UK GEOLOGISTS have developed a new approach for studying volcanic activity which has led to the discovery of a large helium gas field within the Tanzanian East African Rift Valley.
Supplies of helium have been relatively low with significant quantities only found accidently during oil and gas drilling. With all but 0.003% of the Earth’s natural supply escaping into space due to ion outflow, new, dependable, supplies were needed for MRI scanners, pressurisation in rockets, welding and industrial leak detection.
A team from Durham and Oxford universities, in partnership with Helium One, a Norwegian-based helium exploration company, has developed a new exploration approach by tracking volcanic activity which released helium from ancient deep rocks and trapped this helium in shallower fields.
Diveena Danabalan, a doctoral student at Durham University, said: “Volcanic activity likely provides the heat necessary to release the helium accumulated in ancient crustal rocks. However, if gas traps are located too close to a given volcano, they run the risk of helium being heavily diluted by volcanic gases such as carbon dioxide.”
She added that the research is now focussed on establishing a ‘Goldilocks-zone’ where helium release and volcanic dilution is “just right” to identify where other helium gas fields are likely to be.
Early samples and seismic images taken at the Tanzanian field led the team to calculate a probable helium volume of 1.5bn m3 in just one part of the rift valley, enough to fill over 1.2m MRI scanners.
Chris Ballentine, professor of geochemistry at the University of Oxford, said: “Global consumption of helium is about [227m m3/y] and the US Federal Helium Reserve, which is the world’s largest supplier, has a current reserve of just [680m m3]. Total known reserves in the US are around [4.3bn m3]. This is a game changer for the future security of society’s helium needs and similar finds in the future may not be far away.”
The next step will be to find the best location to drill to exploit the reserve and bring it to the surface.
Typical helium discoveries are often significantly less than the volume discovered in Tanzania. Last month, Linde and Renergen signed an agreement to develop a natural gas field in South Africa which contained helium. However, out of the 708m m3 of gas, only 3–4% of which was helium.
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