Development of a strategic framework for the comparative assessment of pipeline decommissioning options: optimising environment and fishing interests

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BackgroundAs part of the exploitation of UK Continental Shelf (UKCS) oil and gas (O&G), more than 27,000 km of pipelines have been installed since the 1960s. To date, only 2% have been decommissioned and there has been little research on the consequences of decommissioning to other industries and the environment [1]. Over the next 6-8 years, approximately 5,600 km of pipelines will require decommissioning on the UKCS [2]. Pipeline decommissioning is considered on a case-by-case basis, by the comparative assessment of the available decommissioning options [3]. As part of the comparative assessment, operators must demonstrate to the regulator (the Department for Business, Energy and Industrial Strategy - BEIS) that any proposed strategy meets international obligations to ensure the safety of fishing and protection of the marine environment. In order to do so, a comprehensive evidence-base and a strategic framework for assessing pipeline decommissioning with respect to fishing and environmental interests is required.The commercial fishing industry is one of largest users of the UK continental shelf (UKCS), and it is known that there is substantial spatial overlap between pipeline infrastructure and fishing [4]. The presence of decommissioned pipelines on the seabed, without rock dump, presents a potential snagging risk to fishers, according to the type of pipeline, seabed type, fishing intensity and gear-type. The UKCS also contains a number of internationally important conservation features (habitats and species), such as those listed in the EU Habitats Directive (e.g. cold-water corals) and those that are included within designated marine protected areas. These conservation features/species (CF/S) are potentially sensitive to pipeline decommissioning as a result of physical impacts, sediment disturbances and the removal of hard substratum which provides additional habitat for the CF/S and/or protection from trawling damage. ObjectiveThis project will result in the quantification of the risks/benefits of all pipeline decommissioning options to both fishing and the environment and the integration of these risks to find the optimal decommissioning solution for each pipe (from the fisher/environmental perspective). This will be achieved by:1. Combining and collating knowledge of species-pipeline associations gained from analysis of video footage of pipelines (collected routinely by the industry for integrity monitoring), spatial data on fishing patterns and snagging incidents, and data on the distribution and sensitivities of CF/S.2. Developing spatial 'risk-layers' that can be flexibly combined to evaluate and minimise the relative risks to conservation interests and fishers, across all UKCS pipelines, from all feasible decommissioning options.3. Embedding the resulting assessment into decommissioning protocols.Impacts and beneficiariesThe main beneficiaries of the project will be the UK Government, their advisors [5], fishers and the oil and gas industry who will benefit from an enhanced evidence-base that is shared across all sectors. The outputs of the project will facilitate cost-effective, rapid, consistent and transparent decision-making in relation to pipeline decommissioning.REFERENCES[1] Oil and Gas UK (2013), Decommissioning of pipelines in the North Sea region[2] Oil and Gas UK (2014), Decommissioning Insight 2014[3] Department for Energy and Climate Change (2011), Decommissioning of Offshore Oil and Gas Installations and Pipelines under the Petroleum Act[4] PipeFish - Optimising the decommissioning of oil and gas pipelines with respect to commercial fishing at the scale of the UK continental shelf. NE/N019369/1[5] Marine Scotland and statutory nature conservation bodies such as Scottish Natural Heritage and Natural England