苏北盆地戴南组泥屑流扇沉积

发布时间：2018-01-20 00:20

本文关键词： 泥屑流扇多因素耦合岩石特征沉积成因戴南组苏北盆地　出处：《石油与天然气地质》2017年03期 　论文类型：期刊论文

【摘要】：针对苏北箕状断陷盆地戴南组的沉积体系、岩性岩相、砂体展布等特征,既不遵循中国东部箕状断陷盆地的一般规律,也不遵循陆相盆地沟槽带是建设扇体、砂体主带的普遍规律,通过大量岩心资料观察,发现戴南组存在一种由砂级泥岩粗岩屑组成的特殊类型沉积岩,其分布具有一定的普遍性和规律性。据此,以岩心观察描述为基础,结合岩石薄片鉴定特征、地层古生物组合特殊面貌及剖面测录井响应的一些特有现象,综合识别这套特殊岩性剖面。研究表明,这套地层是重力流之泥屑流流体的沉积产物—泥屑流扇,扇体可分扇根、扇中和扇端3带。平面上,此类扇发育在断陷湖盆凹缘坡折带,即湖盆沟槽地带;剖面上,此扇主要见于戴南组断陷湖盆低位域,湖侵域无此扇,高位域有个别此扇。分析认为,苏北箕状断陷湖盆有特殊的成盆古地质背景,即由下构造层大型的统一拗陷湖盆解体形成了相互分隔的戴南组箕状断陷群,由此形成了阜四段大套泥岩围限、新老双重物源、构造作用差异、多种搬运输送流态及多样坡折带类型等多因素耦合,共同控制了戴南组沉积特征。由此,发现了断陷凹缘坡折带发育泥屑流扇、富泥扇,断陷凸缘坡折带生长富砂扇的规律。
[Abstract]:In view of the sedimentary system, lithologic lithofacies and sandbody distribution of Dainan formation in the dustpan faulted basin of northern Jiangsu Province, neither the general rules of the dustpan faulted basin in eastern China nor the trench belt of the continental basin is a constructive fan body. Based on the observation of a large number of core data, it is found that there is a special type of sedimentary rock in Dainan formation, which is composed of coarse sand-grade mudstone, and its distribution has certain universality and regularity. On the basis of core observation and description, combined with the characteristics of thin slice identification, the special features of formation paleontological assemblage and some special phenomena of profile logging response, this special lithologic profile is comprehensively identified. This set of strata is the sedimentary product of the mud debris flow fluid of gravity flow, the fan body can be divided into fan root, fan and fan end 3 zones. On the plane, this kind of fan is developed in the slope break zone of the concave margin of the faulted lake basin, that is, the lacustrine trench zone. In the section, this fan is mainly found in the lower basin of Dainan formation, not in the transgressive area, but in the high area. The analysis shows that there is a special basin paleogeological background in the basin of the dustpan depression in northern Jiangsu. That is to say, from the disintegration of the large unified depression lake basin of the lower tectonic layer, the separated Dainan formation dustpan faulted group was formed, thus forming the big set of mudstone confining limit of the fourth member of Fu formation, the new and old double material sources, and the difference of tectonic action. The sedimentary characteristics of the Dainan formation are controlled by the coupling of various transport flow patterns and various slope break types. Therefore, mud debris fan and mud rich fan are found in the slope break zone along the concave margin of the fault depression. The law of sand-rich fan growth in flange slope break zone of fault depression.
【作者单位】：中国石化江苏油田分公司;
【分类号】：P512.2;P618.13
【正文快照】： 苏北盆地基底以陆相中生界为主,盖层为泰州组-阜宁组(K2t-E1f)、戴南组-三垛组(E2d-E2s)、盐城组-东台组(Ny-Qd),上、中、下3套构造层沉积岩总厚度达7 000 m。古新世末,受吴堡事件影响,盆地全面抬升剥蚀;其后,盆地再沉降,断裂和断块体强烈差异活动,将K2t-E1f大型统一湖盆解体

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