Optimum Design of an Ultra-Low Motion Semi-Submersible Platform

Economic and efficient energy resources are keys to a nation's development. Because of their low cost and advancement in drilling and exploration technologies oil and gas based energy systems are most widely used in practice throughout the world. The inexpensive oil and gas based energy systems are used for everything from transportation of goods and people to the harvesting of crops for food to being able see at night. As the energy demand continues to rise, this is pushing further the demands for inexpensive energy solutions. Since, available reservoirs of energy rich fossil fuels at shallow and moderately deep waters have been exploited already, the fossil fuel exploration and production is being forced to move into extremely deep waters. At deep water the expenses associated with fixed production platforms are no longer feasible, and that makes a floating production platform design a far more economical choice. This paper presents a critical parameter driven optimum conceptual design of an ultra-low motion semisubmersible floating oil and gas production system. The design is carried to satisfy the given parameter of weights and dimensions of the platform topsides required for production and drilling, water depth location, and low motion requirements. The proposed design process is highly iterative process of altering the key dimensions of a ‘n -column ring’ pontoon, and it meets applicable regulations and customer requirements while minimizing costs and satisfying the chosen parameters. The chosen parameters are classified into groups depending upon the scientific and technological requirements, and they are: GAaOHD - general arrangement and overall hull design, WaCL - wind and current loading, LaGL - local and global loading, WBS - weight/buoyancy/stability, HMaL - hydrodynamic motion and loading, SaSD - strength and structural design, M - mooring, and EaC - economics and cost.