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Lesson N°11 :
Advanced marine structures :
Oil exploration , which initially started onshore , has now moved to
deep waters because of the paucity of resources in shallow waters .
To date , there are more than 20.000 offshore platforms of various
kinds installed around the world. Geologists and and geophysicists
search for potential oil reserves beneath the ocean floor , and
engineers take the responsibilty
of transporting the oil from the
offshore site to the shore location.
Offshore installation are constructed for various purposes , namely
exploratory and production drilling , processing oil and gas ……….., they
are not classified on the basis of their functional use but on the basis
of their geometric (structural form).
Because the platforms are designed for greater water depth , their
structural form changes significantly ; the same form can not be used at
different water depths.
The present trend is to design and install offshore platforms in regions
that are inaccessible and where the use of existing technologies is
difficult.
Offshore platforms are
classified either as
bottom-supported or
floating .
Bottom –supported platforms can
be further classified as fixed or
compliant structures ;compliant means moving.
Floating structures are classified as neutrally buoyant .
Different types of fixed platforms are ; jacket platforms and gravity
platforms.
Different types of compliant platforms are guyed towers , articulated
towers and tension leg platforms.