From the earliest days of oil exploration, explosives have been used extensively in the abandonment and removal of wellheads, as well as being used to cut up and remove redundant oilfield infrastructure from the sea bed. However, in more recent times there has been a dramatic decline in the use of these services in the North Sea, with Operators (Oil Companies) choosing to favour the use of ‘cold cutting’ techniques such as Hydro-Abrasive grit entrained cutting tools or Diamond Wire saws.

Initially, the main reason for the move away from explosive use would appear to have been driven by environmental reasons such as avoiding harm to Cetaceans (Whales and Dolphins). However, as a consequence of those environmental concerns, there appears to be a misconception that has developed throughout the industry, that the use of explosives is either banned or can only be used as a last resort.

Where has that misconception come from? Why has it developed? and where is the evidence that would suggest that explosives shouldn’t and can’t be used? These are points that need to be better understood and clarified if the use of explosives is to play a significant part in future large scale decommissioning projects and well abandonment campaigns.

Certainly, within current legislation and guidance, it doesn’t state anywhere that explosives are banned or should only be used as a last resort. From recent experience of having met and discussed the use of explosives with representatives from both JNCC (Joint Nature and Conservation Committee) and BEIS (Department for Business, Energy and Industrial Strategy), it is apparent that those two organisations do not flatly reject or oppose the use of explosives. In fact, both organisations seem open to the suggestion that explosives could be used more frequently, completely contradicting the view that oil companies can’t propose the use of explosives for use on well abandonment or decommissioning licence applications.

This reluctance to use explosives, or even consider using them, has been to the detriment of explosive service companies. This has seen some of their product lines almost disappear in recent years due to the decline in explosives use and the preference to use ‘environmentally friendly’ cold cutting techniques.

How does the explosive service provider go about challenging the perception that explosives can’t, or should not be used? Prior to the development of the cold cutting techniques used today, explosives had been used from the earliest days of oil exploration and for decades, had proven to be an efficient and effective method of severance. Like most methods and technology used in the early days of North Sea oil exploration, these explosive severance methods came from the U.S. in the 1970’s. What worked over there at that time, also initially worked successfully here. However, what didn’t happen during that time, was any significant advances or improvements in the technology or techniques being used to provide these services. The methods used remained largely unchanged and weren’t developed over time to improve reliability or efficiency. Resulting in the perception that the use of explosives was rather crude, unreliable and perhaps not the best option.

Going forward the oil and gas industry will be faced with the enormous challenge and expense of decommissioning ageing oil fields, including large structures and the associated seabed infrastructure. Given the potential scale and size of the future decommissioning market and the drive to lower costs, this presents explosives service providers with an opportunity to reinvent themselves and promote their services in a market that will demand reliable, efficient and cost-effective solutions.

The biggest challenge will be to convince the industry to completely change its opinion on the use of explosives. This won’t be an easy task, given that the use of explosives for certain tasks, has been disregarded in the past decade. Many of the current decommissioning managers responsible for decision making, may never have been directly involved, or aware of the many successful large-scale decommissioning projects that were previously completed. These include, Durward/Dauntless, Blenheim/Bladon, Emerald Field, and Maureen. Those fields, along with hundreds of individual wellheads, were all removed using explosives without any documented harm to the environment or marine life.

Going forward, what needs to be done?  

Dialogue between representatives from the Operating Companies, explosive service providers and legislative bodies such as BEIS and JNCC needs to take place in order to clear up any confusion or uncertainty regarding the use of explosives.

There needs to be a forum set up whereby each of the interested parties can discuss the issues surrounding the use of explosives in an open environment. Perhaps this forum could be facilitated by Decom North Sea or the Institute of Explosives Engineers, or even jointly?

Beyond that, providing there is a future willingness to use explosives, the explosive service providers need to look at their existing explosive methods and consider what improvements and advancements can be made.

Things to consider include:

·        Making operations as safe as possible

·        Reducing the Net Explosive Quantity of charges used

·        Reducing environmental impact by using practical blast mitigation techniques

·        Eliminating the chance of possible misfires

·        Improving cutting efficiency

·        Guaranteeing cut success

·        Improving the quality of cut

·        Ease of charge deployment and placement by Remotely Operated Vehicles

·        The use of Finite Element Analysis for charge optimisation     

All of the above can be achieved, but it would be of huge benefit if industry funding could be made available to facilitate the R&D and trials to develop and optimize charge performance to make the cutting methods more effective, whilst also reducing the potential environmental effects.

It is crucial to communicate that explosives are not banned, nor are they only permitted for use as a last resort. Most importantly, if there is a responsibility to perform decommissioning and well abandonment projects as efficiently and cost effectively as possible, then the use of explosives cannot be excluded or ignored.