When an oil or gas well reaches the end of its life (when the resource runs out, or the cost of production begins to outweigh the value of the product), it needs to be permanently decommissioned or temporarily abandoned until more efficient processes can be implemented. That means the well needs to be sealed (or ‘plugged’) to stop leakage and contamination of the surrounding environment, and, where the well has been exhausted, the supporting infrastructure needs to be removed.
Plugging and abandonment (P&A) technology has been around for over a century, but the materials and processes used haven’t really evolved much during that period. Cement has been long-established as the favoured material for sealing wells that have been used up or are no longer viable economically. The technology has moved on, but the industry isn’t rushing to embrace solutions seen as simply adding to the cost of well abandonment. For producers, the priority is minimising cost, rather than thinking about long-term environmental issues. As things stand, the regulations in this area are somewhat lacking.
The first regulations relating to well abandonment came into effect in the 1890s, but they weren’t introduced with the environment in mind. Rather, they were designed to encourage oil producers to ensure that any untapped resources were secured for the future. In the 1970s, concerns about the environment started becoming more prominent, but the technology wasn’t really up to the job. Cement simply degrades over time when exposed to constant erosion from sea water, meaning it can’t really be considered a permanent solution.
At present, there are millions of wells plugged and abandoned with cement around the world. All of them could begin leaking at any time, which would be costly for the people responsible, and bad news for the environment. New technology has been developed, however, which eliminates the problems associated with cement. Alloy metals can now be melted into the wellhead, forming a far more reliable and permanent seal.
Whilst there is an obvious cost to this technology, it should be viewed as an investment by the industry. It means they don’t have to worry about potential leaks at abandoned sites in the future, and they don’t have to worry about deadly explosions of the negative PR impact of a major environmental incident.
Find out more about the latest Bismuth Plug technology.