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of the casing strings within the subsea wellhead housing.
With this housing, a guide base system, consisting of a
temporary guide base (TGB) and a permanent guide structure
(PGS), will provide an anchor for the guidelines and serve as the
initial support structure for installing the wellhead system.
The first piece of subsea equipment used in a typical
floating drilling operation is the TGB, through which the drilling
assembly will be guided to drill the 36-in. diameter conductor
hole.

Figure 2.7 - Temporary guide base. (Courtesy Vetco)

The temporary guide base has four guideline attachments
on a 6-ft radius (fig. 2.8). Its four anchor spikes will penetrate 18
in. of the sea floor. The center of this TGB is a funnel-shaped
landing ring that accepts the gimballed base of the permanent
guide structure, even in soft-bottom conditions.

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