Characteristics and evaluation of marine carbonate reservoir of Triassic Feixianguan Formation in western Sichuan

The marine carbonate reservoir ofTriassic Feixianguan Formation in western Sichuan is mainlycomposed of sparry oolitic limestone,bioclastic limestone and sparry oolitic dolomite.It was formed by the later multi-stage diagenesis and tectonism,with dissolved pores,caves and fractures developed well.The lithologies,reservoir space,types and accumulation capability of the carbonate reservoir are analyzed by means of geologic survey and laboratory analysis.There are various types of reservoir space,and the pore structure is complex.The reservoir can be divided into four types,and the oolite reservoir of the third member of Feixianguan Formation has the best quality.The reservoir quality and distribution are mainly controlled by sedimentary facies,denudation and tectonism.The quantitative evaluation and prediction for the distribution of the high-quality reservoir are carried out by using multi-factor analysis method.The result shows that the favorable zones distribute in the oolitie reservoir of the third member of Feixianguan Formation alonganxiian Chaping,Nanmuyuan,Zhitonggongand Hanwangin western Sichuan.