the swivels passing through a fairlead or over an anchor-handler's stern roller.
Moorlink's tethering system order for Kizomba A order was placed by Saibos, which was responsible for riser installation. This consisted of five tether components that form a structural connection between the standing steel catenary risers and a large support buoy. The support buoy provides some 400 tonnes of uplift to the risers, reducing the weight hung off the FPSO. Each component consists of an 800-kg padeye welded to a pipe that in turn is bolted onto a flange at the bottom of the buoy. The latter is designed to remain in service for 25 years.
Moorlink followed up its success on this project by winning an order for the Kizomba B development. Placed by Saipem, this was in effect a repeat of the tether component order, again for a set of five. A similar design was used, but with larger sizes to handle an increase in the line-load requirements. The main difference was the fabrication of forged cones that are welded to the padeyes. The equipment was delivered on schedule in July and is expected to be installed by early next year.
The company now plans to bid for the Kizomba C development, which is still in the planning stage. This project is also based on an FPSO, with a requirement for similar equipment to that used in the first two stages.
For more information contact Björn Palmquist, Moorlink. Tel +46 31 721 3801, fax +46 31 708 7900, [email protected], www.moorlink.se
