Abstract: The region of Etuokeqi is an important area for increasing reserves and improving productivity of Changqing oilfield, where the tight sandstone gas reservoir of He 8 and Shan 1 member of Upper Paleozoic is developed. In order to systematically study the controlling factors of high⁃quality reservoirs distribution, this paper applies rock thin slices, cast slices and other conventional analysis data to research controlling factors of high⁃quality reservoirs in the aspects of material sources, sedimentary features, diagenesis, hydrocarbon filling and microcrack development. The results show that, the supply environment of near source parent rock is abundant and quartz content is high, which provides material basis for the development of high⁃quality reservoir; the high porous⁃permeable reservoir formed in the main steam channel belt of delta plain, in which the point bar of braided⁃stream and meandering river is the advantageous sedimentary micro⁃facies; the compaction and cementation of reservoir are widespread, relatively the dissolution effectively improve physical property, so the weak cementation and strong dissolution zones are the major ones of high⁃quality reservoir; the filling of high saturate hydrocarbon promotes dissolution and restrains cementation in the high⁃quality reservoir; micro⁃fractures constitute the drainage system in reservoir and play an important role in reservoir pore expansion and natural gas migration and accumulation.

Key words: Etuokeqi area, High quality reservoir, Control factor, Diagenesis, Micro?fracture

摘要： 鄂托克旗地区是长庆油田增储上产的重点开发区域，发育上古生界盒8、山1段致密砂岩气储层。为系统性地研究本地区优质储层发育的控制因素，应用岩石薄片、铸体薄片及其他常规分析资料，在优质储层的物源条件、沉积特征、成岩作用、烃类充注、微裂缝发育方面进行了深入研究。结果表明，近源母岩的供给环境物源充足，石英含量高，为优质储层的发育提供了物质基础；相对高孔渗储层砂体主要沿三角洲平原的主河道方向展布，辫状河心滩、曲流河边滩是优质储层发育的优势相带；储层压实作用、胶结作用明显，溶蚀作用有效地改善了储层的物性，中⁃强等压实下的弱胶结相带、强溶蚀区是研究区优质储层的主要分布区带；高饱和度烃类流体充注促进了优质储层内溶蚀作用的发生，抑制了胶结作用；微裂缝构成了优质储层的疏导体系，在储层增孔扩容、天然气运聚成藏方面作用明显。

关键词: 鄂托克旗地区, 　优质储层, 　控制因素, 　成岩作用, 　微裂缝