Two kinds of margin respectively occur in the Ordos Basin during the Middle-Late Triassic (Yanchang Age), one is foreland margin developed under the background of flexural subsidence by thrusting intensively in the southwest margin, and the other is intracratonic basin margin by stable subsidence in northern and central parts of the basin. The Middle-Late Triassic Yanchang Formation can be divided into four regional third-order sequences, which are separated by gentle angular unconformity or regional erosion surface, made up of lowstand system tract (LST), expanding system tract (EST) and highstand system tract (HST) from lower to upper within a sequence. But there are distinct differences of the sequence framework between the southwest margin and northern and central parts of the basin. The southwest margin develops heavy conglomerate layer and unconformity as a result of orogeny by thrusting, and the intracratonic basin margin by stable subsidence in the northern and central parts grows aggradational sandstone, conglomerate in fluvio-delta system and parallel unconformity. The depositional framework of southwest margin reflects the tectonic evolution from flexural subsidence by thrusting to rebounded uplift. The formation of sequence boundary is related to the resilient uplift and erosion. The sequence stratigraphic framework and depositional system tract configuration in the foreland basin are controlled by structural activity of the fold and thrust belt, and the sequence succession reflects episodic thrusting of the Middle-Late Triassic toward the foreland basin. The sequence evolution in northern and central parts reflects the depositional succession of fluvio-delta system under intracratonic background, composed of coarse-grained sediment in braided channel deposit at the lower, meandering channel deposit in the middle and fine-grained sediment in the flood plain at the upper, dominated by lake level fluctuation. During the deposit of the LST in the intracraton basin, accommodation space is limited, and results in abundant fluvial sediment migration laterally, erosion and transport, forming laterally sandstone composite and aggradational deposit on the alluvial plain, which constitutes specific erosion unconformity boundary.
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浊积岩分序级描述技术是在前人研究与勘探实践基础上,以层序地层学理论为指导,结合较为前沿的地震沉积学理论,分析层序内部结构,明确了浊积岩发育序级的划分原则、对比和划分方法;以地震资料为基础,充分发挥了井震结合的优势,形成了浊积岩的地震识别模式的建立方法.本次研究建立了东营凹陷沙三段和沙四上不同类型浊积岩的地震响应模式,形成了浊积岩分序级描述技术;该技术可以用来预测新的浊积岩发育区.东营凹陷油气勘探实践证明,在浊积岩分序级描述的基础上进行勘探优化部署,可以有效的提高浊积岩油藏的勘探成功率. 相似文献
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利用沉积学、层序地层学理论分析和研究沉积相特征,得出探区内发育的储层主要有冲积扇、河流、三角洲、浊积扇和滩坝五大沉积体系,提出了上第三系”水流控砂”、下第三系”坡槽控砂”的沉积模式,得到储层按构造带分布的规律.隐蔽性油气藏以”断导”模式成藏,与储层发育相匹配形成四个大的隐蔽性油气藏群.研究地震储层描述方法的适应性和敏感性,利用正、反演类比方法研究地震反射特征,实现了地震相和沉积相的转换.剖析典型的油气藏类型,分析成功的经验,总结失败的教训,得到了针对河流、冲积扇、三角洲、滩坝和浊积扇的描述流程和配套技术系列. 相似文献
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在等时层序格架建立的基础上,利用地震资料研究各体系域内部沉积体的空间展布、叠置样式和沉积演化过程,进而预测各体系域中砂体的分布,是层序地层学应用于勘探实践的重要内容.OpendTect系统在三维地震倾角扫描的基础上,①以地震采样点空间信息为导向,实现了层序界面控制下的地震小层自动追踪,可以精细刻画出体系域内部沉积体地震反射结构和空间展布;②通过对各层序单元内部地震小层追踪结果进行层拉平,实现了时间域到Wheeler域的自动变换,可以更加直观地分析地层沉积演化历史;③通过沿沉积体内部小层面提取地震属性,实现了等时地层切片的提取,减少了地震属性多解性,提高了预测精度.OpendTect系统提供了一种新的基于层序地层的地震综合解释技术和思路. 相似文献
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鄂尔多斯盆地中晚三叠世两种不同类型边缘层序构成及对构造活动响应 总被引：5，自引：0，他引：5
中晚三叠世(延长期)鄂尔多斯盆地发育两种不同构造类型的盆地边缘,其中西南缘为强烈逆冲导致的挠曲沉降背景下发育的前陆盆地,北中部为稳定沉降的克拉通内盆地.中上三叠统延长组可划分为四4个区域性的三级层序,它们均由微角度不整合或区域性冲刷面所分隔,内部自下而上由低位体系域、湖进体系域和高位体系域构成,但盆地西南缘和北中部的层序构成在沉积样式上存在明显差异:西南缘由于逆冲造山而发育巨厚的砾岩带和不整合,北中部稳定沉降的克拉通则发育加积的河流相砂、砾岩和平行不整合.西南缘的沉积构成反映了从逆冲挠曲沉降到回弹上隆的演化过程,层序界面的形成与回弹隆起、剥蚀和冲断作用有关.前陆盆地的层序地层格架和体系域的配置受褶皱冲断带活动控制,其层序序列反映了中晚三叠世造山带向前陆盆地不断逆冲的过程.北中部的层序演化反映克拉通缓坡背景下的河流-三角洲沉积序列,由底部的粗碎屑辫状河沉积、中部的曲流河沉积和顶部的细碎屑河漫滩沉积构成,受湖平面升降变化控制.在缓坡背景下的低位体系域沉积期,由于可容纳空间有限,大量的河流沉积物只能通过侧向迁移、侵蚀和搬运,在冲积平原上形成砂体的侧向复合加积,构成特定的侵蚀不整合边界. 相似文献
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沉积相研究是盆地隐蔽油气藏勘探中重要的研究内容之一,综合利用地球物理方法有效识别构造、岩性或沉积相差异是盆地隐蔽油气藏勘探的前提.本文基于重力、航磁、地震等综合地球物理资料,通过重磁异常正演剥离和剖面正反演拟合技术研究了华南桂中地区海相地层的密度分布特征,预测了岩相、沉积相的变化规律.研究发现,本区中、下泥盆统海相地层存在横向的岩性、岩相变化,研究区西北、东南部的台地相区重力异常高、岩石拟合密度值高;中部“X”型台地边缘相区重力异常杂乱、岩石拟合密度变化范围大;东部台沟相区重力异常低、岩石拟合密度值低.利用综合地球物理方法预测沉积相为盆地岩性圈闭油气藏和生物礁油气藏勘探提供了新的研究思路,研究成果已得到初步检验,但还有待进一步完善与实践. 相似文献
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塔里木地台北部寒武纪-奥陶纪层序地层及其与扬子地台和华北地台的对比 总被引：16，自引：0，他引：16
以详细的露头层序地层研究为基础,概述了塔里木地台北部寒武纪-奥陶纪的层序地层系统.该系统以不同级别的层序为基本单元所构成,包括35个三级层序,12个超层序,4个超层序组和2个巨层序.同时,结合地震剖面和钻井资料,对其中的重要层序界面特征进行了讨论,并通过生物地层与层序地层相结合的方法,标定了重要层序界面的年龄.通过对塔里木地台寒武纪-奥陶纪层序地层与扬子地台和华北地台同期层序地层的对比研究发现,其间有较好的对应关系.说明寒武纪-奥陶纪时中国三大地台上碳酸盐岩层序的发育主要受控于大区域和全球性的海平面变化.这为在我国三大地台区寒武系-奥陶系中开展以层序地层学为基础的高分辨率年代地层体制研究提供了理论支持. 相似文献
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介绍了应用钻井和三维地震资料来划分高精度(四级)层序和体系域的地震沉积学方法。其关键技术包括:(1)将地震数据进行90°相位调整来记录岩性,从而获得更完善的测井资料;(2)假设并解释沉积体系中连续的平面地貌特征。下面我们推荐一种新的解释方法,就是将高精度层序地层学的研究重点从解释垂直地震剖面转变为分析更加水平、分辨率更高的地震地貌信息。这方面的研究表明,有岩性限制的地震资料中,地层切片可提供通常为同沉积体系的连续地震图像。反过来,这种图像又可作为识别和划分高频体系域、层序边界以及层序地质年代范围的基础。在路易斯安那近海的中新统地层中,运用测井资料划分的四级层序或层序组,可通过地震资料来划分,地震数据体的主频为30Hz,相当于分辨率为30ft(10m)。所用的这一分辨率在井控外的地震覆盖区,对高精度层序地层格架进行精确再现非常有效。 相似文献
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The results of ecostratigraphy can directly serve sequence stratigraphy. The habitat type curve is useful not only in the
analysis of sequences and parasequences, but also in demonstration of the process of regional sea level change. The various
biological surfaces usually coincide with or relate to the boundaries of sequences or system tracts. The ecostratigraphic
framework composed of coenozones, community sequences and ecotracts with good timing completely corresponds to the sequence
stratigraphic framework of the sedimentary basin. Therefore, through establishment of the habitat type curve in individual
section, recognition of the various biological surfaces, regional ecostratigraphic correlation and the formation of an ecostratigraphic
framework of the sedimentary basin, ecostratigraphy plays an important role in the study of sequence stratigraphy and the
reconstruction of regional and even global sea level changes. 相似文献
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《中国科学D辑(英文版)》2008,(Z2)
With a comprehensive geological and geophysical data base,the Paleogene in the Liaodong Bay area,which consists of the Kongdian,Shahejie and Donghying Formations from the base to top,was divided into 4 second-order sequences and 8 third-order sequences based on the characteristics of the se-quence boundaries. Each third-order sequence is subdivided into the lowstand,lake transgressive and highstand systems tracts. The Lowstand systems tract (LST) is mainly composed of progradational parasequence sets,while the lake transgressive systems tract (TST) largely consists of the retrograda-tional parasequence sets and the highstand systems tract (HST) is dominated by the progradational parasequence sets. The main types of depositional systems include the shallow lake,semi-deep lake,deep lake,delta,fan delta,braided fluvial delta and nearshore subaqueous fan. The braided fluvial delta and fan delta depositional systems are mainly confined to the sequences of the lower SEs4-Ek,SEs3 and SEs1 2,while the sequences of SEd3,SEd2 and SEd1 are dominated by the delta and nearshore subaqueous fan depositional systems with the latter being developed at the downthrown side of the basin-bounding fault in each sequence. The evolution of the depositional systems is always con-trolled by the paleo-tectonic setting and the ancient landform in the space and geological time. It is concluded that the most favorable reservoirs are distributed in the Liaoxi low uplift and the central Liaozhong sag. 相似文献
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Two kinds of margin respectively occur in the Ordos Basin during the Middle-Late Triassic (Yanchang Age), one is foreland margin developed under the background of flexural subsidence by thrusting intensively in the southwest margin, and the other is intracratonic basin margin by stable subsidence in northern and central parts of the basin. The Middle-Late Triassic Yanchang Formation can be divided into four regional third-order sequences, which are separated by gentle angular unconformity or regional erosion surface, made up of lowstand system tract (LST), expanding system tract (EST) and highstand system tract (HST) from lower to upper within a sequence. But there are distinct differences of the sequence framework between the southwest margin and northern and central parts of the basin. The southwest margin develops heavy conglomerate layer and unconformity as a result of orogeny by thrusting, and the intracratonic basin margin by stable subsidence in the northern and central parts grows aggradational sandstone, conglomerate in fluvio-delta system and parallel unconformity. The depositional framework of southwest margin reflects the tectonic evolution from flexural subsidence by thrusting to rebounded uplift. The formation of sequence boundary is related to the resilient uplift and erosion. The sequence stratigraphic framework and depositional system tract configuration in the foreland basin are controlled by structural activity of the fold and thrust belt, and the sequence succession reflects episodic thrusting of the Middle-Late Triassic toward the foreland basin. The sequence evolution in northern and central parts reflects the depositional succession of fluvio-delta system under intracratonic background, composed of coarse-grained sediment in braided channel deposit at the lower, meandering channel deposit in the middle and fine-grained sediment in the flood plain at the upper, dominated by lake level fluctuation. During the deposit of the LST in the intracraton basin, accommodation space is limited, and results in abundant fluvial sediment migration laterally, erosion and transport, forming laterally sandstone composite and aggradational deposit on the alluvial plain, which constitutes specific erosion unconformity boundary. 相似文献
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针对委内瑞拉奥里诺科重油带J区块新老二维地震资料存在的问题,应用精细匹配处理方法,即以精细频率匹配和精细振幅匹配和相位校正为主要手段,结合时间偏移处理以及去噪、混波处理等手段,普遍突出了有效反射信息,提高了不同年度地震剖面之间的闭合精度,大大提高了构造解释的准确性,虽然地震资料很少,但仍解释出了J区块的三层构造图,构造解释结果表明,J区块地层总体是一个北倾单斜,其上发育一些北东和近东西向的断层,油藏类型以岩性油藏为主,断层对油藏主要起复杂化作用,J区块这一构造特征与其所处的构造背景、基底形态和构造应力作用有关. 相似文献
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Landsat 8卫星自2013年2月发射以来,其影像的定标参数经过了不断调整和完善,针对Landsat 8开发的各种算法也相继问世.本文采用最新的参数、算法和引入COST算法建立的大气校正模型,对Landsat 8多光谱和热红外波段进行了处理,反演出它们的反射率和地表温度,并与同日的Landsat 7数据和实测地表温度数据进行了对比.结果表明,现有Landsat 8多光谱数据的定标参数和大气顶部反射率反演算法已有很高的精度,本文引入COST算法建立的Landsat 8大气校正模型也与Landsat 7的COST模型所获得的结果几乎相同,相关系数可高达0.99.但是现有针对Landsat 8提出的地表温度反演算法仍不理想,已提出的劈窗算法误差都较大.鉴于TIRS 11热红外波段的定标参数仍不理想,因此在现阶段建议采用单通道算法单独反演TIRS 10波段来求算地表温度,但要注意根据大气水汽含量的情况选用正确的大气参数计算公式. 相似文献
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