Streamlining the regulatory journey for offshore oil and gas decommissioning


The NSTA is committed to achieving the maximum economic extension of field life and ensuring that decommissioning is executed in a safe, environmentally sound and cost effective manner. These achievements may also deliver significant value and competitive advantage to the UK in the global decommissioning market.

The UK oil and gas industry is largely unfamiliar with large-scale decommissioning projects, but much can be learned and transferred from other industries. While the innovation and transformation underway within the industry will determine our ultimate success, more immediate incremental improvements can also deliver significant results.

The NSTA works with OPRED (the competent authority for decommissioning) to assess decommissioning programmes on the basis of cost, future alternative use and collaboration.

The UKCS decommissioning challenge is significant. It will be expensive and span several decades. It must be carried out safely and with care to protect the environment. However decommissioning presents significant opportunities for innovation, cost reduction and development of UK skills and capability.

Estimates of scope, complexity and cost vary but there are over 320 fixed installations, over 3,000,000 tonnes of structure, over 75,000 tonnes of subsea structures, over 20,000km of pipeline and approximately 4,000 wells, all of which must be decommissioned or re-used.

In accordance with the principles of MER UK, there is a need to significantly reduce decommissioning costs through increased efficiency and, more importantly, industry transformation.

In July 2021, NSTA published a new cost estimate for offshore oil and gas decommissioning in the UK Continental Shelf (UKCS). With a shared objective of industry and government to reduce decommissioning costs by at least 35%, the report shows industry’s progress towards the target of safely decommissioning all current and currently planned future offshore oil and gas infrastructure for less than £39 billion (in 2016 prices), and contains benchmarking of operators’ cost performance.

Better capability and experience in the sector is providing greater certainty of actual UK decommissioning costs with several operators already achieving significant cost savings through adopting different approaches, learning and sharing with others, and challenging previous norms. The supply chain is also bringing new solutions to the market in terms of pricing structures, business models and technology.

Preparation for Decommissioning and Late Life Operations

NSTA's role at this early planning and preparation stage is to ensure plans for decommissioning are being made in accordance with its Decommissioning  Strategy - that is, achieving safe, timely and environmentally sound decommissioning whilst meeting the aims of achieving cost certainty and reduction, supply chain capability and capacity, prioritising cost reduction, supporting the supply chain and working with stakeholders to optimise parameters for decommissioning scope and industry engagement 

Well Plug and Abandonment

Operators must seek approval from NSTA prior to abandoning a well.  Given the potential costs of P&A activity and impact on MER, NSTA are also particularly interested in P&A cost reduction strategies whilst meeting stringent criteria for protecting health and safety and the environment.

Offshore Dismantling and Removal

Under the Pipeline Safety Regulations, no modification to a pipeline, including its decommissioning and/or removal, can be carried out without a Pipeline Works Authorisation (PWA) or variation approved by NSTA.


Lessons Learned

NSTA host a Decommissioning Learning microsite, which acts as an archive of lessons learned from past and current decommissioning projects.  Operators planning new decommissioning projects can refer to the archive to find examples of best practice and cost saving opportunities.