Abundant lacustrine shale oil resources have been discovered in the Eocene saline lake system, Yingxiongling Sag, Qaidam Basin. Compared with the Cretaceous Qingshankou Formation in the Songliao Basin and Triassic Chang 7 Member in the Ordos Basin, the lithofacies of Yingxiongling shale are more complex, featuring thinner single-layer and faster vertical variations. How to establish a reasonable lithofacies classification and evaluate the effectiveness of different lithofacies is the key to unlocking the giant resources of Yingxiongling shale oil. Based on the total organic carbon analysis, rock pyrolysis analysis, fluorescence thin section observation, oil saturation analysis, helium porosity measurement, high pressure mercury intrusion by scanning electron microscopy, focused ion beam-scanning electron microscopy, and nitrogen adsorption analysis, the organic geochemistry, reservoir property, and oil-bearing property were comprehensively analyzed. This paper proposed a lithofacies classification scheme of Yingxiongling shale oil and systematically evaluated the quality of representative lithofacies. The key findings were as follows: (1) Eight types of lithofacies were identified based on the rock structure and mineral composition, namely, thin-bedded/laminated dolomitic limestone, thin-bedded/laminated limy dolostone, thin-bedded/laminated mixed rock, thin-bedded sandstone, and laminated shale. (2) The types and combinations of lamination varied greatly among different lithofacies. Dolomite primarily formed through calcite shrinkage during the dolomitization process, resulting in the formation of abundant intercrystalline pores. (3) More organic matter was observed in the calcite laminae, which was deposited as a result of small calcite particle flocculation. (4) The combination of laminated dolomitic limestone and thin-bedded limy dolostone formed a favorable source–reservoir assemblage, which was the pay zone for horizontal wells. These understandings could further be helpful in understanding shale oil enrichment in the Qaidam Basin and could provide scientific guidance and technical support for the exploration and development of global plateau shale oil.

中文翻译：

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柴达木盆地古近系英雄岭页岩油岩相评价


柴达木盆地英雄岭凹陷始新世盐湖系发现了丰富的湖相页岩油资源。与松辽盆地白垩系青山口组和鄂尔多斯盆地三叠系长7段相比，英雄岭页岩岩相更为复杂，单层厚度较薄，垂向变化较快。如何建立合理的岩相分类并评价不同岩相的有效性是解锁英雄岭页岩油巨大资源的关键。以总有机碳分析、岩石热解分析、荧光薄片观察、含油饱和度分析、氦气孔隙度测量、扫描电镜高压压汞、聚焦离子束扫描电镜、氮吸附分析等为基础，开展有机地球化学研究。 、储层物性、含油性进行综合分析。提出了英雄岭页岩油岩相分类方案，并对代表性岩相质量进行了系统评价。主要研究结果如下：（1）根据岩石结构和矿物成分，识别出薄层/层状白云质灰岩、薄层/层状灰质白云岩、薄层/层状混合岩等8种岩相类型。 、薄层砂岩、层状页岩。 (2)不同岩相层理类型及组合差异较大。白云石主要是在白云石化过程中方解石收缩形成的，从而形成丰富的晶间孔。 (3)方解石纹层中有机质较多，是由于方解石小颗粒絮凝而沉积。 (4)层状白云质灰岩与薄层灰质白云岩组合形成有利的生储组合，是水平井的产层。这些认识有助于进一步认识柴达木盆地页岩油富集情况，为全球高原页岩油勘探开发提供科学指导和技术支撑。