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大庆长垣及以西地区下白垩统泉头组三、四段扶杨油层油气资源潜力较大,是大庆油田近年来后备储量的主要来源。以往以组段为单元的沉积相研究已经不能满足油田的实际需要,随着近年来盆地勘探程度的提高,探井密度的加大和高分辨地震资料的普及,迫切需要开展“纵向细化,横向放大,编制大比例尺沉积相图”。本文就是针对大庆长垣及以西地区下白垩统泉头组三、四段扶杨油层,在三个三级层序、八个体系域及八个油层组高分辨率层序地层格架基础上,通过岩石学特征、地球物理学特征等建立沉积微相类型,系统地研究沉积相。研究区主要为浅水湖泊-三角洲沉积特征,发育以南北物源为主呈环带状展布的浅湖、三角洲前缘、三角洲平原亚相。浅水湖泊主要包括开阔湖、浅湖;三角洲前缘包括水下分流河道、河口坝、远砂坝及分流间湾;三角洲平原包括分流河道、天然堤、决口扇及泛滥平原。河道砂岩单层厚度大、物性好,是有利储层,可形成岩性圈闭。认清砂体沉积微相类型,有利于准确预测河道砂体的分布,对于有效寻找岩性油藏具有重要意义。
Daqing Changyuan and west of the Lower Cretaceous Quantou Formation three or four Fuyang oil and gas reservoir potential is larger, is Daqing oilfield reserve reserve in recent years the main source. In the past, the study of sedimentary facies with unit intervals as a unit has been unable to meet the actual needs of the oilfield. With the improvement of exploration degree, exploration density and high-resolution seismic data in recent years, there is an urgent need to carry out “ Zoom in, the preparation of large-scale sedimentary facies ”. Based on the three third-level sequences, eight systematic systems and eight high-resolution sequence stratigraphy frameworks of the Lower Cretaceous Quantou Formation in the Lower Cretaceous and the west of the Daqingyuan area, , The types of sedimentary microfacies are established through petrological and geophysical characteristics and systematically studied sedimentary facies. The study area is mainly the sedimentary features of shallow lakes and deltas. Developed shallow epicyclic belts, delta front and deltaic subfacies with north and south provenance mainly developed. Shallow lakes mainly include open lakes and shallow lakes; the delta front includes subaqueous distributary channels, estuarine dams, distal sand bars and shunt bays; and deltaic plains include distributary channels, natural dikes, bursts and flood plains. Channel sandstone single thickness, good physical properties, is a favorable reservoir, can form a lithologic trap. Recognizing the sedimentary microfacies type of sand body is good for accurately predicting the distribution of channel sand body, which is of great significance for effectively finding lithologic reservoirs.