- Essential for many medical and industrial processes, helium is in great shortage worldwide. Production is also associated with significant carbon emissions that contribute to climate change.
- This study provides a new concept of gas field formation to explain why helium naturally accumulates in high concentrations just below the surface in rare locations.
- The discovery could help find new reservoirs of carbon-free helium, and potentially hydrogen as well.
A study led by the University of Oxford could help reverse the current supply crisis for helium, a vital societal resource. This study proposes a new model to explain the existence of previously unexplained helium-rich reservoirs. The discovery, published today in Nature, could help find accessible and untapped reservoirs of helium.
The lead author of the study, Dr. Anlan Cheng, Department of Earth Sciences, University of Oxford, said: Entire geological systems act dynamically to influence processes. This model provides a new perspective to help identify environments in which helium gas slows enough to accumulate in commercial quantities.”
Where rare helium-rich underground gas fields are found, they always occur with high concentrations of nitrogen gas. Until now, there has been no explanation for this. This new study, which also includes contributions from the University of Toronto and Durham University, provides answers for the first time.
The researchers built a model to explain these helium-rich deposits, taking into account (for the first time) the presence of nitrogen, which is also released from the deep crust along with helium. The authors identified geological conditions under which nitrogen concentrations were high enough to generate gas bubbles in the pore spaces of rocks.
Such a process could take hundreds of millions of years, but when it does, the associated helium escapes from the water into the air bubbles. These bubbles rise towards the surface due to their buoyancy and hit a type of rock that bubbles cannot pass through. According to the model, helium-rich bubbles collect under the seal and form a substantial gas field. Gases rich in nitrogen and helium do not contain methane or carbon dioxide, so tapping them does not emit carbon dioxide.
When researchers applied the model to a sample system (Williston Basin, North America) using expected nitrogen concentration values, the model predicted the actual observed nitrogen/helium ratio. This model could help identify areas likely to contain similar helium-rich sediments.
Helium is a $6 billion (£5.3 billion) market, and the gas is essential to the operation of MRI scanners, the manufacture of computer chips, optical fibers, and cutting-edge nuclear and cryogenic applications. The current global shortage has driven supply to near-crisis levels and prices have skyrocketed in recent years. The situation was escalated by the Ukraine war as it ruled out helium supplies from the new Russian Amur plant that would supply 35% of the world’s helium demand.
Moreover, almost all helium today is a byproduct of natural gas production, either methane or carbon dioxide. This results in a significant carbon footprint and hinders the goal of achieving net zero carbon emissions by 2050.
Taken together, these reasons mean that identifying alternative carbon-free natural helium sources has become very important.
The model also suggests areas where large amounts of hydrogen gas could accumulate underground, as helium-producing radioactivity splits water to produce hydrogen. With a $135 billion global market, hydrogen is used to make fertilizers and many other compounds vital to the food, petrochemical and pharmaceutical industries. Virtually all hydrogen gas is now produced from coal and natural gas (methane), which alone accounts for his 2.3% of global CO2 emissions. Hydrogen-rich underground deposits may provide an alternative carbon-free source.
Co-author of the study, Professor Chris Valentine, Department of Earth Sciences, University of Oxford, said:
Co-author Professor Barbara Sherwood Roller, University of Toronto, Department of Earth Sciences, added: It has been confirmed underground around the world that some of this hydrogen is actually stored underground in significant quantities. “
Co-author Professor Jon Gluyas: (Durham Energy Institute/Department of Earth Sciences, Durham University) said: As helium, it may still be found.
Original: New study identifies hidden helium gas fields, could help avert global supply crisis
Than: University of Oxford | University of Toronto | University of Durham
