南堡滩海大位移井钻井关键因素优化设计          下载免费PDF全文

朱宽亮  吕艳  胡中志  周岩  刘永辉 《探矿工程》2017,44(1):33-36

大位移井钻井实施过程中表现最为突出的问题是摩阻扭矩大,它制约着井眼轨迹的有效延伸,尤其在常规钻完井技术时表现得更为明显。冀东油田近年来基于常规钻完井技术条件下,通过对井眼轨道优化设计、钻具组合优化、摩阻扭矩精细预测与控制、井眼延伸极限评估等方面的精细研究与优化设计,有效地模拟分析和论证了南堡滩海中深层大位移井钻井井筒力学行为,提升了对大位移井钻井实践可行性认识和指导了钻完井方案的设计。在南堡滩海成功实施了几十口水平位移大于3000 m的大位移井,最大水平位移达4940 m,为南堡滩海在常规经济技术条件下大位移井的钻井实施提供了技术支持。  相似文献   

中宁县黄河滩地傍河取水工程辐射井设计与施工          下载免费PDF全文

张志军  张伟  陈霄  李海伟 《探矿工程》2017,44(3):69-72

中宁县地处黄河中游,黄河滩地地下水受黄河补给,是具有巨大开采潜力的水源地。针对中宁黄河滩地第四系含粘粒土砂卵石地层的傍河水源地,选择辐射井作为取水建筑物,完成5眼辐射井。集水井成孔采用反循环方法,并配有专用钻头打捞含水层中粒径＞200 mm的漂石,用具有扭力、推力、拉力和振冲力的全液压水平钻机进行水平辐射管施工。采用“等效大口井法”计算辐射井抽水量。对抽水试验的数据及相关资料进行分析,比较辐射井、管井和大口井的稳定出水量和降深,结果表明采用辐射井开采类似水源地是有效的取水方式。  相似文献   

规则波导斯托克斯漂移对污染物输移的影响          下载免费PDF全文

任春平  白玉川 《水科学进展》2017,28(4):605-613

为研究斯托克斯漂移对近岸污染物输移的影响,首先建立波导流和考虑斯托克斯漂移的对流扩散数值模型,通过数模结果与实验结果的比较,研究平直斜坡地形下规则波入射时斯托克斯漂移对污染物输移的影响,波导流模型中波浪场基于波能守恒方程来模拟,波导流场基于Longuet-Higgins提出的辐射应力来模拟,污染物对流扩散模型考虑了斯托克斯漂移的影响。其次,利用一个算例来验证对流扩散模型,结果表明数值模型计算结果与解析解吻合良好。最后,利用该模型模拟了两个实验工况下污染物的输移,数值模拟结果与实验结果吻合良好,表明斯托克斯漂移对近岸污染物向岸线方向的输移有比较明显的影响。  相似文献   

海南岛东北部海滩侵蚀与恢复对连续台风的复杂响应   总被引：5，自引：3，他引：2  

龚昊  陈沈良  钟小菁  陈晴  胡进  程武风 《海洋学报》2017,39(5):68-77

在连续台风作用下海滩的侵蚀与恢复是一个复杂的过程。基于海南岛东北部木兰-抱虎湾海滩的现场调查,对比分析台风"威马逊"和"海鸥"登陆前后海滩剖面和后滨沉积物的动态响应。结果表明,超强台风"威马逊"引起海滩的严重侵蚀和强烈的泥沙输移,在木兰湾海滩主要表现出由北向南沿岸海滩的差异性变化,在抱虎湾各海滩变化较为相近;后继登陆台风"海鸥"引起海滩显著堆积,对海滩主要起恢复作用,木兰湾海滩恢复效果明显,海滩后滨沉积物趋于恢复至台风前的状态,由于抱虎湾水下珊瑚礁及近岸岩礁地貌减缓了台风对该处海滩的侵蚀和堆积作用,抱虎湾海滩表现出与台风前较大差异性。两处海湾海滩的不同走向及台风的风向变化也是造成海滩不同响应的重要原因。研究将有助于更好地理解海滩对连续台风作用的复杂响应。  相似文献   

广西万尾岛金滩沿岸输沙计算与分析     

郭雅琼  马进荣  邹国良 《海洋通报》2017,36(4):468-474

依据CERC公式,年内代表浪向作用下,广西万尾岛金滩平直岸滩中部泥沙分别向东西两侧净输沙,意味着金滩中部有淘刷趋势而两端有淤积趋势,而实际上岸滩中部滩面长年基本稳定、未有明显侵蚀现象。分析认为公式计算成果反映的输沙特征定性仍然是正确的,岸滩能够维持稳定是因为还存在自海向岸的横向输沙补给沙源。当岸滩并非平直且足够长时,应完整分析纵、横向输沙才能更为合理地反映岸滩泥沙运动特征。  相似文献   

Ghost crab burrow density at Watamu Marine National Park: An indicator of the impact of urbanisation and associated disturbance?     

HFR Hereward  LK Gentle  ND Ray  RD Sluka 《African Journal of Marine Science》2017,39(1):129-133

Ghost crab (Ocypode species) burrow densities have previously been used as an indicator of anthropogenic impact. This study aimed to assess the burrow density of Ocypode species (O. ryderi and O. cordimanus) at four sites across Watamu Marine National Park, Kenya. Two sites were in front of hotel complexes (denoting a high degree of urbanisation), and two were in front of residential housing among coastal scrub (denoting a low degree of urbanisation). The findings reveal significantly higher burrow densities at sites in front of residential housing, which was the less developed area. This provides further evidence that Ocypode burrow densities can be used, where other methods would be impractical, to estimate the impact of some human activities along beach fronts, such as at Watamu Marine National Park.  相似文献   

中英海滨污染美学的比较研究     

罗伯特·摩根  刘洪 《海岸工程》1999,18(4):35-45

在西方从美学的角度研究海滨环境质量是近３０年的事,近些年来发展更快,发表了一系列文章,对滨海环境的评价主要脸地形地貌、生态植被和水体的环境质量,其中尤其是对水体的评价显得更为重要,将水质分为优质水和劣质水。优质水体表现为洁净、生物丰富、有鱼、水鸟、没有垃圾等;而劣质水则呈深色、漂浮着垃圾、泡沫、死鱼、水底为油污,缺少生物,发出令人难以接受的恶臭等气味。传统环境质量监测可用物理、化学、生物方法进行,并有一系列量化指标,而美学对地貌、环境、垃圾、泡沫、噪声的评价就比较困难,没有统一的标准,只能凭感官、视觉和心理反应做出评价。例如,对海滨垃圾的测量方法也处在初级阶段,不同的机构,不同的研究人员采用不同的方法,在时空上进行对比也非常困难。通常我们采用了采访和问卷的两种调查方式,同时配合出示彩色图片或录相来进行,由于人们的文化背景、经不同,对环境质量从美学上认识有一定差距,故对环境、海岸评价带来一定困难,但原始的、未被破坏的自然景观,被西方人认为是最美,近就是油画、水彩画半自然风光做成永恒主题,经久不衰的原因。中国海滨污染从美学上进行研究还没有起步,,但客观上,我们已经感受到了污染的存在,例如,沿海滨的垃圾,瓢浮在海面上的塑料袋、油污、泡沫、海草、死鱼等;许多污水不经处理直接入海,散发着恶臭……这一切都对生态环境,特别是滨海旅游业发展造成了严重影响,随着中国工业的快速发展,在海岸带局地区造成的污染还将加重。法律保护广大群众的健康,面对法规和广大公众关心海滨环境的压力,英国政府和企业投巨资以便改进滨海环境质量,威尔士最大的自来水公司威尔士水公司于１９９５－２０００年将花费６亿英镑（１０亿美元）用于改进威尔士的污水处理系统（只有２万km^2面积３００万人口）。中国可以从英国经济发展过程中吸取教训,控制好烟、尘、油和固体废弃物向海洋的倾倒。否则,要付出沉痛的代价的。  相似文献   

The role of beach morphology on coastal cliff erosion under extreme waves          下载免费PDF全文

Claire Earlie  Gerhard Masselink  Paul Russell 《地球表面变化过程与地形》2018,43(6):1213-1228

Erosion of hard‐rock coastal cliffs is understood to be caused by a combination of both marine and sub‐aerial processes. Beach morphology, tidal elevation and significant wave heights, especially under extreme storm conditions, can lead to variability in wave energy flux to the cliff‐toe. Wave and water level measurements in the nearshore under energetic conditions are difficult to obtain and in situ observations are rare. Here we use monthly cliff‐face volume changes detected using terrestrial laser scanning alongside beach morphological changes and modelled nearshore hydrodynamics to examine how exposed cliffs respond to changes in extreme wave conditions and beach morphology. The measurements cover the North Atlantic storms of 2013 to 2014 and consider two exposed stretches of coastline (Porthleven and Godrevy, UK) with contrasting beach morphology fronting the cliffs; a flat dissipative sandy beach at Godrevy and a steep reflective gravel beach at Porthleven. Beach slope and the elevation of the beach–cliff junction were found to influence the frequency of cliff inundation and the power of wave–cliff impacts. Numerical modelling (XBeach‐G) showed that under highly energetic wave conditions, i.e. those that occurred in the North Atlantic during winter 2013–2014, with H_s = 5.5 m (dissipative site) and 8 m (reflective site), the combination of greater wave height and steeper beach at the reflective site led to amplified wave run‐up, subjecting these cliffs to waves over four times as powerful as those impacting the cliffs at the dissipative site (39 kWm^‐1 compared with 9 kWm^‐1). This study highlighted the sensitivity of cliff erosion to extreme wave conditions, where the majority (over 90% of the annual value) of cliff‐face erosion ensued during the winter. The significance of these short‐term erosion rates in the context of long‐term retreat illustrates the importance of incorporating short‐term beach and wave dynamics into geomorphological studies of coastal cliff change. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.  相似文献   

Beach recovery from extreme storm activity during the 2013–14 winter along the Atlantic coast of Europe     

Guillaume Dodet  Bruno Castelle  Gerd Masselink  Timothy Scott  Mark Davidson  France Floc'h  Derek Jackson  Serge Suanez 《地球表面变化过程与地形》2019,44(1):393-401

The storm sequence of the 2013–14 winter left many beaches along the Atlantic coast of Europe in their most eroded state for decades. Understanding how beaches recover from such extreme events is essential for coastal managers, especially in light of potential regional increases in storminess due to climate change. Here we analyse a unique dataset of decadal beach morphological changes along the west coast of Europe to investigate the post-2013–14 winter recovery. We show that the recovery signature is site specific and multi-annual, with one studied beach fully recovered after 2 years, and the others only partially recovered after 4 years. During the recovery phase, winter waves primarily control the timescales of beach recovery, as energetic winter conditions stall the recovery process whereas moderate winter conditions accelerate it. This inter-annual variability is well correlated with climate indices. On exposed beaches, an equilibrium model showed significant skill in reproducing the post-storm recovery and thus can be used to investigate the recovery process in more detail. © 2018 John Wiley & Sons, Ltd.  相似文献   

基于无人机技术的潮滩动态监测研究          下载免费PDF全文

裘诚  王岳峰  方略任  张何朕加  张凯嫔  胡进  陈沈良  袁瑞 《海洋开发与管理》2022,39(11):114-120

无人机具有快速高效、体积小和成本低等特点,不仅可以监测淤泥质潮滩不同区域的变化趋势,还可以观测到卫星难以捕获的潮滩短历时发育过程。文章基于无人机航拍测量技术,通过后期图像处理生成正射影像,获取临港新片区潮滩的沙滩和植被区域面积,分析潮滩短周期沙滩和植被时空分布特征和对不同事件的响应。研究结果表明：近年来临港潮滩潮上带从淤泥质海滩逐渐转变为沙质海滩;潮滩植被有明显季节性变化,秋冬季枯萎,春夏季生长茂盛,分布在潮滩西侧的植被变化最为显著;沙滩随着植被枯萎而裸露,易受波浪、潮汐冲刷;相比于季节性转化,沙滩在事件上的响应更为显著,洪水期淤积和台风冲刷导致潮滩变化剧烈。  相似文献