engleski

Anchoring of floating structures in deep sea

Race on for deepwater acreage moves the offshore technology into deeper and deeper seawater. In the last decade exploration drilling has progress up to 2 300 meters of sea depth. In the same time, the oil industry was coping with low oil price and companies had to rationalise their activities. As results we see today many old generation floating platforms used in the conditions which exceed their original design limits. In the article it is given the analytical model used as the base in the feasibility study of upgrading the anchoring system on one old generation semi-submersible drilling platform. The simple analytical model of the composite anchor line calculated the anchor line stiffness properties. The model, which describes the force-displacement relation of the composite anchor line, includes the classical catenary, suspended elastic cable and concentrate buoyant/gravity force in their connection. Besides the static analysis also the dynamic analysis including the first and the second order wave forces was considered. The optimum choice should have to be defined with respect to relation between environmental loading, operating conditions, pre-tension forces and safety factor.

deep sea; anchoring; semi-submersible; drilling platform

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