For the many existing installations currently operating or nearing the end of operations, decommissioning is an inevitable phase and needs to be considered as an integral part of the petroleum operations. A lot of the existing infrastructure in the UKCS has been in place since the early 1960s. So far, over 400 fields have been developed, or are in the process of being developed, in the North Sea with a total of around 832 production facilities (fixed and floating platforms or subsea completions) in development and production operations. The types of installations in operation include semi-submersibles, jack-ups, concrete platforms, steel structures and subsea structures. The UK has more steel structures on its continental shelf than other countries in the North Sea, whilst Norway has the greater number of concrete gravity structures.

According to the DTI, the decommissioning operations will start in earnest in 2009 and a high level of activity will continue until after 2020. It is estimated that about 18 structures will be decommissioned in 2010, 32 in 2015, and 27 in 2020, and 31 in 2030.

The current decommissioning programmes in the UKCS include:

Talisman's Beatrice fixed steel platforms, which will be re-used for wind power generation.

Amoco/ BP's North West Hutton which involves a large steel platform and pipelines in respect of which the footings will remain in place, steel topsides and jacket to top of footings will be removed to shore and the pipeline to be left in situ.

#  Total's MCP 01 concrete platform in respect of which the topsides will be removed to shore for re-use, recycling or disposal and the concrete substructure will remain in place.

Shell's Indefatigible field consisting of platforms groups Juliet, Kilo, Lima, Mike and November in respect of which the topsides and jackets for the installations will be removed to shore for re-use, recycling or disposal and five pipelines will be decommissioned in-situ and two hose bundles will be removed to shore for re-use, recycling or disposal.

The question that begs is to what extent can UK based companies participate in this massive and evolving decommissioning industry.

The main concerns for companies considering decommissioning are the increasing awareness of the marine environment (e.g. which were brought to the fore by the Brent Spar incident) and cost implications. Estimates for the decommissioning of the Ekofisk are around £700 million and Brent about £3 billion. It is now widely acknowledged that over £1 billion will be spent every year in the North Sea over the next decade when the decommissioning activities are going to start in earnest. Clearly a number of opportunities are available to the many players in the industry.

The decommissioning supply chain can be divided into the following activities: subsea studies and site surveys; project management; facility decommissioning; well decommissioning & abandonment; disposal; post survey and residual liability.

The complexity of the decommissioning market requires that companies, operators and contractors develop an understanding of all the aspects involved including the regulatory framework for the decommissioning process. The removal of these installations therefore involves careful planning to address the above concerns and the use of innovative technology to maximise the recovery of oil and gas reserves from the UKCS and also to reduce the costs of decommissioning. Various opportunities for specialised and innovative technologies arise during the removal, and recycling of the installations and structures and also during the monitoring of the seabed and those parts of the decommissioned installations left in place.

During the removal phase a number of opportunities exist for innovative technologies for heavy lift operations (platform topsides), medium lift operations (subsea components), pipeline and flowline removal, cutting, well plugging and seabed clean up. Technological innovation is also required for refurbishment/re-use and resale of components and systems, decontamination and waste treatment and recycling of materials and selling on. Further special mechanisms are also required during the post-decommissioning phase for ongoing inspection and monitoring of fields for hydrocarbon leaks (remotely or using onsite sensors) and environmental laboratories.

The technologies available to remove these large installations and structures are highly technical and specialised and only a few companies in the world have the necessary capacity to do so. However a number of companies are now becoming highly specialised and innovative in this field. There is now also an increasing focus on research and development because the development of new technology and new techniques to tackle the challenges that arise at the decommissioning stage will be particularly important. It is accepted that existing companies in Scotland can undertake all or most of the work involved in the decommissioning process, although some commentators point to the following challenges:

#  Some are of the view that existing personnel do not have adequate experience in managing decommissioning contracts (compared to new field installations);

#  There are no heavy lift vessels in Scotland and the UK;

#  The ports/yards do not currently have adequate facilities to receive, dismantle and/or store large jacket and topsides units. The exception is in Shetland where a number of facilities have been developed to deal with the decommissioning of large structures and there is much potential at sites such as Nigg in the Cromarty Firth.

There is therefore great potential for partnerships between UK and Norwegian companies. An example is the recent success of the Shetland Decommissioning Company and the announcement by Aker Kvaerner to use the Greenhead Base, Lerwick for onshore disposal of parts of the Frigg platform. Additionally, the government, through the DTI, supports industry co-operation and collaboration at the decommissioning stage. Industry support for co-operation and collaboration is mainly channelled through UKOOA (now Oil and Gas UK - OGUK), the ‘Brownfields’ Initiative and the Early Decommissioning Synergy Group (TEDS).