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Installation of a Tendon Leg Platform Offshore

Roke, H.D. (2015) Installation of a Tendon Leg Platform Offshore.

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Abstract:Heerema Marine Contractors (HMC) is together with the Malaysian Engineering Company IEV in the preparation phase of installing Shell’s Malikai Tendon Leg Platform (TLP) by using one of Heerema’s own vessels, the Aegir. This is a platform which floats on seawater and is kept in place by steel pipes (tendons), connected between the platform and seabed. The downside of these tendons are fixed with eight tendon driven piles. These tendons have a high axial stiffness so that there are no vertical displacements of the platform possible due to the motions of the water. In the report, research is covered about five new and improved equipment needed during the TLP installation. All designs were presented and discussed with the client and the Heerema field specialists so that everything will work and fit during the installation. The details of the designs, including the calculations and technical drawings, are written in design reports reviewed by Heerema engineers. The reports contain the following designs: Guide Cone Seafastening Design Guide cones are used to connected the tendons to the driven piles a couple of meters above the seabed. To transport the cones, they are secured on a barge by welding four clip plates to the deck for each cone. The acting stresses in this plate, weld and barge due transportation forces are within the acceptable limits. Rod Lock Mechanism The tendons stand up in the water by clamping a tendon support buoy (TSB) around it. This one is secured by a clamping system on the downside of the TSB. To lock this clamping system, a rod lock is used as a mechanical lock which secures the clamping system till a force of 9.1 mT. Bullnose Guide The tendon porches of the TLP are used to fasten the tendons to the TLP. To guide the tendon into the porches a guide is designed, the bullnose guide, strong enough to work with the pull in forces. H-link Support Frame Part of the installation is to pre-lay 8 mooring lines on the seabed which are build up with a chain on both ends and a polyester rope in the middle. To connect the chain and polyester rope, an H-link is used which is supported by a new designed H-link frame during the assembling of the mooring line. ILT Modifications The tendons will be upended from the barge by the crane of the Aegir. The rigging of the crane contains an internal lift tool (ILT) which must be pulled inside the tendon. All components needed for the pull in are reused and combined from different previous projects to get a suitable pull in procedure for Malikai. All design reports, including the technical drawings, will be provided to the client so they can give their comments and approval to use the equipment and installation procedures.
Item Type:Internship Report (Master)
Clients:
Heerema Marine Contracting, Malaysia
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
Keywords:TLP, Heerema Marine Contractors, Malikai, Offshore
Link to this item:http://purl.utwente.nl/essays/69250
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