鄂尔多斯盆地延长组长8油层浊沸石对储层影响因素

Influence Factors of Turbidite on Reservoir in Chang 8 of Yanchang Formation,Ordos Basin

浊沸石在矿物中通常以长石砂岩和岩屑长石砂岩为主分布在陆相湖盆中,浊沸石密度小、抗压易溶对周围环境非常敏感,在特定的条件下可以作为成储及成藏的示踪矿物。浊沸石的特性影响储层孔隙度、渗透率,导致开采率降低。利用扫描电镜、X衍射、恒速压汞等研究方法,对岩石内部孔渗结构进行观察,以时间作为主轴对储层的成岩史、埋藏史、构造特征及岩石成分成熟度和结构成熟度的研究进行分析,结果表明孔隙之间连通性差,储层非均质性强,储层压实和胶结作用都是由胶结物与浊沸石胶结物影响储层使储层成为一个富集区域。

Among the minerals,turbidite is usually mainly distributed in continental lacustrine basin with feldspar sandstone and lithic feldspar sandstone.Turbidite has low density,pressure resistance and easy to dissolve,and is very sensitive to the surrounding environment.Under specific conditions,turbidite can be used as a tracer mineral for storage and accumulation.The characteristics of turbidite affect the porosity and permeability of reservoir,resulting in the reduction of recovery rate.Using scanning electron microscopy,X-ray diffraction,constant velocity mercury injection and other research methods,the pore permeability structure of the rock was observed,and the diagenetic history,burial history,structural characteristics of the reservoir as well as the research of rock composition maturity and structural maturity were analyzed with time as the main axis.The results show that the connectivity between pores is poor,and the reservoir heterogeneity is strong.The compaction and cementation of the reservoir are caused by the influence of cementation and turbidite cementation on the reservoir and make the reservoir become an enrichment area.