柴达木盆地乌南油田下油砂山组成岩作用研究

不同成岩条件下沉积物作用和变化是进行储层及其评价研究的重点。通过系统取心井的岩心薄片、铸体薄片、黏土矿物X-射线衍射、扫描电镜等的分析研究，总结出乌南油田下油砂山组的成岩作用类型，有机械压实作用及胶结作用、溶蚀作用和交代作用。其中，溶蚀作用是储层物性变好的有利因素；压实作用、胶结作用及交代作用等对储层不利。通过对成岩演化序列的研究表明，乌南下油砂山组储层砂岩的成岩阶段主要处于早成岩B亚期。成岩作用研究有利于建立乌南油田下油砂山组储层分类和评价标准，并对有利储层进行预测。

Study on Diagenesis of Lower Youshashan Formation of Wunan Oil Field in Qaidam Basin

Sedimentation and changes of sediments under different diagenetic conditions is key to the reservoir research and evaluation. Through systematic analyses of core slices,cast thin sections,clay mineral X-ray diffraction and scanning electron microscopy,it is summarized that diagenesis of the lower Youshashan Formation in the Wunan oilfield includes mechanical compaction,cementation,dissolution and metasomatism. Dissolution is a favorable factor for the improvement of reservoir properties,while compaction,cementation and metasomatism are unfavorable to the reservoirs. Studies on diagenetic sequence demonstrate that reservoir sandstones of the lower Youshashan Formation in the Wunan oil field are during the early diagenetic B substage. Researches on diagenesis are beneficial to the reservoir classification and evaluation of the lower Youshashan Formation in the Wunan oil field,as well as prediction of favorable reservoirs.