福建北部近岸海域晚更新世以来典型地震剖面声学反射特征

根据2015年采集的3 500km浅地层剖面资料,以层序地层学为理论基础,运用地震地层学的分析方法,结合沉积学原理的相关理论,对福建北部近岸海域典型浅地层地震剖面声学反射特征进行了系统的分析和解释。根据本次获得的浅层地震剖面资料和以往的相关解释结果,将研究区浅部地震剖面划分为6个主要的地震反射界面(从上至下定名为QT1、QT2、QT_2~1、QT3、QT_3~1、QT4),这些界面将剖面划分为5个地震单元(从上至下定名为SU1、SU2、SU3、SU4、SU5)。详细描述了每个地震单元的反射界面特征及其层序内部特征,合理推测了每个地震单元的沉积地层特征及其演化,为研究福建北部近岸海域的沉积环境提供科学依据。     

山东芝罘湾附近海域浅地层结构特征

通过分析与研究烟台芝罘湾附近海域420 km浅地层剖面资料及6个钻孔岩心资料,划定了芝罘湾附近海底浅地层层序,并讨论了该研究区海洋地质灾害分布及影响.运用层序地层学和地震地层学的方法,结合钻孔信息对地层反射界面进行了划分,结果显示研究区海域浅地层可划分为5个海陆相交互地层单元,代表了本区浅地层自晚更新世以来经历的3次海...     

大陆架科学钻探南黄海陆架区首钻300m选位研究

大陆架科学钻探300m首钻选址于南黄海陆架区,以钻穿第四纪地层为目标。针对钻孔施工要求及后续研究的需要,提出钻孔部署的原则。在分析南黄海陆架区地形地貌、水深、第四纪沉积物厚度、沉积历史及沉积演化特征的基础上,结合调查区多道地震、单道地震、浅地层剖面及钻孔等资料,敲定了井场调查合理区。同时,在调查区对限制钻探工作的地貌类型和地震相进行了分析,最终选定钻探位置。另外,还根据调查区单道地震的特征对首钻300m钻孔的纵向地层及岩性特征进行了预测,为实施第四纪地层全取心钻探提供依据。近日,海上300.1m钻探取心的成功实施,表明孔位选取和沉积地层预测的技术方法是行之有效的。     

三瞬属性在南黄海第四纪地震地层分析中的应用

浅剖和单道地震是大范围研究新近纪以来沉积特征的主要技术方法,由于地震资料分辨率的限制,往往只能划分大的沉积单元,不能识别亚相、微相等,而地震资料的瞬时属性可以更加精细地刻画地层信息。基于2013年在南黄海陆架获得的单道地震资料,对南黄海中西部海域第四系进行了分析,并利用单道资料的三瞬属性对地层进行地震地层单元划分、沉积环境分析,总结出该区域不同沉积相的三瞬波阻特征。研究结果表明,在测线的Qc2钻孔位置处,根据三瞬属性在海底以下74.64m深度内划分了7个地震地层沉积单元,并划分出多个亚相。它所反映的沉积相与该区已知Qc2钻孔的地层对应度较高。瞬时相位较为清楚的显示地下地层的接触情况,更好地展示了地震层序在空间上的关系,解决了该测线在常规地震剖面上无法清晰、精细识别沉积相的问题。三瞬属性的应用可以在缺少钻井资料时提高在地震资料剖面划分地层、识别接触面的能力,为大陆架科学钻探项目中未知井位选址提供参考。     

现代长江水下三角洲浅地层地震相特征

利用传统的地震相分析方法,分析总结现代长江水下三角洲浅地层地震剖面反射波的几何形态、内部反射结构、连续性、振幅等特征,形成对长江水下三角洲各典型地震相特征的认识,圈定相应的地震相范围,并结合钻孔资料,解释了长江口范围三角洲前积、浅海沉积、古河道等各沉积相的分布。结果表明,现代长江水下三角洲浅地层各地震相特征明显。典型的三角洲前积地震相主要分布在长江口外东北部,其余大部为典型浅海沉积地震相,且浅海地震相特征向口内逐渐变弱,表现为浅砂或淤泥型地震相,向口外逐渐有晚更新世基底地震相出露,并发育古河道地震相,此外,浅层气地震相嵌入区内各个地震相范围。     

红星地区沙一段储集砂体展布特征研究

以层序地层学及沉积学等理论为指导,综合区域地质资料,地震、测井及岩心资料分析等,在红星地区开展层序地层和沉积体系研究.在已有的区域层序地层格架内,识别出三角洲前缘水下分流河道、河口坝、前缘席状砂坝、分流间湾和滨浅湖等多种沉积微相类型,并总结了各种沉积微相的测井响应特征,进一步探讨了沙一段有利储集相带的分布规律.结合四级湖平面变化、同沉积断裂、火山活动、沉积相分布等分析了沙一段砂体分布的控制因素.     

南黄海新近纪以来地层沉积特征研究的地震技术方法

地震技术方法是研究海底之下地层沉积特征的主要手段。针对地震资料特点和研究需求,开展了新近系以来的沉积特征的地震方法研究,利用资料净化、多次波压制和高分辨率岩性处理等技术方法,提高了地震资料的信噪比和分辨率;采用基于多道地震叠加速度资料基础的速度分析和时间—深度转换方法,保证了沉积地层埋藏深度的计算精度;以海洋地质学、地震地层学的方法为指导,预测地层岩相并评判了沉积环境。CSDP-1孔的钻探结果证明研究方法的有效性。     

东海北部外陆架MIS 6以来的沉积地层格架及古环境演化

利用最新采集的高分辨率浅地层剖面资料,结合SHD-1钻孔岩心资料,对东海北部外陆架MIS 6以来的地层结构进行了分析,建立了MIS 6以来的沉积地层格架,并对地层的地质年代进行了厘定。根据Octavian Catuneanu(2005)的层序地层学理论,研究区地层划分出海侵和高位体系域、下降期体系域、海退和低位体系域。研究表明,过孔的浅地层剖面与钻孔岩心的沉积地层有很好的对应关系。东海北部外陆架MIS 6以来可划分出7个不整合界面(D7—D1)和7个地震单元(SU_7—SU_1)。东海外陆架的海进层序与海退层序有规律地交替发育,它们与海平面变化曲线也有很好的对应关系。其中,地震单元SU_1、SU_5分别为MIS 1、MIS 5形成的海侵沉积,主要发育浅海沉积层,100 m以浅的位置发育潮流沙脊;地震单元SU_2、SU_4、SU_6分别对应MIS 2、MIS 4和MIS 6低海平面时期形成的河流/河口—三角洲沉积;地震单元SU3、SU4为下降期体系域,这两个亚单元分别对应MIS 3和MIS 4晚期。MIS 4—MIS 3发育厚层且分布广泛的水下三角洲,但MIS 4发育的水下三角洲的规模不及MIS 3大。总之,对MIS 6以来沉积地层格架的建立和古环境研究可为东海外陆架晚第四纪地层的海平面变化、古环境演化等相关研究提供参考。     

基于地震沉积学方法的沉积相研究——以珠江口盆地番禺4洼古近系为例

油气勘探与开发实践表明,在少井、无井及低分辨率地震资料的海域,利用地震沉积学的方法和技术,可有效建立高频层序地层格架,刻画沉积体系演化规律,这是陆相断陷湖盆地层—岩性油气藏勘探的有效手段。本研究以番禺4洼古近系文昌组为例,在地震沉积学理论指导下,基于高分辨率处理地震资料,在三级层序地层格架约束下,以体系域旋回为单位,结合单井的岩性资料,利用90°相位转换、地层切片及定量岩石物理分析技术,对珠江口盆地番禺4洼始新统文昌组开展了地震沉积学研究,划分了6个三级层序,建立了地层岩性与地震极性关系,并对已钻井开展岩石物理分析,最终在SQ2筛选不同时期切片,雕刻了文二段沉积时期,东、西两侧向湖盆推进的扇三角洲、近岸水下扇及辫状河三角洲的沉积体系展布和演化规律。     

黄河口现代海洋沉积高分辨率地震地层学研究

本文运用地震地层学的知识,结合KDG2和S3钻孔资料,对2002年得到的现代黄河口地区的浅地层地震剖面进行了分析解释,共划分出中更新世以来11个地震地层单元,对每个地震地层单元进行了地震相的有关描述,对剖面上出现的地质现象给予了合理推测和详细分析,并结合相邻的钻孔资料,与全球冰期进行对比,构筑了黄河口地区晚第四纪以来地层的沉积模式。     

SCOPIX – digital processing of X-ray images for the enhancement of sedimentary structures in undisturbed core slabs

X-ray images of sediment core allow recognition of fine-scaled sedimentary structures which traditional epoxy casts or lacquer peels are unable to resolve. The X-ray imaging system SCOPIX has the additional advantage of acquiring high-resolution digital pictures suitable for further analysis by advanced image processing techniques. Because of the frequent presence of both physical and biogenic sedimentary structures in undisturbed sediment cores, two image analysis procedures have been established which simplify the information contained in the images (in term of structures and facies), and allow a quantitative characterization of the observed structures. This form of parametrization of the image structure constitutes an additional source of information for a better interpretation of the physical processes responsible for the generation of the sedimentary structures.     

济阳坳陷陡坡带油气富集特征

依据构造样式和沉积特征将济阳坳陷陡坡带分为板式、铲式、断阶式、坡坪式4种类型。断阶式和坡坪式陡坡带砂砾岩扇体类型多,成藏条件优越,各类油气藏发育完全,在纵向上组成较完整的油气藏序列。板式和铲式陡坡带砂砾岩扇体主要为近岸水下扇,其次为扇三角洲,油气藏类型单一,在纵向上油气藏序列发育也不完整。此外,板式陡坡带由于断裂不发育,沉积相带窄,油气相对贫瘠。油气在断阶式中最为富集,其次为坡坪式和板式,铲式相对贫乏。     

南海南部海域新生代万安运动的构造意义及其油气资源效应

南海南部海域在中中新世末发生了一次区域构造运动,被命名为万安构造运动。这次构造运动在新生代沉积中的表现是断裂、块断、挤压背斜和向斜。部分地区发育逆冲构造等。根据南海区域构造分析产生这次构造运动的起因可能与菲律宾海板块和欧亚板块于13MaBP在民都洛岛处发生碰撞．以及澳大利亚板块和欧亚板块在苏拉威西岛处发生碰撞(10MaBP)有关。这两次碰撞事件均对南海南部海域产生挤压,尤其是第一次碰撞挤压(向西方向)很强烈,是这次构造事件的主导因素。万安构造运动在南海南部海域沉积盆地中产生了许多挤压构造;而该海域沉积盆地中生烃的关键时刻是6MaBP,构造形成时间在生烃关键时间之前。因此,该海域形成了极其丰富的油气资源。     

Bedforms and depositional sedimentary structures of a barred nearshore system, eastern Long Island, New York

The depositional sedimentary structures and textures of a single-barred nearshore system on the Atlantic coast of eastern Long Island, New York, were studied along seven shore-normal transects. Data along these transects consisted of textural analysis of 160 sediment samples, temporal bedform observations, and 42 can cores for the analysis of sedimentary structures.

Six sedimentary subenvironments were observed, based on distinct combinations of sediment color and texture, bedforms, physical, and biogenic sedimentary structures, and benthic infaunal communities. The shoreface environment is divided into the upper shoreface, the longshore trough, and the longshore bar. The divisions of the inner shelf environment are the shoreface-inner shelf transition, the offshore, and the coarse-grained deposit. The first five subenvironments are arranged in bands parallel to the shoreline, whereas the coarse-grained deposit occurs in patches across the inner shelf.

The location of fair-weather wave base, coinciding with a reduction in slope (3.0–0.3°) from the shoreface to the inner shelf, is characterized by the cessation of debris surge in the troughs of ripples, the formation of a “rust layer” of microorganisms over the bedform surface, and a sediment color change caused by an increase in organic detritus. The sequence of bedforms and physical sedimentary structures observed in this system fits well with existing wave-generated (oscillatory) flow regime models. These models explain the observed sequences as a response to the degree of asymmetric flow created by shoaling waves. Distribution of biogenic structures and assemblages of infaunal organisms is influenced by the distance landward or seaward of fair-weather wave base.

The overall relationships of this nearshore system can then be summarized as a hypothetical prograding stratigraphic sequence. The entire sequence is underlain by organic-rich, bioturbated, offshore deposits. Overlying the offshore is the planar-laminated sediments of the transition. Grading upward from the transition are the cleaner, planar-laminated, seaward slope deposits of the longshore bar. Above this, is a distinct erosional surface indicating the base of the massive to cross-laminated coarse sediments of the longshore trough. Capping the sequence are the cross- to planar-laminated, clean sands of the upper shoreface and foreshore.     

平衡剖面技术及其在济阳坳陷桩海地区的应用

平衡剖面技术在研究盆地演化方面有着重要的作用,可以编制盆地发育演化剖面,广泛地用于研究石油构造分析。平衡剖面的最基本原理就是在地层变形前后物质的总量是不变的。利用2DMove软件对济阳坳陷桩海地区的两条地震剖面进行构造恢复,编制了构造发育剖面,恢复该区的构造演化史。桩海地区在三叠纪一中侏罗世由于印支运动的强烈挤压作用而抬升剥蚀;晚侏罗世一早白垩世时期,在中国东部发生了强烈的伸展作用,发育了大量的断裂和接受了巨厚的沉积地层;在晚白垩世,由于郯庐断裂的左行走滑作用,桩海地区抬升并遭受剥实;在古近纪,受区域构造伸展作用,桩海地区发育成为断陷盆地。古近纪末,发生右行走滑运动和构造抬升。新近纪以来该区表现为稳定的坳陷沉积盆地。     

全新世以来珠江三角洲快速沉积体的初步研究

根据珠江三角洲代表性钻孔资料以及PRD-LTMM长周期"动力-沉积-形态"模型分析了珠江三角洲形成发育过程中的快速沉积现象,提出了珠江三角洲快速沉积体的概念,并且对典型快速沉积体的成因进行了初步分析。快速沉积体有明确的沉积环境和特定的沉积动力成因,沉积速率为每年厘米级,研究它可以深入地揭示珠江三角洲基本沉积单元的形成过程,为探索珠江三角洲的形成、发育机制打下基础。初步发现的快速沉积体有古汇潮点快速沉积体、古涨潮射流快速沉积体和台地周边快速沉积体。研究结果表明,快速沉积体的形成多与特定的地形边界条件下形成的中、小尺度动力结构有关,具有高度的时空变化。掌握珠江三角洲地形边界的特点、变化过程及其作用下的中、小尺度动力结构是研究珠江三角洲快速沉积体的关键。     

Development of a sound reflection system for profiling sediments in shelf and slope depths

A sound reflection system for obtaining profiles of sedimentary structures in shelf and slope depths to 500 m has been developed, based on an Edgerton 1 kJ boomer as sound source. A logarithmic response receiver allows optimal recording of signals over a wide dynamic range. Penetrations of up to 500 m have been obtained from structures within both unconsolidated sediments and folded lower Tertiary structures. The equipment works reliably at speeds up to 9 knots.     

SCOPIX: A new X-ray imaging system for core analysis

SCOPIX is a new digital X-ray imaging system for core analysis that uses an X-ray source coupled to a high-energy brightness amplifier and a CCD camera. SCOPIX’s numerical files are images in 256 gray levels equal in value to X-ray densities. Possible data processing approaches include: core logging using grayscale profiles to define the characteristics of sedimentary sequences and image processing to define and quantify lithologic facies and the geometry of physical and biological structures. Applications are: recognition of facies and sedimentary processes, study of sedimentary rhythms and geological cycles, and study of biological and geochemical processes.     

Geological control of shallow gas and pockmarks in the Norwegian Channel; high resolution shallow subbottom profiling of small scale features

High resolution bathymetric and fine-scale parametric subbottom profiling along a line to the SW of Stavanger, Norway near the NE flank of the Norwegian Channel, show pockmarks clustered over neotectonic shallow fold structures in Quaternary sediments. Detailed profiles of the pockmarks indicate that they are collapsed gas seeps, rather than being collapse structures that followed doming and breaching with a more dramatic gas burst. The gentle folding and weak structures along the margin of a Mesozoic through Cenozoic sedimentary basin are probably due to differential uplift generating light compressional strain.     

Facies, internal structures and sequences of modern Gironde-derived muds on the Aquitaine inner shelf, France

Seventy cores from the Aquitaine continental shelf were examined using radiographic and grain-size techniques in order to describe the sedimentary structures of the muddy deposits, and to evaluate their depositional processes. Four lithofacies are identified in this fine-grained deposit: (a) homogeneous silty sand, (b) interbedded homogeneous mud and sand, (c) silty-clayey mud, and (d) mottled mud. They show a logical pattern in relationship to the water depth and the distance from the coast.

Primary structures are present particularly in the landward and central portion of the mud fields, where the sediment is organized into sequences with a sharp-based erosional contact, overlain by a fining-up succession (centimetre to decimetre scale). The beginning of each of these is characteristic of a high-energy storm event, which is common on this shelf. The settling of suspended fine sediment corresponds to the flood estuarine discharge during quiet periods. Primary sedimentary structures decrease in the distal area where the muddy sediment is frequently reworked by infauna. Finally, primary structures and their preservation depend on the relative magnitudes of surface waves, storms, infaunal mixing and fluvial sediment deposition rates (i.e. floods).