This paper concentrates steranes and terpanes in high mature - over mature oil and source rock using distillation method and identifies with column chromatography and chromatography - mass spectrum , achieving better identification effect 用精馏法对该类原油和生油岩中的甾萜类化合物进行富集，然后通过柱色层分析和色谱质谱鉴定，得到了较为理想的甾萜类化合物鉴定效果。
The data of gc / ms of the whole oils show that there are three oil groups in the basin : group a with abundant 4 - melhylsterancs . group b with relative low 4 - methylstcrane contents , and group c with relative lowest maturity 全油定量gc ms分析结果显示，珠江口盆地存在三类原油： a类原油以丰富的4 -甲基甾烷为特征； b类原油以低4 -甲基甾烷含量为特征； c类原油以相对低成熟度为特征。
In combination with the source characteristics , the three oil groups can be extrapolated to three end - member oils , or three oil populations : population a derived from wenchang source rock , population b derived from enping formation with absence of 4 - methylsterane , and population c might be sourced from the wenchang source rocks in the leftover sags with lowest maturity as a typical feature 结合源岩分子组成特征，上述三类原油可被外延至三类端员油： a类端员油，来于文昌组源岩； b类端员油，来于恩平组源岩； c类端员油，可能来于残留洼陷文昌组源岩。
