沁水盆地煤系地层页岩储层评价及其影响因素

以沁水盆地中部及南部的煤系地层的泥页岩取芯为研究对象，重点剖析了石炭系太原组及二叠系山西组两套主力产气层位，分别从烃源岩、岩石学性质、储层物性及其影响因素等方面进行分析。研究表明，沁水盆地泥页岩样品生烃潜力较好，样品总有机碳含量在厚层泥岩发育段具有较高值，有机质成熟度指标Ro在1.33%~2.17%，已达到生气窗，有机质显微组分以腐泥组为主，有机质类型均为I型干酪根；全岩分析表明，泥页岩样品脆性矿物含量较高，多数在40%以上；黏土矿物主要以伊/蒙混层矿物及高岭石为主，绿泥石及伊利石含量次之；经扫描电镜观察，泥页岩中矿物溶孔、粒间孔及微裂隙较为发育；孔隙度分布于0.7%~3.8%，略低于北美页岩，渗透率在0.002 8×10-15~0.127 3×10-15 m2，与北美页岩无太大差异；黏土矿物中高岭石及伊利石对储层物性影响较大，其中前者对孔渗发育具有建设作用，而后者含量越多对储层物性影响越不利。各项有机地球化学参数表明沁水盆地泥页岩具有较高的生烃潜力，储层孔隙度及渗透率适中，较高的脆性矿物含量有利于页岩气的后期储层压裂改造。

Evaluation of shale reservoir and its influencing factors in coal-bearing strata of Qinshui Basin

Based on the coring samples of shales in the center and south of Qinshui Basin,this study focuses on Taiyuan formation in Carboniferous system and Shanxi formation in Permian system which are the main gas production layers and analyses on the aspects including source rocks,petrology characteristics,reservoir property and its influence factors.The research shows that the shale samples has good hydrocarbon generating potential and the high content of TOC is found in the areas with thick shale.As one of the organic matter maturity indexes,Ro is between 1.33%-2.17%,which reaches the threshold of gas generation.The organic matter types are all type I kerogen.Whole rock analysis shows that shale samples has a high content of brittle minerals,and most of the content of which is more than 40%.The illite/smectite mixed layers and kaolinite contains the highest content of clay minerals,next is chlorite and illite.According to the scanning electron microscope,shale develops mineral dissolution pores,intergranular pore,and microfractures.The porosity is between 0.7%-3.8%,which is little lower than that in North American shale,and the permeability is between 0.002 8×10-15-0.127 3×10-15 m2,which has no much difference with that of North American shale.It is the kaolinite and illite in the clay minerals which have great influence on reservoir physical properties.The kaolinite plays a constructive role in the development of porosity and permeability.While the higher content of illite is,the worse the effect on reservoir is.The parameters of organic geochemistry show that the shale in Qinshui Basin has high hydrocarbon potential.The porosity and permeability of the reservoir is well and the high content brittle minerals in it are favorable to the shale reservoir fracturing treatment.