Characteristics and Controlling Factors of Glutenite Reservoir in the Footwall of Major Pinghu Fault in Xihu Sag,East China Sea

Based on the data of cores,thin sections,scanning electron microscopy,petrology and sedimentology,the author analyzed the characteristics of glutenite reservoirs in the footwall of Pinghu major fault in Xihu Sag,East China Sea,and thinks that the reservoirs are mainly composed of sandy gravels and gravelly sandstones,with middling maturity of texture and composition;the pore types are dominated by intergranular pore,followed by intergranular dissolved pore and intragranular dissolved pore;reservoir performance is generally in the scope of medium porosity and permeability to low porosity and permeability.The sedimentary facies of glutenite in the area belongs to the coastal subaqueous fan,and can be further divided into root fan,middle fan and marginal fan,of which the reservoirs of braided channel microfacies in the middle fan are the best in physical properties,and can supply the favorable reservoir space for oil and gas.The study of diagenesis mechanism in the study area shows that compaction,cementation and dissolution are the main diageneses that affect the reservoir property.Compaction and cementation are destructive diagenesis,and dissolution is constructive.The texture and composition of rock particles reduce the pore space of glutenite.