Our Durham Energy Institute researchers are part of an international team that has identified hidden natural helium gas fields.
Their research could avert a global helium supply crisis.
The study proposes a new model to account for the existence of previously unexplained helium-rich reservoirs and could help locate untapped accessible helium resources.
The findings could help locate new reservoirs of carbon-free helium – and potentially hydrogen.
Carbon-free source of natural helium
Helium is a £5.3billion market and is essential for many medical and industrial processes. A global shortage has pushed supplies almost to a crisis point, with prices skyrocketing.
Almost all helium today is also 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.
Identifying alternative, carbon-free sources of natural helium has become critically important.
Gas field formation
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.
Where rare helium-rich underground gas fields have been found, they always occur alongside high concentrations of nitrogen gas. Until now, this has been unexplained.
The researchers built a model to account for these helium-rich deposits by factoring in the presence of nitrogen, which is also released from the deep crust along with helium.
The researchers 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.
No methane or carbon dioxide
The model shows that the helium-rich gas bubbles then collect beneath the seal and form a substantial gas field. These nitrogen and helium-rich gases contain no methane or carbon dioxide so extracting them will not release carbon emissions.
The model also identifies regions where large amounts of hydrogen gas may accumulate underground, since the naturally occurring radioactivity that generates helium can also split water to form hydrogen and oxygen.
Hydrogen gas is currently produced from coal and natural gas (methane), contributing 2.3 per cent to global CO2 emissions. Hydrogen-rich underground deposits could provide an alternative carbon-free source of hydrogen.
