Research Themes

The function of a structure as an artificial reef

The concept of oil and gas platforms acting as a combination of artificial reef and refuge from fishing pressure has received considerable attention in some parts of the world. Numerous studies have been carried out in Northern Gulf of Mexico, where the largest artificial reef in the world exists with over 4000 platforms scattered across the continental shelf. Less is known about the impacts of such structures in the North Sea where there are around 600 offshore platforms.

The before and after effects of Subsea structure installation

The Buzzard SERPENT Mission provides a unique opportunity to follow the change from a fished area of the North Sea through to an artificial reef refugium. Through collaboration between SERPENT Science partners FRS Marine Lab and Aberdeen University’s Oceanlab, two biological survey have been completed at the site before the Buzzard platform installation process began. As the jackets and subsea infrastructure are being installed, Nexen are providing access to ROV footage which will enable the SERPENT team to study the immediate effect on the invertebrate and fish population.

Combining sampling techniques to expand the picture

The Buzzard Mission benefits from having access to the FRS Marine Lab Research Vessel Scotia, allowing sampling outside the exclusion zone of the platform. Biological data collected by trawl, sediment grab and from deployments of Oceanlab’s baited underwater camera, ROBIO, will compliment the ROV studies closer to the structure.

In addition, the Buzzard Control site has now been added as one of the routine stations sampled by RV Scotia, during biennial trawl surveys of the groundfish populations and TV sledge Nephrops surveys of the North Sea. This will allow the abundance and diversity of the local fish population in the vicinity of the Buzzard platform to be monitored over time in the context of the wider North Sea.

Comparisons between new and mature installations

Working with Nexen provides access to new structures at Buzzard and more established structures further North in the Scott/Telford area. Being able to view ROV footage from both these locations will allow comparison of their fish and macrofauna populations and encrusting growth compared to the developing system at Buzzard.

The growth of encrusting marine fauna

How marine life growth builds up on a subsea structure has large implications on how that structure may function as a reef. The marine growth may provide shelter and food to a wider range of fish and invertebrate species. Using ROV video assessments required to determine growth for structure integrity and any opportune surveys we will study the species composition and map growth rates of encrusting fauna.

The Invertebrate Community

Using video footage and trap samples collected by ROV from within the installation footprint, the benthic megafauna (animals larger than 2cm) will be characterized. These results will be combined with those from traditional sampling methods carried out from research vessel surveys outside the exclusion zone and baited camera photographs at both sites to examine the artificial reef effect of the platform.

The Fish Community

Fish such as saithe, cod and Norway pout are known to aggregate in large numbers at many North Sea platforms. The build up of fish populations around the Buzzard platform will be monitored using ROV and baited cameras and compared with data collected at the control site and in the wider context of this region of the North Sea. Behavioural observations and diet studies will be used to deduce how different species utilize the platform. Whether fish use the structure as a temporary shelter while passing through or as a permanent refuge is a key question. The SERPENT team hope to use telemetry experiments to help answer this question.

Research Locations

Buzzard Field

The Buzzard field is located in the Outer Moray Firth, central North Sea, 100km northeast of Aberdeen. The field straddles two licences - P.986 (Blocks 19/10 and 20/6) and P.928(S) (Blocks 19/5a and 20/1S) - and the water depth in the area is about 100m. It is operated by Nexen 43.2 % PetroCanada 29.89%, BG 21.73%, Edinburgh 5.16%.

The field will be developed by three bridge-linked platforms supporting the wellhead facilities (W), production facilities (P) and a third platform supporting living quarters and utilities (UQ).

The base case anticipates 27 production wells, eight of which will be pre-drilled and available for production start-up in late 2006.exico so far and many more are planned for the future.

Scott Telford

The Scott and Telford fields straddle Blocks 15/21a and 15/22, and are located approximately 188 kilometres northeast of Aberdeen, Scotland. Water depth for both is approximately 140 metres. Oil and gas is produced through numerous subsea wells and from wells drilled from the Scott platform. Oil is delivered to the Grangemouth, Scotland refinery via the Forties pipeline. Gas is exported via the SAGE pipeline to a terminal at St. Fergus in northeast Scotland.

New Assets

Nexen have a number of smaller discoveries on operated blocks near Scott, Buzzard or third-party facilities. Ettrick (20 km away) from Buzzard, while Perth, Black Horse and Bugle are closer to Scott Telford. Farragon should begin producing in late-2005, with a 20%, Nexen non-operated share of production.