Originally invented by Ed Horton and Lyle Finn, the Buoyant Tower technology was first applied to BPZ CX-15 project offshore Peru when both Ed and Lyle worked for Horton Wison Deepwater Inc. (HWD), now renamed as Wison Offshore Technology Inc. with 130+ patents originated by Ed Horton and his fellows transferred from HWD. Since its delivery from Wison’s Nantong Yard in August 2012, the CX-15 platform has been in stable operation.
The Buoyant Tower is a self-installed floater. The concept eliminates the costly T&I process needed for conventional jackets. In addition, with some greater water depth, more savings could be expected as its weight (hence the cost) is insensitive to the water depth. For example, at a water depth of 150 meters, EPC of a buoyant tower might cost as much as 50% less of that for a jacket. Now with the add-on storage capability, a buoyant tower solution presents more economic advantages compared to a traditional “Jacket + FSO” or “Jacket + Export Oil Line” solution due to the cost elimination of an FSO or an export oil line.
The new Buoyant Tower solution is flexible and scalable for topsides up to 10,000 tonnes, with 10,000~30,000 tonnes of dry storage for condensate or oil, at a water depth up to 300 meters.
The configuration of the hull has been designed to accommodate the storage tank (hard tank) in the center while the surrounding ballast tanks remain balanced with hydrostatic pressure. The buoyant tanks near the water surface coupled with the solid ballast at the bottom provide the Buoyant Tower with permanent stability. The anti-rotation design of the SCF (suction can foundation) can provide further in-place stability. The analysis has shown that the tower demonstrates excellent motion performance at greater water depth.
“The buoyant tower is a compliant structure with very long eigen period. Within its application limits, the tower works better in deeper water. This prevents the platform from resonant motions in severe wave conditions. Therefore, a Buoyant Tower can support most E&P operations such as drilling, production (dry tree), gas compression or treatment, crude stabilization, water treatment or injection, power generation and other utility purposes” said Dr. Weimin CHEN, Senior Solutions Director of Wison Offshore and Marine.