区分渤中坳陷三套烃源岩的地球化学参数组合

渤中坳陷有东营组下段、沙河街组一段及三段等 3套烃源层。如何通过地球化学特征区分沙河街组和东营组烃源岩 ,进而确定该区的主力烃源层 ,是长期困扰有关地球化学研究者的问题之一。文中对渤中坳陷及其周边陆区 31块烃源岩样品和 35个原油样品的饱和烃、芳烃进行了色谱 质谱分析和研究 ,提出用伽马蜡烷 /C31升藿烷 (S R)、4 甲基甾烷 /C2 9规则甾烷、三芳甾烷 /三芳甲藻甾烷和稳定碳同位素等 4个地球化学参数组合 ,可以有效地区分渤中坳陷的 3套烃源层 ,并初步确定了用于判断该区混源油的 3个地球化学参数的下限值。

The comprehensive geochemical parameters for distinguishing three sets of source rock in Bozhong depression

There are three sets of source rock in Bozhong depression,i.e.Lower Dongying Formation, Member 1 and 3 of Shahejie Formation. It is one of the puzzling problems for the geochemists to distinguish between Shahejie and Dongying source rocks based on their geochemical characteristics and to identify the main source in the area. Both saturated and aromatic hydrocarbons from 31 samples of source rock and 35 samples of crude oil collected in the depression and its surrounding areas have been analyzed by GC/MS, and the results suggest that 4 geochemical parameters such as gammacerane /C 31homohopane (S R), 4_methylsterane/ C 29 regular sterane, triaromatic sterane/ triaromatic dinosterane and stable carbon isotope value, can be comprehensively used to differentiate the three sets of source rock in the depression. In addition, the low limits for 3 of these parameters to diagnose oil with mixed source rocks has been proposed in this paper.