APPROACH ON SEDIMENTARY FACIES AND REEF WITH FAVOURABLE HYDROCARBON BEARING FACIES BELTS IN CHANG XING SERIES OF UPPER PERMIAN IN EASTERN SICHUAN AND WESTERN HUBEI

Based on field practice and synthesis and analysis of a vast amount of data,the main pattern of sedimentary facies during Chang Xing period in eastern Sichuan and western Hubei was restored.It is recognized that the area during Chang Xing period was not a flat platform,and there are evi-dences of facies differentiation,including platform facies,platform trough facies,platform-basin facies,and biologic beach facies.There are shallow water facies,as well as deep water facies;and open sea facies,as well as restricted sea facies.The reef is characteristized by special sequence of for-mation and certain sedimentary environment,and hydrocarbon bearing facies belts were formed,which has been proved through petroleum exploration.