珠江三角洲网河近20年河床演变特征分析

总结了20世纪80年代前珠江三角洲网河河床演变特征,并采用80年代和90年代末的河道地形图,通过对比珠江三角洲各主要河道的深泓线、平均河底高程以及河道容积、河床断面宽深比的变化,分析珠江三角洲80年代后的河床演变特征。对比分析结果表明珠江三角洲在不同时期呈现出不同的河床演变规律——20世纪80年代前以淤积为主,80年代至90年代末转变为以冲刷为主。     

黄河下游河道萎缩致灾机理探讨

本文基于水力学原理，结合实体模型试验及原型实测资料分析，探讨了黄河下游河道萎缩的概念、致灾效应和致灾机理。分析表明，河道萎缩是造床过程中河道排洪输沙功能衰退的一种演变现象，其致灾效应是使洪水涨率增大，同流量下洪水水位不断抬升。致灾的现象主要表现在畸型河势增加、工程险情增多、直接造成工程损失及滩区经济损失等。试验研究揭示，主河槽宽度缩窄造成洪水水位涨幅增大，河底平均高程抬升和过水断面面积减小造成洪水水位起涨的基准面抬升是河道萎缩致灾的主要原因。河道萎缩致灾效应的大小与萎缩模式有关，其中以“集中淤槽”模式所形成的致灾效应尤为明显。     

微地震相分析在河流储层精细描述中的应用

传统地震相分析满足不了目前油田勘探开发的需要。神经网络微地震相分析将神经网络应用于高质量三维地震数据体中，可对单一反射同相轴进行波形信号分析和训练，建立模型地震道，并对实际地震道分类，进而得到在平面和剖面上精度较高的微地震相分布。采用该方法并结合测井资料，在研究区块中建立的微地震相分布图能够清晰地表现出该区块的沉积微相特征，且较好地解释了工区内2口井的产能差异，表明神经网络微地震相分析是可靠和有效的。     

Fish assemblages and stream hydraulics: consistent relations across spatial scales and regions

General relationships between organisms and their habitat, consistent across spatial scales and regions, suggest the existence of repeatable ecological processes and are useful for the management of stream networks. From published data, we defined four guilds of European fish species with contrasting preferences for microhabitat hydraulics within stream reaches. At the scale of stream reaches and across 139 French sites (590 460 fishes sampled), we analysed how fish guild proportions were related to reach hydraulics (proportion of pools vs. riffles %POOL; median discharge by unit width Q50/W). The strongest correlations were observed between two fish guilds and %POOL (p < 0.001, r² ≥ 0.41) and between one fish guild proportion and Q50/W (p < 0.001, r² = 0.10). These reach–scale relationships were consistent across six large French basins, and consistent with the analyses made at the microhabitat scale. Therefore, microhabitat preferences for hydraulics are strong enough to generate consistent reach‐scale community responses to hydraulics across regions, despite the influence of other filters such as temperature, nutrient levels or history. The distribution of basic geomorphic features (pools, riffles) in streams and their modification (by dams, weirs and dikes) can modify the proportion of fish guilds by up to 80%, probably contributing to the long‐term decline of riffle‐dwelling species in Europe. Copyright © 2006 John Wiley & Sons, Ltd.     

黄河下游平滩流量对来水来沙变化的响应

本文探讨了平滩流量对来水来沙的滞后响应规律，发现平滩流量不仅与当年的水沙条件有关，而且与前期水沙条件有关，是一定时期内的水沙条件累积作用的结果。当采用滑动平均值来反应前期水沙条件的累积影响时，得出平滩流量与滑动平均汛期流量和滑动平均来沙系数的相关程度分别在4年和5年时达到最大值。据此建立了能够反映来水流量和来沙系数前期综合影响的平滩流量计算方法，可以用来估算黄河下游主要测站平滩流量随水沙条件的变化。     

济阳坳陷沾车地区中生界沉积体系

随着油气勘探开发的不断深入，济阳坳陷中生界油气藏日益受到重视。针对济阳坳陷沾车地区中生界缺乏详细地质分层和沉积体系研究、勘探开发受到地震资料解释和层位对比严重限制的实际问题，以该区近130口钻录井、测井层序、古生物和三维地震等资料为基础，采用沉积体系分析方法，将其中生界划分为下一中侏罗统坊子组、中侏罗统三台组、上侏罗统蒙阴组和下白垩统西洼组4个层位；建立了沾车地区中生代地层充填系列，并识别出主要发育的河流沉积体系（包括曲流河和辫状河）、冲积扇沉积体系、湖泊沉积体系和三角洲沉积体系，系统研究了各沉积体系的类型、特点、分布和空间演化。     

Valley floor landscape change following almost 100 years of flood embankment abandonment on a wandering gravel‐bed river

Critical to restoring the nature conservation value of many river corridors is an understanding of how alluvial landscapes will respond to cessation of river management and land use practices that have previously degraded the environment. This paper analyses changes in valley floor landforms and vegetation patch dynamics, in relation to fluvial disturbance, over a period of almost 100 years following flood embankment abandonment on a wandering gravel‐bed river, namely the River Tummel, Scotland. Such rivers were once typical of many draining upland areas of northern maritime Europe. Prior to abandonment the valley floor landscape was agriculturally dominated and the river for the most part was single thread confined between flood embankments. The pattern of landform change and vegetation patch development over time following a decision in 1903 not to maintain embankments was tracked by geomorphic and land cover mapping utilizing successive sets of aerial photography for the period 1946 to 1994. A historical context for these changes was also feasible because the channel planform in 1900 and earlier channel planform changes dating back to 1753 were known due to the availability of old maps and earlier geomorphic studies. The land cover mapping was validated by comparison of results produced from the interpretation work on the 1994 aerial photographs with the field‐based UK National Vegetation Classification protocol. The findings of the study illustrate that bordering the River Tummel fluvial landforms and vegetation patch mosaics, presumably resembling those that occurred before valley floor land use intensification, evolved in less than 50 years after flood embankment abandonment with a resultant increase in habitat diversity. The change relates primarily to flood‐induced channel planform change and moderate levels of fluvial disturbance. The general significance of this change to plant species diversity on the valley floor of the River Tummel and elsewhere is discussed as is possible implications of the upstream impoundment and scenarios for climatically induced changes in flood frequency and magnitude. The overall outcome is the strong possibility that simple changes in river management and land use practices could result in re‐establishment of the nature conservation value of similar river corridors in Europe over the medium term without active restoration efforts. Copyright © 2002 John Wiley & Sons, Ltd.     

GEOLOGICAL MODEL EVALUATION THROUGH WELL TEST SIMULATION: A CASE STUDY FROM THE WYTCH FARM OILFIELD, SOUTHERN ENGLAND

This paper presents an approach to the evaluation of reservoir models using transient pressure data. Braided fluvial sandstones exposed in cliffs in SW England were studied as the surface equivalent of the Triassic Sherwood Sandstone, a reservoir unit at the nearby Wytch Farm oilfield. Three reservoir models were built; each used a different modelling approach ranging in complexity from stochastic pixel‐based modelling using commercially available software, to a spreadsheet random number generator. In order to test these models, numerical well test simulations were conducted using sector models extracted from the geological models constructed. The simulation results were then evaluated against the actual well test data in order to find the model which best represented the field geology. Two wells at Wytch Farm field were studied. The results suggested that for one of the sampled wells, the model built using the spreadsheet random number generator gave the best match to the well test data. In the well, the permeability from the test interpretation matched the geometric average permeability. This average is the “correct” upscaled permeability for a random system, and this was consistent with the random nature of the geological model. For the second well investigated, a more complex “channel object” model appeared to fit the dynamic data better. All the models were built with stationary properties. However, the well test data suggested that some parts of the field have different statistical properties and hence show non‐stationarity. These differences would have to be built into the model representing the local geology. This study presents a workflow that is not yet considered standard in the oil industry, and the use of dynamic data to evaluate geological models requires further development. The study highlights the fact that the comparison or matching of results from reservoir models and well‐test analyses is not always straightforward in that different models may match different wells. The study emphasises the need for integrated analyses of geological and engineering data. The methods and procedures presented are intended to form a feedback loop which can be used to evaluate the representivity of a geological model.     

Benchmarking Fluvial Dynamics for Process‐Based River Restoration: the Upper Rhine River (1816–2014)

Multi‐temporal analysis of river‐floodplain processes is a key tool for the identification of reference conditions or benchmarks and for the evaluation of deviations or deficits as a basis for process‐based river restoration in large modified rivers. This study developed a methodology for benchmarking fluvial processes at river segment level, focusing on those interrelations between morphodynamics (aggradation, erosion, channel shift) and vegetation succession (initial, colonization, transition) that condition habitat structure. Habitat maps of the free‐flowing Upper Rhine River downstream from Iffezheim dam (France–Germany border) were intersected with a geographic information system‐based approach. Patches showing trajectories of anthropization, changeless, progression and regression allowed for the identification of natural and human‐induced processes over almost 200 years. Before channelization, the riverine system was characterized by a shifting habitat mosaic with natural heterogeneity, high degree of surface water connectivity and equilibrium between progression and regression processes. On the other hand, the following 175 years of human interventions led to severe biogeomorphologic deficits evidenced by loss of natural processes and habitat heterogeneity, hydrological disconnection between the river and its floodplain and imbalance of progression versus regression dynamics. The main driving forces of change are found in hydromorphological impacts (channelization, regulation and hydropower plant construction). Regression processes are now almost absent and have to be the objective of process‐based river restoration measures for the studied river‐floodplain system. A sustainable view on water management and river restoration should aim at a more resilient riverine system by balancing the recovery of natural processes with societal needs. Copyright © 2016 John Wiley & Sons, Ltd.     

河流相正韵律厚油层注水方向研究

河流相的不同微相砂体具有不同物性特征,决定了其不同的产液、吸水能力及注水运动方向。在油藏精细描述的基础上,应用油藏数值模拟方法,按注水方向与河道方向的不同夹角,设计了9种布井方式。在不同生产时期以及不同的渗透率级差下,对油田河流相正韵律厚油层储层的注水方向进行研究,可知注水方向与河道的垂线夹角为26°时,最终采收率最高,而注水方向与河道方向平行时,最终采收率最低。