Abstract: Based on the high resolution sequence stratigraphy theory, 42 wells and 2745 well logging curves are used to study the evolution of all levels of base level cycles and the development pattern of high⁃resolution sequence in the P reservoir in the southern part of Songfangtun area. The results show that the 4 sequence interface of the grape flower beds in the Songfangtun area can be divided into 2 medium⁃term, 5 short term and 12 ultra short term sequences. On this basis, the sedimentary microfacies type and distribution evolution law have been carried out. It is considered that the shallow water delta depositional system is developed in P reservoir in the Songfangtun area. The main development of delta front subfacies is to identify 8 kinds of microfacies such as subwater distributary channel, inter channel, inter channel, slime, overflow sand, mouth fan, estuarine dam, far sand bar and mat sand. The underwater distributary channel sandbodies are widely developed at the front of the delta. Due to frequent bifurcations and diversions, the underwater distributary channel sandbodies cut and overlap each other, forming branches and striped sand bodies. The sandbody reservoir has good physical property and is the main reservoir sand body with oil and gas enrichment. Through detailed study of sedimentary microfacies, it provides a reference for further exploration and development of lithologic reservoirs in this area.

Key words: Base level cycle, Fine sedimentary microfacies, Shallow water delta, Underwater distributary channel, Songfangtun area, Songliao basin

摘要： 应用高分辨率层序地层理论，利用42口井岩芯和2 745口井测井曲线，对松辽盆地宋芳屯地区南部P油层内各级次基准面旋回的演化规律及高分辨率层序发育模式进行研究。结果表明，宋芳屯地区P油层发育4类层序界面，共划分为2个中期、5个短期和12个超短期层序，并在此基础上开展了沉积微相类型及分布演化规律研究。研究认为，宋芳屯地区P油层发育浅水三角洲沉积体系，主要发育三角洲前缘亚相，进而识别出水下分流河道、席状砂、决口扇、漫流砂、河口坝、远砂坝、河道间和席间泥等8种微相砂体。其中水下分流河道砂体广泛发育，延伸距离较远，由于频繁的分叉和改道，水下分流河道砂体纵向叠置、横向连片，平面上呈树枝与条带状展布，该砂体物性较好，为主力储集体。通过沉积微相精细研究，为该区岩性油气藏的下步勘探与开发提供了参考依据。

关键词: 基准面旋回, 精细沉积微相, 浅水三角洲, 水下分流河道, 宋芳屯地区, 松辽盆地