Bio-oil tested as way to seal orphaned oil wells and store carbon

A recent study led by Iowa State University explores using bio-oil derived from farm and forest waste—such as corn stalks and wood debris—to both seal orphaned oil wells in the US and sequester carbon underground. The process involves fast pyrolysis, where dried organic matter is rapidly heated in an oxygen-free environment to produce a dense, carbon-rich liquid bio-oil. Injecting this bio-oil into abandoned wells not only permanently stores carbon dioxide but also safely plugs wells that otherwise pose environmental risks like methane leaks and water contamination. This dual-purpose approach addresses two pressing challenges: reducing atmospheric carbon and managing the estimated 300,000 to 800,000 undocumented orphaned wells in the US, which are costly to cap. The researchers propose deploying a network of 200 mobile fast pyrolysis units, each processing about 10 tons of biomass daily near agricultural and forested areas. The study estimates the cost of carbon sequestration via this method at approximately $152 per ton, with potential reductions