Sandstone petrology,geochemistry and diagenetic features of Shihezi Formation in Majiatan area,western Erdos Basin

The Shihezi Formation is the focus point of natural exploration gas layer in Majiatan area of Ordos Basin.The research on rock characteristics and diagenesis of Shihezi Formation in the Majiatan area indicates that the stone box set of reservoir rock types are mainly quartz sandstone,lithic quartz sandstone and small amounts of feldspar-lithic sandstone.The main type of reservoir sandstone diagenetic are compaction and pressure solution-quartz overgrowth-cementation-dissolution.According to the characteristics of diagenesis and sandstone reservoir,a symbiosis of diagenetic sequence is established: authigenic illite-authigenic chlorite-quartz overgrowth-kaolinite-calcite.Ordos Basin is a CO2 buried potential target area in China.The petrological saudy on the diagenesis and buried layer section may provide information for numerical simulation of CO2 geological research.