TlpTEC™
Tension leg Platform (TLP) Technology
The main principal of the TLP is to assure that the vertical
forces acting on the platform are in balance, i.e. fixed
and variable platform loads plus tendon tension are equal
to its displacement. The VCG should be close to the platforms
geometrical center. Positive displacement is obtained by
locking the platforms draft below the fixed and variable
payload displacement draft. This will result in an upward
force applied to the tendons, thereby keeping them in constant
tension.
 As
a consequence the vertical platform motions (heave) is almost
eliminated, except for motions resulting from tendon elasticity
and vertical motion as result of environmental introduced
lateral platform motions. The tendons do allow a lateral
motion of the platform as a result of wind, wave and current.
This motion is similar to an inverted pendulum except for
the fact that the displacement variation by pulling the hull
down is giving a restoring force to the lateral movement.
The tendon tension is set within predefined values, or window
of operation. If the variable load of the platform exceeds
these values by adding risers or drilling loads etc., the
tendon pretension is adjusted by re-ballasting of the platform. Consequently
the hull is compartmented into void, machinery and ballast
spaces. The TLP has a control system monitoring ballast and
VCG. Seawater is used for ballast adjustment.
As an evolution of the Classic TLP design, the ETLP (Extended Tension Leg Platform)
has been developed. FloaTEC, LLC now exclusively owns the rights
to the ETLP technology. Some of the drivers behind this design
development are:
- Wider tendon base for greater pitch stiffness (stability)
- Smaller spacing of deck supports for more efficient structure
- Lower rotational inertia for hull and deck for lower
pitch natural period
- A large moonpool can accommodate conventional top tension
risers.
- De-coupling of tendon porch separation distance from
the topsides deck design produces maximum design flexibility.
ETLPs
have been successfully designed, fabricated, and installed
at the Kizomba A, Kizomba B Located offshore Angola and Magnolia
locations in the Gulf of Mexico.
Typical
TLP Heave Motion RAO’s;
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Copyright © FloaTEC, LLC 2007 |
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