页岩中纳米级有机黏土复合孔缝的发现及其科学意义——以松辽盆地白垩系青山口组页岩为例  

Discovery of nano organo-clay complex pore-fractures in shale and its scientific significances:A case study of Cretaceous Qingshankou Formation shale,Songliao Basin,NE China

作　　者：孙龙德 王凤兰 白雪峰[1,4] 冯子辉 邵红梅[1,4] 曾花森 高波[1,4] 王永超 SUN Longde;WANG Fenglan;BAI Xuefeng;FENG Zihui;SHAO Hongmei;ZENG Huasen;GAO Bo;WANG Yongchao(State Key Laboratory of Continental Shale Oil,Daqing 163712,China;China National Petroleum Corporation,Beijing 100007,China;Daqing Oilfield Company Ltd.,PetroChina,Daqing 163002,China;Exploration and Development Research Institute,PetroChina Daqing Oilfield Company Ltd.,Daqing 163712,China)

机构地区：[1]多资源协调陆相页岩油绿色开采全国重点实验室,黑龙江大庆163712 [2]中国石油天然气集团有限公司,北京100007 [3]大庆油田有限责任公司,黑龙江大庆163453 [4]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《石油勘探与开发》2024年第4期708-719,758,共13页Petroleum Exploration and Development

基　　金：中央引导地方科技发展专项科技创新基地项目(ZY20B13)。

摘　　要：以松辽盆地白垩系青山口组页岩TOC、R_o和X射线扫描等分析为基础,利用氩离子抛光-场发射扫描电镜分析,结合能谱、聚焦离子束三维重构等技术,首次发现一种新的孔隙类型——纳米级有机黏土复合孔缝。孔隙特征及演化研究结果表明:(1)有机黏土复合孔缝多呈海绵状、缝网状集合体存在于页岩基质中,单个孔隙呈方形、长方形、菱形、板状,直径一般小于200 nm,不同于国内外页岩中已发现的呈圆形或椭圆形的有机质孔;(2)随页岩成熟度增加,有机黏土复合物的C、Si、Al、O、Mg、Fe等元素发生规律性变化,反映有机质生烃体积收缩、黏土矿物转化共同影响纳米级有机黏土复合孔缝的形成;(3)青山口组页岩高成熟阶段,纳米级有机黏土复合孔缝是主要储集空间,最高占总孔隙的70%以上,三维空间内孔隙连通性明显优于有机质孔,反映高演化阶段这类孔隙是泥纹型页岩的主力孔缝类型,也是陆相页岩油核心区主要油气储集空间。纳米级有机黏土复合孔缝的发现,改变了陆相页岩无机质孔隙是油气主要储集空间的传统认识,对于泥纹型页岩油的形成机理、富集规律研究具有重要的科学意义。A new pore type,nano-scale organo-clay complex pore-fracture,was first discovered based on argon ion polishing-field emission scanning electron microscopy,energy dispersive spectroscopy and three-dimensional reconstruction by focused ion-scanning electron in combination with analysis of TOC,R_(o) values,X-ray diffraction etc.in the Cretaceous Qingshankou Formation shale in the Songliao Basin,NE China.Such pore characteristics and evolution study show that:(1) Organo-clay complex pore-fractures are developed in the shale matrix and in the form of spongy and reticular aggregates.Different from circular or oval organic pores discovered in other shales,a single organo-clay complex pore is square,rectangular,rhombic or slaty,with the pore diameter generally less than 200nm.(2) With thermal maturity increasing,the elements(C,Si,Al,O,Mg,Fe,etc.) in organo-clay complex change accordingly,showing that organic matter shrinkage due to hydrocarbon generation and clay mineral transformation both affect organo-clay complex pore-fractures formation.(3) At high thermal maturity,the Qingshankou Formation shale is dominated by nano-scale organo-clay complex pore-fractures with the percentage reaching more than 70% of total pore space.The spatial connectivity of organo-clay complex pore-fractures is significantly better than that of organic pores.It is suggested that organo-complex pore-fractures are the main pore space of laminar shale at high thermal maturity and are the main oil and gas accumulation space in the core area of continental shale oil.The discovery of nano-scale organo-clay complex pore-fractures changes the conventional view that inorganic pores are the main reservoir space and has scientific significances for the study of shale oil formation and accumulation laws.

关 键 词：松辽盆地 白垩系青山口组 泥纹型页岩油 纳米级 有机黏土复合孔缝 有机黏土复合物 成岩演化 

分 类 号：TE122.2[石油与天然气工程—油气勘探]