摘要:
对采自西峰油田三叠系延长组六个油砂样品中游离烃、束缚烃的饱和烃、芳烃和氯仿馏分进行了系统的分析。在氯仿馏分中检测出一系列异常丰富的正构烷基酮化合物，其碳数分布范围C13～ C33,具有强烈的奇碳优势。研究表明：正构烷基酮的演化受热演化（成熟度）的影响，在成熟度较低的束缚烃中，主要分布正构烷基2酮；而在成熟度较高的游离烃中，主要为正构烷基3,4,5,6（或更高）酮异构体。表现为随着成熟度的增加，正构烷基酮的羰基(∶CO)由2位向更高位迁移的趋势。正构烷基酮的形成是由于菌藻类和高等植物类脂中的脂肪酸，在粘土矿物等催化作用下，经β氧化后脱羧基而形成。在束缚烃和游离烃中正构烷基酮的分布特征，可用于油气成藏差异的研究。
Abstract:
Ordos basin is an important MesozoicCenozoic petroliferous basin in West China. Xifeng Oilfield, in the southwest of Ordos Basin, was discovered in recent years. The crude oil reserve in this oilfield is about 100 million tons. Chloroform fractions of free oil and bound oil，which are extracted from six oil sands of Yanchang Formation in Xifeng oilfield, have been analyzed by GC/MS. The nalkaneones in six samples show an strong odd carbon number predominance, carbon number ranging from C13 to C31. This study shows that thermal evolution(maturity) has an effect on the evolution of nalkaneones. The nalkane2ones distribute in bound oil with low maturity, whereas nalkane3, 4,5,6(or more)ones distribute in free oil with high maturity. That is, with the increase of maturity, the carbonyl group distribution of nalkaneones shifts to the higher homologues isomers. The origin of these nalkaneones has been attributed to microbial production from nfatty acids from bacteria, seaseed and higher plant lipid by βoxidation and decarboxylation. The distribution characteristics of nalkaneonesin different state hydrocarbon can be used in dating petroleum accumulation.
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