lang=EN-US style="FONT-SIZE: 14pt; LINE-HEIGHT: 150%">There exist three secondary pore zones vertically in the Cenozoic reservoirs in the west slope of the Yuanyanggou subsag, as manifested by the measured porosity data,lang=EN-US style="FONT-SIZE: 14pt; LINE-HEIGHT: 150%">thin sections,lang=EN-US style="FONT-SIZE: 14pt; LINE-HEIGHT: 150%">blue epoxy resin-impregnated thin sections and scanning electron microscopy. This caused the high-quality reservoirs to have developed. The distribution of high-quality reservoirs of the third middle-top member of the Shahejie Formation are delineated by superposing the diagenetic facies map on the microfacies map. They are mainly distributed in the middle part of the slope.