Abstract: The evolution degree of sapropel-type Kerogen and humic-type Kerogen may be defined by the feature of gas components. But this method is not applicable for mixing gas source material including sapropel-type Kerogen and humic-type Kerogen.In this paper,a general formula applicable for mixing gas source material including sapropel-type Kerogen and humic-type Kerogen was built up,based on the formulas given by previous scholars.With this formula,it is identified that the natural gas of Tertiary in North Fault Block in Qaidm Basin is from the coal-bearing series of Jurassic and the natural gas in west depression is from the source rocks with ⅡA-Ⅰ Kerogen type of Tertiary.

Key words: gas, Kerogen type, evolution degree, quantitative model

摘要： 依据天然气组分特征可以判别煤型气和油型气这两种极端类型天然气的母质转化程度,但对于既有煤型气又有油型气或介于煤型气和油型气之间的天然气则不适用.在前人判别煤型气和油型气母质类型和转化程度公式的基础上,建立了既适用于煤型气又适用于油型气母质来源的统一的判别公式.用这一公式判别出柴达木盆地北部断块第三系天然气来源于侏罗系煤系地层,西部坳陷天然气来源于第三系A-类母质烃源岩.

关键词: 天然气, 母质类型, 转化程度, 定量模式