二连盆地白音昆地凹陷腾2块下白垩统烃源岩特征

The characteristics of Lower Cretaceous hydrocarbon source rocks in Teng 2 block, Baiyinkundi sag, Erlian Basin

针对二连盆地白音昆地凹陷腾2块烃源岩缺乏系统研究与认识的问题,以岩心、岩屑为研究对象,以油气地球化学分析技术为主要手段,对烃源岩有机质丰度、有机质类型、有机质成熟度等有机地球化学参数进行测试分析。研究表明:腾2块烃源岩主要分布在沙海组和九佛堂组,累计厚度在700m以上,有机质丰度总体表现为中等—好级别,有机质类型以Ⅱa—Ⅱb型为主,热演化程度达到生油阶段,下部层位烃源岩有机质成熟度高于上部;九佛堂组烃源岩的生油潜力要远好于沙海组烃源岩的生油潜力,原始生烃潜量平均达到13.26mg/g,排烃量平均达到7.68mg/g,平均油气转化系数随埋深逐渐增大。

To get systematic research and deep understanding of the source rock in the Teng 2 block, Baiyinkundi sag, Erlian Basin, using cores, cuttings, and geochemical technology, the geochemical parameters of the source rocks were tested and analyzed, including the abundance, type and maturity of the organic matter. The research result shows that the source rock in the Teng 2 block are mainly distributed in the Shahai Formation and Jiufotang Formation; the cumulative thickness is above 700m; the organic matter abundance is generally in the medium-good level; the type of the organic matter is IIa-IIb; the thermal evolution has entered the oil generating window; the maturity of the organic matter in the lower source rock is higher than that in the upper source rock. Moreover, the oil generating potential of the Jiufotang Formation is much better than that of the Shahai Formation; the average original hydrocarbon generation potential is 13.26 mg/g; the average hydrocarbon expulsion potential is up to 7.68 mg/g; and the average oil-to-gas conversion coefficient gradually increases with the depth of burial.