Lessons to be learned from onshore decommissioning

The decommissioning of oil and gas facilities in the North Sea presents a huge challenge, quite literally, but drawing on the knowledge and experience of UK land-based consultants and contractors could help smooth the process, argues Richard Vann, Managing Director of RVA Group.

In cost alone it is projected that the cumulative expenditure on removing these outdated production platforms will be in the region of £35 billion (US$56 billion) over the next 30 years. And given that this is still a relatively new industry, it is acknowledged that there are considerable supply chain weaknesses and bottlenecks to overcome. Perhaps the biggest obstacle is the lack of engagement with those most able to help.

Traditional or onshore demolition is significantly more advanced and offers much by way of knowledge and experience that offshore operators can draw on directly to potentially overcome some of the hurdles and issues it is currently facing.

Things have come a long way since the days of sledgehammers and wrecking balls. Highly sophisticated techniques and machinery are now used to decommission complex and hazardous sites and facilities over short, medium and long-term timescales. There are several major players in the UK – consultants, engineers and contractors – managing and undertaking multi-million dollar, large-scale, high-hazard and complex plant dismantling projects as a matter of routine across the globe.

So how do we take this capability and employ it in the offshore sector? Firstly, oil and gas companies need to recognise the developments made in the demolition arena over the last two decades. In particular, it needs to consider piece small dismantling as a mainstream approach over the traditional ‘bring it back as it went out’ methodology.

In practice, this means dismantling platform plant and equipment in-situ. Hazardous materials, including asbestos and NORM, can be removed offshore while waste streams can be segregated at source ready for processing and disposal onshore.

This piece small dismantling approach has several advantages, including the potential to reduce the cost of any one particular project. It provides for the opportunity to use or share resources over a number of gas or oil platforms in an economic and concurrent or consecutive sequence. Work can also be phased to maximise weather window efficiencies with the operator retaining a higher level of flexibility over the whole project.

Furthermore, piece small dismantling relies less on HLV, so existing supply vessels and barges can be used for the majority of operations. It also provides opportunities to use a wider range of reception facilities and there are increased choices in the onshore disposal of arisings. Even if the HLV approach is selected for a platform, tackling 50 metre tall structures, weighing up to 30,000 tonnes and with a footprint of 70-80 square metres should not be underestimated. Here again the leading organisation form the traditional demolition industry, will have a great deal to bring to the table.

So what’s the next step? I’d like to see a commitment from platform operators to seriously investigate piece small methodology. Improved engagement with onshore professionals and the contracting supply chain is also required coupled with making use of the tried and tested good practice in the decommissioning, decontamination, dismantling and demolition industry.

Just like our colleagues out at sea, we fully understand the importance of balancing cost effective, innovative and pragmatic dismantling solutions with EHS excellence. There is much invaluable knowledge and experience that will translate and add considerable value to offshore dismantling programmes.