Dry and Wet Tree Damper Chamber Column Semisubmersible Design in Harsh Environment

The Damper Chamber Column Semi is a new semisubmersible conceptual design that is developed to provide a cost effective solution that can be used in deepwater dry or wet tree applications. The new semisubmersible design resembles the conventional design with a ring pontoon. However, in the new design, the columns have been configured with free flooding inner damper chambers; hence the name Damper Chamber Column Semi (DCC Semi). At quayside and during wet tow, the column configurations provide large water plane area for stability purposes, while for the in service conditions the inner chambers are flooded and the trapped water provides considerable amount of “free” added mass that significantly reduces the semisubmersible motion response. In this paper the performance of the DCC Semi located in Gulf of Mexico (GoM) environment has been simulated using fully coupled time domain analysis. Numerical results are presented for the platform motion and the tensioner stroke to demonstrate the platform performance feasibility. Structural design is performed to confirm the steel weight and establish the column connection details of the new design. The paper also presents the topside to hull quayside integration approach for this case study.