Near-surface soil geochemistry of Muli natural gas hydrate area, Tianjun County，Qinghai Province

Based on analyzing hydrocarbon gas of fifty soil and headspace gas samples collected from near-surface soil in Muli permafrost of Qinghai Province by such means as acidolysis hydrocarbon, headspace gas and content of ΔC, the authors found that C1-C3 can be detected from headspace gas, and C1-C5 from soil. Acidolysis hydrocarbon and carbonate show significant positive correlation. The hydrocarbon gas in near-surface area seems to be derived from crude oil associated gas, condensate oil-associated gas and coal-related gas, being of the same source as the hydrate gas and showing deep pyrolysis characteristics. The results obtained are of important scientific significance for geochemical exploration of gas hydrate in permafrost regions.