松辽盆地古龙页岩有机质丰度旋回性与岩相古地理

Cyclicity of organic matter abundance and lithofacies paleogeography of Gulong shale in Songliao Basin

有机质丰度旋回性变化特征与岩相古地理演化是进行松辽盆地古龙页岩油甜点预测的基础。以岩心精描、薄片鉴定、岩石热解分析、常微量分析及X射线衍射全岩矿物分析等方法,深入分析了松辽盆地青一、二段有机质丰度旋回性变化特征与岩相古地理演化特征。结果表明:古龙页岩有机质丰度纵向上呈现多期次、多级次的旋回变化,平面上受控于古地貌和沉积相带;在古地貌和半深湖—深湖相背景下,沉积物源、火山喷发、古生物繁殖、浊流沉积、岩浆热流等间断性地质事件的综合影响形成了大面积贫、富有机质旋回变化的不同纹层密度的页岩,奠定了页岩油形成演化的物质基础。研究成果为松辽盆地页岩油勘探开发提供了重要技术支撑。

Cyclic variation of organic matter abundance and lithofacies paleogeography are the basis of sweep spot prediction of Gulong shale oil in Songliao Basin. Cyclic variation characteristics of organic matter abundance and evolution characteristics of lithofacies and paleogeography in Member Qing-1 and Qing-2 of Qingshankou Formation in Songliao Basin are analyzed by means of core description,thin section identification,rock pyrolysis analysis,major and minor elements analysis and XRD analysis of whole rock minerals. The study shows that organic matter abundance of Gulong shale presents vertically multi-stage and multi-order cyclic changes,and is controlled areally by paleogeomorphology and lithofacies paleogeography. In the background of paleogeomorphology and semi-deepdeep lacustrine facies,the comprehensive influence of intermittent geological events of sedimentary provenance,volcanic eruption,paleontological reproduction,turbidite deposition and magmatic heat flow formed a large area of shale with different laminar density with cyclic changes of rich and poor organic matter,providing material foundation for formation and evolution of shale oil. The research provides important technical support for exploration and development of oil shale in Songliao Basin.