FPSO Ocean Producer: A Unique Design for Shallow Water Marginal Fields
Authors: Hewlett C.W. 
Published: October 2008

In remote areas such as West Africa, low cost FPSO's can provide an attractive solution to the problem of marginal oil field development. This paper describes the conversion of a 78,000 DWT tanker to a low cost 15,000 BOPD FPSO called the Ocean Producer. All aspects of the conversion including vessel selection, engineering, project management, construction, certification and installation are discussed in detail.

INTRODUCTION

In today's world of low and uncertain oil prices, there is a need for low cost Mobile Offshore Production Systems (MOPS) which can be used to exploit marginal reserves in relatively benign areas such as West Africa. Typically, these areas can also be characterized as remote and lacking in oilfield infrastructure. Therefore, a selfcontained system, capable of taking oil directly from the wellhead, processing, storing and delivering a refinery specification product to the rail of an export tanker, is ideally suited for the application. In other words, a tanker based Floating Production, Storage & Offloading system or FPSO.

While the technology of FPSO's is reasonably well established, this paper describes a particularly cost effective and short lead time FPSO conversion. The FPSO Ocean Producer was recently installed on a leased basis, offshore Gabon. The following sections describe the design, fabrication and installation of the FPSO,Ocean Producer.

ENGINEERINQ AND PRQJECT MANAGEMENT

Budget and Schedule

In order to provide economically viable lease rates for oil production rates in the 5000 to 15,000 BPD range, a total capital budget of $25 million was established for the conversion, including mobilization and installation. An overall project schedule of one year from contract execution through first oil, was imposed by the first client of the FPSO. As longer schedules invariably equate to higher costs, fast project execution is also key to financial success. A summary project schedule is shown as Figure 1.

Project Organization

Achieving the ambitious budget and schedule goals established required commitment to success by both the client and contractor. Small, dedicated project teams were set up by both parties and duly authorized to act on all matters relating to project execution. A chart of the contractors organization is shown in Figure 2. All resources below the level of Project Engineer were non-dedicated and sourced externally through sub-contracts. Engineering, project management and construction supervision, including class approvals, accounted for approximately eight percent of the project budget.

FIELD PARAMETERS

The FPSO Ocean Producer was converted for its first application in the Gombe Beta Field offshore Gabon. The relevant field parameters are as follows:(available in full paper)

Of all the parameters specified for the FPSO, the shallow water depth affected many aspects of the design and posed the greatest challenge.

VESSEL SELECTION

In consideration of the cost and time required to new build and outfit a hull, a converted tank ship will, under normal circumstances, result in lower costs and a faster schedule.