Anatec are experienced in performing risk assessments for North Sea oil and gas operators, enabling them to make informed choices and satisfy Regulators (e.g., BEIS), their consultees (e.g., MCA, Trinity House and Northern Lighthouse Board) and Stakeholders (e.g., SFF and NFFO) when seeking consent for decommissioning projects. We have been operating in this field of expertise since 2001 and our Principals have been at the forefront of the marine hazard analysis and risk management field for the past 20 years.

Our research has ensured the risk to maritime stakeholders of options such as leaving platform footings, pipelines, bundles and other subsea structures in place are considered on a case-by-case basis as part of the comparative assessment required by the BEIS decommissioning guidance. This allows for a full reasoned argument for the consent process, tailored to the specific circumstances of the location.

We can also assist oil and gas companies in meeting the decommissioning guidelines issued by the General Lighthouse Authorities (GLAs) to meet their requirements during decommissioning and total removal of offshore structures. In consultation with BEIS, all changes to Aids to Navigation (AtoN) will require prior consent from the relevant GLA. This applies to establishment of new AtoN as well as disestablishment or changes to existing AtoN. The application must be accompanied by a Navigational Risk Assessment.

Each piece of infrastructure and each phase poses a different risk and hazards can vary according to the different types of maritime stakeholder using the area, for example, free spans would affect fishing vessels but not merchant shipping.

Our assessments are able to:

  • Identify the maritime activity present using real-time AIS (from offshore receivers), VMS and other vessel tracking data.
  • Analyse the risk of interaction with infrastructure left in situ, e.g. passing vessel collisions, fishing vessel collisions and fishing gear snagging.
  • Estimate consequences in terms of impact energies, Potential Loss of Life (PLL) and Individual Risk Per Annum (IRPA).
  • Estimate the impact on shipping navigation and ship-to-ship collision risk from transporting structures back to port, e.g., using barges or HLVs.
  • Identify risk controls and mitigation measures appropriate to each phase.

The risk modelling is capable of accounting for the potential challenges of:

  • Variance in infrastructure design and the potential hazards posed.
  • Risk reduction measures such as trenching, burial, rock-dumping and mattressing.
  • Future changes in shipping routes and activity post-decommissioning.
  • Trends in fishing activity. 
  • Removal of Safety Zones and ERRVs. 
  • Long term change in risk as structures degrade over time.

Sensitivities can be performed by varying inputs, such as assumed mitigation measures. Assessments are performed using our industry best-practice models, such as ShipRoutes and COLLRISK, which are referenced by IOGP.

With regard to the GLA Decommissioning Guidelines, Anatec can prepare a Navigational Risk Assessment (NRA) to assess any changes to Aids to Navigation and/or deviation from the Standard Marking Schedule, for example, during a period of cold storage when solar powered AtoNs may be used.

The scope of the NRA must cover the following:

  • Shipping Traffic Survey using up to date shipping data (within 12 months) within 10 nautical miles of the location(s). The survey should identify key users in the area who should be consulted in order to understand impacts.
  • Increase in risk of vessel-to-vessel encounters / collisions as a result of vessels involved in decommissioning activities and their impact on vessels’ routeing in the area.
  • Risks associated with vessels colliding with structures partially decommissioned and left in situ (surface and/or subsurface).
  • Identification and enactment of appropriate mitigation measures during different stages of the decommissioning process including lighting and marking, buoyage, AIS, guard vessels, safety zones, collision avoidance procedures and information circulation, with justification of measures proposed for different stages of the operation.
  • Assessment of the provision of Search and Rescue services during all operations.
  • Potential Cumulative and In-Combination Impacts associated with any nearby activities.
  • Risk Assessment process should include consultation with key navigational stakeholders including MCA, General Lighthouse Authority (TH, NLB or CIL), Fishing Industry (NFFO / SFF), RYA, & Cruising Association (if relevant)and Chamber of Shipping, as well as any location-specific stakeholders such as ports or regular vessel operators.
  • For decommissioning of subsea infrastructure such as wellheads and pipelines, a suitable risk assessment will need to be carried out on the risk to mariners (fishing / anchoring) from any materials left behind which could pose an interaction risk (if not already covered within the ES or other works)
The results and recommendations help our clients, such as Shell, ConocoPhillips, Perenco, Maersk, TOTAL and CNRI, satisfy Regulators and make optimal decisions when reviewing the decommissioning options. It can also inform the final ‘continued liability’ phase of decommissioning, ensuring that the most suitable mitigation methods are utilised to minimise the risks present.

 

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