Abstract: Abstract：In consideration of the poor hydrocarbon exploration of the study area，the authors firstly studied the petrologic characteristics and reservoir characteristics，and divided diagenesis into two types on the basis of an analysis of diagenesis and diagenetic sequence，and then conducted the quantitative analysis of the E1t1上and E1t1下 separately，which developed the porosity evolution model and deepened the understanding of the reservoir formation procedure as well as the influencing factors. The result shows that the porosity evolution features were controlled jointly by the sedimentary environment，material source，parent rock properties of the provenance，diagenesis，and tectonic process.