东营凹陷始新统风

发布时间：2018-04-23 11:05

本文选题：风-源-盆 + 滩坝　；参考：《中国地质大学(北京)》2016年博士论文

【摘要】：风场是一项重要的气候指标,不仅反映大气环流信息,作为一种地质营力也控制了沉积过程。但在古气候研究中,有关古风场的研究较少,原因是古大气流场活动遗留下来的有效信息极少,难以从地质记录中加以恢复。中国东部古近系滨浅湖环境发育了大量的滩坝砂体,并成为了油气增储上产的新领域,其形成与古风场关系密切。本文以东营凹陷沙四上亚段为例,通过研究风浪对滩坝沉积过程的控制,借助岩心、测录井、地震等资料,引进古风场的研究;指出滩坝沉积受控于风场-物源-盆地系统(简称“风-源-盆”系统)。主要成果有:(1)总结了“风-源-盆”系统沉积动力学的研究思路与研究方法。指出古风场及其控制下的古气候控制了沉积体的构造、结构特征;古物源提供了物质基础;古地貌与古水深决定了沉积体的发育位置、范围与规模,三者共同作用决定了沉积体的时空展布,为研究含油气盆地砂体的形成和分布提供了新思路;(2)开展了东营凹陷沙四上亚段层序地层划分和沉积体系分析。将目的层段划分为一个三级层序、三个体系域,重点地区精度达到准层序的级别,为“风-源-盆”系统的研究建立了等时格架;根据岩心、测录井等资料,共识别出了七种典型的沉积体系:扇三角洲、水下重力流、三角洲、滨浅湖滩坝、碳酸盐滩坝、半深湖风暴沉积、半深湖-深湖细粒沉积,并确定了各沉积体系发育规律;(3)建立了滩坝的成因模式。依据滨岸带波浪动力特征,将发育在破浪带的沙坝称为远岸坝;发育在碎浪带或内破浪带的沙坝称为近岸坝;发育于冲浪回流带的沙坝称为沿岸坝。发育在波浪遇浅带、波浪重生带、冲浪回流带的沙滩分别称之为外缘滩、坝间滩、沿岸滩,在平面上,滩主要以席状的形式包围于沙坝周围,即“坝间和坝外为滩”;滩坝的形成受控于“风-源-盆”系统的统一作用;(4)提出了利用古湖泊中滩坝沉积定量恢复古风场的方法。包括:①根据破浪沙坝的走向及横向不对称性恢复古风向;②根据破浪沙坝和沿岸砾质沙坝的厚度定量恢复古风力。研究表明,风场可能还控制了气候要素中冷暖干湿的变化;本文提出的方法为古风场乃至古气候的恢复开辟了新的思路,也为滩坝砂体的形成和预测研究提供了方法。
[Abstract]:Wind field is an important climatic index, which not only reflects the information of atmospheric circulation, but also controls the sedimentary process as a kind of geological force. However, in paleoclimate research, the paleolian field is less studied, because there is little effective information left over from paleo-atmospheric flow field activity, so it is difficult to recover from geological records. The paleogene shallow lake environment of eastern China has developed a large number of beach and dam sandbodies and has become a new field of oil and gas accumulation and production, and its formation is closely related to the paleo-wind field. Taking the upper submember of Sha 4 in Dongying sag as an example, this paper introduces the study of paleo-wind field by studying the control of beach and dam sedimentation process by wind and wave, with the help of core, logging and seismic data. It is pointed out that the deposit of beach and dam is controlled by the system of wind field, material source and basin (referred to as "wind-source-basin" system). The main results are as follows: (1) the research ideas and methods of the sedimentary dynamics of the "wind-source-basin" system are summarized. It is pointed out that paleogeomorphic field and paleoclimate controlled by paleoclimate control the structure and structural characteristics of sedimentary body, ancient source provides material foundation, paleogeomorphology and paleogeomorphology and paleo-water depth determine the development position, scope and scale of sedimentary body. The interaction of the three factors determines the spatial and temporal distribution of sedimentary bodies and provides a new idea for the study of the formation and distribution of sand bodies in oil-bearing basins. The sequence stratigraphic division and sedimentary system analysis of the upper member of Sha 4 in Dongying Sag have been carried out. The target interval is divided into a third order sequence, three system tracts, and the precision of key area reaches the level of quasi sequence. The isochronous framework is established for the study of "wind-source-basin" system, according to the data of core, logging and so on. Seven typical sedimentary systems were identified: fan delta, underwater gravity flow, delta, shoreline beach dam, carbonate beach dam, semi-deep lake storm deposit, semi-deep lake-deep lake fine-grained deposit. The genetic model of beach and dam is established. According to the wave dynamic characteristics of the shoreline zone, the sand dam developed in the breaking wave zone is called the far shore dam, the sand dam developed in the cataclysmic zone or the inner breaking zone is called the nearshore dam, and the sand dam developed in the surf return zone is called the coastal dam. The beaches developed in wave shallow zone, wave rebirth zone and surf return zone are called outer edge beach, dam beach and coastal beach respectively. On the plane, the beach is mainly surrounded by the sand dam in the form of matting form, that is, "the beach between the dam and outside the dam is the beach"; The formation of beach dam is controlled by the unified action of "wind-source-basin" system. It includes: 1 restoring palewind direction according to the strike and transverse asymmetry of breaking sand dam and restoring paleolian force quantitatively according to the thickness of breaking sand dam and gravel sand dam along the coast. The results show that the wind field may also control the changes of cold and warm dry and wet in climatic elements, and the method proposed in this paper has opened up a new way of thinking for the restoration of paleo-wind field and paleoclimate, as well as provided a method for the formation and prediction of beach bar sand bodies.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P618.13;P534.613

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