GEOCHEMISTRY OF PETROLEUM MIGRATION DURING THE FORMATION OF KARAMAY OIL FIELD

The phenomena of geochemical migration during the formation of the Karamay Oil Field have been revealed by correlating the compositions of non-hydrocarbon, asphaltene, steranes and terpanes from between oils and rocks. The study on abnormal compaction observed in a deep well, which is located between the source area and the oil field, and the corresponding depletion of hydrocarbons further clarifies the conditions of the migration of oil and gas. Results show that the necessary condition for the formation of this giant oil field is a long distance of lateral migration of oil and gas followed by a redistribution along Ka.-Ur. large fault before accumulation in a large uplift.     

STERANES AND TERPANES IN UPPER TERTIARY OF QAIDAM BASIN AS INDICATORS FOR SOURCE ROCKS AND THEIR MATURITY

This paper studies the evolutional characteristics and the geochemical significance of the immature, mature, highly mature steranes and polycyclic terpanes of the Upper Tertiary in a deep well of Qaidam Basin, on the basis of their compositions and configurations obtained from GC-MS analysis. The informations are further used to determine the threshold depth of main oil generation zone in combination with ESR data, and to identify the source of their precursors in combination with stable carbon isotopic data. It is concluded that the precursors are mainly terrigenous. Pregnane is common in the sample and a complete series of tricyelic diterpanes (C_(16)-C_(28)) is made up after the organic matter becomes mature.     

柴达木盆地新第三系中甾烷和萜烷作为油源和成熟度标记的研究

本文应用柴达木盆地新第三系的深井色质分析资料,研究了未成熟、成熟和高成熟阶段中甾烷和多环萜类在组成和构型上的演化特征及其地球化学意义。对其中所显示的主成油门限,结合顺磁共振资料作了进一步讨论。还结合稳定碳同位素资料,探讨了沉积物中的母质来源,结论是以陆源为主。样品中普遍存在有孕甾烷;成熟以后还出现了一个完整的三环二萜系列(C_(16)～C_(28))。     

克拉玛依油田形成中石油运移的地球化学

本文利用石油和岩石之间在非烃、沥青质、甾烷和萜烷组成上的差别,揭示了克拉玛依油田形成中鲜明的运移地球化学现象。对油源区与油田之间深井中欠压实带和烃类亏损现象的研究,进一步阐明了油气运移的条件。结果表明,油气经长距离侧向运移,而后在大型隆起带上聚集起来,并沿克-乌大断裂重新分配,是这个大油田得以形成的必要条件。