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from place to place; and can be lowered into or raised by altering
the amount of flooding in buoyancy tanks; they are generally
anchored by cable anchors during drilling operations, though they
can also be kept in place by the use of dynamic positioning. Semi-
submersible can be used in depths from 600 to 6,000 feet.
Jack-up Platforms, as the name suggests, are platforms that
can be jacked up above the sea, by dint of legs than can be lowered
like jacks. These
platforms, used in
relatively low
depths, are
designed to move
from place to place,
and then anchor
themselves by
deploying the jack-
like legs.
Drillships, a
maritime vessel that has been
fitted with drilling apparatus.
It is most often used for
exploratory drilling of new oil
or gas wells in deep water but
can also be used for scientific
drilling. It is often built on a

modified tanker hull and outfitted
with a dynamic positioning
system to maintain its position
over the well.
Floating production
systems are large ships equipped
with processing facilities and
moored to a location for a long

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