摘要
This paper considers, through a lot of measured data of coal-bed gas, that the coal-bed gas is a kind of mixed gas of complex composition with some heavy hydrocarbons. In general, it is not a dry gas. The coal-bed hydrocarbon gases can obviously be divided into three stages of gas-storage: "poor hydrocarbon-storing stage", "rich hydrocarbon-storing stage" and "declining hydrocarbon stage". Authors point out that the normal gas geochemical indexes can relatively well show the geochemical chatacteristics of coal-bed gas. But, "the Benzene Index (B)" is a good indicator to identify the gas original types, and "the Hexane Index(H)" can show the gas evolution law and the organic matter maturity.
This paper considers, through a lot of measured data of coal-bed gas, that the coal-bed gas is a kind of mixed gas of complex composition with some heavy hydrocarbons. In general, it is not a dry gas. The coal-bed hydrocarbon gases can obviously be divided into three stages of gas-storage: 'poor hydrocarbon-storing stage', 'rich hydrocarbon-storing stage' and 'declining hydrocarbon stage'. Authors point out that the normal gas geochemical indexes can relatively well show the geochemical chatacteristics of coal-bed gas. But, 'the Benzene Index (B)' is a good indicator to identify the gas original types, and 'the Hexane Index(H)' can show the gas evolution law and the organic matter maturity.
