This paper makes an approach to the characteristics of the compound and carbon iso-topic composition of condensate in the Sichuan, Shaanxi-Gansu-Ningxia, Dongpu and Jiyangbasins in China. The results we have obtained show that the compound properties are re-lated to the maturity. The Paraffin Index Ⅰ and the Saturated-Aromatic Index (SAI) increasegradually from the immature to mature (or over mature) condensate. and the SAI valueincrease from 2 to more than 30. The carbonisotopic composition of condensate is control-led by the type of parent matter. If the oil and condensate come from the same source rock,they will have similar carbon isotopic composition. In the same region there is an obviousdifference in carbon isotopic composition between the condensate generated from coal-bear-ing strata and that from oil-source rocks. The difference can be regarded as a parameter fordistinguishing the coal-type gas from the oil-type gas. In the same basin the carbon isotop-ic composition of the natural gas-oil-co
展开▼