海拉尔盆地乌南凹陷原油芳烃组成特征及来源分析

COMPOSITION CHARACTERISTICS AND SOURCE ANALYSIS OF THE AROMATIC HYDROCARBON IN THE CRUDE OIL OF SOUTH WUERXUN SAG OF HAILAR BASIN

采用GC—MS分析技术分析了乌南凹陷原油和源岩中芳烃化合物，结果表明，不同构造带原油在芳烃化合物组成上存在明显差异。乌东斜坡和巴彦塔拉构造带的乌11井原油以菲系列和三芳甾烷系列为主，菲系列含量高于三芳甾烷系列，不含脱羟基维生素E；乌中北部构造带原油以菲系列占绝对优势，三芳甾烷含量较低，不含脱羟基维生素E；巴彦塔拉构造带原油以三芳甾烷系列化合物为主，菲系列次之，含有一定数量的脱羟基维生素E。原油中含量相对较高的惹烯可能是藻类等低等水生生物贡献的反映。甲基菲、烷基萘、二苯并噻吩及脱羟基维生素E多项指标显示出，乌南凹陷原油为成熟油，且巴彦塔拉构造带原油的成熟度略低于其他地区。油岩对比认为原油主要来源于本地区的南屯组和铜钵庙组源岩，推断油气以垂向运移为主，侧向运移不明显，有效源岩分布区为有利勘探区。

The aromatic hydrocarbons of the crude oil and source rock in South Wuerxun Sag are analyzed by the GC-MS technique. The results show that there are obvious differences in the compositions of aromatic hydrocarbons in the crude oils of different structural belts. The crude oil in Wu No. 11 Well in East Wuerxun Slope and Bayantala Structural Belt takes phenanthrene and triaromatic-steroid serieses as main forms, the content of the former is higher and moreover there is no dehydroxyl-vitamin E ; the crude oil in the northern structural belt of Central Wuerxun Sag is absolutely dominated by phenanthrene series, but the content of triaromatic steroid is rather lower, and furthermore there is no dehydroxyl-vitamin E ; the crude oil in Bayantala Structural Belt has higher content of triaromatic steroid series compounds, the next is phenanthrene series and moreover there are a certain amount of dehydroxyl-vi tamin E. The relatively higher content of retene in the crude oil maybe the response of the contribution of the lowclass aquatic organism such as algae and so on. There are lots of indices including methylphenanthrene index （MPI）, alkyl-naphthalene, dibenzothiophene （DBT） and dehydroxyl-vitamin E show that the crude oil in South Wuerxun Sag is mature, and moreover the oil maturity in Bayantala Structural Belt is lower than in others. The oil and source rock correlation indicates that the crude oil is mainly from the source rocks in Nantun and Tongbomiao Formations. So it can be deduced that the oils may mainly migrate vertically and there are no obvious evidence in lateral migration. The distribution of the source rocks are regarded as favorable exploration area/play.