Managing Design and Construction of the Central North Sea FPSO
Authors: van Berkel P. 
Published: October 2008

Shell UK Exploration and Production, operating in the North Sea on behalf of Shell UK and Esso UK is presently developing the Teal and Guillemot Fields in the Central North Sea (CNS). As part of this development it contracted with Single Buoy Moorings Inc. (SBM) for the design, supply and installation of a new built Floating Production Storage and Offloading (FPSO) vessel. The work is executed in close cooperation between Shell Expro (Client) and SBM (Contractor) and its main sub contractors. The system is due to he installed during the third quarter of 1996.

After a short description of the field development and the FPSO vessel this paper outlines the contractual arrangements and the organization set-up to perform the work.

A summary of the lessons learned (by SBM) is given. The opinions expressed in this paper are entirely that of the author and may not necessarily reflect the opinion of other parties involved in the CNS FPU project,

Introduction

In January 1994, SBM was awarded a Contract for the design, supply and offshore installation of a new built FPSO for the Shell U.K. Central North Sea (CNS) Teal and Guillemot Fields, to be hooked-up offshore by the third quarter of 1996.

A Lump sum Contract was originally awarded for the engineering phase only, with an option for the rest of the Contract to be declared by the Ist August 1994 after development consent had been obtained and the Client was convinced that the system could be built as planned, within the budget and that [he detailed design would meet the requirements to economically produce the small fields in the CNS based on the latest reservoir data and development plans.

The Contract covered the complete FPSO including the mooring system (bu[ excluding the flexible risers and all upstream systems) installed and hooked up at the designated offshore site in the CNS.

At Contract award SBM had already selected 2 major subcontractors (Fig. l):-STORK PROTECH (Schiedam, Holland) for design and supply of topsides.MITSUBISHI HEAVY INDUSTRIES (Nagasaki, Japan) for design and supply of the barge including accommodation and tandem offloading system.

All other work (overall management, mooring system, tow and offshore installation) would be taken care of by SBM.

The distribution of Contract Value between these 3 parties was about 35%/40 %/25 % (SBM/SP/MHI) on a total Contract Lump sum of about US$ 400 million. Other subcontractors and suppliers were mentioned on an approved suppliers list, but were not yet selected.

The Contract between SE and SBM was based on performance specifications, but the proposals submitted during the tender period were included in the Contract as a reference for the interpretation of the performance requirements. Only MHI insisted on a very detailed building specification and procedures. They were signed off at Contract award by all parties involved, including Shell Expro.

Systems Description

Although the intention of this paper is to highlight the management of the Contract for the CNS FPSO, a few technical characteristics are indispensable.

The topsides and process facilities are presented in detail in OTC paper OTC 8075