中文摘要：

轻烃(LH ) 是在原油的主要石油部分之一，并且关于原油的基因起源和改变带许多信息。但是第二等 alterationsespecially biodegradationhave 在原油的 LH 的作文上的重要效果。因为大多数在油影响的 LH 经历了仅仅细微的 biodegradation (在 biodegradation 规模上的等级 1 ) ， LH 的变化能被用来更描述 biodegradation 的精制特征。这里，从在 Tarim 盆的 Dawanqi 油矿的 23 原油， NW 中国，其十一个是到不同程度的 biodegraded，被分析以便在 C ₆-C₇ LH 上调查忽视的效果到次要的 biodegradation。学习结果证明 biodegradation 导致了直链的链烷的优先的弄空，由分叉的链烷列在后面。在细微、次要的 biodegraded 油，如此的 biodegradation 规模不能足够地影响 C ₆-C₇ cycloalkanes。为分叉的 C ₆-C₇ 链烷，通常， monomethylalkanes 是比 dimethylalkanes 和 trimethylalkanes 早的 biodegraded，它显示分叉的链烷对 biodegradation 更抵抗，随父母戒指上的代替的甲基组的增加。完化的度是 C ₆-C₇ LH 的 biodegradation 上的主要控制因素之一。有一个特别案例：尽管 2,2,3-trimethylbutane 有相对更高的完化度， 2,2-dimethylpentane 比 2,2,3-trimethylbutane 对 biodegradation 更抵抗。2,2-Dimethylpentane 对在分叉的 C ₆-C₇ 链烷的 biodegradation 最抵抗。而且， 2-methylpentane/3-methylpentane 和 2-methylhexane/3-methylhexane 比率与增加 biodegradation 稳定地减少了，它暗示双边的甲基组的异构体是对相对中间链的异构体的细菌的攻击敏感的更多。碳骨骼上的烷基的位置也是控制 biodegradation 的率的关键因素之一。与增加 biodegradation，芒果树 LH 参数 K1 价值减少和 K2 价值增加， n-heptane 和 isoheptane 的价值减少，并且 methylcyclohexane 和环己烷的索引增加。LH 参数应该为 biodegraded 油小心地被使

英文摘要：

Light hydrocarbons （LHs） are one of the main petroleum fractions in crude oils, and carry much infor- mation regarding the genetic origin and alteration of crude oils. But secondary alterations--especially biodegrada- tion--have a significant effect on the composition of LHs in crude oils. Because most of the LHs affected in oils underwent only slight biodegradation （rank 1 on the biodegradation scale）, the variation of LHs can be used to describe more the refined features of biodegradation. Here, 23 crude oils from the Dawanqi Oilfield in the Tarim Basin, NW China, eleven of which have been biodegraded to different extents, were analyzed in order to investigate the effect of slight to minor biodegradation on C6--C7 LHs. The study results showed that biodegradation resulted in the prior depletion of straight-chained alkanes, followed by branched alkanes. In slight and minor biodegraded oils, such biodegradation scale could not sufficiently affect C6- C7 cycloalkanes. For branched C6--C7 alkanes, generally, monomethylalkanes are biodegraded earlier than dimethylalkanes and trimethylalkanes, which indicates that branched alkanes are more resistant to biodegradation, with the increase of substituted methyl groups on parent rings. The degree of alkylation is one of the primary controlling factors on the biodegradation of C6-Cv LHs. There is a particular case： although 2,2,3-trimethylbutane has a rela- tive higher alkylation degree, 2,2-dimethylpentane is more resistant to biodegradation than 2,2,3-trimethylbutane. 2,2- Dimethylpentane is the most resistant to biodegradation in branched C6-C7 alkanes. Furthermore, the 2-methylpen- tane/3-methylpentane and 2-methylhexane/3-methylhexane ratios decreased steadily with increasing biodegradation, which implies that isomers of bilateral methyl groups are more prone to bacterial attack relative to mid-chain iso- mers. The position of the alkyls on the carbon skeleton is also one of the critical factors controlling the rate of biodegradation. With increasing biodegr