Over the next 25 years, as the world shifts away from fossil fuels, the oil and gas wells that have sustained the fossil fuel age will have to be plugged. No big deal, you might think, drilling those wells was the hard part. Plugging them should be no problem. But think again. The Norwegian Continental Shelf, as an example, is punctured by more than 2000 wells. Harald Linga, centre director for SWIPA (see box), a Centre for Research Based Innovation based at SINTEF, Scandinavia's largest independent research institute, estimates that plugging them using today's technology will cost upwards of NOK 800 billion -- that's USD 73 billion. And while oil companies are responsible for plugging the wells, Norwegian taxpayers will have to shoulder 78 per cent of these costs. And that's just Norway. The total number of oil wells across the globe could number in the millions, all of which at some time will have to be plugged. Today's technology involves using a cement plug that can be between 50-100 metres long. These plugs, it turns out, aren't that great. They can develop leaks over the long run, for many different reasons, says Lewaa Hmadeh, a PhD candidate at the Norwegian University of Science and Technology (NTNU's) Department of Geoscience and Petroleum who is also affiliated with SWIPA. One of the most troubling problems is that leaking abandoned petroleum wells can be a significant source of greenhouse gas emissions, he said. "Every year, the Norwegian Oil and Gas Association sets a roadmap for new plugging and abandonment technologies needed to solve problems faced by the industry, and ever since 2015, finding an alternative to cement has always been there," Hmadeh said. But there's hope in sight. Hmadeh's PhD research involves studying the use of bismuth as a substitute and/or additive for plugging wells. He's one of many scientists across the globe trying to find a better solution for this challenge. And if his... |