从端点走向连续:河流沉积模式研究进展述评

从河道类型的划分、河床演变与河型转换、河道沉积与河流砂体的建筑结构要素、河漫滩沉积、季节性河流与分支河流体系、河流沉积相模式、河流沉积学研究技术与方法等方面对国内外河流沉积模式的研究进展进行了综述,认为近十年来河流沉积学的理论和方法都发生了重要的变化。地貌学家、沉积学家和工程师认识到河道形态是连续可变的,而不是只有4~40多个端点类型。河床的演变受河床比降、流量变幅、河岸沉积物粒度构成、气候、植被以及构造沉降速率等多方面的影响。垂向剖面分析法难以对古河流类型做出正确的判断,运用建筑结构要素分析法重建河道内大型底形的地貌形态是河型判别和河流相模式重建的正确方法。河漫滩是河流沉积事件记录最为齐全的部位,对河漫滩、天然堤和泛滥平原沉积层序的研究能够揭示更多古河流沉积过程以及古环境、古气候和古生物方面的信息。对季节性河流、受季风强烈影响地区的河流、以及不同气候带河流所发育的独特沉积构造和建筑结构要素的研究不断增加。分支河流体系的概念得到越来越多的应用,但也得到不少质疑。我国学者应当注重对现代河流地貌形态和沉积过程的观察,把河床演变学的定量方法与沉积学的观点、理论和资料相结合,利用露头、三维地震资料和探地雷达技术建立河流砂体内部建筑结构信息数据库,加强对古河流河漫滩和泛滥平原的沉积过程、特征及其控制因素的研究,加强对不同构造和气候条件下河流沉积的差异性研究,不断发展河流沉积学研究技术,加强河流沉积学实验室建设和研究队伍建设,加强国际交流与合作,使我国河流沉积学为国家经济社会发展提供更加有力和有效的支撑,为推动国际河流沉积学发展做出中国人自己的贡献。     

Stratigraphy and fluvial sedimentary facies of the Neocomian lower Strzelecki Group,Gippsland Basin,Victoria

The Strzelecki Group incorporates Berriasian to Albian, fluvial sediments deposited in the Gippsland Basin during initial rifting between Australia and Antarctica. Neocomian strata of the lowermost Strzelecki Group are assigned to the Tyers River Subgroup (exposed in the Tyers area) and the Rhyll Arkose (exposed on Phillip Island and the Mornington Peninsula). The Tyers River Subgroup incorporates two formations: Tyers Conglomerate and Rintoul Creek Formation. The latter is subdivided into the Locmany and Exalt Members. Ten fluvial sedimentary facies are identified in the lowermost Strzelecki Group: two gravelly facies; four sandy facies; and four mudrock facies. Associations of these facies indicate: (i) prevalence of gravelly braided‐river and alluvial‐fan settings during deposition of the Tyers Conglomerate; (ii) more sluggish, sandy braided to meandering fluvial systems during Locmany Member sedimentation; and (iii) a return to active, sandy, braided‐river settings for deposition of the Exalt Member. The Tyers Conglomerate and Rhyll Arkose rest on an irregular erosional surface incised into Palaeozoic rocks of the Lachlan Fold Belt. The overlying Rintoul Creek Formation incorporates more mature sediments where lithofacies associations varied according to base‐level change, variations in subsidence rates, and/or tectonic uplift of the principal sedimentsource terranes to the northwest.     

Integration of outcrop and borehole image logs for high-resolution facies interpretation: example from a fluvial fan in the Ebro Basin, Spain

Electrical borehole image logs yield high-resolution information about variations in micro-resistivity along the borehole wall. To interpret these variations in terms of sedimentary structures and lithofacies types, calibration with real rock is needed. Normally, the only real rock available is core, and this only provides one-dimensional information. In this paper, the interpretation of fluvial facies types from borehole image logs was established by direct comparison with outcrops. Four fluvial facies associations were established in an outcrop study of a low net-to-gross fluvial succession: (i) meandering rivers, (ii) braided rivers, (iii) crevasse deltas, and (iv) crevasse splays. The lithofacies characteristics and palaeocurrent distributions of each fluvial facies association were established. Two 200 m deep wells were drilled behind the cliff face outcrops. One well was cored to a depth of 150 m and borehole image logs were recorded in both wells. The wells were correlated with the outcrop. The borehole image logs were analysed by their vertical colour succession and the dipmeter pattern. Image log facies were established, and these were interpreted in terms of the fluvial facies associations encountered in the corresponding outcrops. The study of borehole image logs yields a set of diagnostic criteria for a detailed fluvial facies interpretation and the establishment of depositional trends, and thus provides a powerful tool for the direct interpretation of fluvial facies in a reservoir setting.     

河流沉积学研究热点与进展--第11届国际河流沉积学大会综述

第11届国际河流沉积学大会于2017年7月17日-21日在加拿大卡尔加里大学举行,每四年举行一次的国际河流沉积学学术会议,吸引了当今北美、欧洲、澳洲及亚洲从事河流沉积学及相关学科研究的众多知名学者参会,研究成果充分体现了当前国际河流沉积学研究取得的重要进展和发展方向。重要进展有:1）河流动力学及其变化过程研究。其中包括将今论古法论现代河流沉积过程与古老地层对比,河道-洪泛平原体系的越岸复合沉积动力学,河流动力学与变化过程研究展望,恢复河道迁移过程:新一代平面图演化模式的讨论,冲积河流和基岩河流的湍流、颗粒间作用和沉积作用;2）陆缘河流。包括河流入海处的地貌动力学与沉积学,河流补给边缘的沉积物搬运、地貌和地层特征,干旱地区河流、冲积扇体系与风的相互作用,植被生长前、无植物生长、或是植被发育区河流的沉积过程研究;3）河流沉积地层及其地下资源。包括源-汇系统,"河流相模式"是否有用的讨论,辫状河、网状河、曲流河概念的厘定等;4）河流地貌变化。包括气候改变、泥泞植被洪泛平原等对河流沉积物通量、河流模式等产生影响,河道中冲积岛屿的演化和稳定河流的蛇曲化,河流环境中沉积物生物作用等。基于上述资料分析,认为河流演化过程从定性向定量化研究,物理模拟与数值模拟技术是河流沉积学研究不可或缺的手段,应用定量建模、数学计算等方法进行精准研究,碎屑锆石U-Pb定年技术是新一代从源到汇研究的重要工具等诸多方面,是我国学者应该重视并开展研究的方向。     

From Alluvial Fan to Playa: An Upper Jurassic Ephemeral Fluvial System, Neuquén Basin, Argentina

The Upper Jurassic fill of the back-arc Neuquén Basin includes a lowstand wedge known as the Tordillo Formation. The studied deposits crop out along a N-S oriented belt that runs parallel to the Andean magmatic arc. They are limited to the south by the east-west oriented positive structure of the Huincul arch formed as a result of Upper Jurassic tectonic inversion. The Tordillo deposits were formed in an arid fluvial-dominated system characterised by systematic downstream changes in architectural style. A gravelly and sandy bedload fluvial system is recognised in the southern upstream sector. The reduced thickness and the coarse grain size suggest steep gradients, excess of bedload supply and a low subsidence rate. Thicker and finer-grained deposits prevail to the north and northeast. They were formed under arid conditions in a wadi-sand flat-playa fluvial system. This distal facies association indicates increased accommodation owing to high rates of subsidence relative to coarse siliciclastic sedimentation rates. These low-gradient deposits are characterised by cyclic alternations of mud-dominated and sand-dominated packages interpreted as high- and low-accommodation systems tracts. The overall fining upward stacking pattern of the Tordillo Formation suggests a change towards higher accommodation rates. This is accompanied by frequent development of soil horizons and darker primary and reworked pyroclastic deposits. These attributes indicate a stronger explosive volcanic activity associated with increased precipitation and high water table emplacement towards the end of the Tordillo lowstand wedge.     

Multi‐scale classification of fluvial architecture: An example from the Palaeocene–Eocene Bighorn Basin,Wyoming

Fluvial channel geometry classification schemes are commonly restricted in relation to the scale at which the study took place, often due to outcrop limitations or the need to conduct small‐scale detailed studies. A number of classification schemes are present in the literature; however, there is often limited consistency between them, making application difficult. The aim of this study is to address this key problem by describing channel body geometries across a depositional basin to ensure that a wide range of architectures are documented. This was achieved by studying 28 locations over 4000 m of vertical succession in Palaeocene‐aged and Early Eocene‐aged deposits within the Bighorn Basin, Wyoming, USA. Five different channel body geometries have been defined based on the external geometric form, and internal arrangement and nature of storey contacts. These include the massive channel body geometry, semi‐amalgamated channel body geometry, internally amalgamated channel body geometry and offset stacked channel body geometry, which are considered to be subdivisions of the sheet geometry of many other classifications. An isolated channel body geometry has also been recognized alongside splay channel and sheet sandstone geometries in the floodplain facies associations. Field evidence, including the stacking style of storey surfaces, suggests that the different geometries form a continuum. The nature and degree of amalgamation at the storey scale are important in producing the different geometries and are related to the degree of channel migration. It is speculated that this is the result of differences in sediment supply and available accommodation. In contrast to previous schemes, the classification scheme presented here recognizes the importance of transitional geometries. This geometrical range has been recognized because of the basin‐scale nature of the study.     

断陷盆地缓坡带河流沉积砂体定量表征及控制因素分析:以霸县凹陷文安斜坡东营组三段为例

断陷湖盆缓坡河流成因砂体是重要的油气储集单元.根据岩心观察、钻井岩/电特征并结合地震沉积学方法,分析断陷湖盆缓坡河流沉积体系和砂体时空分布特征,能为油气精细勘探提供可靠的依据.研究表明,霸县凹陷文安斜坡中部东营组三段周期性地发育4条呈NE-SW辫-曲复合型河流沉积,由河道沉积、砂坝沉积和泛滥平原沉积3种亚相以及辫状河道...     

渤海海域W油田新近系明化镇组河流相砂体结构特征

利用野外露头、现代沉积和大量岩心以及钻测井资料,以高分辨率层序地层学原理为指导,结合地震和探地雷达,分析了W油田新近系明化镇组明下段河流相层序格架和砂体结构的沉积特征,总结了砂体的发育规模特征,建立了河流相砂体的沉积模式,为海上油田开发及后期调整提供依据和指导。研究表明,渤海海域明化镇组河流相砂体结构划分为堆叠型、侧叠型和孤立型3种类型共7种样式,其中侧叠型又分为紧密型、疏散型和离散型;孤立型又分为下切侵蚀型、孤立河道和决口扇;河道砂体厚度为2.1~15m,平均6.75m;宽度为200~1 225m,平均宽度519m。决口扇砂体厚约2~3m,宽度为150~450m,平均宽度300m。河流相砂体结构受控于湖平面的变化。不同的湖平面变化下发生堆叠型、侧叠型和孤立型规律性的砂体结构变化。     

Recognizing products of palaeoclimate fluctuation in the fluvial stratigraphic record: An example from the Pennsylvanian to Lower Permian of Cape Breton Island,Nova Scotia

Tectonics and climate are the major extrinsic upstream controls on both the external and internal architectures of fluvial channels. While the role of tectonics has been well‐documented, the role of climate has received less attention. Because both tectonics and climate can produce similar stratigraphic architectures, the ability to recognize and differentiate these has major ramifications for the interpretation of fluvial stratigraphy. The Pennsylvanian to Permian succession of the Maritimes Basin complex on Cape Breton Island is ca 5 km thick, and is composed of predominantly non‐marine strata deposited within a series of depocentres characterized by different subsidence regimes. Basins in the west are transtensional depocentres characterized by episodic fault movement. In contrast, basins in the east were formed during prolonged periods of passive thermal subsidence. The stratigraphy is composed of four second‐order sequences (A to D), each 5 to 10 Myr in duration. These sequences are composed of amalgamated fluvial channel deposits that fine upwards into extensive mud‐dominated floodplain deposits with isolated fluvial channel bodies. A spectrum of fluvial styles is recorded within the study area including perennial, perennial/intermittent and ephemeral. Four stratigraphic intervals (E1 to E4) are recognized in which the deposits of strongly seasonal perennial/intermittent fluvial deposits are predominant. These intervals, 2 to 6 Myr in duration, are correlated across the study area between basins with differing tectonic regimes and do not correlate with a particular position in second‐order sequences. This suggests that climate exerted the dominant influence on the formation of these intervals and can be differentiated from tectonic imprints. While the tectonic regime of a particular basin exerted a fundamental control on the external architecture, a coherent record of climate change is recognized in the internal architecture of fluvial units. This study demonstrates that tectonic and climatic controls can be recognized and differentiated in vertical successions by evaluating the changes in fluvial architecture.     

Facies architecture of asymmetrical branching distributary channels: Cretaceous Ferron Sandstone,Utah, USA

Distributary channel systems are an important component of deltaic systems, but details of their branching pattern, stream‐order, internal variability and relation with adjacent levée, bay and bayhead delta are rather poorly documented in ancient examples. Photomosaic and measured sections collected along a gooseneck‐shaped canyon in southern Utah allow direct mapping of the branching pattern of an ancient distributary system. The main channel belt is ca 250 m wide and narrows to ca 200 m downstream of the branching point. A subordinate channel belt, ca 80 m wide, branches off of the main channel, forming a distinctly asymmetrical branching pattern. Water discharge in the main channel is estimated to be 85 to 170 m³ sec^?1. Comparison with palaeodischarge estimates of trunk rivers mapped in previous studies suggests that the branching documented in this study probably is a fourth‐order split. The distributary channels are characterized by a U‐shaped geometry filled with medium‐grained, cross‐bedded sandstone, and are dominated by lateral accretion, suggesting limited lateral migration and moderate sinuosity. Tidally influenced facies and limited trace fossils indicate direct marine influence. The distributary channels erode into adjacent levée and underlying heterolithic bay‐fill deposits, and the marine influence suggests that they were deposited on a lower delta plain, rather than on a non‐marine floodplain. The subordinate channel fed a bayhead delta, suggesting that it was formed by a partial avulsion, rather than bifurcation around a mouth bar, as is more characteristic of terminal distributary channels. Channel‐floor drapes, bar‐accretion drapes and abandoned channel fills within the sandstone channel belts represent the most important heterogeneity from the perspective of reservoir characterization.     

Late Glacial fluvial response of the Niers‐Rhine (western Germany) to climate and vegetation change

The Niers valley was part of the Rhine system that came into existence during the maximum Saalian glaciation and was abandoned at the end of the Weichselian. The aim of the study was to explain the Late Pleniglacial and Late Glacial fluvial dynamics and to explore the external forcing factors: climate change, tectonics and sea level. The sedimentary units have been investigated by large‐scale coring transects and detailed cross‐sections over abandoned channels. The temporal fluvial development has been reconstructed by means of geomorphological relationships, pollen analysis and ¹⁴C dating. The Niers‐Rhine experienced a channel pattern change from braided, via a transformational phase, to meandering in the early Late Glacial. This change in fluvial style is explained by climate amelioration at the Late Pleniglacial to Late Glacial transition (at ca. 12.5 k ¹⁴C yr BP) and climate‐related hydrological, lithological and vegetation changes. A delayed fluvial response of ca. 400 ¹⁴C yr (transitional phase) was established. The channel transformations are not related to tectonic effects and sea‐level changes. Successive river systems have similar gradients of ca. 35–40 cm km^?1. A meandering river system dominated the Allerød and Younger Dryas periods. The threshold towards braiding was not crossed during the Younger Dryas, but increased aeolian activity has been observed on the Younger Dryas point bars. The final abandonment of the Niers‐Rhine was dated shortly after the Younger Dryas to Holocene transition. Traces of Laacher See pumice have been found in the Niers valley, indicating that the Niers‐Rhine was still in use during the Younger Dryas. Copyright © 2005 John Wiley & Sons, Ltd.     

河流相储层构型研究新理论、新方法——海上油田河流相复合砂体构型概念、内容及表征方法

基于陆上油田密井网的河流相储层构型研究,经过数十年积累,理论基础及表征方法已比较成熟,然而,将其应用于海上油田稀疏井网条件时,依然面临较大的挑战。笔者团队经过多年探索,基于海上油田开发地质研究方法,形成了井震结合、以"复合砂体"为核心的海上河流相复合砂体构型理论与表征方法,其特点在于运用三维原型建模、地震构型相预测及地震驱动确定性建模等技术,重点表征影响海上油田开发的五、六、七级构型单元(复合河道带、单一河道带、复合点坝),针对开发阶段的小层细分对比及不连续渗流屏障刻画等方面具有明显的优势。目前,应用这套理论及方法开展精细地质建模和数值模拟依然存在挑战,需要进一步发挥地震资料作用并探索人工智能的地震解释新途径。     

The Sis palaeovalley: a record of proximal fluvial sedimentation and drainage basin development in response to Pyrenean mountain building

The Sis conglomerate body represents the Middle Eocene to Oligocene transfer‐zone trunk palaeovalley fill of the Sis fluvial system, a drainage system established within the Pyrenees during Late Palaeocene times. The spatial stability of the fluvial transfer zone (active for at least 38 My), and hence the longevity of its aggradational palaeovalley component (>19·5 My), was controlled by its location between long‐lived pre‐existing structures. Coarse‐grained fluvial facies dominate the palaeovalley fill, with alluvial fan facies shed from its defining marginal structures. The detailed sedimentology of very proximal fluvial facies deposited within the dominantly erosional realm of an active mountain belt has rarely been documented before because of their poor preservation potential. The Sis conglomerate body contains a robust internal stratigraphy with stratigraphic units defined by distinct bounding surfaces, across which there are pronounced changes in facies and provenance. These mark the reorganization of the headward portions of the Sis fluvial system during the evolution of the Pyrenean Axial Zone antiformal stack. Major changes in discharge resulted, demonstrating the highly variable nature of even mountain belt‐scale fluvial systems when viewed on timescales of several to tens of millions of years. Provenance details indicate that initial unroofing of Hercynian granitoids, situated within the Pyrenean Axial Zone, occurred around 54·5 Ma (early Ypresian) immediately before the first significant exhumation event within the drainage basin of the Sis fluvial system. This is earlier than previously constrained by apatite fission track studies. Rock uplift accelerated in the Lutetian and Bartonian with the initial aggradation of the palaeovalley fill (the Cajigar and Cornudella Formations and Sis One and Two Members). This became marked in the Priabonian (Sis Three and Four Members), with significant activity on local structures including the Morreres backthrust. An increase in basement‐derived clasts and a headwater decapitation event also indicate pronounced Axial Zone antiformal stack development at this time. Axial Zone development intensified further in the Oligocene with the deposition of the Collegats Formation and the switch in the main depositional loci of the system from the Tremp‐Graus thrust‐sheet‐top basin to the Ebro Basin to the south.     

河流相砂体识别预测及古气候响应: 以渤中坳陷石南地区明下段为例

河流相砂体的识别预测及其发育演化对古气候变化的响应是当前河流相沉积研究的热点。基于地震沉积学方法,采用三步走的河流相砂体识别预测方法(井震结合建格架→90°相位调整标岩性→切片属性辨砂体),在渤海湾盆地渤中坳陷石臼坨凸起南部(石南)新近系明化镇组下段(简称“明下段”)识别出了顺直和蜿蜒河道砂、河道—堤坝复合体、点砂坝、河口坝、牛轭湖和决口扇6种河流相砂体。依据明下段泥岩颜色,结合藻类种属记录和孢粉记录分析,认为石南地区明下段沉积早期到中期经历了干湿交替→湿润主导的湿润化气候演变; 而明下段沉积中期到晚期经历了湿润主导→干旱主导的干旱化气候演变。润湿化气候演变使得明下段沉积中期河流相砂体宽度和单层厚度减小、弯曲度增大,且带状孤立河道砂体更发育; 而干旱化气候演变使得明下段沉积晚期流相砂体宽度和单层厚度增大、弯曲度减小,且带状河道—溢岸复合带和河口坝砂更发育。研究成果可为其他断陷盆地河流相砂体识别、预测提供参考,对指导构造活动相对较弱的湖盆萎缩期油气勘探实践具有一定的实践价值。     

河流相砂体识别预测及古气候响应: 以渤中坳陷石南地区明下段为例

河流相砂体的识别预测及其发育演化对古气候变化的响应是当前河流相沉积研究的热点。基于地震沉积学方法,采用三步走的河流相砂体识别预测方法(井震结合建格架→90°相位调整标岩性→切片属性辨砂体),在渤海湾盆地渤中坳陷石臼坨凸起南部(石南)新近系明化镇组下段(简称“明下段”)识别出了顺直和蜿蜒河道砂、河道—堤坝复合体、点砂坝、河口坝、牛轭湖和决口扇6种河流相砂体。依据明下段泥岩颜色,结合藻类种属记录和孢粉记录分析,认为石南地区明下段沉积早期到中期经历了干湿交替→湿润主导的湿润化气候演变; 而明下段沉积中期到晚期经历了湿润主导→干旱主导的干旱化气候演变。润湿化气候演变使得明下段沉积中期河流相砂体宽度和单层厚度减小、弯曲度增大,且带状孤立河道砂体更发育; 而干旱化气候演变使得明下段沉积晚期流相砂体宽度和单层厚度增大、弯曲度减小,且带状河道—溢岸复合带和河口坝砂更发育。研究成果可为其他断陷盆地河流相砂体识别、预测提供参考,对指导构造活动相对较弱的湖盆萎缩期油气勘探实践具有一定的实践价值。     

断陷湖盆缓坡带古河道定量恢复方法及油气地质意义：以霸县凹陷文安斜坡东营组为例

河流沉积砂体定量表征是油田高效勘探开发的重要基础。文章综合利用定量岩心分析、测井相分析、定量地震沉积学和三维地震剖面识别方法,对霸县凹陷文安斜坡东营组古河道砂体厚度,河道（带）宽度,（满岸）河道水深等河流参数进行了定量化计算。研究表明,文安斜坡东营组发育北部苏桥、中部文安和南部长丰镇三个物源输入口,河流呈NEE-SWW向分散于文安斜坡带,其中河道带宽度（w）为1.04~2.61 km,平均宽度（wcb）为1.71 km;主河道宽度（W）为15.2~179.6 m,平均宽度（Wc）为84.4 m;主河道沉积水深（D）为1.34~5.21 m,平均水深（Dc）为3.29 m;主河道满岸水深（Dmax）为2.35~9.15 m,平均满岸水深（Dmaxa）为5.77 m;主河道沉积厚度（H）为2.15~8.32 m,平均厚度（Hc）为5.25 m,河道长度（L）为18.5~28.2 km,平均河道带长度（Lcb）为25.1 km,流向（A）为40°~65°。确定文安斜坡东营组发育辫状河沉积,斜坡东侧中外带为主要的砂岩卸载区,河流以垂向挖掘性河流为主,侧向迁移为辅,河道砂岩平面呈“条—带”状。文安斜坡西侧内带以侧向迁移河流为主,下蚀作用为辅,河道砂岩呈“席—带”状。东营组河道砂岩具有“下生上储”的有利成藏条件,具有良好的岩性、构造—岩性圈闭（油气藏）勘探前景。     

低渗透储层成岩作用定量表征与成岩储集相——以吉林新立油田泉头组三、四段为例

作者采用铸体薄片、阴极发光、扫描电镜等手段,统计了新立油田泉头组三、四段储层的视压实率和视胶结率,对成岩作用强度进行了定量表征。引入了成岩系数和成岩储集相的概念,并按照成岩系数大小,将储层划分为4种成岩储集相,即强溶蚀次生孔隙成岩储集相(A相),中等压实-弱、中胶结混合孔隙成岩储集相(B相),强压实-弱、中胶结混合孔隙成岩储集相(C相)和碳酸盐强胶结成岩储集相(D相)。其中以A相最有利于油气聚集,B相次之,C相较差,D相最差。分析了各类成岩储集相特征和演化,认为晚成岩A亚期的酸性水溶蚀作用形成次生孔隙是改善储层物性的关键因素。     

尼日尔三角洲高分辨率层序地层及沉积相研究——以尼日利亚M区块为例

本文采用高分辨率层序地层学理论,研究尼日尔三角洲中尼日利亚M区块的层序及沉积特征。选择基准井对全井段的岩屑资料进行细致的观察描述,确定自然伽马、声波等曲线对岩性的响应特征;解释主要钻井的岩性剖面;根据岩性剖面,参照地震剖面中揭示的钻井相对于沉积倾向剖面中所在的位置,选择相应的模型划分不同级别的基准面旋回;通过对钻井基准面旋回的形态、厚度、出现频率等属性特征的分析,进行基准面旋回对比,建立等时的层序格架。研究总结了不同级次旋回界面和旋回类型的识别特征,将研究层段分为9个长期旋回。基于对该区构造、沉积背景、物源供应状况及演化特征,分析了该区三角洲的基本类型、随层序及体系域的时空演化等要素。总结了分流河道、水下分流河道、砂坝等若干骨架沉积微相的旋回组合特征、叠加样式等,为储、盖组合及勘探目标评价提供了的依据。     

A methodological approach of fluvial dynamics oriented towards hydrosystem management: case study of the Loire and Allier rivers

Abstract

This study was conducted as part of the European LIFE Loire Nature program for the conservation and management of a 110-km-long section of the Loire and Allier rivers, an area renowned for its ecological richness. The methodological approach is based on statistical analysis (bivariate and multivariate analyses) of hydro-geomorphologic and biogeographical variables, complemented by reach typology and mapping. The main results show, on the one hand, the great spatial variability of fluvial mosaic complexity along the river continuum and on the other hand, some independence between the riparian forest characteristics and the channel forms. The fluvial pattern (e.g. anabranching) and the forest establishment along the Loire river register specific features. © 2000 Éditions scientifiques et médicales Elsevier SAS     

综合指数法在河流相储层非均质性研究中的应用——以胜坨油田二区沙二段34储层为例

在储层建筑结构划分、测井多参数处理结果的基础上,根据熵的原理,应用熵权法定量计算了胜坨油田二区沙河街二段3砂层组4小层(简称沙二段3⁴)河流相储层的非均质综合指数,按照不同的开发时期详尽分析了储层的层间、层内、平面非均质性特征,并阐述了储层非均质性的主要影响因素。结果表明:沙二段3⁴储层层内、层间及平面非均质性中等-较强;随着注水开发的进行,非均质性有继续增强的趋势,平面非均质性较之层内和层间非均质性更强烈。同一小层及韵律层在不同开发时期的非均质程度有明显的差异。建筑结构控制储层非均质程度,成岩作用使非均质性复杂化,注采井网不完善加剧了非均质性的差异性。研究成果为剩余油的挖潜提供了重要依据。