页岩中的沥青纳米孔是页岩气主要赋存空间,查明页岩孔隙特征和纳米孔形成机制,对于研究页岩气成藏和开展地质评价具有重要意义。通过采用聚焦离子束电镜技术识别出黑色页岩中的多种孔隙类型,在国内首次建立页岩孔隙的形态学分类,采用偏光显微镜、热模拟装置对原油中纳米孔形成过程进行模拟,再现了沥青质纳米孔形成的动态过程,查明纳米孔的气泡成因机制,认为页岩中的沥青质纳米孔形成与原油裂解产气有关,原油裂解残余沥青有利于气泡保存,气孔内具有超低的含水饱和度,孔的圆球度指示孔内压力,较高的圆球度对页岩气超压富集区具有重要指示意义。

The asphalt nanopore in shale is the main occurrence space of shale gas.It is of great significance to identify the pore characteristics and formation mechanism of nanopore in shale reservoir for the study of shale gas reservoir formation and geological evaluation.By using focused ion beam electron microscopy technology, various pore types in black shale can be identified.A morphological classification scheme of pore types in black shale has been established for the first time in China.The formation process of nanopore in crude oil has been simulated by polarizing microscope and thermal simulatorand the dynamic process of nanopore formation has been reproducedand the nanopore has been identified.The mechanism of bubble forming suggests that nanopore existed in solidified asphaltene of shale is related to the gas production from crude oil pyrolysis.The residual asphalt is beneficial to the preservation of gas bubbles.The pore has ultra-low water saturation.The sphericity of the pore indicates the characteristics of high pressure and gas-rich, which is of great significance to the formation of over-pressure enrichment zone.