OTL presented a technical paper written by Dr. Tuanjie Liu, Marine and Riser Manager, to the ISOPE Conference in Rhodes, Greece (June 26-July 1). The paper, "Tapered Column Deep Draft Semi-Submersible (TCCD-Semi) Platform for Dry-Tree Application," presents a new concept featuring lower hull geometry with a gradually varying column cross section in contrast to the conventional semi-submersible design with uniform columns. The enlarged lower columns, in combination with properly sized upper columns and pontoons, provide sufficient buoyance and stability for topside quayside integration and offshore preservice operations such as submergence and wet-tow.

Most importantly, this new TCDD-Semi concept with tapered columns optimizes the cancellation effect of wave force and is able to reduce the heave motion in harsh environmental conditions to such an extent that the utilization of top-tensioned drilling and production riser system with dry trees is feasible. Additionally, the tapered shape of the columns helps to reduce the vortex-induced motions (VIM) of the platform in currents.