This paper investigates the coupled analysis of a floating production system (F.P.S.) composed of platform, rigid risers, riser tensioners and mooring lines. Besides enabling to check the individual results obtained for the system's components as well as to calculate the influence of the riser/tensioning system in the rig's static and dynamic behavior, the approach provides means to improve the accuracy of the tensioning system's design. The static and dynamic problems are analysed separately and a brief description of both methods is made. The present approach is applied to a semisubmersible based F.P.S. dedicated for deepwater Campos Basin Offshore Oil Production. The analysis results are used for sizing the tensioning system's stroke and working window and allow the operability verification of the riser pipe.
The discoveries of considerable oil and gas reserves in deep and ultra-deep waters has pushed oil companies towards new technological frontiers. Amongst various solutions for the recovery of these reserves, floating production systems stand out for their small sensitivity to increases in water depths. In areas were mild environmental conditions are encountered, such as offshore Brazil, the use of conventionally moored semisubmersibles with dry christmas trees and rigid risers is being found to be both technically and economically attractive. The conventional design approach analyses the floating structure, mooring and riser systems separately, and criteria are established in order to achieve results which are consistent with one another. The present work deals with the static and dynamic analysis of the entire production system (hull, mooring, risers and tensioners) as a whole, in an integrated way. The horizontal restoring forces due to the mooring and riser system are considered in the static analysis in order to compute platform offset, riser stroke and riser maximum stress.
