Abstract: The research on the abiogenic origin theory in China is in the forward position in the world.Extensive scientific research and practice have proven that a relatively large percentage of hydrocarbons,especially oil,are generated organically.However,this does not rule out the possibility that another large proportion of hydrocarbons,gas in particular,may be of abiogenic origin.The identifications of organic and abiogenic gases are as the follows:1) The abiogenic origin CH₄ has a δ¹³C₁ value greater than -30‰; 2) The abiogenic alkane gases have negative carbon isotope sequences; 3) CH₄/³He values aren×10^5~7; 4) Abiogenic δ13Cco₂ values are greater than -8‰.The Changde Gas Field is possible the first abiogenic hydrocarbon gas field in the world. Favorable locations for abiogenic gas fields can be selected by following criteria:1) Existance of Moho up-pouring or mantle plume; 2) High thermal or thermal structural area with a heat flow value greater than 1.3 HFU and a geothermal gradient higher than 3.5℃/100m; 3)Anomalous R/Ra>1, especially R/Ra>2 zones;4) Presence basalt rock zone along the faults near the gas resource.

Key words: abiogenic hydrocarbon, Changde Gas Field, the identification of abiogenic gas

摘要： 我国无机成因油气理论的研究走在世界的前沿。科学实践证明,在油气中很大部分,特别是石油是有机成因的,然而并不排除在油气中相当多的部分,特别是天然气是无机成因的。无机成因的烷烃气的甲烷一般δ¹³C₁>-30‰,具负碳同位素系列,甲烷的CH₄/³He值为n×10^5～7。无机成因的二氧化碳的δ¹³Cco₂>-8‰。我国的昌德气田可能是迄今为止发现的第一个以烷烃气为主的无机成因气藏。无机成因二氧化碳和烷烃气有利发育带主要分布在:莫霍面隆起或地幔柱上隆地区;热流值大于1.3HFU,地温梯度大于3.5℃/100m的高热-热构造区带;R/Ra>1正异常带,特别在R/Ra>2的地带往往发现气藏;近期或较新时代玄武岩或岩浆活动带,以及沿气源断裂区等。

关键词: 无机成因油气, 昌德气藏, 无机成因气鉴别