子洲地区山西组及盒8段有利砂体成因探讨

目的为了查明鄂尔多斯盆地东部子洲地区山西组及盒8段有利砂体的特征及成因,进而寻找有利砂体及高产天然气聚集区。方法采用野外观察与室内研究相结合的方法。结果大量的砂岩样品统计显示,山西组砂岩类型以岩屑砂岩、石英砂岩为主,其次为岩屑石英砂岩,盒8段砂岩主要为岩屑砂岩、岩屑石英砂岩;不同类型的砂岩物性不同,石英砂岩物性最好,其次是岩屑石英砂岩,岩屑砂岩物性最差;沉积相分析认为,子洲地区山西组主要为三角洲前缘,盒8段发育辫状河三角洲前缘,探明了重点气层组山23及盒82沉积微相的平面展布。结论有利的天然气储集体主要形成于水下分流河道微相,由于山西组和盒8段形成时古地理条件的不同,其砂体类型及储集性能也有一定的差异。

Formation cause discuss of favorable sandy body of Shanxi Formation and He 8 segment in Zizhou Region

Aim To ascertain depositional system in Zizhou Region of Upper Paleozoic,further-more probe favorable sand body and high-yield gas area.Methods Combined research method of field exploration and indoor analysis are adopted.Results A mass of sandstone samples show that lithic sandstone and quartz sandstone are main sandtone types.Secondly,lithic quartz sandstone in Shanxi Formation;lithic sandstone and lithic quartz sandstone in He 8;physical property of different sandstone types are varied,the physical property of quartz sandstone is the best,that of lithic quartz sandstone is the second and that of lithic sandstone is the worst.It is held that normal delta front in Shanxi formation and braided river-controled delta front in He 8 segment are mainly developed in Zizhou Region by sedimentary facies analysis,The sedimentary microfacies of main gas segment in plane,including Shan 23,He 82,are discussed.Conclusion Sandy body for good natural gas resevior are mainly formed in subaqueous distributary channel.sandstone types and reservoir characteristic are different in Shanxi formation and He 8 segment because of diverse paleo-geography.