共查询到20条相似文献，搜索用时 109 毫秒
1.
2.
《Marine and Petroleum Geology》2003,20(6-8):601-613
Reservoir in the Ormen Lange field, offshore Norway, is provided by Upper Cretaceous and Lower Paleocene turbidite sandstones deposited in a sand-rich submarine fan. Systematic vertical and down-fan changes in facies and section properties (thickness, percentage sand and percentage amalgamation) are documented. Bulk sediment accumulation rates are very low suggesting that the system was not directly delta-fed. Paucity of mud in the supply mix prevented the development of channel-overbank systems with strong segregation of sands in channel-fills and muds in overbank areas. The resultant architecture is externally tabular with internally varying degrees of erosional amalgamation between beds. A novel approach to 3D quantitative reservoir modelling has been taken. At a regional-scale (475×180×3 km3), 3D models integrate all well and structural information and provide a context for field-scale models. Nested within the regional models, high-resolution hierarchical reservoir models of the field have been generated. Models combine detailed sedimentological observations in core with petrophysical, pressure, seismic amplitude and structural data. Modelling rules are derived from partial analogues and a forward geometric model that addresses the nature of distal and lateral sandstone body terminations. 相似文献
3.
琼东南盆地新近系莺二段物源体系及其控制下的深水重力流沉积 总被引：1，自引：0，他引：1
近年来在琼东南盆地超深水区莺歌海组发现了多个深水气藏,展现了广阔的勘探前景。但随着油气勘探进一步推进,关于莺二段的储层物性问题日益凸显,严重制约了下一步的勘探进程。本文研究基于前人总结的区域地质资料,结合岩芯、测井和三维地震等资料,建立了莺二段三级层序格架,综合分析了层序格架内物源体系及其控制下的重力流沉积特征。研究表明,重力流沉积体系主要发育在莺二段下、中层序,具有南、北、轴向三大物源体系。不同物源体系控制了重力流储集体的空间展布和沉积特征:(1)南物源控制的海底峡谷充填深海泥岩,而北物源控制的海底峡谷充填的厚层浊积水道砂岩,孔渗物性好,是良好的储集层;(2)轴向物源影响的溢岸漫滩沉积,由于物性条件好,可以作为良好的油气储层;(3)南物源控制海底扇砂岩的厚度薄、粒度细、泥质含量较高,而北物源和轴向物源供应的海底峡谷和海底扇朵体的砂体面积广、厚度大、粒度粗、物性好,是深水区莺二段最重要的优质产气储层。 相似文献
4.
Stratigraphic grade is the similarity of the morphology of successive slope-to-basin profiles in a genetically related depositional system. In this article we use data collected from regional cross-sections of six depositional systems, stratal architecture derived from outcrops of the Lewis Shale (Wyoming, USA), and the Ross Sandstone (Ireland), and supplementary outcrop and subsurface data from other depositional systems to determine how stratigraphic grade relates to stratal (reservoir) architecture in deepwater systems.Four methods are developed that collectively define stratigraphic grade: (1) regional stacking patterns of fourth-order stratigraphic surfaces, (2) the relationship between the trajectory of the shelf edge (Tse) and the trajectory of the depocenter (Td) for fourth-order stratigraphic units, (3) morphology of the slope-to-basin profiles of fourth-order stratigraphic surfaces, and (4) the similarity of the morphologies of slope-to-basin profiles of fourth-order surfaces in a system (σs, σr). Several characteristics of stratigraphic (reservoir) architecture of fourth-order stratigraphic cycles are related to stratigraphic grade: (1) longitudinal distribution of sandstone in fourth-order cycles, (2) location of maximum sandstone relative to the depocenter of fourth-order cycles, (3) lengths of fourth-order submarine fans, and (4) longitudinal and vertical distribution of architectural elements. Stratigraphic grade is thus a predictor of reservoir architecture and can thereby be used to reduce the uncertainty in the interpretation of subsurface data.The concept of stratigraphic grade is useful in understanding the stratigraphic evolution of deepwater systems. Most deepwater systems analyzed in this study initiated as out-of-grade and temporally evolved to graded systems over a time span of millions of years. Systems rarely evolve from graded to out-of-grade. First-order controls on stratigraphic grade are determined to be angle of slope, tectonically forced changes in angle of slope during deposition, and sediment supply. 相似文献
5.
Small turbidite systems in a complex tectonic setting (SW Mediterranean Sea): morphology and growth patterns 总被引：1，自引：0，他引：1
Three small turbidite systems (Almeria, Sacratif, and Guadiaro), each tens of kilometres long, are developed in the complex morpho-structural setting of the northern Alboran Sea and have similar primary architectural elements (canyons, channel-levee systems, lobes). However, comparison reveals differences in the axial gradients of their canyons, depth/physiographic location, morphological framework, and lateral and longitudinal sedimentary shifts of turbidite deposition. The depositional architecture and sedimentary evolution from late Pliocene to Quaternary seems to be conditioned by number of submarine feeding sources (canyons), sea-level fluctuations and local tectonic (e.g. margin/canyon-channel gradients, faults). We group the Alboran turbidite systems into two models: mud/sand-rich submarine point-source and mud/sand-rich multiple submarine source ramp. 相似文献
6.
Comparison of modern submarine fans and ancient turbidite sequences is still in its infancy, mainly because of the incompatibility
of study approaches. Research on modern fan systems mainly deals with morphologic aspects and surficial sediments, while observations
on ancient turbidite formations are mostly directed to vertical sequences. The lack of a common data set also results from
different scales of observation.
To review the current status of modern and ancient turbidite research, an international group of specialists formed COMFAN
(Committee on Fans) and met in September 1982 at the Gulf Research and Development Company research facilities in Pennsylvania.
Margin setting represents fan and/or source area 相似文献
7.
Submarine canyons and associated submarine fans are in some cases located at the end of a littoral cell where they act as conduits for the transfer of eroded terrigenous sediments to the marine environment. Such fans are generally found in deep-water settings at >500 m water depth. Offshore the Moisie River Delta (NW Gulf of St. Lawrence, Eastern Canada), high-resolution multibeam bathymetry and seismic data led to the discovery of an unusually shallow submarine fan (≤60 m) located at the end of a littoral cell. Sediment is transported westward on the shallow coastal shelf, as demonstrated by the downcurrent displacement of oblique nearshore sandbars where the shelf narrows to less than 1 km. The steep slope near the end of the littoral cell is incised by a channel that feeds a submarine fan composed of smaller channels and depositional lobes. According to existing Holocene evolution models for the region, the fan formed within the last 5,000 years. Its evolution is largely due to the transport of sediment by longshore drift. Multibeam echosounder and seismic data also reveal that the gravity-driven accretion of the submarine fan is characterized mainly by two processes, i.e., frequent small-scale, downslope migration of sandwaves on the slope, and more episodic slumping/turbidity-current activity in the deeper part of the fan. This study documents that, besides their common deep-water location, smaller-scale submarine fans can occur also in very shallow water, implying that they could be more frequent than previously thought both in modern environments and in the rock record. 相似文献
8.
《Marine and Petroleum Geology》2003,20(6-8):649-676
High-resolution multichannel 2-D and 3-D seismic data, primarily from upper fan reaches of near-seafloor channel-levee systems on the Niger Delta slope and in the Arabian Sea, reveal a high level of detail and architectural complexity. Several architectural elements are common to each system examined in this study. They include inner levees, outer levees, erosional fairways, channel-axis deposits, rotational slumps blocks, and mass transport deposits. Although the scale of individual systems varies significantly, similarities in first-order architectural elements and their configurations suggest that common depositional processes are involved regardless of scale differences.Most of the channel-levee systems examined in this study are characterized by a basal erosional fairway that is bordered by outer levees of varying thickness. Together these elements define the base and margins of the channel-belt, where channel-axis deposits and inner levees are the dominant architectural elements. Vertical, sub-vertical, and lateral stacking patterns of sinuous and/or meandering channels create seismic facies that range from narrow to wide zones of high amplitude reflections (HARs) with chaotic to continuous and shingled to horizontal reflections. Some HARs appear as isolated or stacked asymmetric to symmetric u- and v-shaped reflections, referred to here as channel-forms. Channel-belts evolve within the confines of the scalloped erosional fairway walls (flanked by outer levee), and are similar in morphology to meander-belts in fluvial systems, but commonly have a greater component of vertical aggradation. Detailed study of one particular channel-levee system on the Niger Delta slope shows a period of incision followed by three distinct phases of channel development during its aggradational history. Each fill phase corresponds to a different channel stacking architecture, planform geometry, and nature of terrace development, with important implications for reservoir architecture. In some cases, multiple phases of inner levee growth are observed, each intimately linked to the channel migration and aggradation history. Channel sinuosity evolves dynamically, with some meander loops undergoing periods of accelerated meander growth at the same time that others show little lateral migration. 相似文献
9.
Basin floor fans contain some of the largest deep-water hydrocarbon accumulations discovered, however they also demonstrate extremely complex stratigraphic architecture, understanding of which is crucial for maximum recovery. Here we develop a new method, based upon palynofacies analysis, for the distinction of the different depositional environments that are commonly associated with basin floor fans. Previous studies and our sedimentological analysis allow good confidence in the discrimination of the different depositional environments of the outcropping Marnoso-Arenacea Formation fan system. One hundred and thirty-five samples were collected from mudstones in conjunction with sedimentary logging of 871 m of outcrops. Six lithofacies associations are described and interpreted to represent lobe axis, lobe fringe, fan fringe, contained interlobe, basin plain, and starved high depositional sub-environments. Palynofacies of these elements demonstrate turbidites to be rich in terrestrial organic matter, with sixteen categories of matter recognised. The abundances and proportions of particles varies between sub-environments, with lobe axis deposits containing the largest, densest particles, with a transition to ever smaller and lighter particles moving toward the basin plain. Fuzzy C-means statistical analysis was used to explore this trend. Distribution of organic matter is not random, but is dominated by hydrodynamic sorting and sequential fall-out of particles as turbidity currents passed across the basin. This allows a palynofacies classification scheme to be constructed to assist the identification of depositional environments of submarine fans, which may be combined with subsurface data to assist reservoir characterisation. 相似文献
10.
琼东南盆地深水区新近系海底扇沉积特征与资源潜力 总被引：1，自引：1，他引：0
综合利用钻井、岩心、薄片及分析化验资料研究了琼东南盆地深水区新近系海底扇沉积特征,并利用最新的三维地震资料,通过井震精细标定、多属性融合技术、方差体切片、三维地貌砂体镂空等综合技术手段,精细刻画了海底扇砂体的空间分布特征。研究结果表明,深水区新近系海底扇是由陆架区的砂体滑塌并二次搬运形成,形成过程具有多期次性。受不同物源的影响,海底扇岩性和物性存在较大的差异。海底扇岩性及沉积构造具有砂质滑塌、碎屑流、浊流和深水底流改造的特征。海底扇的沉积微相、厚度、砂泥比和砂泥岩空间配置关系直接控制了地震振幅反射强度和频率的变化。砂体纵向叠置,横向连片,并被后期泥质水道切割分块形成多个岩性圈闭。综合分析认为,深水区海底扇砂体发育区烃源条件优越,储盖配置关系和圈闭条件良好,具备形成大中型岩性油气藏的有利条件,具有较大的油气勘探潜力。 相似文献
11.
To help understand factors that influence submarine fan deposition, we outline some of the principal sedimentary, tectonic,
and sea-level controls involved in deep-water sedimentation, give some data on the rates at which they operate, and evaluate
their probable effects. Three depositional end-member systems, two submarine fan types (elongate and radial), and a third
nonfan, slope-apron system result primarily from variations in sediment type and supply. Tectonic setting and local and global
sea-level changes further modify the nature of fan growth, the distribution of facies, and the resulting vertical stratigraphic
sequences.
Margin setting represents fan and/or source area 相似文献
12.
Sedimentary,tectonic, and sea-level controls on submarine fan and slope-apron turbidite systems 总被引：1，自引：0，他引：1
To help understand factors that influence submarine fan deposition, we outline some of the principal sedimentary, tectonic, and sea-level controls involved in deep-water sedimentation, give some data on the rates at which they operate, and evaluate their probable effects. Three depositional end-member systems, two submarine fan types (elongate and radial), and a third nonfan, slope-apron system result primarily from variations in sediment type and supply. Tectonic setting and local and global sea-level changes further modify the nature of fan growth, the distribution of facies, and the resulting vertical stratigraphic sequences. 相似文献
13.
Blanca fan is a submarine fan composed of Miocene volcaniclastic strata. Parts of the fan system are exposed on Santa Cruz
and Santa Rosa Islands, and possibly correlative strata crop out on San Miguel and Santa Catalina Islands.
The Blanca fan and underlying breccia reflect regional transcurrent faulting in the California Continental Borderland and
development of a system of rapidly subsiding basins and uplifted linear ridges during early and middle Miocene time. Erosion
of uplifted crystalline basement rocks followed by the onset of silicic volcanism created linear sediment sources for the
alluvial and submarine fans, respectively.
Margin setting represents fan and/or source area 相似文献
14.
Blanca fan is a submarine fan composed of Miocene volcaniclastic strata. Parts of the fan system are exposed on Santa Cruz and Santa Rosa Islands, and possibly correlative strata crop out on San Miguel and Santa Catalina Islands. The Blanca fan and underlying breccia reflect regional transcurrent faulting in the California Continental Borderland and development of a system of rapidly subsiding basins and uplifted linear ridges during early and middle Miocene time. Erosion of uplifted crystalline basement rocks followed by the onset of silicic volcanism created linear sediment sources for the alluvial and submarine fans, respectively. 相似文献
15.
Oddvar Longva Heidi A. Olsen David J.W. Piper Leif Rise Terje Thorsnes 《Marine Geology》2008,251(1-2):110-123
The origin of acoustically transparent fan deposits overlying glacial till and ice-proximal sediments on the southern margin of the Norwegian Channel has been studied using high-resolution seismic-reflection profiles and multibeam bathymetry. The first deposits overlying glacigenic sediments are a series of stacked, acoustically transparent submarine fans. The lack of glaciomarine sediments below and between individual fans indicates that deposition was rapid and immediately followed the break up of the Late Weichselian ice cover. The fans are overlain by stratified glaciomarine sediments and Holocene mud. Because of the uniformity of this drape, the upper surface of the fan deposits is mimicked at the present seafloor, and the bathymetric images clearly show the spatial relationship of the fans to bedrock ridges and the presence of braided channel-levee systems on the surface of the youngest fans. The acoustically transparent character of the fan deposits indicates that they comprise silt and clay, and their lobate form and lack of internal stratification indicates that they were deposited by debris flows. The channel-levee morphology indicates deposition from more watery hyperconcentrated fluid flows. The fan sediments were either derived from 1) erosion of Mid Weichselian lake deposits in southern Skagerrak or 2) from Late glacial ice-margin lake deposits, ponded against the Norwegian Channel ice stream, which collapsed catastrophically when the lateral support was removed as the ice disintegrated. Fans composed almost exclusively of fine-grained sediment need not, therefore, rule out an origin in a deglacial setting relatively close to the former margins of glaciers and ice sheets. 相似文献
16.
We present field evidence from the Middle Eocene deep-marine Ainsa Basin, Spanish Pyrenees, to show channel-like features likely created by erosive subaqueous debris flows. Evidence from this basin suggests that the most erosive subaqueous debris-flows may create megascours removing up to ∼35 m thickness of sandy submarine-fan deposits from base-of-slope and lower-slope settings. This study suggests that individual debris flows may have been more erosive than turbidity currents, an observation that is opposed to many previous studies from the Ainsa Basin and other ancient deep-water clastic systems. In the Ainsa Basin, many of the debris flows deposited pebbly mudstones immediately above the basal erosion surfaces into which gouging flow-parallel grooves and pebble scours left isolated pebbles embedded in the immediately underlying sandstones. In one particularly well-exposed case, the sandstones immediately below the eroding debris flow were incorporated into it and preserved as sheared, disaggregated, brecciated, and partially liquefied sandstone beds within the pebbly mudstone. Our study suggests that erosion by large-volume debris flows in base-of-slope settings can be at least as important, if not more so, than turbidity currents in producing submarine megascours (probably chutes that, in cross section, superficially resemble submarine channels). This has important implications for understanding the erosivity of debris flows versus turbidity currents in modern and ancient environments, and it has significant implications for hydrocarbon reservoir continuity and heterogeneity, including the origin and recognition of mudstone-filled chutes or channels. 相似文献
17.
花东盆地晚中新世以来沉积演化特征 总被引：1，自引：0，他引：1
利用近年来在台湾东部海域采集的多道地震和多波速测深资料，对该海域花东海盆区晚中新世以来的沉积充填演化特征进行描述和分析。通过对花东海盆区域地形特征描述、层序地层格架的建立和地震剖面的解译，在本区晚中新世以来的沉积充填中刻画出6种典型地震相类型，并分析其对应的沉积相类型，包括浊积扇、浊积水道充填、块体流、沉积物波、海底峡谷－伴生沉积物滑塌变形－充填、深水扇沉积。结合地震相平面分布及垂向沉积相叠置关系，将晚中新世－第四纪沉积充填演化划分为3个阶段:晚中新世晚期开始受到块体流冲蚀阶段，到海底峡谷冲刷－沉积物失稳－峡谷充填－再侵蚀阶段，到峡谷输送的大量沉积物在上新世以来主要堆积发育了沉积物波、浊积扇、深水扇等沉积体系阶段。 相似文献
18.
Preliminary considerations on the potential influence of submarine fans on marine delimitation 总被引：2，自引：1，他引：1
The complex issues associated with marine delineation for the outer limit of continental shelf and the boundary delimitation have provoked considerable attention among researchers in a variety of academic circles, particularly in the juristic filed and the geo-science field. In the present contribution, we start from an overview of submarine fans, as one of common types of sediment-deposit bodies in the ocean, and ex- plore the related geological features which may be of relevance to the marine delimitation in accordance with the 1982 United Nations Convention on the Law of the Sea. We carry out a comparative assessment of certain significant geological features of submarine fans, using the Bengal fan as an example, which is the biggest submarine fan in the world and represents an important factor in the maritime boundary dispute between the neighboring states currently. The relationship between the special geological bodies and the international principle in the 1982 United Nations Convention can be established by combining geological and juristic analyses. This preliminary observation on the effect of submarine bodies both on the marine entitlement and boundary delimitation indicates that it is important for the international society to appro- priately deal with this problem so that the marine right of any state can be protected. 相似文献
19.
20.
Comparison of modern submarine fans and ancient turbidite sequences is still in its infancy, mainly because of the incompatibility of study approaches. Research on modern fan systems mainly deals with morphologic aspects and surficial sediments, while observations on ancient turbidite formations are mostly directed to vertical sequences. The lack of a common data set also results from different scales of observation. To review the current status of modern and ancient turbidite research, an international group of specialists formed COMFAN (Committee on Fans) and met in September 1982 at the Gulf Research and Development Company research facilities in Pennsylvania. 相似文献