双环倍半萜的分布特征及其意义

Characteristics and Significance of Bicycllc Sesquiterpances

对中国南海原油样品的分析发现 ,双环倍半萜异常丰富。双环倍半萜分布特征显示 ,A区原油重排补身烷含量相对较高 ,C区原油补身烷含量相对较高 ,这一特征与塔里木盆地海相和湖相原油特征相一致 ,暗示南海A、C区原油可能属不同成因类型 ;这一特征与其原油分子组成的非均质性在油区内的变化颇具一致性。此外 ,绝对定量分析发现 ,多数原油样品双环倍半萜的含量基本上恒定于 10 0 0～ 2 0 0 0 μg/g之内 ;但藿烷含量的变化幅度十分明显 ,变化范围为 179～ 4130 μg/g 。

It is found in the analysis of crude oil sample from the South China Sea that the bicyclic sesquiteances are very rich in the samples. The distributional characters of bicyclic sesquctecpances show that rearranged drimanes are relatively rich in the samples in Region A and relatively poor in Region C, but drimanes are relatively poor in Region A and rich in Region C. The characteristics are consistent with that of the marine and terrestrial oil in Tarim Basin, which implicates that the crude oil in Region A and C belongs to different genetic types. The characteristics are consistent with the change of molecule composition of crude oil in the areas. In addition, it is found also in absolute quantitative analysis that the content of the bicyclic sesquiterpances in most of the oil samples is basically constant within the range of 1 000 to 2 000μg.g -1 ,but the content of hopane are obviously changed in the range of 179 to 4 130μg.g -1,which may indicate that bicyclic sesquiterpanes have different bioprecursors from hopemes.