The paper describes two innovative concepts. Firstly, the combining of all 4 main functions of an offshore production facility into one unit being:

  • production gathering

  • processing, treating and gas disposal

  • storage

  • measurement and transportation (terminating)

The Floating Production Storage and Offloading System (FPSO) for Cadlao field in the Philippines combines all of these functions into a single tanker based unit. The development of this production system requirement system required the application of existing operating experience together with new component deign and applied research effort for specialized system features.

The secondary conceptual, but important consideration, is the ability to lease such an integral system. The leasing concept introduced opens a new economic potential. It also initiates a new facet to the offshore oilfield service potential. It also initiates a new facet to the offshore oilfield service industry by joining the existing major contract services market such as drilling, offshore construction, supply boats and tugs, etc., Amoco Philippines Petroleum Company, the operator of the Cadlao field, and Terminal Philippines Petroleum Company, the operator of the Cadlao field, and Terminal Installations, Inc., the owner of the FPSO, have entered into a leasing arrangement for an integrated FPSO.

Introduction

The FPSO concept applies to those potential offshore production developments where any of the following pre-requisites need to be met:

  • extended reservoir evaluation, utilizing production data, prior to full field development

  • limited, remote or underdeveloped shore facilities

  • early generation of revenues

  • development of an area containing a single or multiple of small reservoir(s)

This paper describes the development of the above concepts into a real system; an integrated floating, production, storage and offloading system for the Cadlao field provided on a lease basis.

The integration of the production gathering and processing equipment onto a 125,000 DWT vessel moored in 300 feet of water and closed coordination and cooperation of the two classification societies involved. Lloyds and ABS, Overall system design approval was obtained.

Major system components are described. Special attention is given to those sub-systems containing the result of innovative work which was necessary to meet both conceptual requirements of providing the four production faces and be leasable.

The concepts of leasing the FPSO and the structure of the lease is reviewed briefly.

Selection Of The Offshore Production System

Once oil is discovered at an offshore location, the company must consider the best overall development scheme for most cost effective exploitation of the reservoir. The different basic development schemes which a company can use to develop offshore oilfields are:

Fixed platforms utilizing pipelines to transport oil to shore based storage. Movement of oil from storage to market would be by means of onshore pipelines by a tanker loaded at a shoreside dock or by a tanker loaded at an offshore terminal (usually an SPM).

Fixed platforms using offshore storage and export terminal. The most common scheme for storage utilizes a tanker with either rigid yoke mooring, or an SPM with soft mooring, for storage. Export of the oil is accomplished by shuttle tankers loaded directly from the storage tanker or by alternating tankers (such as the Montrose field in the North Sea). In some cases, oil is loaded onto a shuttle tanker moored to a separate SPM.

Floating production systems include the use of semisubmersible rigs or tankers. The use of a semisubmersible rig requires subsea completions and a moored tanker for storage. The system which integrates production, storage and offloading into a single unit utilizes a tanker with a rigid yoke mooring permanently anchored at the location. This system, known as FPSO, is a relatively new concept which offers several advantages discussed later in this paper. The FPSO receives production directly from the wells paper. The FPSO receives production directly from the wells which can be completed subsea, on wellhead platforms or wellhead jackets.

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