沁水盆地石炭-二叠系页岩储层特征及评价

Characteristics and Evaluation of Carboniferous-permian Shale Reservoir in Qinshui Basin

通过对沁水盆地石炭-二叠系页岩采样,应用有机碳分析、岩石热解检测、镜质组反射率测定、X射线衍射分析、扫描电镜和孔渗的分析化验手段,研究该区页岩的储层特征并对其进行评价。结果表明:沁水盆地石炭-二叠系页岩有机质丰度平均为2.59%,有机质类型以Ⅲ型干酪根为主,岩石热解峰温基本上都超过435℃,有机质丰度高,有机质演化处于高成熟—过成熟阶段;页岩储层主要由粘土矿物和石英组成,粘土矿物平均含量为59%,石英平均含量为36%,粘土矿物主要有高岭石、绿泥石和伊利石,有利于页岩气的吸附和在孔隙空间的聚集;孔隙度平均值为4.05%,渗透率平均值为0.012 mD;该地区层间裂隙、微裂缝和黄铁矿铸模孔十分发育,为页岩气的储存提供了丰富的储集空间。

By sampling the Carboniferous-Permian shale in Qinshui Basin,the reservoir characteristics of the shale were studied and evaluated by a variety of testing methods,including organic carbon analysis,rock pyrolysis detection,vitrinite reflectance measurement,X-ray diffraction analysis,scanning electron microscopy,and porosity analysis.The results show that,in the Carboniferous-Permian shale in Qinshui Basin,the average abundance of organic matter is 2.59%,the organic matter is mainly type Ⅲ kerogen,and the peak temperature of rock pyrolysis exceeds 435℃.Thus,the abundance of organic matter is high,and the organic matter evolution is at the stage from high-mature to over-mature.Shale reservoir is mainly composed of clay minerals and quartz,with an average content of 59%and 36%respectively.The clay minerals mainly include kaolinite,chlorite and illite,which are conductive to the adsorption of shale gas and the accumulation in pore space.The average porosity is 4.05%,and the average permeability is 0.012 mD.Interlayer fissures,micro-cracks and pyrite mold holes are well developed in this area,which could provide abundant storage space for the shale gas.