- Helium – essential for many medical and industrial processes – is in critically short supply worldwide. Production is also associated with significant carbon emissions, contributing to climate change.
- This study provides a new concept in gas field formation to explain why, in rare places, helium accumulates naturally in high concentrations just beneath the Earth’s surface.
- The findings could help locate new reservoirs of carbon-free helium – and potentially also hydrogen.
Research led by the University of Oxford could help overturn the current supply crisis of helium, a vital societal resource. The study proposes a new model to account for the existence of previously unexplained helium-rich reservoirs. The findings, published today in Nature, could help locate untapped reservoirs of accessible helium.
Dr Anran Cheng (Department of Earth Sciences, University of Oxford), lead author of the study, said: ‘Our model shows the importance of factoring in the high diffusivity of helium and the long timescales needed to accumulate significant gas quantities, and the fact that the entire geological system acts dynamically to affect the process. This model provides a new perspective to help identify the environments that slow helium gases down enough to accumulate in commercial amounts.’
Where rare helium-rich underground gas fields have been found, they always occur alongside high concentrations of nitrogen gas. Until now, there has been no explanation for this. For the first time, this new study, which also involved the University of Toronto and Durham University, provides an answer.
The research team built a model to account for these helium-rich deposits by (for the first time) factoring in the presence of nitrogen, which is also released from the deep crust along with helium. The authors identified the geological conditions where the concentration of nitrogen becomes high enough to create gas bubbles in the rock pore space.
Such a process can take hundreds of millions of years, but when it happens the associated helium escapes from the water into the gas bubbles. These bubbles rise, because of buoyancy, towards the surface until they hit a rock type that doesn’t allow the bubbles through. According to the model, the helium-rich gas bubbles then collect beneath the seal and form a substantial gas field. The nitrogen and helium-rich gases contain no methane or carbon dioxide so tapping them does not release carbon emissions.
When the researchers applied the model to an example system (Williston Basin, North America) using expected nitrogen concentration values, the model predicted the observed nitrogen/helium proportions in real life. The model could help identify areas likely to contain similar helium-rich deposits.
Helium is a $6 billion (£5.3 billion) market, with the gas being essential for the operation of MRI scanners, computer chips and fibre optic manufacture, and state of the art nuclear and cryogenic applications. A current global shortage has pushed supplies almost to a crisis point, with prices skyrocketing in recent years. The situation has been escalated by the Ukraine war, since this ruled out helium being supplied from the new Russian Amur plant, planned to supply 35% of the global helium demand.
In addition, almost all helium today is a by-product of methane or carbon dioxide natural gas production. This carries a significant carbon footprint and hinders ambitions to achieve net-zero carbon emissions by 2050.
Together, these reasons mean that identifying alternative, carbon-free sources of natural helium has become critically important.
The model also suggests regions where large amounts of hydrogen gas may accumulate underground, since the radioactivity that generates helium also splits water to form hydrogen. With a global market of $135 billion, hydrogen is used to create fertiliser and to produce many compounds essential for the food, petrochemical, and pharmaceutical industries. Virtually all hydrogen gas is currently produced from coal and natural gas (methane), and this alone accounts for 2.3% of global CO2 emissions. Hydrogen-rich underground deposits could provide an alternative carbon-free source.
Prof Chris Ballentine (Department of Earth Sciences, University of Oxford), co-author for the study, notes: ‘The amount of hydrogen generated by the continental crust over the last 1 billion years could power society’s energy needs for over 100,000 years.’
Prof Barbara Sherwood Lollar (Department of Earth Sciences, University of Toronto), co-author, adds: ‘Much of this hydrogen has escaped, been chemically reacted or used up by subsurface microbes – but we know from studying the gas in deep locations in the subsurface around the world that some of this hydrogen is indeed stored underground in significant quantities’.
Prof Jon Gluyas: (Durham Energy Institute/Department of Earth Sciences, Durham University), co-author, states ‘This new understanding of helium accumulation provides us with the critical start of a recipe to identify where significant amounts of geological hydrogen, as well as helium, might still be found.’
Notes to editors:
The paper ‘Primary N2-He gas field formation in intracratonic sedimentary basins’ will be published in Nature.
After the embargo lifts, the paper will be available at: https://www.nature.com/articles/s41586-022-05659-0 (DOI 10.1038/s41586-022-05659-0)
For media inquiries, and to view a pre-embargo copy of the paper, contact Dr Anran Cheng or Prof Chris Ballentine at the Earth Sciences Department, University of Oxford:
Images of the lead researchers are available on request: firstname.lastname@example.org
A more technical description of this research can be found at: https://www.earth.ox.ac.uk/2023/02/houdini-gases-unchained/ (Link will go live after the embargo lifts)
University of Toronto contacts:
Barbara Sherwood Lollar, University Professor
Department of Earth Sciences, University of Toronto
Josslyn Johnstone, Communications & Media Relations Specialist
Faculty of Arts & Science, University of Toronto
Durham University contacts:
Professor Jon Gluyas, Department of Earth Sciences and Executive Director of Durham Energy Institute, Durham University, is also available for interview on (office) +44 (0)191 334 2302; (mobile) +44 (0)7951274552; or email@example.com.
Kate Hatton, Policy & Communications Manager, Durham Energy Institute, Durham University. DH1 3LE
Funding: This work was funded by the China Scholarship Council, the UKRI Oil and Gas DTP, The University of Oxford Dept of Earth Sciences, NSERC and CIFAR (Canadian Institute for Advanced Research).
About the University of Oxford
Oxford University has been placed number 1 in the Times Higher Education World University Rankings for the seventh year running, and number 2 in the QS World Rankings 2022. At the heart of this success are the twin-pillars of our ground-breaking research and innovation and our distinctive educational offer.
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About the University of Toronto
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Together, we continue to defy gravity by taking on what might seem unattainable today and generating the ideas and talent needed to build a more equitable, sustainable and prosperous future.
About Durham University
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We conduct boundary-breaking research that improves lives globally and we are ranked as a world top 100 university with an international reputation in research and education (QS World University Rankings 2023).
We are a member of the Russell Group of leading research-intensive UK universities and we are consistently ranked as a top 10 university in national league tables (Times and Sunday Times Good University Guide, Guardian University Guide and The Complete University Guide).
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Primary N2-He gas field formation in intracratonic sedimentary basins
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