Scientists have developed a large-scale economical method to extract hydrogen (H2) from oil sands (natural bitumen) and oil fields. ... The process can extract hydrogen from existing oil sands reservoirs, with huge existing supplies found in Canada and Venezuela. Interestingly, this process can be applied to mainstream oil fields, causing them to produce hydrogen instead of oil.
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The researchers have found that injecting oxygen into the fields raises the temperature and liberates H2, which can then be separated from other gases via specialist filters. Hydrogen is not pre-existing in the reservoirs, but pumping oxygen means that the reaction to form hydrogen can take place.