【作者】 沈玉林；

【导师】 郭英海； 付金华；

【作者基本信息】 中国矿业大学 ， 矿产普查与勘探， 2009， 博士

【摘要】 基于层序界面识别,将鄂尔多斯中东部地区上古生界划分为5个二级层序(层序组)、18个三级层序和50个体系域,建立了陆表海背景下的缓坡盆地边缘Ⅰ型和缓坡Ⅱ型、陆表海衰亡背景下的曲流河-浅水三角洲、辫状河-缓坡型浅水辫状河三角洲以及曲流河-湖泊三角洲等5个二级层序充填模式。在层序格架内阐述了主要沉积相、古地理格局及演化特征。在研究区上古生界识别出了8沉积相、18沉积亚相和23沉积微相类型;晚石炭世主要为碳酸盐潮坪-障壁砂坝-泻湖-浅水三角洲沉积,海水主要来自E及NE方向;早二叠世早期形成以开阔陆表海沉积为主、曲流河-浅水三角洲-障壁砂坝-泻湖-碳酸盐潮坪共存的格局,海水改由SE方向侵入;早二叠世晚期以曲流河-浅水三角洲-近海湖泊沉积为主;中二叠世形成以冲积扇、辫状河-三角洲-湖泊沉积面貌;至晚二叠世晚期演化为曲流河-三角洲-湖泊共存的格局,结束了研究区晚古生代沉积充填发育史。由此,将研究区晚古生代沉积演化分为受限陆表海、开阔陆表海、陆表海衰亡、近海湖盆和内陆湖盆等5个充填阶段。以活动论为指导,结合海西运动的幕式活动,探讨了古地理演化的动力机制;物源来自伊盟隆起,受板块碰撞作用影响,物源区差异性抬升明显,具东西分区的特征。研究区晚古生代古地理格局及演化、晚石炭世末海侵方向转变(相对于现今地理位置),主要是板块碰撞形式的转变所引发的区域古构造体制的改变、物源区的差异性隆升、古地貌特征的演变、基底断裂间歇性的拉张复活以及区域海平面变化综合作用的结果。基于研究区晚古生代沉积演化阶段及其与北部造山带的关系、物源特征、古气候等研究,建立了5种构造-沉积充填模式。双山地区太原组高效储层的发育主要受控于构造格局及古地理,并与物源区母岩性质、海平面变化、成岩作用及板块碰撞引发的基底断裂间歇性活动等因素有关;伊金霍洛旗地区盒8段高效储层的发育主要受控于母岩性质及古地理格局,同时受成岩作用和基底断裂后期活动等因素的影响。更多还原

【Abstract】 Based on the identification of sequence boundary, the upper Paleozoic in the eastern part of Ordos are divided into 5 second-order sequences, eighteen third-order sequences and fifty system tracts. Further more, five second-order sequence filling modes are established, such as typeⅠin the basin with ramp margin and typeⅡin SQⅠ, SQⅡwith epicontinental sea background, meandering river - shallow-water delta sequence filling model in SQⅢwith decline and fall of epicontinental sea, braided river - the gentle slope-type shallow braided river delta sequence filling model, SQⅤmeandering river - lake delta sequence filling model.The character of main sedimentary facies, palaeogeographic distridution and evolution are discussed in sequence stratigraphic framework. 8 sedimentary facies, 18 Sedimentary subfacies and 23 Sedimentary microfacies are identified in upper Paleozoic in study area. Late Carboniferous the deposition pattern of carbonate tidal flat- barrier dams- lagoon- shallow-water delta is shown in study area and seawater is mainly from the direction of E and NE; early Early Permian the palaeogeographic pattern is formed which epicontinental sea sediments take the initiative, coexisting with meandering river- shallow-water delta- barrier dams- lagoon- carbonate tidal flat, seawater intrudes by the SE direction; late Early Permian meandering river- shallow-water delta-coastal lake mainly constitutes the Palaeogeographic pattern; Middle Permian, the deposition pattern of alluvial fan- braided river-delta– lake sediments is formed; late Late Permian, the palaeogeographic pattern is evoluted to meandering river - delta - lake, and the history of late Paleozoic sedimentary filling for study area is ended. The sedimentary filling in study area for late Paleozoic is divided into 5 stages, such as restricted epicontinental sea, development of epicontinental sea, decline and fall of epicontinental sea, coastal basin and inland basin.Under the guidance of activity theory, dynamic mechanism of palaeogeographic evolution is discussed with the infulence of screen activity of Hercynian movement. Source is from the Yimeng uplift , otherness uplift in source area is obvious, and characteristics of east-west division are taken on. It pointes out palaeogeographic evolution of late Paleozoic in study area, the spatial distribution of depositional system and changes in the direction of transgression are controlled by the combined effects such as restructuring of regional palaeostructure system triggered by changes in the form of plate collision, otherness uplift in source area, evolution of ancient features of sedimentary basin, intermittent extension resurrection of basement fault, regional sea-level changes. Based on the research of sedimentary basin development and evolution, relations with the northern belt, source characteristics, paleoclimate research etc, 5 structural- sedimentary filling models are established.Efficient reservoir development of Taiyuan formation in Shenmu-Shuangshan gas-bearing area is controlled by palaeogeography and structural framework, and related to the rock nature of source area, sea-level changes, diagenesis, intermittent activities of basement fault triggered by plate collision. Efficient reservoir development for member 8 in Xiashihezi fomation in Wushenzhao-Yijinhuoluoqi area is mainly controlled by nature of source and palaeogeographic pattern, and related to sequence filling model, diagenesis and late activities of north-east basement fault.更多还原