坪北油田储层成岩作用与孔隙演化

根据15口取心井普通薄片、铸体薄片的镜下观察及扫描电镜、阴极发光、X衍射等资料的研究，坪北油田长4＋5、长6油组储层砂体在整个成岩演化过程中，孔隙得到不同程度的改造。其中机械压实作用、胶结作用是原生孔隙损失的主要原因，可导致大约18％～27％的孔隙损失；溶蚀作用可平均新增孔隙5％左右，其产生的次生孔隙是主要的存储空间。最后总结了本地区储层的成岩序列与孔隙演化模式。

Diagenesis and porosity evolution in the reservoir rocks from the Pingbei Oil Field in Shaanxi

The integration of scanning electron microscopy, cathodoluminescence and x ray diffraction analysis of the thin sections and caststone thin sections from 15 wells shows that the porosities of the reservoir sandstones from the Chang4+5 and Chang 6 oil formations in the Pingbei Oil Field, Shaanxi have been subjected to reworking throughout the whole diagenetic processes by mechanical compaction and cementation which may have caused 18% to 27% of porosities to be lost. The dissolution may increase the porosities by about 5%. The secondary porosities are considered as the prevailing pore spaces favourable for the oil storage.