Development Of Floating Production Systems For The New Era
Authors: Wennesland J.M. 
Published: October 2008

Maritime Group will give a presentation of present and future trends within the floating production area.

Based on the successful operation of Petrojarl 1 (Tentech 885) and now lately the Gryphon A (Tentech 850 C) operated by Kerr McGee a number of floating production systems are now under construction/design for North Sea applications.

A status of three developments will be given with emphasise on field development scenarios and market opportunities for the vessels.

Based on these on-going projects a discussion of future development trends and possibilities will be presented with special attention to making smaller North-Sea oil fields economically profitable.

INTRODUCTION

In the recent years we have seen an increased interest for evaluation and use of floating production units for offshore field development projects.

The growing interest for floating production units may be explained by:fewer very large offshore prospectsneed to develop prospects in deeper waterincreased awareness of flexibility related to mobilityacceptance of technologyreusabilitydemobilisation cost

BACKGROUND

In 1978 the Maritime Group company Tentech International AS launched the idea of producing North Sea oil fields by use of a ship shaped floating production unit Since then a number of offshore fields have been developed by use of various floating concepts ranging from:Semi submersibles (conversions and newbuilds)Turret moored tankers (conversions and newbuilds)Spread moored tankers (conversions)BargesTLP's

In addition other floating concepts have been launched over the years without being able to break through in the marked so far.

Examples of these are:SPAR buoys (first launched by Trosvik Engineering in 1975)Deep concrete floaters.

The recent years of experience with floating production units in terms of reliability and field operability combined with todays cost levels seem to indicate that ship shapes and semisubmersibles are the leading concepts in terms of cost effectiveness for a large number of fields scenariosworld wide.

Floating production systems in the North Sea have been dominated by four purpose built units and converted semisubmersibles. The purpose built units are:

1. Balmoral (Sun Oil)

The first purpose built semi-submersible production vessel, a GVA 5000, moored by an eight chain catenary anchor system and equipped with 4 azimuthing thruster of 2400 KW each has been in operation for more than eight years (since November 1986).

2. Petrojarl 1 {Tentech 685)

In 1986 the turret moored production and testing vessel Petrojarl 1 was delivered by the Japanese shipyard Nippon Kokan (NKK).

The original design, was developed by Tentech International AS. The vessel was built under a License agreement.

Petrojarl 1 has been operating successfully in the North Sea since 1986 serving as a vessel for extended well testing (Norsk Hydro Oseberg, Esso Balder, Norsk Hydro Troll, Conoco Lyell), storage (Shell Fulmar) and, lately, permanent production (Amerada Hess, Angus Hudson, Arco Blenheim).

3. SWODS

BP's SWOPS system comprises a dynamically positioned tanker with integrated oil production processing facilities, a riser system and wellhead. It is designed for production from marginal fields and production testing. The vessel was delivered in 1988.