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pressure and stresses anticipated during drilling of the well under
all weather conditions (Fig. 2.32). The drilling-riser assembly
consists of the lower riser package, the intermediate drilling riser
joints, and the top section.

Figure 2.31 - 183/4-in. wellhead stackup
The lower riser package is run at the bottom of the string
and locks the riser to the subsea wellhead. It permits angular
deflection of the riser with respect to the subsea wellhead due to
surging of the TLP. The 163/4-in., 5,000-psi WP connector with
metal-to-metal seals provides pressure integrity to the subsea
wellhead. It will withstand riser tension and transmit bending
moments without overstress or fatigue.
The 20-in. diameter riser string, extending from the lower
riser package at the sea floor to the TLP substructure at the
surface, is made up of 20-in. OD x 1.375-in. wall joints of 80 KSI
minimum yield seamless pipe joined by high-pressure riser
connectors. The integral connections are stronger in both tension
and bending than the pipe body. Each joint contains three integral
hydraulic lines for control of the connector in the lower riser
package (lock, primary and secondary release). The riser joints are

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