Title : Generation, migration accumulation characteristics and enrichment mechanisms of helium rich gas reservoirs in China
Abstract:
This study systematically investigates the spatial distribution, genetic mechanisms, and enrichment patterns of helium-rich gas reservoirs in China through reservoir characterization and geochemical analysis. Spatially, helium-bearing strata display an east-to-west age progression from Cenozoic deposits in eastern basins to Paleozoic-Mesozoic formations in western regions, predominantly accumulating at shallow depths (<4,500 m). Geochemical signatures reveal distinct regional variations: eastern reservoirs are dominated by non-hydrocarbon gases (He-CO2, He-N2, and He-Hydrocarbon subtypes) with mixed crustal-mantle helium origins, while central-western reservoirs exhibit hydrocarbon-dominated compositions featuring crustal-derived helium. Genetic analysis identifies dual helium sources: crustal contributions from U/Th-rich ancient granitic-metamorphic complexes and organic-rich black shales, supplemented by mantle-derived fluids. Helium migration is facilitated by carrier systems (natural gas, groundwater, and mantle volatiles) through deep-seated fault networks, with accumulation controlled by carrier gas charge volume, structural trap configurations, and preservation conditions. The formation of economically viable reservoirs requires synergistic coupling of six key factors: sufficient helium supply, efficient migration pathways, effective carrier systems, optimal gas accumulation capacity, favorable tectonic traps, and robust preservation mechanisms. These findings establish a conceptual framework to guide future helium exploration in China’s sedimentary basins.
