古近系页岩油赋存特征——以济阳坳陷为例

Paleogene Shale Oil Occurrence Features:A Case of Jiyang Depression

通过大量岩心观察、薄片鉴定、X-衍射全岩矿物分析和扫描电镜分析,将济阳坳陷古近系泥页岩划分为10余种类型岩相。在岩相划分的基础上,分析了济阳坳陷页岩油赋存特征。富有机质纹层状泥质灰岩相/灰质泥岩相是页岩油赋存的最有利岩相;济阳坳陷的泥页岩的储集空间主要包括各类基质的孔隙和裂缝,最有利赋存空间是各类裂缝(层间缝、构造裂缝、超压裂缝);页岩油具有薄膜状游离态和浸染状吸附态两种赋存相态,在泥页岩裂缝、碳酸盐晶间孔中以游离态为主,在有机孔、黄铁矿晶间孔、黏土矿物晶间孔中以吸附态为主;通过页岩油油源对比、成熟度、地层异常压力、地层水水型等方面的证据确定济阳坳陷页岩油具有"非原位、短距离源内运聚"的特征。

According to many core observation,thin section identification,X-ray diffraction and scanning electron microscopy,shales in the Paleogene in Jiyang depression can be divided into over10lithofacies.On the basis of lithofacies,this study analyzed shale oil occurrence features.Organic-rich laminated argillaceous limestone facies/calcareous mudstone facies are the most advantageous shale lithofacies.Shale reservoir spaces in jiyang depression include matrix pores and fractures.The most advantageous reservoir spaces are fractures(bedding fractures,structural fracture,abnormal pressure fracture);occurrence phases of Shale oils include thin film free phase and disseminated absorbed phase.They are free phases in shale fractures and carbonate intercrystal pores.They are absorbed phase in organic matter pores,pyrite intercrystal pores and clay mineral intercrystal pores.Shale oil have features with not original place and short distance in-source migration and accumulation i Jiyang depression according to oil-source correlation,maturity,abnormal pressure and water type of formation water.