Identification method for the origin of natural hydrogen gas in geological bodies

Abstract

As one of the clean energies, hydrogen has attracted more and more global research interest. With the acceleration of hydrogen energy economic construction in China, higher requirements have been put forward for the production and storage of hydrogen. At present, the main way to obtain hydrogen is to produce hydrogen artificially. Whether there is a high content of hydrogen in nature and its origin are the premise for the discovery and utilization of natural hydrogen, but the related research is weak. The discrimination of hydrogen origin, especially deep and shallow source origin, depends mainly on the isotopic composition characteristics of accompanied rare gases, which is difficult to be determined in some cases, the origin of hydrogen is then difficult to be identified. Based on the analysis and analytical results of hydrogen and associated gas content and isotopic composition in different structural parts, this paper analyzes the duration and content variation characteristics of high content hydrogen in the Kansas Basin, USA. A discrimination method for hydrogen genesis based on the relationship between methane and hydrogen content and hydrogen isotopic composition has been proposed, access of hydrogen genesis identification is easier to be achieved. Based on the above research, it is believed that there is a hydrogen supplement mechanism with underground conditions, which can continuously produce high content of natural hydrogen. It is considered that it is a favorable distribution area for high content of hydrogen around the plate collision zone. The hydrogen source can be classified by the hydrogen isotopic composition of -700‰ (VSMOW) and ln(CH4/H2). Shell source hydrogen has a δD value generally greater than -700‰ and a ln(CH4/H2) value lower than -8. Mantle derived hydrogen has a δD value generally lower than -700‰ and a ln(CH4/H2) value greater than -4. Hydrogen remaining after CO2 rich fluid is oxidized on the surface has a δD value greater than -700‰ and a ln(CH4/H2) value greater than -8. After the deep source hydrogen rich fluid is oxidized on the surface, the residual hydrogen has a δD value lower than -700 ‰ and a ln(CH4/H2) value under -4. This proposed method can quickly classify the origin of hydrogen without determining the composition and isotopic composition of rare gases.

Keywords

• geological body
• hydrogen gas
• origin
• identification method