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1.
渤海湾中部南堡35-2地区新第三系河流沉积及油气勘探意义 总被引：4，自引：8，他引：4
渤海湾中部南堡35-2地区新三系河流沉积十分发育，可分为曲流河沉积和辫状河沉积两种类型。曲流河沉积以发育点砂坝、决口扇、天然堤和泛滥平原等微相单元为特征。辫状河沉积主要发育河道和心滩微相，泛滥平原微相不太发育。本重点研究了河流沉积各类微相的沉积特点，并将河流沉积的垂向层序归纳为6种类型。本还探讨了各类砂体的储集物性特征，认为点砂坝和心滩砂体是形成大油气田的优质储层，而油气藏的形成除与砂体的储集物性有关外，主要与区域构造条件密切相关。 相似文献
2.
主要通过岩心观察、粒度分析、参数计算、录井及测井分析等手段,充分吸收国内外河流研究成果,结合研究区区域地质背景,总结出渤海湾盆地垦东凸起北坡新近系馆陶组上段沉积相模式。研究认为：馆上段为河流相沉积,从沉积物特征和平面形态角度可以将研究区馆上段河流理解为介于辫状河与曲流河之间的过渡河型。其平均河道弯曲度大于1.7,垂向层序表现为泥多砂少,具有曲流河的特征;但沉积层序顶部常直接覆盖河漫/洪泛平原沉积,特别是河道内砂坝发育造成河道分汊河,砂坝沉积物粒度特征反映的受洪水控制的震荡性特点而与曲流河有重要差别。作者借用在水利学界和地貌学界广为使用的分汊河概念,建立了馆上段沉积相模式,包括河床、堤岸、河漫/洪泛平原和废弃河道等4个亚相,其沉积物组成下粗上细的正韵律。其中,河道砂坝是其主要砂体,顶部常被洪泛平原直接覆盖;决口扇是仅次于河道砂坝的次要砂体。 相似文献
3.
济阳坳陷东部埕北地区Ng上段曲流河沉积相及砂体展布研究 总被引：1，自引：0，他引：1
埕北地区Ng~上段主要为曲流河沉积,储油砂体微相为由流河冲积平原亚相的曲流砂坝。由于它的单层薄,横向上变化大,分布复杂,直接影响到对它的勘探开发和储量计算。通过研究取芯井段的岩相、岩相组合、垂相沉积层序及各种电测井资料等,将Ng~上段曲流河沉积砂体划分为三种亚相,并建立了由流河沉积砂体的剖面结构和平面分布模式,进一步又以沉积小层和砂层组为单元研究了曲流河砂体的平面分布特征及纵向演化规律等,为下一步的精细油藏描述研究打下了可靠的基础。 相似文献
4.
针对浅水湖盆三角洲储层构型模式研究的不足,在考察鄱阳湖现代浅水湖盆三角洲沉积和解剖扶余油田扶余油层古代浅水湖盆三角洲储层构型的基础上,综合应用卫星照片、岩心、测井等资料,建立了浅水湖盆三角洲平原分流河道和三角洲前缘水下分流河道的沉积构型模式。研究结果表明:浅水湖盆三角洲主要发育三角洲平原上部曲流型分流河道、三角洲平原下部顺直型分流河道和三角洲前缘顺直型水下分流河道3种砂体类型,曲流型分流河道主要为侧积的点砂坝沉积构型模式,顺直型分流河道主要为垂积的心滩坝沉积构型模式,顺直型水下分流河道主要为垂积的分流砂坝沉积构型模式。同时从沉积亚相、砂体几何形态、夹层倾向及倾角、废弃河道、决口扇、粒度分析等几个方面总结了不同类型的分流河道及水下分流河道砂体的判别标志,为浅水湖盆三角洲储层内部构型及地质建模研究工作奠定了基础。 相似文献
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6.
曲流河古河道储层构型精细解剖——以孤东油田七区西馆陶组为例 总被引：12，自引：3，他引：9
以胜利油区孤东油田七区西为例,在沉积微相研究的基础上,主要应用研究区岩心、测井,动态等资料,对曲流河古河道砂体进行了系统的储层层次构型精细解剖。在点坝定量分布模式的指导下,根据点坝砂体垂向上典型的正韵律、砂体厚度大以及紧邻废弃河道分布等特征,在研究区Ng522单层复合河道砂体内部识别出2个单一点坝。综合露头和现代沉积的研究成果、经验公式预测以及对子井分析,建立了研究区点坝内部构型定量模式,以单井上识别的泥质侧积层作为依据,点坝内部定量模式及动态监测结果作为指导,进行模式拟合,达到系统解剖点坝内部构型的目的。建立了点坝内部泥质侧积层控制的剩余油分布模式,提出了采用在点坝砂体中上部钻水平井的方式开采侧积层控制的剩余油。点坝构型解剖成果在研究区得到了较好的应用效果,而且对类似油田储层精细研究及剩余分布预测都有较好的借鉴作用。 相似文献
7.
晚二叠世初期,在晴隆大厂一带,以"大厂层"为基底的山间盆地中,形成了一条自北东流向南西的规模较大的曲流河。该河流微相发育,其沉积物包括河道砾岩、边滩砂屑岩和洪泛平原泥质岩等。这套沉积地层上与上二叠统峨眉山玄武岩下与"大厂层"或局部与中二叠统茅口组接触。此乃峨眉地幔隆起边缘的沉积效应。 相似文献
8.
主要通过岩心观察、粒度分析、参数计算、录测井分析等手段,充分吸收国内外河流研究成果,结合研究区区域地质背景,揭示垦东凸起北坡馆上段沉积相模式。得到以下认识：研究区馆上段地层为河流相沉积,从沉积物特征和平面形态角度可以将研究区馆上段河流沉积理解为介于辫状河及曲流河之间的过渡河型。其平均河道弯曲度大于1.7,垂向层序表现为泥多砂少,具有曲流河的特征;但沉积层序顶部常直接覆盖河漫/洪泛平原沉积,特别是河道内砂坝发育造成河道分汊河,砂坝沉积物粒度特征反映受洪水控制的震荡性特点而与曲流河有重要差别。本文借用在水利学界和地貌学界广为使用的分汊河概念建立了研究区馆上段沉积相模式,包括河床、堤岸、河漫/洪泛平原、废弃河道等4个亚相,组成下粗上细的正旋回。其中,河道砂坝是其主要砂体,顶部常被洪泛平原直接覆盖;决口扇是仅次于河道砂坝的第二大砂体。 相似文献
9.
埕岛油田馆陶组发育典型的高弯度曲流河沉积。通过分频融合地震属性提取与优选、储层构型模式指导、动态响应特征约束等手段,对研究区海上稀井网条件下曲流带和点坝进行精细刻画。研究表明: (1)分频融合地震属性的储层预测方法提高了曲流带的预测精度,振幅类属性与砂体厚度相关性最好,以最大峰值振幅为最佳,相比原始地震属性,分频融合得到的最大峰值振幅属性更好地刻画了曲流带砂体边界与砂体厚度分布;(2)复合正韵律、砂体厚度大、紧邻废弃河道分布为点坝三大重要识别标志,与此相对应,点坝表现为高最大峰值振幅、高反演属性的地震响应特征,而废弃河道呈弯月状低振幅属性、“顶平底凸”的低反演属性特征;(3)在应用地震属性确定点坝位置的基础上,通过经验公式推算点坝跨度,可认知研究区点坝的规模,有效指导地下点坝识别,动态信息的约束也为点坝识别提供了依据。井震结合的曲流带及点坝识别方法可为相似油田构型分析提供借鉴。 相似文献
10.
柴达木盆地跃进二号油藏沉积相及平面展布 总被引：1，自引：0，他引：1
跃进二号油田含油层位包括下油砂山组(N21)、上干柴沟组(N1)和下干柴沟组下部(E31)三个主力油组。长期以来,一直认为它是一般的辫状河三角洲沉积,主要砂体类型为分流河道、河口坝和席状砂。笔者在研究过程中,通过岩心观察、测井相分析,并根据沉积物粒度、砂体空间展布规律和现代河流沉积模式类型,认为本区大的沉积背景仍然为辫状河三角洲,但沉积微相类型和砂体成因模式与一般辫状河三角洲不同,即骨架砂体以水下分流砂坝为特征,分流河道和河口坝欠发育。主力油组沉积时期,研究区湖盆水体浅,入湖水流在向湖推进过程中,流水动能强,分流河道主要起输送沉积物通道作用,沉积作用弱,而分流河道之间水体能量相对弱的区域沉积作用强,因而形成了以分流砂坝沉积为主的沉积特征,这种沉积模式打破了传统三角洲沉积以河道和河口坝沉积为主的相模式,建立了以土豆状散布于河道间的分流砂坝为格架的沉积微相新模式。 相似文献
11.
Some deep-marine channels show striking similarities to fluvial channels, despite major differences in the properties of the flows that they conduct. Some field observations from deep-marine channel deposits within a Late Cretaceous palaeo-canyon in the Rosario Formation of Baja California, Mexico, that bear on these comparisons have been reported. These channel deposits contain erosively based lateral accretion sets. These sets are generally a few metres thick and resemble fluvial point bar deposits. Sediment movement and deposition within these accretion deposits was induced by turbidity currents several to many times thicker than the depth of the channel, moving at several metres per second. The inclined sets define laterally migrating and sinuous channels locally at a high angle to the confining canyon. The instantaneous channel widths varied from 6 to 39 m, the depths from 2·5 to 4 m and the sinuosities from 1·3 to 3·1. Palaeocurrent data, taken mostly from clast imbrication in conglomerates, indicates current modes along the channel thalweg, but with other directions representing either secondary flow (oriented primarily up the point bar) or over-passing canyon-confined flow. It is suggested that, at times, the lower part of the turbidity currents flowing down the channels behaved similarly to within-bank fluvial currents, with a cross-channel component of flow towards the cut bank, and return flow at the bed sweeping up the point bar. At other times, this secondary circulation may be absent or reversed, which may be related to changes in flow thickness, coupling with the overriding flow and possible flow separation. 相似文献
12.
DERALD G. SMITH STEPHEN M. HUBBARD† DALE A. LECKIE‡ MILOVAN FUSTIC‡ 《Sedimentology》2009,56(6):1655-1669
Counter point bar deposits in the meandering Peace River, North‐central Alberta, Wood Buffalo National Park, are distinct from point bar deposits in terms of morphology, lithofacies and reservoir potential for fluids. Previously referred to as the distal‐most parts of point bars, point bar tails and concave bank‐bench deposits, counter point bar deposits have concave morphological scroll patterns rather than convex as with point bars. The Peace is a large river (bankfull discharge 11 700 m3 sec?1, width 375 to 700 m, depth 15 m, gradient 0·00004 or 4 cm km?1) in which counter point bar deposits are dominated by silt (80% to 90%), which contrasts with sand‐dominant (90% to 100%) point bar deposits. Beginning at the meander inflection (transition from convex to concave), counter point bar deposit stratigraphy thickens as a wedge‐like architecture in the distal direction until the deposit is nearly as thick as the point bar deposits. The low permeability silt‐dominant lithofacies in counter point bar deposits will limit reservoir extent and movement of fluids in both modern and ancient subsurface fluvial deposits. In the exploration and extraction of bitumen and heavy oil in subsurface fluvial rocks, identification and mapping of reservoir potential of point bar deposits and counter point bar deposits is now possible in the fluvial‐dominated tidal estuarine Lower Cretaceous Middle McMurray Formation, North‐east Alberta. Recent geophysical advances have facilitated imaging of some ancient buried point bar deposits and counter point bar deposits which, on the basis of morphological shape of sedimentary bodies observed from seismic amplitude, can be interpreted and mapped as depositional elements or blocks that contain associated sandstone or siltstone dominant lithofacies, respectively. As counter point bar deposits exhibit poor permeability and thus limit reservoir potential for water, natural gas, light crude, heavy oil and bitumen, counter point bar deposits should be avoided in resource developments. Geophysical imaging, interpretation and mapping of point bar deposit and counter point bar deposit elements provide new opportunities to improve recovery of bitumen and heavy oil and reduce development costs in subsurface cyclic steam stimulation and steam‐assisted gravity drainage projects by not drilling into counter point bar deposits. 相似文献
13.
JOHN SHAW 《Boreas: An International Journal of Quaternary Research》1977,6(2):189-201
Tills are described which occur in ridges and mounds arranged both parallel and transverse to the flow direction of the depositing glacier. Field localities are drawn from the English Midlands, Western Canada, and South Victoria Land, Antarctica. The tills retain textural and structural properties associated with glacial transport, and have suffered a minimum of redistribution suhsequent to their release from glacier ice. It is shown that ridges and mounds cannot he explained in terms of preferential till accretion. An alternative mechanism is presented in which form and structurc are a result of redistribution of debris in transport by secondary flows in ice.
Flutings are longitudinal forms which are related to helicoidal flow cells. Fabric distributions, patterns of till thickness, and internal structure support the helicoidal flow hypothesis.
Debris entrainment by Antarctic cold-based glaciers is explained by consideration of the morphology and sedimentology of the ice margin and the pattern of glacier flow. Deposition by sublimation and melt-out produces an upwards succession of (1) undisturbed proglacial deposits; (2) a complex of poorly sorted flow deposits intercalated with sorted and stratified water-lain deposits; (3) foliated till with sub-horizantal jointing and isolated clasts. A section shobbing this succession is described from Taylor Valley, Antarctica.
Transverse asymmetric ridges are related to till stacking by over-folding in the marginal compressive zone of cold-based glaciers. Plastic deformation of the debris-laden ice may be enhanced by incorporated salts. The folding process is illustrated by structures within Taylor glacier, and is used to explain Pleistocene landforms and structures in Shropshirc, England and Taylor Valley, Antarctica. 相似文献
Flutings are longitudinal forms which are related to helicoidal flow cells. Fabric distributions, patterns of till thickness, and internal structure support the helicoidal flow hypothesis.
Debris entrainment by Antarctic cold-based glaciers is explained by consideration of the morphology and sedimentology of the ice margin and the pattern of glacier flow. Deposition by sublimation and melt-out produces an upwards succession of (1) undisturbed proglacial deposits; (2) a complex of poorly sorted flow deposits intercalated with sorted and stratified water-lain deposits; (3) foliated till with sub-horizantal jointing and isolated clasts. A section shobbing this succession is described from Taylor Valley, Antarctica.
Transverse asymmetric ridges are related to till stacking by over-folding in the marginal compressive zone of cold-based glaciers. Plastic deformation of the debris-laden ice may be enhanced by incorporated salts. The folding process is illustrated by structures within Taylor glacier, and is used to explain Pleistocene landforms and structures in Shropshirc, England and Taylor Valley, Antarctica. 相似文献
14.
Peter P. Sakalowsky 《Earth》1974,10(2):121-138
Meandering is one of the most complex problems associated with the behavior of rivers. Several explanations (derived from both field and laboratory flume) have been advanced to account for stream meandering, among them being the earth's rotation, excess current energy, transverse oscillations, initial current deflection, local disturbances, changes in stages of discharge and bed load and helicoidal flow. Foremost among these is the effects of helicoidal flow within the stream flow. The purpose of this paper is to review and analyze selected meander theories that contribute either directly or inherently to current meander concepts which revolve around the effect of helicoidal flow.Prevalent ideas concern meandering as being dependent not only on stream flow but also on the rate of stream discharge, sediment load, size and type of sediment, channel roughness, depth, width, velocity of flow, and quality of water itself. The characteristics of helicoidal flow seem to be the best explanation for the development of meanders. Theories for meandering do not clearly explain the cause of helicoidal flow. Most of its intricacies have been learned through laboratory flume experiments. Interestingly, earlier work on river meandering was the product of long days in the field; in more recent years such research has been undertaken in the laboratory. One feels that a return to the stream would be a healthy complement to flume measurements. Further study should include hypothesis testing in a variety of material both homogeneous and heterogeneous. 相似文献
15.
济阳坳陷孤东油田七区西馆陶组上段为典型的曲流河沉积,其中Ng522单层发育2个大型点坝砂体,在系统的点坝砂体构型表征的基础上,探索了储集层构型界面的几何建模方法,将构型界面模型嵌入到基于三维结构化网格体的相模型中,建立了研究区26-295井区真正意义上的、更符合地下实际的三维储集层构型模型,再现了成因微相内部构型单元及界面的空间分布特征,满足了三维油藏数值模拟的需要。点坝内部的侧积层向废弃河道方向倾斜,延伸到距点坝顶三分之二的位置,点坝砂体表现为“半连通体”特征。建立了点坝内部剩余油分布模式,并指出挖潜措施。该方法在研究区应用效果较好,并可以推广到其他相似油田,这对丰富储集层地质学理论及提高油田开发效率均具有重要意义。 相似文献
16.
Christopher M. Herbert Jan Alexander Kathryn J. Amos Christopher R. Fielding 《Sedimentology》2020,67(1):576-605
Unit bars are relatively large bedforms that develop in rivers over a wide range of climatic regimes. Unit bars formed within the highly-variable discharge Burdekin River in Queensland, Australia, were examined over three field campaigns between 2015 and 2017. These bars had complex internal structures, dominated by co-sets of cross-stratified and planar-stratified sets. The cross-stratified sets tended to down-climb. The development of complex internal structures was primarily a result of three processes: (i) superimposed bedforms reworking the unit bar avalanche face; (ii) variable discharge triggering reactivation surfaces; and (iii) changes in bar growth direction induced by stage change. Internal structures varied along the length and across the width of unit bars. For the former, down-climbing cross-stratified sets tended to pass into single planar cross-stratified deposits at the downstream end of emergent bars; such variation related to changes in fluvial conditions whilst bars were active. A hierarchy of six categories of fluvial unsteadiness is proposed, with these discussed in relation to their effects on unit bar (and dune) internal structure. Across-deposit variation was caused by changes in superimposed bedform and bar character along bar crests; such changes related to the three-dimensionality of the channel and bar geometry when bars were active. Variation in internal structure is likely to be more pronounced in unit bar deposits than in smaller bedform (for example, dune) deposits formed in the same river. This is because smaller bedforms are more easily washed out or modified by changing discharge conditions and their smaller dimensions restrict the variation in flow conditions that occur over their width. In regimes where unit bar deposits are well-preserved, their architectural variability is a potential aid to their identification. This complex architecture also allows greater resolution in interpreting the conditions before and during bar initiation and development. 相似文献
17.
近10年来,国内外的沉积构型研究从之前的以精细表征为主扩展到成因机制分析。文中以同生逆断层控制的冲积扇、可容空间影响下的曲流河点坝、浅水缓坡背景下的三角洲指状砂坝以及大陆斜坡微盆地背景下的重力流沉积等为例介绍相关研究进展。(1)挤压盆地边缘复杂的同生逆断裂构造活动控制了冲积扇的构型要素类型、叠置样式、分布演化及定量规模,表现出有别于构造稳定条件下的冲积扇构型模式;(2)曲流河在可容空间较小的情况下可发育顺流迁移型点坝,表现出特殊的微相类型、分布样式及旋回特征,而随着A/S值的不断增大,曲流河点坝可由鳞片状逐步演变为条带状,最后变为点状;(3)浅水三角洲中可发育类似于河控较深水三角洲中的指状砂坝沉积,其平面形态、微相组合样式、定量规模等特征受气候、沉积物供给、沉积水体等多因素的影响;(4)大陆斜坡微盆地内部可发育重力流水道、朵叶体、块状搬运体等多种构型要素类型,不同构型要素的空间分布样式、定量规模及构型演化模式受复杂地形地貌及构造活动的影响较为明显。综合原型模型分析、沉积物理模拟及数值模拟开展系统的定量化研究,建立定量的、可预测的碎屑岩沉积构型模式,是今后碎屑岩沉积构型研究的发展趋势。 相似文献
18.
Paul R. Durkin Stephen M. Hubbard John Holbrook Zennon Weleschuk Paul Nesbit Chris Hugenholtz Tania Lyons Derald G. Smith 《Sedimentology》2020,67(6):2819-2849
Downstream migration of point bars is an important process in meander belts. Inherent to downstream migration is sediment accumulation in concave channel banks, immediately adjacent to and downstream of convex point bars. Despite this, associated concave bank processes are often overlooked, with depositional products sparsely identified in the stratigraphic record. Counter-point-bar deposits are a type of concave-bank deposit that have been positively identified in subsurface three-dimensional seismic datasets, yet outcrop examples are not well-constrained. This study characterizes and establishes recognition criteria of counter-point-bar deposits in outcrop using extensive exposure of Late-Cretaceous meander-belt deposits in eastern Alberta, Canada. Using a combination of traditional field-based sedimentological analyses and three-dimensional outcrop mapping with an Uncrewed Aerial Vehicle and Structure-from-Motion photogrammetry, point bar, counter-point bar, and associated abandoned-channel deposits, as well as adjacent floodplain deposits are identified. Bed-scale characteristics of counter-point-bar deposits include interlaminated and interbedded siltstone and fine-grained sandstone, abundant organic detritus, and evidence of deformation and slumping. At the bend scale, accretion packages bounded by internal erosion surfaces are composed of dipping siltstone and minor sandstone beds that extend from the top to the base of the meander belt. At the belt scale, positive identification relies on concave accretion surface mapping, their orientation relative to the meander-belt edge (i.e. dipping away), and consideration of meander-bend evolution. These results have implications for recognition of counter-point-bar deposits in analogous, less-constrained data sets, which provides a foundation for more complete palaeoenvironmental interpretations. 相似文献
19.
不同流量级下,分汊河段进口主流摆动导致江心洲头部的平面冲淤分布呈现出复杂变化特征。为探究江心洲头部冲淤与来流过程之间的响应关系,借助长江中下游多个分汊河段内水沙、地形资料,对江心洲头部水动力特征实施了数值模拟,并对不同流量级下的河床变形强度进行综合比较。研究表明:江心洲头部低滩的冲淤动力随着流量涨落呈现出明显的临界特性,冲淤过程中存在大、小两个临界流量Q1与Q2,在介于两个临界流量之间的流量级持续作用下,洲头低滩发生冲刷;流量大于Q1或小于Q2时,洲头低滩表现为淤积。由于不同流量级造成的冲淤效果不同,因而水文过程中各级流量的持续时间,是影响洲头低滩年内、年际变形的主要因素。 相似文献
20.
This study examines the groundwater characteristics in the Silver Bell Mountains, Arizona, USA, using a numerical model. Groundwater modeling is developed to describe the flow pattern in the study area and subsequently explores the possible interaction with regional porphyry copper deposits. A conceptual model is developed for the study area and regional hydrogeological conditions are simulated using the finite-difference groundwater flow model, MODFLOW-2005. The model results show that groundwater flow in the Silver Bell Mountains is strongly influenced by topography and its velocity varies with depth. In addition, the numerical model supports the idea of a continuous sustained interaction between groundwater flow and porphyry copper deposits in the Silver Bell Mountains. This interaction may result in continuing leaching of trace elements from the ore deposit, an important implication for continuing supergene alteration and enrichment of the porphyry copper deposit. 相似文献