准噶尔盆地莫北油田侏罗系储层低孔低渗成因分析

Genesis of low porosity and permeability Jurassic reservoir in Mobei oilfield, Junggar Basin

从影响储层物性的一般因素入手 ,分析了压实作用、岩石矿物成分、沉积微相、粒度特征、胶结作用、溶蚀作用等对莫北油田侏罗系三工河组和八道湾组储层物性的影响。结果表明 ,莫北油田侏罗系储层物性主要受塑性岩屑含量、岩石颗粒粒度、压实强度控制 ,并受成岩环境的影响。与三工河组相比 ,八道湾组储层物性差的主要原因是储层深埋、岩石颗粒较细、煤系地层偏酸的成岩环境 ,造成了其岩石碎屑机械强度降低 ,压实作用是关键因素。三工河组储层物性 ,特别是渗透率的高低则主要取决于储层岩石的颗粒粒度大小 ,岩性愈粗 。

This paper studies the influence of compaction, mineral composition, sedimentary micro facies, grain size, cementation, and dissolution on the petrophysical property of Sangonghe and Badaowan formation in Jurassic of Mobei oilfield. The result shows that, petrophysical property of this reservoir mainly subjected to plastic debris content, rock grain size, compaction strength, and diagenetic environment. Comparing with Sangonghe formation, the reason that Badaowan has poorer property is: deeply buried, fine grain size, and acid-prone diagenetic environment of coal measure strata, resulting in low physical strength of rock debris. The compaction effect is a key factor. The propertis of Sangonghe formation, especially the permeability, mainly depends on rock grain size. The coarser the lithology is, the better is the petrophysical property.