通过岩心观察、相标志和测井相研究表明,松辽盆地安达地区泉头组四段主要发育三角洲平原和三角洲前缘2种亚相,进一步划分为分流河道、分流河道间、决口扇、水下分流河道、水下分流河道间和席状砂6种微相。应用高分辨率层序地层学原理和方法,把安达地区泉头组四段分为1个长期旋回、6个中期旋回和10个短期旋回层序。K1q4-sq1和K1q4-sq2层序中主要发育三角洲平原亚相沉积,K1q4-sq3层序中主要发育三角洲前缘亚相沉积。综合分析D25,DS401等7口钻井资料认为,该区主要储层为分流河道和水下分流河道砂体,上覆沉积的青山口组一段泥岩构成良好的烃源岩和盖层。
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.