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An accident leads to a more stable floating platform. In 1961 a deployed
drilling rig was not sufficiently buoyant and ended up floating half way between
the pontoons and deck. It was discovered that this arrangement created a quite
stable system and inspired a purposefully designed semi-submersible vessel (fig.
1.9).
a b
Figure 1.9 – Semi-submersible vessel Deepwater Horizon (a) and scheme (b)
1.2 Classification of water depths
Offshore platforms are used for exploration of Oil and Gas from under Seabed
and processing. The First Offshore platform was installed in 1947 off the coast of
Louisiana in 6M depth of water. Today there are over 7,000 Offshore platforms
around the world in water depths up to 1,850M
Platform size depends on facilities to be installed on top side eg. Oil rig,
living quarters, Helipad etc.
Deepwater continues to be an important oil supply in the world (not only in
US) and will continue to increase in the future (fig. 1.10).
The contribution from deepwater fields rises from around 5.4 Mbd in 2011 to
11.2 Mbd in 2035.
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