黄骅坳陷天然气中多成因二氧化碳的判识及其混合模型

A MIXED MODEL FOR POLYORIGINAL CARBON DIOXIDE OF NATURAL GAS IN HUANGHUA DEPRESSION

对２６个样品的组分及碳、氦同位素研究表明，黄骅坳陷天然气中存在３种成因的二氧化碳：有机成因、幔源－岩浆成因和碳酸盐岩变质热分解成因。根据二氧化碳含量和３Ｈｅ／４Ｈｅ比值确认，存在３种多元气混合模型：有机成因与慢源－岩浆成因均匀混合型、变质热分解成因二氧化碳混入型、二氧化碳与慢源氦差异混合型。

A study on the components, carbon and helium isotopic compositions of 26 gas samples indicates that there are three origins of CO2 in natural gases of Huanghua depression:organic origin, mantle-derived and magmatic origin and metamorphic origin of carbonates rocks. According to the relationship of CO2 contents and 3 He/4He ratios of gases,three types of mixedmodels for CO2 are established; homogenous mixed type of organic CO2 with mantle-derivedand magmatic CO2 mixed type of addition of metamorphic CO2, and mixed type of differencemigrations of inorganic CO2 with mantle-derived He.These models coincide with the carbonisotopic compositions of CO2.