Sandstone diagenesis of Chang-8 reservoir in Xifeng Oilfield of Ordos Basin

Based on the analysis of casting lamella,scan electron microscope and X-ray diffractions,this article researched into the characteristics of petrology and diagenesis on Chang-8 reservoir in Xifeng Oilfield of Ordos Basin.The study result showed that the main sandstone in the area is feldspathic litharenite with low compositional maturity.The diagenetic characteristics of Chang-8 sandston show that this set of sandstones are in the early period of the late diagenetic stage at present.The early diagenetic compaction and multi-mineral cementation are major effective factors that lead to poor petrophysical property of Chang-8 reservoir,while dissolution,in particular dissolution of feldspar,is one of significant factors controlling the quality of the reservoir.