基于能量法的跨航道海底管线抗落锚实验研究

随着跨航道海底管线应用越来越普遍,航道、水港等海域的抛锚作业对海底管道带来的安全风险问题越来越引起人们的关注。文章针对海底管道堆石保护方法,通过模拟实验研究了抛锚作业过程中海底管道的应力状态,并对其进行了损伤分析。通过绘制不同影响因素下管道变形的对比曲线,研究了覆盖石材、抛锚速度、埋深等因素对管道损伤的影响,并基于正交试验原理分析了不同影响因素对海底管道响应的敏感性。结合标准DNV RP-F107中的能量计算方法研究了不同影响因素对海底管道响应的工况,分析得出管道的最小推荐设计埋深。     

堆石混凝土技术在水运工程中的应用

堆石混凝土技术以其低水化热、施工工艺简便、施工效率高、施工质量高等优势广泛应用在水利水电工程混凝土结构施工中,但在水运工程存在有大体积混凝土结构部位（如胸墙）中却很少得到应用。文中以黄骅港围堰二期工程为例,从施工方案设计、综合评定分析等方面介绍了堆石混凝土技术在该工程中的成功运用,优势明显。本工程也为堆石混凝土技术应用在水运工程敲开了大门,前景宽广。     

整体浇筑堆石混凝土拱坝施工期温度监测方法

为规范拱坝施工期温度,本文开展整体浇筑堆石混凝土拱坝施工期温度监测方法的设计研究。根据工程需求,选用温度传感器作为温度监测仪器,按照规范进行仪器设备的选型与埋设布置;考虑到通过温度传感器直接获取的温度数据往往存在各种误差和异常值,因此,在接收仪器设备采集数据后,进行施工期监测温度数据的预处理;通过对拱坝施工期温度场的计算,进行堆石混凝土拱坝施工期温度的监测分析。实例应用实验结果表明,设计的方法监测结果具有可靠性。     

未经夯实堆石结构蠕变沉降估算

在以往的水运工程设计中、仅考虑软土地基的沉降和蠕变,忽略堆石体自身的蠕变沉降。引堤、防波堤、岸壁式码头后方回填等堆石体结构不能有效夯实且结构较厚时,其长期蠕变沉降可能影响使用功能。结合巴基斯坦某引堤、防波堤工程,应用反馈分析法及室内试验研究法,对堆石体蠕变量进行计算,并结合沉降观测数据与计算结果进行对比分析。结果表明,反馈分析法对于水运工程堆石体蠕变沉降计算的适用性较强,与实际观测数据吻合较好,可为类似工程提供参考。     

堆石混凝土技术的研究与应用

宝泉抽水蓄能电站上水库冲沟回填和部分副坝坝体浇筑，通过现场试验证实了使用堆石混凝土的叮行性，进一步确定了不同强度等级自密实混凝土的配合比，研究了适合堆石混凝土浇筑的堆石块体的粒径选择。该技术经过在副坝及各冲沟处的施工应用，证明堆石混凝土其具有施工效率高、经济效益好、质量稳定等优点。     

堆石混凝土技术在水工围堰中的应用

堆石混凝土技术虽然在很多工程上已经取得了成功的应用范例,但是还属于比较新的技术,尤其在水工程中应用较少。本文结合工程实例,分析堆石混凝土技术在水工围堰中的应用。通过此技术的运用,使工程建设中的材料能源消耗降低,工作效率提高,使围堰工程更加经济、环保。     

堆石混凝土重力坝施工方法及质量控制研究

本文以重庆某水库为例,通过自密实混凝土大坝试验段施工、堆石料筛选、堆石料入仓、模板选型、混凝土浇筑、养护方式开展分析,对堆石入仓过程质量、自密实混凝土生产质量、浇筑质量进行研究,可为同类工程施工提供参考.     

堆石混凝土技术在深溪河水库重力坝中的应用

利用自密实混凝土的高流动性及抗分离性,在粒径较大的块石内随机填充而形成自密实堆石混凝土。该技术具有低碳环保、低水化热、工艺简便、施工速度快、造价低廉等特点,基于上述原因,文章对在深溪河重力坝设计中采用的堆石混凝土技术进行了分析研究。实践证明,该方案经济技术优势明显,可为类似工程的设计提供参考和借鉴。     

基于跨越保护架的海管交叉跨越技术

设计一种用于新铺海底管道与现有海底管道发生交叉时的海管交叉跨越保护架,保护架采用截面形状为Ω形的钢制结构,根据海底土壤的承载力和抵抗海流和渔网的在位稳定性要求,保护架两侧设置防沉板。该海管交叉跨越保护架在LBL水下定位系统和ROV协助下可实现一次性吊装安放,与常规海底管道跨越处理方法相比具有安全、高效的优点,可推广应用于深水开发工程中。     

海底管道悬空隐患成因及防治

海底管道是海上油田生产系统中心的一个重要组成部分,维护海底管道的安全是保证安全生产和保护海洋环境重要环节.本文对埕岛海区平台附近与立管连接的海底管道出现悬空的安全隐患进行了详细的调查,并对产生悬空原因进行了分析.对悬空管道的悬空控制进行了对策研究,形成了采用"水下支撑桩"方法进行管道悬空治理的施工方案,此对策实施后取得了显著效果,为保证海底管道安全,保护海洋环境提供了有利借鉴.     

深水抛石管强度分析与研究

水下抛石作为一种海底管道保护措施之一,在国内外海洋石油开发中已得到广泛应用,现已由浅水应用到深水。本文的研究目标落管抛石船为深水精确抛石作业船型,文章研究了深水抛石作业系统,确定总体落管抛石作业工艺流程,计算出系统中抛石管线的强度,比较了不同航速、水深下抛石管线的强度。后又研究了落管抛石水下机器人（ROV）在管线强度计算中产生的影响与作用,最终确定了这类船型在不同作业水深下的最大航速预报方法。     

用于预报离岸管线膨胀的简化技术（英文）

In this study, we propose a method for estimating the amount of expansion that occurs in subsea pipelines, which could be applied in the design of robust structures that transport oil and gas from offshore wells. We begin with a literature review and general discussion of existing estimation methods and terminologies with respect to subsea pipelines. Due to the effects of high pressure and high temperature, the production of fluid from offshore wells is typically caused by physical deformation of subsea structures, e.g., expansion and contraction during the transportation process. In severe cases, vertical and lateral buckling occurs,which causes a significant negative impact on structural safety, and which is related to on-bottom stability, free-span, structural collapse, and many other factors. In addition, these factors may affect the production rate with respect to flow assurance, wax, and hydration, to name a few. In this study, we developed a simple and efficient method for generating a reliable pipe expansion design in the early stage, which can lead to savings in both cost and computation time. As such, in this paper, we propose an applicable diagram, which we call the standard dimensionless ratio(SDR) versus virtual anchor length(LA) diagram, that utilizes an efficient procedure for estimating subsea pipeline expansion based on applied reliable scenarios. With this user guideline,offshore pipeline structural designers can reliably determine the amount of subsea pipeline expansion and the obtained results will also be useful for the installation, design, and maintenance of the subsea pipeline.     

国外海底管道局部屈曲研究综述

海底管道是海洋油气集输系统中最重要的组成部分之一,从铺设到服役都将承受多种载荷的作用,并可能发生局部屈曲且沿管道传播开来,由此造成严重的后果。海底管道的局部屈曲在管道安全性方面具有重要意义,已成为海底管道设计与评估中重要的内容。详细阐述了国外关于海底管道受外压、弯矩和轴力作用下的局部屈曲研究成果,论述了在单个载荷和多个载荷联合作用下的局部屈曲破坏机理,并提出了未来研究的建议。     

Simplified Technique for Predicting Offshore Pipeline Expansion

In this study, we propose a method for estimating the amount of expansion that occurs in subsea pipelines, which could be applied in the design of robust structures that transport oil and gas from offshore wells. We begin with a literature review and general discussion of existing estimation methods and terminologies with respect to subsea pipelines. Due to the effects of high pressure and high temperature, the production of fluid from offshore wells is typically caused by physical deformation of subsea structures, e.g., expansion and contraction during the transportation process. In severe cases, vertical and lateral buckling occurs, which causes a significant negative impact on structural safety, and which is related to on-bottom stability, free-span, structural collapse, and many other factors. In addition, these factors may affect the production rate with respect to flow assurance, wax, and hydration, to name a few. In this study, we developed a simple and efficient method for generating a reliable pipe expansion design in the early stage, which can lead to savings in both cost and computation time. As such, in this paper, we propose an applicable diagram, which we call the standard dimensionless ratio (SDR) versus virtual anchor length (L_A) diagram, that utilizes an efficient procedure for estimating subsea pipeline expansion based on applied reliable scenarios. With this user guideline, offshore pipeline structural designers can reliably determine the amount of subsea pipeline expansion and the obtained results will also be useful for the installation, design, and maintenance of the subsea pipeline.     

Stress analysis of the subsea dynamic riser baseprocess piping

Thesubsea dynamic riser base （SDRB） is an important piece of equipment for the floating production platform mooring system.One end is connected to the rigid pipeline, carrying a rigid pipeline thermal expansion load and the other end is connected to a flexible riser, carrying the dynamic load of the flexible riser, so its function is a transition connection between the flexible riser and the rigid pipeline which fixes the flexible riser on the seabed. On the other hand. as a typical subsea product, the design will satisfythe requirements of the standards for subsea products. By studying the stress analysisphilosophy of the topside piping and subsea pipeline, a physical model and procedure for piping stress analysis of the SDRB have been established.The conditions of the adverse design load have been considered, and a combination of the static load from the rigid pipeline and the dynamic load flexibility has also been optimized. And a comparative analysis between the AMSE, DNV and API standards for piping stress with the checking rules has been done.Because theSDRB belongs to the subsea pipeline terminal product, the use of DNV standards to check its process piping stress is recommended. Finally, the process piping stress of the SDRB has been calculated, and the results show that the jacket pipe and the carrier pipe stress of the SDRB process piping satisfy the DNV standards as a whole.The bulkhead cannot be accurately simulated by the AutoPIPE software which uses the FEA software ANSYS inthe detailed analysis, but the checking results will still meet the requirements of the DNV standards.     

Reliability-based design of subsea light weight pipeline against lateral stability

The application of non-metallic light weight pipeline (LWP) in subsea oil/gas transmission system is subject to subsea pipeline on-bottom stability problem because of their light weight. Additional weight required for the stabilization of subsea LWP is a critical item to consider when decreasing the cost of the pipeline system. This paper presents an effective approach to determine the additional weight by utilizing a reliability-based assessment of subsea LWP against on-bottom stability. In the approach, a dynamic non-linear finite element model (FEM), including a model of fluids-pipe-soil interaction for the subsea pipeline, is used to study the pipeline displacement response. In-place analysis of a flexible pipe is presented as an example of the authors' methodology. Results show that displacements are largely affected with and without considering the lift force. Additionally, the uncertainties of all parameters used in the model are considered. With 145 cases of FEM calculations being the samples, a response surface model (RSM) is developed to predict the pipeline lateral displacement using the software Design-Expert. Combing with the RSM equation, the Monte Carlo simulation method is employed to estimate the probability of exceeding pipeline stability. To calculate the reliability of LWP for different submerged weights, the method introduces a calibrated factor into the serviceability limit state (SLS) function. The proposed approach can be used to determine the additional weight required for the on-bottom stability of subsea pipelines while considering the uncertainties of all relevant parameters.     

水下管道连接器设计研究及应用

随着全球海洋石油天然气开发从浅水走向深水,由于潜水员下潜深度有限,海底油气管道的连接必须通过水下机器人代替潜水员完成此项工作。因此各种管道连接技术也越来越多地应用于海洋石油开发中。水下管道连接器作为一种重要的自动安装连接装置,涉及到机械、液压、材料、防腐、密封等各个方面,具有免潜水员操作、安装便捷、可靠性高等特点,可广泛应用于水下油气管道连接。本文对已成功应用于南海某气田中水下采气树跨接管连接的水平机械式管道连接器和水下管汇发球器连接的垂直液压式管道连接器,从密封结构、导向结构、锁紧结构的设计进行了深入的阐述,并在连接器样机型式试验、产品防腐、水下安装等方面也进行了详细的说明。     

一条海底输油管道的定量风险评估其检测标准设计(英文)

该报告描述一条预设海底管道的基于定量风险分析(QRA)的泄漏检测标准(LDc)设计问题.定量风险分析的结果会反映出统计泄漏检测方法是否必要.如果必要,恰当的泄漏检测标准必须建立.在分析中,著名的英国PARLoc 2001数据库将会用来估算管道实效概率.而来自MMS的POSVCM模型则用来做泄漏模拟计算.定量风险分析的结果说明,统计方法的泄露检测系统能打幅度地减少泄漏检测所需时间,从而减轻泄露的事故后果.根据QRA的分析结果,以及许多泄漏检测系统买主的建议,合理的西漏检测标准被设计出来.一旦泄漏事故产生,它可以帮助紧急事故相应组(ERT.)快速检测,定位以及采取方法减轻泄漏.     

Efficient methods to mitigate SCR-induced walking of short subsea flowlines

Steel catenary riser is a long-established option for subsea projects in deep-water regions. Sustained pulling force of steel catenary risers on subsea flowlines in combination with cyclic thermal load throughout the system lifetime may lead to progressive global axial displacement of subsea pipelines which has been termed as ‘walking’. One of the challenges in the deep-water industry is long-term walking of subsea flowlines in a cumulative manner. Common practice methods for walking mitigation are quite expensive operations. State-of-the-art mitigation strategies are proposed in the paper by means of modifying pipe pieces before the installation operation. Bowed pipe pieces and miter joints are two recommended approaches for walking mitigation. The presented mitigation strategies are relatively cost-effective solutions for the pipe-walking challenge and they are able to considerably cease the potential cyclic walking. Comprehensive FE analyses in ABAQUS software are performed to evaluate the proposed deformed pipelines response subject to two loading conditions. Through-life integrity of the suggested pre-deformed pipeline is assessed in terms of effective axial force, local buckles and excessive axial strains. A comparison of the presented method with conventional techniques shows the effectiveness of the proposed configuration. The proposed methods can significantly reduce effective axial force throughout the subsea pipeline by means of artificially introduced deformations. The cumulative walking of the presented method is practically zero. In addition, the influence of combined triggering mechanisms to the walking phenomenon is assessed when the pipeline is located on a sloping seabed and it is subject to non-uniform thermal loads. A parametric study is performed to improve confidence in design and provide a reasonably practical technique with an optimal shape.     

海底管道腐蚀后的剩余强度评价

海底管道通常会因腐蚀而形成各种不同类型的缺陷,影响管道的承载能力和使用寿命。本研究在准确掌握管道缺陷发展情况的基础上,分别根据行业规范和采用有限元方法对海上油田含有腐蚀缺陷的原油管线进行剩余强度评价,判定海底管道修复的必要性和修复的紧迫程度,以确定最终的管线修复方案,可供类似海底管道修复工程参考。