页岩纳米孔隙分形特征  

Fractal Characteristics of Nanopore in Shales

作　　者：杨峰[1] 宁正福[1] 王庆[1] 孔德涛[1] 彭凯[2] 肖丽芳[3] 

机构地区：[1]中国石油大学(北京)石油工程教育部重点实验室北京102249 [2]中国石油冀东油田分公司,河北唐山063004 [3]中国石油冀东油田南堡作业区,河北唐海063200

出　　处：《天然气地球科学》2014年第4期618-623,共6页Natural Gas Geoscience

基　　金：国家自然科学基金资助项目(编号:51274214);教育部科学技术研究重大计划(编号:311008);油气资源与探测国家重点实验室自主研究课题(编号:PRP/indep-3-1108)联合资助

摘　　要：以氮气分子为探测介质,采用氮气吸附分形分析方法研究了页岩孔隙结构及其不规则性,计算了页岩纳米孔隙分形维数,给出了分形维数与有机碳含量、页岩组成、孔隙结构参数之间的关系曲线,讨论了分形维数对气体吸附和渗流的影响。结果表明,页岩纳米孔隙具有明显的分形特征。分形维数与有机碳含量、微孔发育程度有关。有机碳含量越高,分形维数越大。分形维数反映了页岩微孔的发育程度,微孔越发育,平均孔径越小,比表面积越大,分形维数越大。分形维数对气体的赋存和运移有着不同的影响,分形维数越大,孔隙结构趋于复杂,这有利于气体吸附存储,但不利于气体渗流。Abundant nanopores are present in shales,and the nanopore structure plays an important role on gas adsorption and migration.Taking nitrogen molecular as probe medium,we use the nitrogen adsorption fractal analysis method to measure the pore structures and roughness in shales.The fractal dimension was obtained from the nitrogen adsorption isotherm using the Frenkel-Halsey-Hill equation.The relationship between shale composition,organic matter content,pore structure parameters and fractal dimension were plotted.The impact of fractal dimension on gas adsorption and transportation was also discussed.Results show that the pore structure in shales is fractal,and the fractal dimension is related to organic matter and micropores.The more enriched organic matter and developed micropore are associated with the much bigger fractal dimension.The degree of fractal dimension indicates the micropore development.The smaller the average pore diameter,the larger the specific surface area,and the higher the fractal dimension.Fractal dimension increases with the increasing micropores.The higher the fractal dimension,the more complicated of pore structure,which is favorable for gas adsorption rather than gas transportation.

关 键 词：页岩 孔隙结构 分形特征 氮气吸附 吸附 渗流 

分 类 号：TE135[石油与天然气工程—油气勘探]