Abstract:

There are not only wide distribution, great thickness and various types of Marine carbonate rocks of Lower Triassic in Feixianguan Formation in the northeast Sichuan basin, but also many periods of evolution which involve the diagenesis and tectonism, the rocks have evolved into bank facies dolomite reservoir with excellent reservoir property. Based on the study of the sedimentaiotn, diagenesis, tectonic burial history and the heat evolution of organic matter, the authors research the dissolution which is very important to the development and evolution of reservoirs in Feixianguan Formation in the northeast Sichuan. According to the dissolution characteristics and geochemical characteristics of chemical fillers, four stages of dissolution are identified, they are quasisyngenesis stage, liquid hydrocarbon stage, gaseous hydrocarbon stage and structure lifting stage, and then the forming mechanism of dissolution of different periods is further studied. At last, a model of the burial dissolution at liquid and gaseous hydrocarbon stage is proposed and the influence of dissolution on reservoirs concluded.

Key words: Feixianguan Formation, reservoir, dissolution, mechanism, Sichuan basin