苏北盆地古近系阜宁组二段富有机质页岩特征与沉积环境  

Characteristics and sedimentary environment of organic-rich shale in the second member of Paleogene Funing Formation,Subei Basin

作　　者：段宏亮[1] 刘世丽[1] 付茜[1] DUAN Hongliang;LIU Shili;FU Qian(SINOPEC Jiangsu Oilfield Branch Company,Yangzhou,Jiangsu 225009,China)

机构地区：[1]中国石化江苏油田分公司,江苏扬州225009

出　　处：《石油实验地质》2020年第4期612-617,共6页Petroleum Geology & Experiment

基　　金：中国石化科技项目(P18060-4);国家科技重大专项(2017ZX05049001-005)资助。

摘　　要：苏北盆地古近系阜宁组二段(E1f2)发育两套富有机质页岩,分布广泛,油气显示丰富,页岩油形成条件有利。通过对大量岩心及薄片的观察,结合系统的有机地球化学、全岩X-衍射及微量元素测试资料,研究了苏北盆地E1f2两套富有机质页岩特征及沉积环境。苏北盆地E1f2两套富有机质页岩特征截然不同,其中第一页岩层(E1f2页1)以深灰色块状含灰泥岩和硅质泥岩为主,微显层理;页岩有机碳含量平均介于2.21%~3.41%,有机质类型以Ⅰ型为主。第二页岩层(E1f2页2)为灰黑色油页岩与纹层状含云、含灰泥岩、泥云岩、泥灰岩互层,纹层发育,有机碳含量平均介于2.02%~2.99%,有机质类型以Ⅰ型为主。苏北盆地E1f2沉积古气候经历了自半干热、还原、半咸水环境向干热、强还原、盐湖环境,再向温湿、氧化、淡水环境演化的过程;富有机质页岩形成于强还原、干热、咸水环境向氧化、温湿、正常淡水环境过渡的最大湖泛面附近,其中E1f2页2形成于强还原、干热的咸水—盐湖环境,E1f2页1形成于强还原、半潮湿—半干热的半咸水环境。沉积环境演化,造就了E1f2泥页岩层间及富有机质页岩内部岩性、电性及烃源岩品质的差异。Two sets of organic-rich shales are developed in the second member of Funing Formation(E1f2)in the Subei Basin,which are E1f2shale 1 and E1f2shale 2.They are widely distributed,with rich shows and favorable shale oil conditions.Based on core and thin section observations,and combined with systematic organic geochemistry,X-ray diffraction and trace element analyses,the characteristics and sedimentary environment of the organic-rich shales were studied.The characteristics of the E1f2shale 1 and E1f2shale 2 are totally different.The E1f2shale 1 mainly consists of dark gray blocky limestones and siliceous mudstones,with slight bedding,2.21%-3.41%organic carbon content,and type I organic matter.The E1f2shale 2 mainly consists of dark oil shales and dolomitic mudstones,calcite mudstones,muddy dolomites and muddy limestones,with laminar bedding,2.02%-2.99%organic carbon content,and type I organic matter.The sedimentary palaeo climate of E1f2 has experienced semi-arid,reducing,brackish water,to dry,strongly reducing,salt lake,and to warm humid,oxic,freshwater in the Subei Basin.The organic-rich shales were formed in the transition formations near the maximum flooding surface,between strongly reducing,dry and hot,saltwater environments and oxic,humid,normal water environment.The E1f2shale 2 was formed in a strongly reducing,dry and hot,salt lake environment,while the E1 f2shale 1 was deposited in a strongly reducing,damp to semi-arid and brackish water environment.Sedimentary environment evolution resulted in the differences of lithology,electrical properties,and quality of hydrocarbon source rocks,occurring in the muddy shale interlayer and internal organic-rich shale.

关 键 词：富有机质页岩 沉积环境 页岩油 阜宁组二段 古近系 苏北盆地 

分 类 号：TE122.23[石油与天然气工程—油气勘探]