黄骅坳陷北部拾场次洼沙三段井震联合沉积相研究

Study on sedimentary facies of the third member of Shahejie Formationin,Shichang Sub-sag of Huanghua Depression based on well-to-seismic integration

以黄骅坳陷北部拾场次洼沙三段地层为例,据岩心、测录井、地震等资料,在洼陷内构造、物源体系简析基础上,开展单井/联井相分析及地震相识别与划分研究,结合反演及地震多属性优选成果,完成对拾场次洼沙三段地层沉积相分析。研究认为:研究区主要发育北西向、北东向及北东东向三个物源体系,以发育扇三角洲、湖泊、冲积扇等为主;洼陷内主要存在席状-平行反射、丘形/楔形-杂乱反射、丘形/楔形-前积反射、透镜状反射等7类地震相;提出“岩心+测井分析定点、地震相+属性及反演趋势定面”的井震联合沉积相分析方法,识别研究区沙三段时期河控扇三角洲平原、(湖)浪控席状扇三角洲前缘等四类沉积模式,呈冲积扇→扇三角洲平原→扇三角洲前缘→湖泊相递变规律,为“急湖侵→缓湖退→缓湖侵”的基准面上升湖侵环境。

According to the data of core,logging,seismic,and so on,taking the third member of Shahejie Formation in Shichang Sub-sag of Huanghua Depression as example and based on the brief analysis of the structure and provenance systems in the depression,we analyzed the characteristics of single and continuous well facies. And then it was achieved the recognition and division of seismic phase depending on external geometry,internal reflection structure and geophysical parameters on seismic profiles. Finally,combined with the results of inversion and seismic multi-attribute optimization,the sedimentary facies of the third member of Shahejie Formation in Shichang Sub-sag was analyzed by the omni-directional and multi-angle research. The following observations have been obtained:① there are three main provenance systems:the NW,NE and NEE,and three main sedimentary systems:fan delta,lacustrine and alluvial fan facies;② there are 7 types of seismic facies in Shichang Sub-sag which are the mat-parallel reflection (strong vibration and connection,middle vibration and connection),the mat-subparallel reflection,the hilly/wedge disorderly reflection,the hilly/wedge progradational reflection,the blank reflection and the lenticular reflection;③ there are four types sedimentation models in the third member of Shahejie Formation in Shichang Sub-sag which are littoral sediment,river-dominated fan delta plain,wave-dominated fan delta front and scattered turbidity sediment,and it shows the law of gradual change from alluvial fan facies,fan delta plain,fan delta front to lacustrine facies,indicating the ascending of datum plane environment by the fast transgressive→gradual regressive→gradual transgressive.