摘要
在野外地质观察基础上,对羌塘盆地托纳木地区上侏罗统—下白垩统沥青脉开展了详细的有机地球化学特征研究,探讨了沥青脉有机母质来源及母质形成的沉积环境。沥青脉样品中检测出丰富的正构烷烃、类异戊二烯烃、萜类化合物和甾类化合物。正构烷烃主碳数分别为n C17或n C18,奇偶优势为0.81-1.10,Pr/n C17值为0.73-1.36,Ph/n C18值为0.80-1.66,Pr/Ph值为0.64-0.90.萜类化合物以C30藿烷占优势的五环三萜烷为主,含有三环萜烷和伽马蜡烷。甾类化合物以规则甾烷为主,C27,C28和C29甾烷构成了不对称的＂V＂字型,C29甾烷ααα20S/C29甾烷ααα（20S＋20R）和C29甾烷αββ/C29甾烷（ααα＋αββ）的值分别为0.33-0.45和0.15-0.49.饱和烃色谱-质谱特征表明,沥青脉有机母质来源于具有水生生物和高等植物的混合来源,揭示了沥青脉母质形成于一定盐度缺氧还原环境。油源对比显示沥青脉与索瓦组泥页岩的饱和烃、萜烷、甾烷等生物标志物参数具有一致性,说明它们具有亲缘关系,也证实了该地区烃源岩具有较好的生烃潜力。
Based on the field observation, this paper studied in detail the geochemical characteristics of the Upper Jurassic-Lower Creta-ceous bituminous vein in Tuonamu area of Qiangtang basin and discussed the bituminous kerogen origin and the forming environment. Andabundant biomarkers such as n-alkanes, isoprenoids, terpanes and steranes were detected from the samples by GC and GC-MS. The carbonnumber of n-alkane appears as n C17 and n C18, with OEP of 0.81-1.10, Pr/n C17 of 0.73-1.36, Ph/n C18 of 0.80-1.66 and Pr/Ph of 0.64-0.90.The terpanes are dominated by pentacyclic triterpane with tricyclic terpane and gammacerane, in which C30 hopanes are dominant. The ster-anes are dominated by regular steranes, in which C27-C28-C29ααα20R distributes in asymmetric＂V＂shape. The C29ααα20S/（20S＋20R） valueranges from 0.33-0.45 to 0.15-0.49, respectively. The GC-MS characteristics of saturated hydrocarbons show that the bituminous kerogenis originated from the mixed sources of phytoplankton and higher plants, revealing such a kerogen is formed in anoxic reducing environ-ment with some salinity. The oil source correlation indicates that the bituminous vein＇s biomarkers are consistent with those of the Suowashale in terms of saturated hydrocarbons, terpanes and steranes, confirming that they have close affinity and the hydrocarbon source rocksin this area have better hydrocarbon generation potentials.
出处
《新疆石油地质》
CAS
CSCD
北大核心
2015年第1期14-19,共6页
Xinjiang Petroleum Geology
基金
地质矿产调查评价专项(1212011221106)
国家科技重大专项(2011ZX05004001-006)
