The Top Tensioned Risers (TTRs) for well completion have their advantages in allowing direct vertical access to production wells. However, due to tensioner stroke limitation, the use of TTRs requires a floating system that provides minimal heave response.
Semisubmersible floaters have their advantages as offshore host facilities. They offer large and ventilated deck, topside-hull integration at quayside, and are less restrictive to the maximum payloads. However, conventional semisubmersible heave response is not suitable for TTR applications.
Two state-of-the-art high performance semisubmersible designs are discussed in this paper. These designs are the Free-Hanging Solid Ballast Semi (FHSB Semi) and the Damper Chamber Column Semi (DCC Semi).In this paper, the DCC Semi has been designed to support dry tree application in the Gulf of Mexico (GoM) for similar conditions; payload, environment, water depth and number of risers such as these applied to the Holstein Spar platform in the GoM.
Numerical results for the DCC Semi motion response and TTR stroke in extreme hurricane conditions are presented in this paper. A comparison of this DCC Semi design and performance to the Holstein Spar and the equivalent FHSB Semi are also developed and presented in this paper.