鄂尔多斯盆地中东部上古生界三角洲沉积特征

上古生界是鄂尔多斯盆地重要的含气层系，天然气的聚集受相带的控制，其主产层均为三角洲沉积体系。通过对盆地中东部上古生界野外露头、岩心及测井曲线等的综合分析，将区内上古生界三角洲沉积体系划分为辫状河三角洲及曲流河三角洲。分析表明，研究区两类三角洲沉积在岩性、沉积构造、沉积序列、测井曲线等方面存在差异。辫状河三角洲主要发育在中二叠世下石盒子组下部盒₈、盒₉段气层组，主体为辫状河三角洲前缘亚相；曲流河三角洲主要发育在早二叠世山西组山₂段气层组，以曲流河三角洲前缘沉积为主。勘探实践表明，曲流河三角洲沉积体系对于研究区天然气的富集有着更为重要的作用。今后应重点加强对山₂段气层组曲流河三角洲沉积体系中有利储集相的寻找，同时兼顾盒₈、盒₉段气层组的辫状河三角洲沉积体系。     

现代潮白河岩相与沉积相特征

以北京市通州区现代潮白河白庙沉积体为例,通过对深挖探槽、探坑和野外剖面的详细解剖,结合密集采样的分析结果,详细研究了现代潮白河白庙沉积体内部的沉积相类型。研究表明,现代潮白河白庙沉积体是一个曲流河沉积体。在现代潮白河白庙沉积体内部,共识别出8 种岩相,即块状层理细砾岩相（泥砾为主）、大型低角度槽状交错层理细砂岩相、小型低角度槽状交错层理细砂岩相、同沉积变形层理细砂岩相、平行层理细砂岩相、板状和波状交错层理细砂岩相、薄层块状层理粉砂质泥岩与细砂岩相及块状层理泥质粉砂岩相;主要发育了2 种沉积亚相和5 种沉积微相,即河道和河漫滩亚相以及河床滞留沉积、边滩、天然堤、决口扇和泛滥平原微相。潮白河白庙沉积体在垂向上共发育了3 期沉积旋回,其形成主要受沉积物供给、气候和河岸性质的控制。现代潮白河岩相和沉积相的研究,对于寻找古代曲流河岩性油气藏会有重要的启示意义,同时对潮白河今后的开发利用也具有重要的意义。     

黄河流域河湖生态环境复苏研究

通过评价黄河流域河湖生态环境演变特征,探究其存在的问题,分析黄河流域河湖生态环境复苏目标与总体格局,探讨并提出黄河流域河湖生态环境复苏的实现路径.结果表明,黄河流域河湖生态环境系统正在由无序发展向有序发展转变.针对黄河流域河湖生态环境复苏面临的河湖生态环境脆弱、区域地下水超采、流域水土流失等主要问题,应从强化河湖监管、...     

苏里格气田苏14 井区盒8 段河流相砂体展布与演化规律研究

河流相砂体横向相变快,连续性和连通性差,储层非均质性强,严重影响了河流相储层的开发效果。依据储层沉积学的研究方法,对苏里格气田苏 14 井区盒 8 段河流相砂体展布与演化规律进行了研究。结果表明：苏 14 井区盒 8 段属于早期辫状河沉积向晚期曲流河沉积逐渐转化的沉积背景,其主要沉积微相包括河道滞留沉积、心滩、边滩、决口扇、天然堤、河漫砂及泛滥泥。 受基准面升降与沉积物供应的共同作用,该区河流相砂体演化呈阶段性变化,大致经历了辫状河繁盛发育期、辫-曲共存转化发育期及曲流河繁盛发育期 3 个阶段,其中辫状河繁盛发育期的心滩砂体与辫-曲共存转化发育期的心滩及边滩砂体是主力含气储层。 研究区优质储集砂体的发育受沉积微相展布与基准面旋回的控制。     

复式河道漫滩水流计算方法研究

对复式顺直河道和复式游荡型河道中漫滩洪水的计算方法进行了研究.其中，对复式顺直河道，从Shiono-Knight方法出发，将二次流项归并入雷诺切应力项，并将主槽和滩地的流速分布曲线直接相接，推导出一套不需联立求解系数方程组的漫滩水流流速和床面切应力分布的计算公式以及床面平均切应力的解析计算公式；对复式游荡型河道，建立了一种新的上层水流计算方法.文中的计算结果与前人的实验资料基本一致，初步表明文中的方法是合理的.     

弯曲河道对水流流态影响数值模拟

蜿蜒型河流是冲积平原常见的河型之一。针对具体河流的特定自然条件,需要对不同河道形态下的河道特性做出预测,以便选择和调整相应方案。采用集水动力模块、泥沙输运模块、污染物运移模块和水质预测模块为一体的环境流体动力学模型,利用计算机进行数值模拟,对京郊某弯曲河道3种河道形态在50年一遇洪水过程下进行数值模拟,在此基础上对3种工况下河道的水流特性进行分析,发现工况一弯道处凸岸流速先增加后减小,凹岸流速先减小后增大,凹岸水位明显高于凸岸水位;工况二两岸流速分布较为对称,叉道起到分洪滞洪作用;工况三两岸水流摆动现象不如工况一明显,衬砌工程量较小,并提出相应河道保护措施。     

特高含水开发期曲流河储层构型深化研究及应用

针对孤岛油田Ng3油藏非均质的地质特征,采用油藏综合分析、测井响应分析及数值模拟等方法,开展了特高含水开发期高弯度曲流河储层构型深化研究。解析了单河道、点坝及点坝内部构型单元等不同级次曲流河的储层构型模式,通过采用层次约束、模式拟合的构型表征方法,系统地进行了复合曲流带、单一曲流带、单一点坝及点坝内部侧积体精细表征．建立了密井网区三维构型模型及参数模型。同时针对特高含水期储层构型控制下的剩余油分布特点,开展了井网调整转流场＋非均相复合驱先导试验。,结果表明：中心井区日产油量由4．5t上升到71．0t,含水率由98.8％下降到83．5％,累计增油26539t．预计井网调整转流场提高采收率2．3百分点,非均相复合驱提高采收率6．2百分点,试验区采收率达到63．6％．     

Review of the natural conditions and anthropogenic threats to the Ethiopian Rift Valley rivers and lakes

This review article considers the lakes found within the Ethiopian Rift Valley system and the rivers draining from the highlands towards them. The Ethiopian Rift Valley system extends in a north‐east–south‐west direction, bisecting the Ethiopian highlands. They differ in sizes and hydrological and hydrogeological settings. The lakes support a variety of flora and fauna, mainly fishes, reptiles, birds and mammals. The lakes and their feeder rivers, however, are currently being subjected to more human use pressure than previously experienced, attributable mainly to water abstractions for irrigation, household water supply and industrial activities in the catchments. Soil erosion, primarily attributable to the lack of soil conservation practices on farm lands, overgrazing and deforestation, along with unregulated irrigation practices, are generating large quantities of silt reaching the lakes. Improper utilization of water and land resources in the catchments, along with population growth and climate change impacts, is escalating the threats to the health of the lake and river ecosystems. As a result, some of the lakes exhibited reduced water levels and increased salinity. This article reviews the major environmental changes happening to these lakes and their feeder rivers. Visits were made to the area to update previous information while also consolidating the trends of change in the aquatic systems and the watersheds attributed to intense development practices.     

明渠水流阻力研究现状分析

只有正确深入地把握水流阻力规律,才能掌握解决水力学及河流动力学中各种实际问题的主动性。本文通过系统评述和研究分析前人成果,对相关问题有所澄清。历史上曾经影响较大且不需要调整参数的杜博公式、艾特魏因公式、曼宁第二公式,可反映曼宁公式所代表的平均情况,但难以像曼宁公式那样能够适应自然界复杂多变的摩阻特性。至于巴辛公式,若将其河道粗糙特征的系数与曼宁糙率系数建立关系,同样能够适用于水流阻力计算。对于动床阻力问题,众多学者已认识到水流强度、河床形态的变化及流体中含沙浓度的重要影响,也通过不同角度建立了一些经验或半经验公式。为能找出实用性强或精度高的计算公式,还必须注重分析水流、河床与泥沙运动之间相互影响的内在机理,尤其需要在各种因子的影响机理及计算途径上开展深入研究。     

IDENTIFICATION OF FLUVIAL WOOD USING GOOGLE EARTH

Fluvial wood has long been known to enhance stream complexity by creating aquatic habitat and by increasing complexity in channel hydraulics and morphology. Although the presence and dynamics of large wood in river floodplains have been studied in a multitude of settings due to its importance in monitoring and managing ecohydrologic systems, limitations occur when studying fluvial wood on a basin scale. I postulate that with the employment of Google Earth, satellite images may be used to identify large wood and measure floodplain width across broader spatial scales previously inhibited by expensive and incomplete geospatial data. In this study, large wood was correctly identified within the floodplain of the Queets River, Washington, USA, through Google Earth; however, correct identification within the wetted channel was only possible during low flow if at least 50% was above water level. Within the study area, fluvial channel widths are measured as well. Google Earth proves to be an effective tool to discern large wood across greater spatial scales if the high‐resolution imagery is available for the study area. Results of statistical analyses derived from the downstream hydraulic geometry of the river reveal that this channel is influenced by bankfull width, the orientation of the wood to the channel, and whether it is located on a bar or within the wetted channel. In addition, wood counts analyzed in the context of the geometry of the river indicate that the fluvial wood has an influence on overall channel behavior. Copyright © 2013 John Wiley & Sons, Ltd.