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利用该区8口系统取心井的岩石薄片、粒度分析、古生物等资料,以层序地层学理论为指导,在层序界面识别的基础上,建立陆东凹陷前河地区层序地层格架。并将上侏罗统划分为1个Ⅱ级层序和3个Ⅲ级层序,自下而上分别对应九佛堂组、沙海组、阜新组。其中九佛堂组层序发育完整,由低水位体系域、水进体系域和高水位体系域组成,沙海组由湖侵及高位体系域组成,阜新组由湖退体系域组成。根据层序分析结果,对层序格架内的沉积体系类型和沉积相特征进行分析,编制了前河地区九佛堂组及沙海组各个体系域的沉积相图,结果表明九佛堂、沙海时期陡坡一侧以近岸水下扇沉积为主,发育岩性—构造圈闭。西北缓坡带以扇三角洲及滨浅湖滩坝沉积为主,发育地层超覆及透镜体圈闭。
Based on the sequence stratigraphy theory, based on the identification of sequence boundaries, the sequence stratigraphic framework of the Qianhe area in Luodong Depression was established based on the data of rock slices, grain size analysis and palaeontology of 8 system coring wells in this area. . The Upper Jurassic is divided into one Ⅱ-level sequence and 3 Ⅲ-level sequence, which correspond to Jiufotang Formation, Shahai Formation and Fuxin Formation from bottom to top respectively. Among them, the Jiufotang Formation sequence is well developed and consists of low-water system tract, water-in-system tract and high-water system tract. The Shahai Formation is composed of lake invasion and highstand system tract, and the Fuxin Formation is composed of retreat system tract. According to the results of sequence analysis, the type of sedimentary system and characteristics of sedimentary facies in the sequence framework are analyzed, and the sedimentary facies charts of the Jiufotang Formation and Shahai Formation in Qianhe area are compiled. The results show that, On the steep side of the Shahai Sea, the nearshore subaqueous fan deposits mainly develop lithologic-structural traps. The northwestern gentle slope belt is dominated by fan delta and bank shallow beach dam, with stratigraphic overgrowth and lens body trap.