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通过钻测井、地震等资料,将辽河滩海西部地区沙三段划分为2个三级层序,并深入研究了层序界面不整合构型及分布特征。层序界面整体表现出明显的纵向继承性与横向分带性,洼陷区持续接受沉积,地层接触关系以整合为主;斜坡区发育多级次坡折带,各时期地层超覆其上,形成超覆不整合;上斜坡区地层遭受剥蚀,为上超下削型不整合区。纵向上,不同盆地演化阶段湖盆范围发生变化,相对沙三底,沙二底整合区的范围相对向西扩大,反映该时期湖盆扩张,水体范围增大。滩海西部地区沙三段层序发育总体具有北厚南薄、中间厚两侧薄的特征。西部斜坡带层序发育齐全,但厚度相对较薄,层序结构清晰,东部海南洼陷带层序厚度大,沉积了一套湖相细粒沉积。
By drilling, logging and seismic data, the third member of Shahejie Formation in western Liaohe Sea beach is divided into two third-order sequences, and the unconformity of sequence boundaries and its distribution are studied. The sequence interface shows obvious longitudinal inheritance and lateral zonation, and the depression area continues to be deposited. The strata contact relationship is mainly integrated. The slope area develops multi-level slope break zones, Forming unconformity. The strata in the upper slope area suffered erosion and formed the unconformity area of the upper and lower undercut. Longitudinally, the range of lake basin changes in different basin evolution stages, and the scope of the integration area relative to sand-bottom and sand-bottom increases relatively westward, reflecting the expansion of lake basin and the increase of water body range during this period. The sequence stratigraphic development of the third member of the sand bank in the western part of the Tanhai Sea has the characteristics of thin thickness of the north and south and thin thickness on both sides of the middle thickness. The sequence of western ramp zone is well developed, but its thickness is relatively thin, and the sequence structure is clear. The thickness sequence of the Hainan sub-sag zone is large, and a set of lacustrine fine sediments are deposited.