渤海海域沙一段特殊岩性烃源岩特征及生烃模式

The Special Lithologic Characteristics of Sha-1 Member Source Rocks and Hydrocarbon Generation Models in the Bohai Sea Area

根据岩心、岩屑观察结果以及电性特征分析,将渤海海域沙一段特殊岩性烃源岩按岩性组合分为两类:钙质页岩组合和灰质泥岩组合。结合古地貌、沉积相分析,建立了两类特殊岩性组合的发育模式。生烃热模拟实验表明,两类岩性组合产烃率均较高,钙质页岩组合产烃率最高达500 mg/gTOC,灰质泥岩组合产烃率达300 mg/gTOC。两类岩性组合TOC平均含量均超过了1%,为优质烃源岩。通过地球化学研究,建立了两类特殊岩性组合的生烃模式:钙质页岩组合生油门限相对较浅,为低熟-成熟强双峰型生烃模式;灰质泥岩组合生油门限相对较深,为微弱双峰型生烃模式。

The special lithology of Sha-1 Member source rocks in Bohai Sea can be divided into two categories, calcareous shale combination and calcareous mudstone combination, by core or cuttings observation and analysis of electrical characteristics. Com- bined with analysis of palaeo-geomorphology and sedimentary facies, two kinds of development pattern for the special lithologic combination have been established. The thermal simulation experiments on hydrocarbon generation indicated that the hydrocarbon generated from these two kinds of lithology association was higher, with hydrocarbon yield of calcareous shale combination up to 500 mg/gTOC, and calcareous mudstone combination was about 300 mg/gTOC. Those two kinds were both high quality source rock, with TOC over 1.0%. The hydrocarbon generation models for these two kinds of special lithologic combination have been established through geochemical study. The oil generation threshold depth of calcareous shale combination was shallow, and the hydrocarbon generation model is immature-mature strong double peak model. The oil generation threshold depth of calcareous mudstone combi- nation was very deep, the hydrocarbon generation model is small double peaks model.