松北宾县—绥化地区下白垩统沉积相研究

Study on Sedimentary Facies of Shahezi Formation(Cretaceous) in Binxian Fault Subsidence in the Northern Songliao Basin

松北宾县—绥化地区下白垩统发育沙河子组、营城组、登娄库组三套沉积地层,四个断陷区块。通过对其地震反射层的振幅、连续性、内部结构、外部形态的特征研究分析发现,该区下白垩统发育六种类型的地震相。重点根据地震相的平面分布规律,综合钻井、测井、录井资料及野外露头分析研究,该区下白垩统主要发育冲积扇、河流相、扇三角洲、辫状河三角洲、湖泊相及火山岩相六种类型的沉积相。通过分析不同沉积地层沉积相的平面展布特征及发育情况,认为松北宾县—绥化地区下白垩统沉积主要以断陷期的粗粒充填为主,沉积物源受深大断裂控制,主要来自于各断陷靠近断裂的陡坡带。断陷深部的细粒沉积物有利于烃源岩的发育,上覆的粗粒沉积物又可作为油气的有利储层,预测宾县断陷和北安断陷为该区今后油气勘探的重点区块。

Three sedimentary layers including Shahezi Formation, Yingcheng Formation, Denglouku Formation and four fault-depressed blocks developed in lower Cretaceous layers of Binxian-Suihua area in the north of Songliao Basin. Six seismic facies developed in the area through the characteristic analysis on the amplitude, continuance, inner structure and formalness of the seismic reflection stratum. Through the data of muhidisciplinary analysis with the outcrop, core observation and description, drilling-well logging, laboratory test and especially the seismic facies interpretation, six styles of sedimentary facies formed in lower Cretaceous layers are alluvial fan facies, fluvial facies, fan-delta facies, braided stream-delta facies, lacustrine facies, and volcanite facies, respectively. Through analyzed the plane distributed and developed character of the sedimentary facies in different layers, it was concluded that the lower Cretaceous layers were made up of coarse sediments mainly in the fault subsidence period. The sedimentary provenance which was controlled by the major fault came from the arctic region near the major fault in each fault depression. The fine grained sediments were favorable for the source rock and the coarse sediments of the overlying were favorable reservoir. The result was that Binxian and Beian fault depression maybe the priority area for the oil and gas exploration in the future.