This paper considers some of the major problem areas which are being encountered in offshore oil and gas developments. The case is then presented for the consideration of floating production systems as an alternative to fixed platform solutions.
Floating production has been in operation for some years. The concept has been demonstrated as being both practical and economically attractive. The principal basis for development has been the use of converted offshore drilling vessels. Such proven technology is now being supplemented by a number of proposed designs based on specific application and wider ranging production capability. A review is given of the available structures.
The principal component parts of floating production systems in general are considered. Principal requirements, limitations and areas which require development are given with a view to the achievement of improved design and performance.
In conclusion the advantages of floating production systems are summarized and recognition is given to the potential which they present for marginal field development, early production and deep water applications.
In the face of the continually recurring challenges of deeper (Fig. 1) (Ref. 1), rougher water and rapidly rising costs, the offshore oil and gas industry is moving towards a new generation of production systems. These are the floating production systems (FPS) where rigid support from the seabed has been replaced by a flexible mooring system which creates less sensitivity to water depth, economic attractions and a new marriage of offshore technologies aimed at solving some current offshore problem areas.
With the original single-purpose piled steel platforms as the first generation of offshore structures, the later multi-purpose steel or concrete platforms as the second generation, so floating production platforms may be viewed as the third generation of this family tree.
Such a shift in the development emphasis from fixed to floating platforms is a fundamental variation in the philosophy of offshore field development. Competition and reaction against high costs have initiated a need for change and what had become conventional fixed structure offshore technology is likely to be joined by floating systems, subsea systems and hybrid combinations of these. Fixed structures gained their foothold in shallower waters. They are likely to retain their application in such areas but in the move into the recovery of deeper water reserves, floating production systems have large potential advantages.
The FPS concept can be defined as a buoyant platform structure moored over seabed wellheads with the two connected by a flexible production riser. The platform may be either a conversion of a floating structure built for some other purpose or one which has been designed and built to specification. Currently the former (semi-submersibles or tankers) have been established due to availability, established performance and low relative cost while the latter exist on many drawing boards awaiting acceptance by the industry.
