SEDIMENTARY CHARACTERISTICS AND OIL-AND-GAS DISTRIBUTION IN MEMBER 4 OF QUANTOU FORMATION, ANDA AREA, SONGLIAO BASIN

Researches of core samples,main facies markers and well logging facies have indicated that,2 main subfacies(delta plain and delta front) generate in the Member 4 of Quantou Formation,Anda area,the Songliao Basin.6 microfacies are further classified: distributary channels,interdistributary bays,crevasse splays,subaqueous distributary channels,subaqueous interdistributary bays and sheet sand.Using high-resolution stratigraphic theory and research methods,the Member 4 of Quantou Formation in Anda area is divided into 1 long-term sequence cycle,6 medium-term sequence cycles and 10 short-term sequence cycles.Delta plain subfacies develop in sequence K₁q₄-sq₁ and K₁q₄-sq₂,while delta front subfacies develop in sequence K₁q₄-sq₃.According to data from 7 wells such as D25 and DS401,main reservoirs in the study area are distributary channels and subaqueous distributary channels facies.Lake facies mud in the Member 1 of Qingshankou Formation works as good source and cap rocks.