| Based on the thin sections， cathodoluminescence images and geochemical data synthetically, lithological characteristics, diagenesis and evolution of reservoirs in the Middle Triassic Lei-4 Member of Leikoupo Formation in Pengzhou area of western Sichuan Basin are discussed. It is shown that algal dolomite, microcrystalline dolomite, dolomite powder, dolarenite and calcite-containing dolomite are favorable reservoir, and the algal skeleton pore, intercrystal dissolved pore, intercrystal pore and micro-pore are the main types of pore space. The diagenesis are varied and multi-period. The widespread diagenesis in this area principally includes seven types, and the compaction, cementation and dedolomitization are the main factors in reducing porosity and permeability, and the dissolution and fracture are the main factors in forming secondary pores and improving physical property. According to the diagenetic sequences, the mutual crosscutting relations between minerals and the porosity evolution characteristics in diagenetic process， some features were summarized firstly for Lei-4 Member of Leikoupo Formation in Pengzhou area． |
