The Use of Unmanned Production Buoys to Develop Marginal or Submarginal Stranded Fields or End of Life Hydrocarbon Resources
Authors: Bone David 
Published: September 2011

This paper summarises original development work implemented by Ocean Resource into a new type of Unmanned Production Buoy facility, the Sea Producer. This work, which is both comprehensive and wide-ranging, covers the use of autonomous buoy technology to develop various offshore oil and gas production scenarios which would otherwise be uneconomic or indeed impossible. Recently this technology has received considerable interest as it represents, for some smaller developments, possibly the only sensible and economic way forward.

Ocean Resource has developed and pioneered the concept over a period of 20 years and is the only company with specific experience and expertise in this complex area. Ocean has operated and maintained its own high stability buoy systems and has completed a number of buoy designs for working buoy systems in use with Apache, Mossgas Pty, Exxon-Mobil and others for oil related operations. More recently Ocean Resource has been responsible for the design of a 5MW Power Buoy for CNR International UK Ltd (Canadian Natural Resources). Unfortunately Monitor Oil PLC, the principle constructor, went into liquidation prior to completion of the project but it is envisaged that this unit, which is 95% complete will shortly be redeployed on another field. The Power Buoy located at Dundee is subject to an option agreement for the purpose.

Ocean Resource's low cost autonomous buoy systems represent a game-changing technology that will enable the economic development of hitherto unexploitable or stranded oil and gas reserves. The technology is generally branded as Sea Commander where it relates to field control buoys (a developed product) and Sea Producer where it relates to production.

Sea Producer enables a step-change in offshore development expenditure lowering capital costs at the start of project together with greatly reduced operational costs leading to low "through-life" costs for standalone, step-out developments or early production scenarios. Furthermore the relatively minimal nature of the offshore facilities comprising the buoy and storage system leads to rapid deployment and hence faster income and profit return to any offshore project.

The unique autonomous buoy technology has been developed by Ocean Resource over a period of 20 years and is an evolution of existing systems. It is therefore both mature and proven. It can be used for sub-sea oil and gas field control, remote pigging, multi-phase pumping, chemical injection, subsea production support and remote flaring.

The allied Sea Producer system which is the subject of this paper will be used for full production. Major buoy systems applying Ocean Resource's unique concept are presently operating in a number of oil field geographies, including the East Spar Field Control Buoy, offshore North-West Australia, the Mossgas Field Control Buoy offshore Mossel Bay in the Republic of South Africa and the Zafiro Remote Flare Buoy in Equatorial Guinea. Ocean Resource Buoy systems have been designed to meet the requirements of various international codes and standards and design issues have been reviewed by Lloyds Register, Det Norske Veritas, American Bureau of Shipping, Bureau Veritas and others. Our systems have also been subject to detailed review by the HSE authorities in the UK, Australia, South Africa and Norway.

The Sea Producer Unmanned Production Buoy can be applied to the following development scenarios:

Early Production Field Extension Marginal Production using Stand-alone Facilities (avoiding costly transit tariffs) End-of-Life Production Enhanced Oil Recovery (Ocean's Sea Sequestor Concept) Field Proving (proving of reserves in proven undeveloped discoveries, PUD's)

There is now a clear need for unmanned production buoys with a particularly large gap in the market below, say, 5000 bopd per day production. Current methods including subsea tie-backs and mini FPSO's tend to be economic upwards from 5000 bopd. Sea Producer represents an economic solution to operate through this barrier to develop small accumulations (maybe with single wells), marginal fields, for proving reserves and for tail-end production. For water depths greater than 70 metres there is currently no other economic solution. Figure 1 illustrates the applicability of the system.

Ocean's development work has included both actual design and feasibility and pre-feed studies of a number of buoy concepts for most of the oil majors and many of the mid-range developers. An outline is provided of the system, the work that has been completed to demonstrate its viability and provides a preliminary indication of the likely system cost. The length of this paper precludes a full description of the breadth of systems that have been developed but it is worth noting that there is little that can be implemented on a small platform that cannot be carried out on a Sea Producer Unmanned Buoy System.