成岩作用对滇东地区筇竹寺组页岩孔隙特征的控制机制

基于滇东地区筇竹寺组钻井岩样压汞实验数据，并结合X射线衍射及SEM观察，从成岩作用入手研究其对页岩孔隙特征的控制。结果表明：筇竹寺组页岩孔径从超大孔至微孔均有发育，过渡孔及微孔是孔容及孔比表面积的主要贡献者；压汞孔隙度与TOC含量及黏土矿物含量呈正相关关系，与脆性矿物含量呈负相关关系；基于进汞曲线形态及孔径分布，将本区页岩气储层孔隙结构划分为退汞效率低，孔隙联通性好的S型，及退汞效率较高，孔隙联通性较好的反S型。受控于成岩作用中高岭石的伊利石化，伊利石继承高岭石孔隙结构特征，随着含量的增加，开放联通型中孔、过渡孔及微孔孔容会迅速增加，孔隙度增大；但成岩过程中产生的溶解硅重结晶使部分孔隙受到石英的胶结及堵塞，成为封闭孔及半封闭孔，随着石英含量的增加，孔隙度减小，两者共同作用，形成了本区筇竹寺组页岩S型及反S型孔隙结构类型。

Diagenesis controlling mechanism of pore characteristics in the Qiongzhusi Formation Shale，East Yunnan

In order to study its pore characteristics from the point of diagenetic mechanism，according to the experiment data of mercury injection，the authors analyzed pore characteristics，and combined with the X ray diffraction experiment data and the SEM observation of Qiongzhusi Shale in the area of East Yunnan.The results show that the Qiongzhusi Shale pores range from ultra-large pore to micropore.The transitional pores and micropores enhance pore volume and pore specific surface area.The pressurized mercury porosity has the positive correlated relationship with TOC content，but has a negative correlation with mineral content.Based on the forms of mercury curves and pore size distribution，the shale gas reservoir pore structure in this area is divided into S type which has low efficiency of mercury-ejection，but has good pore connectivity and reversed S type which is just the opposite of S type.Because of the associated reaction of illitization of kaolinite，the illite inherits the pore structure characteristics of kaolinite.The pore volume of open interconnected mesopores，transitional pores and micropores increase rapidly，and lead to the increase of porosity.However，because of the recrystallization of dissolved silicon during the diagenetic process，the cemented quartz makes part of the pores closed and semi-closed.With the increase of quartz，porosity decreases.With the effect of the two aspects，Qiongzhusi Shale pore structure has S type and reversed S type in this area.