THE RISK ASSESSMENT OF THE LONG-DISTANCE OILPIPELINE ENGINEERING

The oilfield construction and long-distance oil pipeline engineering has been developed extensively in China. The risk assessment of oil industry will, however, be an important objective to cope with the development of oil industry , The risk assessment of oil industry has many subjects worthy to be studied.The major purpose of the paper is to research the risk cases of long-distance oil pipeline engineering in Ganshu and Shaanxi provinces.

A Proposed Meta-Reality Immersive Development Pipeline: Generative AI Models and Extended Reality (XR) Content for the Metaverse

The realization of an interoperable and scalable virtual platform, currently known as the “metaverse,” is inevitable, but many technological challenges need to be overcome first. With the metaverse still in a nascent phase, research currently indicates that building a new 3D social environment capable of interoperable avatars and digital transactions will represent most of the initial investment in time and capital. The return on investment, however, is worth the financial risk for firms like Meta, Google, and Apple. While the current virtual space of the metaverse is worth $6.30 billion, that is expected to grow to $84.09 billion by the end of 2028. But the creation of an entire alternate virtual universe of 3D avatars, objects, and otherworldly cityscapes calls for a new development pipeline and workflow. Existing 3D modeling and digital twin processes, already well-established in industry and gaming, will be ported to support the need to architect and furnish this new digital world. The current development pipeline, however, is cumbersome, expensive and limited in output capacity. This paper proposes a new and innovative immersive development pipeline leveraging the recent advances in artificial intelligence (AI) for 3D model creation and optimization. The previous reliance on 3D modeling software to create assets and then import into a game engine can be replaced with nearly instantaneous content creation with AI. While AI art generators like DALL-E 2 and DeepAI have been used for 2D asset creation, when combined with game engine technology, such as Unreal Engine 5 and virtualized geometry systems like Nanite, a new process for creating nearly unlimited content for immersive reality is possible. New processes and workflows, such as those proposed here, will revolutionize content creation and pave the way for Web 3.0, the metaverse and a truly 3D social environment.

DESIGN AND EVALUATION OF A PIPELINED FORWARDING ENGINE

Recent advances in broadband technology have caused forwarding engines to handle pack- ets with over 10 gigabit per second. In this paper, we present a high-speed forwarding pipeline which can finish all of the routing and forwarding tasks in the way of pipelining. We also establish the analysis model of the pipeline with which one can evaluate some key performance parameters of the forwarding engine such as forwarding rate and forwarding delay. We find that the pipeline is of good scalability and can forward unicast packets up to the speed of 40Gbit/s.

Experimental investigation on the wave-induced pore pressure around shallowly embedded pipelines

A series of regular wave experiments have been done in a large-scale wave flume to investigate the wave-induced pore pressure around the submarine shallowly embedded pipelines. The model pipelines are buried in three kinds of soils, including gravel, sand and silt with different burial depth. The input waves change with height and period. The results show that the amplitudes of wave-induced pore pressure increase as the wave period increase, and decay from the surface to the bottom of seabed. Higher pore pressures are recorded at the pipeline top and the lower pore pressures at the bottom, especially in the sand seabed. The normalized pressure around pipeline decreases as the relative water depth, burial depth or scattering parameters increase. For the silt seabed, the wavelet transform has been successfully used to analyze the signals of wave - induced pore pressure, and the oscillatory and residual pore pressure can be extracted by wavelet analysis. Higher oscillatory pressures are recorded at the bottom and the lower pressures at the top of the pipeline. However, higher residual pressures are recorded at the top and the lower pressures at the bottom of the pipeline.

Intensity measures for the seismic response evaluation of buried steel pipelines under near-field pulse-like ground motions

Ground-motion Intensity Measures (IMs) are used to quantify the strength of ground motions and evaluate the response of structures. IMs act as a link between seismic demand and seismic hazard analysis and therefore, have a key role in performance-based earthquake engineering. Many studies have been carried out on the determination of suitable IMs in terms of effi ciency, suffi ciency and scaling robustness. The majority of these investigations focused on ordinary structures such as buildings and bridges, and only a few were about buried pipelines. In the current study, the optimal IMs for predicting the seismic demand of continuous buried steel pipelines under near-fi eld pulse-like ground motion records is investigated. Incremental dynamic analysis is performed using twenty ground motion records. Using the results of the regression analysis, the optimality of 23 potential IMs are studied. It is concluded that specifi c energy density (SED) followed by VSI[ω1(PGD+RMSd )] are the optimal IMs based on effi ciency, suffi ciency and scaling robustness for seismic response evaluation of buried pipelines under near-fi eld ground motions.

Centrifuge model test on performance of thermosyphon cooled sandbags stabilizing warm oil pipeline buried in permafrost

The thaw settlement of pipeline foundation soils in response to the operation of the first China-Russia Crude Oil Pipeline along the eastern flank of the northern Da Xing'anling Mountains in Northeast China was simulated in a physical model test(with a similitude ratio of 1/73) in a geotechnical centrifuge. Two pipes of a supported and an unsupported section were evaluated over a testing period for simulating 20 years of actual pipeline operation with seasonal cyclically changing oil and ambient temperatures. The results show that pipe settlement of the supported pipe was 45% of settlement of the unsupported pipe. Settlement for the unsupported section was approximately 35% of the thaw bulb depth below the initial pipe elevation, only 30% of that for the supported pipe due to the influence of the supports. The final thaw bulbs extended approximately 3.6 and 1.6 times of the pipe diameter below the unsupported and supported pipe bottom elevations, respectively. The sandbag supports kept frozen during the test period because of cooling effect of the thermosyphons. The maximum bending stress induced over the 20 m span length from bearing of the full cover over the pipe would be equivalent to40% specified minimum yield strength(SMYS). Potential buckling of the pipe should be considered as the ground thaws.This study also offers important data for calibration and validation of numerical simulation models.

Influence of yield-to-tensile strength ratio(Y/T) on failure assessment of defect-free and corroded X70 steel pipeline

The effect of yield-to-tensile strength ratio(Y/T) on failure pressure of X70 pipeline without and with corrosion defects was investigated.The stress-strain response of materials was characterized by a power-law hardening curve.Two formulas to estimate the strain hardening exponent n for a special Y/T were obtained by least squared regression method and the influence of Y/T on n was analyzed.As an application of n-Y/T expression,the analytical solutions of burst pressure for X70 pipeline without and with corrosion defects were also obtained.The results indicate that the burst pressure of defect-free X70 pipe without corrosion defects is a function of the Y/T,pipe geometry t0/D0 and engineering tensile strength,and increases as Y/T or t0/D0 increases; whilst the burst pressure of corroded X70 pipe decreases with the increase of defect depths,d/t.Comparisons indicate that the present analytical solutions closely match available experimental and numerical data.

Experimental investigation of hydrate formation in water-dominated pipeline and its influential factors

Blockage in water-dominated flow pipelines due to hydrate reformation has been suggested as a potential safety issue during the hydrate production.In this work,flow velocity-dependent hydrate formation features are investigated in a fluid circulation system with a total length of 39 m.A 9-m section pipe is transparent consisted of two complete rectangular loops.By means of pressurization with gas-saturated water,the system can gradually reach the equilibrium conditions.The result shows that the hydrates are delayed to appear as floccules or thin films covering the methane bubbles.When the circulation velocity is below 750 rpm,hydrate is finally deposited as a“hydrate bed”at upmost of inner wall,narrowing the flow channel of the pipeline.Nevertheless,no plugging is observed during all the experimental runs.The five stages of hydrate deposition are proposed based on the experimental results.It is also revealed that a higher driving pressure is needed at a lower flow rate.The driving force of hydrate formation from gas and water obtained by melting hydrate is higher than that from fresh water with no previous hydrate history.The authors hope that this work will be beneficial for the flow assurance of the following oceanic field hydrate recovery trials.

A visualization fatigue analysis of a pipeline joint in a special medium environment

In this paper,authors have discussed predominately unidirectional Fluid Structure Interaction,i. e. a given field in which a high speed/pressure and high temperature thermal flow affect the interface between pipelines joints. Surface forces at the fluid-structure interface allow designers to investigate the effects of fluid flow on the structural deformation and stresses. Possible failure modes have been compared with different loads from steady thermal flow analysis results. CFD code SC/Tetra and FEA code ANSYS are used in this study. These studies can be used in protecting certain fatigue failures for pipeline joints under critical cyclic load conditions from both thermal expansion and hydraulic pressure in municipal and environmental engineering applications as well as oil and gas fields.

Research status of corrosion environment failure and safety assessment of pipeline welded joint

Pipeline transportation is an economical, safe, and efficient transportation method for transporting oil, natural gas, mineral slurry, and other fluids.Welding is the most critical construction process in pipeline engineering and is crucial in the safe operation and service of an entire pipeline system.Theoretically, the girth welded joint is the weakest link in a pipeline system.The unevenness of the structure and performance of the joint caused by welding frequently results in the failure of the welded joint before the failure of the base material of the pipe body, causing the pipeline to leak or even break.For steel pipes used in an acidic corrosive medium environment, the integration of the corrosive medium and mechanical load will accelerate the failure of the welded joint.This article reviews the failure modes of pipeline welded joints in acidic corrosive media, including stress corrosion cracking, hydrogen-induced cracking, and corrosion fracture, and corrosion fatigue considering the diffusion and accumulation of H;at the crack tip.It also reviews service pipelines in acidic corrosive media.The general processing technology of pipe joint engineering critical assessment(ECA) is investigated to provide a reference for the future development of technology in this field.

海底管道边界条件类型及其对走管行为的影响

针对深海海底管道两端通常与井口、悬链线立管、器管收集器等相连,管道端部边界条件复杂的情况,为了探究不同的管道边界条件对走管行为的影响,将海底管道端部边界条件简化为3种类型,即类型Ⅰ两端水平力、类型Ⅱ一端水平力一端倾斜力和类型Ⅲ一端弹性边界一端水平力,建立不同边界条件下海底管道走管数值模型,对比分析不同类型边界条件下海底管道走管行为。结果表明:类型Ⅱ边界条件与类型Ⅰ相比,随着管道端部拉力倾角增加,管道轴向拉力减小,走管量也减小,管道拉力倾角从0°增至60°,最大轴向拉力减小6.73%,走管率减小50%,这意味着悬链线立管形态改变,使得作用于海底管道的拉力方向改变,相应的海底管道走管量也随之改变;类型Ⅲ与类型Ⅰ边界条件相比,类型Ⅰ边界条件下海底管道走管率为恒值,随着升降温循环次数的增加,海底管道走管量近似线性增长;类型Ⅲ边界条件下海底管道走管率受器管收集器弹性刚度影响,弹性刚度越大,第1次升降温循环走管率越大;随着升降温循环次数增加,管道走管率快速衰减,直至为0,类型Ⅲ边界条件下多次升降温循环最终走管量通常小于类型Ⅰ。3类边界条件下海底管道走管行为差异很大,可为实际工程中分析海底管道端部边界条件类型、选定合适的边界条件提供参考。

分段管廊装载供水管道穿越地裂缝适宜性研究

在活动地裂缝影响下,供水管道拉裂、错断现象时有发生,并引发严重的次生灾害。本文以西安市西南郊水厂拟建球墨铸铁管道穿越地裂缝为工程背景,建立管道45°穿越活动地裂缝的数值模型,分析地裂缝影响下管道的内力响应与变形特征,结果表明:地裂缝作用会使管道接口偏转角过大而导致其防水失效。因此提出一种分段管廊装载供水管道穿越地裂缝的方法,建立分段管廊装载供水管道穿越地裂缝的数值模型,分析管道与管廊通缝、错缝两种工况、不同分段管廊长度、不同地裂缝位置、不同穿越角度下管廊与管道的内力响应与变形特征。得出管廊装载管道穿越地裂缝的最佳方案为管道与管廊通缝布设,采用单节长度为18 m的分段管廊,使地裂缝位于管廊的2/3处,并尽量以小角度穿越地裂缝。研究成果对城市供水管道穿越活动地裂缝的工程建设与灾害防治具有实际意义。

浅埋黄土地层隧道在不同交角下穿既有地下管线的模型试验

为探究浅埋黄土地层盾构隧道施工下穿对不同特性地下管线的变形受力影响机制,依托河南省某公路隧道工程,以工程黄土为试验材料进行室内模型试验。通过设置3种管隧交角,研究两种接头刚度的非连续管线和连续管线的沉降、弯矩和管土接触压力变化规律,并在管隧正交工况下,研究不同地下管线的遮拦效应及地表沉降变形规律,得出预测管线沉降的拟合公式。结果表明:在3种管隧交角下,地下管线沉降存在3个阶段,在管线沉降集中区阶段低密度聚乙烯(Low Density Polyethylene,LDPE)接头非连续管线的平均沉降增长速率是聚氯乙烯(Polyvinyl Chloride,PVC)接头非连续管线的2倍;管隧交角的减小,使得非连续管线的最大正负弯矩均减小,PVC接头非连续管线弯矩曲线由“W”形转变为“V”形;管隧交角和接头刚度对土压力变化曲线和峰值位置几乎无影响,土压力变化均呈“M”形;在管隧正交下,管线整体刚度越大对地表沉降抑制作用越显著,管线沉降与地表沉降呈指数关系。

超效率SBM-Malmquist模型在燃气管道完整性管理效能评价中的应用

为解决燃气管道完整性管理效能评价时,无法准确对比各评价单元完整性管理水平的差异,以及无法动态测算同一评价单元完整性管理效能的问题,提出了一种基于超效率松弛值测算(Slacks-Based Measure, SBM)的模型和Malmquist模型相结合的方法,对管道完整性管理效能评价进行研究。首先,综合考虑完整性管理实施过程、效果与效益,并结合专家意见和相关规范标准,构建效能评价指标体系,该指标体系由3项一级指标和14项二级指标进行表征。其次,采用考虑非期望产出的超效率SBM模型解决各评价单元的比较与排序问题,再将Malmquist模型与超效率SBM模型相结合,测算各评价单元效能的动态变化趋势。最后,针对5家燃气公司在2019—2022年的完整性管理效能,采用所提出的效能评价模型开展评价。结果表明,超效率SBM模型和Malmquist模型相结合是实现管道完整性管理效能客观定量评价的有效方法,通过横向对比和动态测度发现短板并提出针对性的改进意见,其分析结果与实际工程相吻合,证明该方法能够有效评估完整性管理效能,为管道完整性管理提供了一种评价思路。

采用改进FRAM模型方法的管道爆裂事故分析

近年来,主蒸汽管道爆管事故频发,为了找出管道爆裂事故的致因路径,有效预防和控制此类事故发生,以某重大蒸汽管道裂爆事故为例,采用时间和事件序列图(Sequentially Timed Events Plotting,STEP)技术和蒙特卡罗模拟方法对功能共振分析法(Functional Resonance Analysis Method,FRAM)进行改进,进行事故致因分析并建立屏障措施。结果表明,改进后的FRAM模型可以全面识别功能信息并且定量确定FRAM模型中各功能的变化及耦合关系,减少功能性能变化及潜在耦合变化分析的主观性,找出系统发生共振的功能及失效连接。最后,根据失效连接制定相应屏障措施来预防此类事故的发生。

膨润土粉体对管网甲烷爆炸的抑制特性及抑爆机理

为了探寻高效的抑爆剂,有效降低甲烷爆炸事故发生率,最大限度地降低事故损失,利用自主搭建的爆炸管网测试系统进行了膨润土粉体抑爆试验。将爆炸超压峰值、爆炸威力指数和爆炸火焰首次到达管网两出口的时刻作为表征抑制剂抑爆性能的参数,探究了不同粒径膨润土粉体对管网甲烷爆炸的抑制性能,利用热解特性分析和分子动力学仿真探究了膨润土粉体的物理和化学抑爆机理。结果表明,粒径为>27~33μm的膨润土粉体对于管网甲烷爆炸的抑制性能最佳。膨润土粉体的物理抑爆机理为通过热解吸收反应热来实现抑爆目的;其化学抑爆机理为膨润土分子能够有效消耗反应体系中的自由电子和活性自由基,减缓甲烷链式反应速率。研究结论可为提高甲烷运输的安全性、有效降低灾害风险提供理论参考。

管道工程穿越既有轨道交通安全评估与监测实例分析

由于管道工程临近地铁保护区的项目不断增加,安全评估和专项监测的应用非常必要。论文以某出水管工程涉及轨道交通5号线为例,设计了专项监测方案,重点分析了管道施工影响既有地铁车站结构安全评估预测与实测的监测变形,验证了安全评估的预测值与实际监测数据的符合性。

基于数理统计和文本挖掘的埋地钢制燃气管道失效分析

近年来燃气管道事故频发,严重威胁周边人民群众生命财产安全。为准确认识埋地钢制燃气管道失效特征及致因,针对性开展风险管控,以某管道燃气公司2018—2021年共计1338条埋地钢制燃气管道失效记录为分析蓝本,采用数理统计方法分析失效总体趋势及管道敷设位置、压力等级、外防腐层类型、失效原因、管龄对应的失效特征;采用文本挖掘技术共计提取26项埋地钢制燃气管道潜在失效致因,通过词云可视化方式分析高频失效致因;构建失效致因共现网络探索不同致因之间的耦合关系,并根据特征向量中心性辨识主要失效致因。结果表明:中压庭院管道是风险管理的重点;腐蚀失效频次与管龄总体呈正相关,且从第4 a开始失效频次快速增长,在第19 a左右达到峰值;土壤腐蚀、防腐层破损、杂散电流、未安装阴极保护系统、管道服役年限较长、管体缺陷、防腐层老化和敷设环境发生变化是埋地钢制燃气管道失效主要致因,是风险管控的关键点。

《工业设备及管道防腐蚀工程技术标准》GB/T 50726-2023修订技术内容解读

国家标准《工业设备及管道防腐蚀工程技术标准》GB/T 50726-2023是在合并原《工业设备及管道防腐蚀工程施工规范》GB 50726-2011和《工业设备及管道防腐蚀工程施工质量验收规范》GB 50727-2011基础上增加设计内容修订而成,本文对新修订的技术内容进行了解读,以便于工业设备及管道防腐蚀工程设计、施工、质量检验和验收等工程技术人员能准确理解和使用本标准。

基于集成算法的腐蚀管道失效压力预测研究

为了提高腐蚀管道剩余强度的预测精度、解决单一预测模型易受训练数据的质量影响而发生运行及预测输出不稳定的问题,引入两种集成模型方法。首先对于串行结构集成方法,以支持向量回归(SVR)融合正余弦策略改进的黑猩猩优化算法(IChOA)为基础建立AdaBoost-IChOA-SVR模型;其次对于双层并行结构方法,根据预测问题筛选出相关性低且学习效果良好的预测算法作为第一层基预测器,调节新数据集形成方式及相关参数设置,建立Stacking堆叠集成模型。以含腐蚀缺陷管道失效压力爆破数据为例,利用MATLAB分别进行仿真模拟,与基础SVR和PSO-ELM模型的预测结果及评价指标进行对比分析。研究结果表明:集成预测模型具有更好的预测输出性能,且串行结构的AdaBoost集成学习模型的构造流程较为简洁,运行速度及精度更高;该模型对腐蚀缺陷管道失效压力预测问题的拟合度可达0.996,相对误差均值可达3.69%,可为后续腐蚀管道相关预测模型建立和防护维修策略制定提供参考。