Ultra-tight sandstone diagenesis and mechanism for the formation of relatively high-quality reservoir of Xujiahe Group in western Sichuan
川西须家河组超致密砂岩成岩作用与相对优质储层形成机制

Xujiahe sandstone in west Sichuan of China which is not only the important gas reservoir and producing pay, but also the one of the most deeply buried and tightest clastic reservoir rock has developed relatively favorable reservoirs for natural gas accumulation. After burial, this sandstone has experienced a complex change in the process of diagenesis, so that the secondary porosity and primary porosity coexisted in it. Bsed on the study of petrography, mineralogy, geochemistry and characteristic of diagenesis of this sandstone reservoir, we generalize the reservoir diagenetic features of Xujiahe sandstone in west Sichuan in the condition of deep burial, and then, conclude its formation mechanism of relatively high quality reservoirs.