泌阳凹陷生物降解油“基线鼓包”成因及化合物组成  

Genesis and composition of ‘baseline hump'in biodegraded oil samples from Biyang Depression

作　　者：国朋飞 何生[1] 朱书奎[1] 柴德蓉 张万峰[1] 代威[1] 张君立[1] 

机构地区：[1]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074

出　　处：《石油与天然气地质》2014年第3期317-325,共9页Oil & Gas Geology

基　　金：高等学校学科创新引智计划资助项目(B14031);国家自然科学基金项目(41072093)

摘　　要：选择泌阳凹陷北部斜坡带的5个生物降解油,利用全二维气相色谱-飞行时间质谱(GC×GC/TOFMS),结合气相色谱(GC)和气-质谱(GC/MS)等方法研究了生物降解油中"基线鼓包"的成因及其化合物组成。所选油样的原始化学组成相似、成熟度相近、降解等级分别为2,3,5,6,8级。随着降解等级增加,原油中的正构烷烃、异构烷烃、低分子量芳烃、甾萜类、多环芳烃等化合物依次被降解,化合物的种类显著减少;生物降解作用导致抗降解能力强,极性差别小的环烷烃同系物逐渐成为原油的主要组成,这些化合物在GC谱图中共流出,形成"基线鼓包",其中的化合物被称为"未知复杂混合物(UCMs)"。全二维结构化谱图及标准样品验证分析表明,UCMs主要由环烷烃及其同系物组成,其碳环以六元环为基本组成单元,且可被区分为6类(Ⅰ—Ⅵ)化合物;其中Ⅰ和Ⅱ类UCMs分别由C16—C26长侧链烷基环己烷和C11—C16烷基十氢化萘等一环和二环环烷烃及其同系物组成,它们可能是微生物降解原油产生的新化合物;Ⅲ—Ⅵ类分别由倍半萜烷、三环萜烷、低分子量甾烷及重排甾烷、降藿烷等二环—五环环烷烃及其同系物组成,这些化合物主要由原油中抗降解能力较强的烃类富集而来。Five biodegrade d oil samples from the north slope of Biyang Depression were analyzed by integrating the two -dimensional gas chromatography/time-of-flight mass spectrometry（GC ×GC/TOFMS）,gas chromatography（GC）and gas chromatography-mass spectrometry （ GC-MS） to reveal the composition and genesis of ‘baseline hump ’ .All the oil sam-ples analyzed are of similar original compositions and thermal maturities ,but different degradation levels at 2,3,5,6 and 8,respectively.With the increasing of oil degradation level ,n-alkanes,iso-alkanes,aromatic hydrocarbons with low molec-ular weight,steranes,terpanes and polycyclic aromatic hydrocarbons are degraded successively ,resulting in the significant decrease of the number of compound types .The cyclic alkanes and isomers with similar polarities and strong resistance to biodegradation are enriched relatively in the biodegraded oil ,and their co-elution in GC chromatograms results in ‘base-line hump’ or so-called ‘unresolved complex mixtures （UCMs）’.Total 2D characteristic mass spectrums and standard compound tests show that cyclic alkanes and their homologues are the major components of the UCMs ,with a basic frame-work of cyclohexane .Additionally ,the UCMs can be divided into six types （ typeⅠto typeⅥ） .The typeⅠandⅡare com-posed of C16 -C26 long chain alkyl-cyclohexanes,C11 -C16 alkyl-decalins and their isomers.These cyclic alkanes with one or two rings might be the new compounds from the microbial transformation of normal oils .TypeⅢ-Ⅵare composed of sesquiterpenoids ,tricyclic terpanes , low molecular weight steranes , diasteranes and norhopanes , originated from the en-richment of hydrocarbons having relatively strong resistantance to degradation in the normal oils .

关 键 词：基线鼓包 未知复杂混合物 全二维气相色谱-飞行时间质谱 生物降解油 泌阳凹陷 

分 类 号：TE133[石油与天然气工程—油气勘探]