鄂尔多斯盆地张家湾地区延长组长7湖相页岩中已发现了页岩气和部分工业油流。页岩层系中的孔隙类型、孔径大小和分布特征等对页岩储层的储集能力、渗透性、页岩油气赋存状态和含量均有重要影响。利用氩离子抛光和场发射扫描电镜分析、低压CO₂与N₂吸附、XRD等测试方法，分析了长7页岩油气储层的地球化学特征、孔隙类型、孔径分布及影响因素。结果表明，该区长7页岩厚度大(30~110m)，有机质丰度和含油量高(TOC值平均为4.97%，可溶烃含量平均为4.54mg/g，氯仿沥青“A”含量平均为0.80%)，R_O值主要介于0.6%~1.1%之间，热解峰T_max值为430~469℃。页岩孔隙类型多样，残余粒间孔、粒间溶蚀孔、粒内溶蚀孔、黄铁矿集合体和黏土矿物晶间孔、有机孔等均发育，有机孔孔径多数小于50nm，为微孔和介孔，占有机孔总数的61%，部分大于100nm。刚性颗粒间孔、粒内溶孔、刚性颗粒和黏土矿物间的无机粒间孔的孔径相对较大，黏土矿物粒内孔孔径相对较小。该区长7页岩孔隙度介于0.8%~7.7%之间，平均为3.2%。孔隙孔径主要介于0.8～10μm之间，具有多峰分布的特点，不同岩性和岩石组合样品的孔径分布曲线存在较大差异。页岩中粉砂岩纹层越发育，刚性碎屑的粒度越大，石英和长石含量越高，黏土矿物含量越低，中大孔越发育，孔隙度越大；TOC、有机质热演化程度越高，有机孔越发育。

Shale oil and gas have been drilled in the Chang 7 lacustrine shale in Zhangjiawan area of Ordos Basin.The pore type,pore size and distribution of shale have important effects on the physical property,reservoir permeability,the occurrence state and content of shale oil and gas.The Chang 7 shale reservoir geochemical characteristics and pore types,pore size distribution and influencing factors were analyzed by using argon ion polishing and field emission scanning electron microscopy (SEM) analysis,the low pressure CO₂,N₂ adsorption,XRD and other test methods in this paper.Results show that the thickness of the shale ranges from 30 to 110m.The average TOC is 4.97%,the average content of soluble hydrocarbon is about 4.54g/g,the average content of chloroform bitumen “A” is 0.80%,and RO is between 0.6% and 1.1%.Shale pore types include residual intergranular pores,intergranular dissolution pore,intragranular dissolution pore,intercrystalline pores of pyrite and clay minerals,organic pores.About 61 percent of the organic pores are micro-pores and meso-pores,with diameter less than 50 nm.The pores of intergranular pores and intraplasmic dissolution pores are relatively large.The diameters of the pores of clay minerals are relatively small.The porosity of Chang 7 shale is between 0.8% and 6.5%,with an average of 3.2%.The pore diameter is between 0.8nm and 10μm,and it has the characteristics of multi-peak distribution.The pore diameter distribution curves of samples with different lithology and rock composition are quite different.The more developed the siltstone and fine sandstone laminar in shale,the larger the particle size of detritus,the higher the content of quartz and feldspar,the lower the content of clay minerals,the more developed the middle and large pores,and the greater the porosity.The higher the total organic carbon content and organic matter evolution,the more developed the organic pore.