基于同轴线相位法的多相流仿真分析系统设计

在采油高含水期,为适应水平井采油及产出剖面测井的需要,开展了油水两相流流型流态的实验研究,为分析油水两相流流型流态对仪器响应的影响特性,设计了一套系统分析油水两相流的流型流态,采用希尔伯特黄变换和复杂性测度的方法分析对比数据,并用人工神经网络SVM的方式进行预测仿真,为更进一步分析流型流态对测井仪器的响应性能。采用可移植的、轻量级的方式,设计研发了一种同轴相位传感器的流型流态模拟分析系统软件,仿真结果表明,上述系统能适应分析需求,能够快速识别流型,对研究流型流态对仪器响应的影响提供了借鉴。     

RBF神经网络在油水两相流含率超声测量中的应用

介绍了一种油水两相流含率测量新方法——超声散射法．该方法利用超声波散射效应测量流体中的分相含率，通过非集流方式，在基本不改变流体流动状态的情况下实现油水两相含水率的测量．动态实验结果表明，该方法在油水两相条件下，可以实现分相的测量．但由于受流型、油泡直径及吸收系数等因素的非线性影响，使得测量模型难于建立．文章通过构建RBF神经网络，对含水率进行预测，提高了含水率测量精度．     

气液两相流电导传感器测量波动信号的Wigner-Ville分析

流型是两相流中非常重要的流动参量,不同流型下的两相流流动特性及传热传质性能有很大不同。流型也严重影响着两相流参数测量的准确性。利用新近研制的两相流电导传感器,在垂直上升气液两相流管中采集了不同流型下的电导波动信号,采用W igner-V ille分布(WVD)在时频域内处理了电导波动信号,观察到了WVD特征与流型之间的关系,取得了较好的气液两相流流型辨识效果。     

油水两相流流型的混沌时间序列分析

采用一种基于互信息第一极小值计算法确定了相空间重建延迟时间,用Mackey-Glass方程及Lorenz奇异吸引子数据作算例检验了该计算方法的可靠性．通过计算的混沌吸引子关联维对油水两相流流型进行了表征,结果表明对含水率为61％～91％及总流量为10～60(m^3／d)的水包油流型,油水两相流电导波动信号的关联维与含水率及总流量有着良好的相关关系,而对含水率为51％的油水两相流过渡流型,关联维随总流量呈现不规则突变,表明了混沌吸引子关联维数对油水两相流流型变化具有敏感的“指示器”特性．     

基于神经网络和D-S证据理论辨识两相流流型

提出一种基于电容层析成像(ECT)系统、神经网络和证据理论辨识两相流流型的方法。这种方法采用神经网络与D-S证据理论相结合的方法来辨识两相流流型,并对两相流的几种常见流型进行了辨识。仿真实验结果表明:此种方法在两相流流型辨识中具有较高的判别精度,为两相流流型辨识提供了一种有效的手段。     

基于高速摄影传感器的气液两相流型分层模糊识别

气液两相流流型的客观和智能识别对两相流其它参数测量具有重要意义。用高速摄像机作为检测传感器,获取内径为50 mm 的绝热垂直管段内气液两相流流型图像,提取流型灰度图像的均值、标准差及二值图像的最大物体面积、宽度和高度五个特征向量,采用分层模糊推理方法实现泡状流、块状流、塞状流和乳沫状流的流型识别。对于131幅实验图像,该方法的识别正确率平均达到93.13%。     

电容层析成像技术在气力输运粉体两相流流型可视化识别中的应用

流型是两相流参数检测中的重要参数之一。本文将电容层析成像技术诮地气力输运粉体两相流流型可视化识别中,仿真结果表明,该技术能较好地识别出各种流型。     

基于经验模态分解的油气两相流流型状态监测

基于经验模态分解技术,采用能量评估和阈值概率统计手段,提出了一种油气两相流流型状态监测的新方法.油气两相流差压信号是一典型的非平稳多组分信号,经验模态分解首先将差压信号分解成9阶本征模函数,按照频率范围可以划分为3个子带:高频带(30～50 Hz),中频带(5～30 Hz)和低频带(0～5 Hz).在不同流型下,中频带的能量变化很显著,跟踪捕捉中频带能量变化可以监测两相流流型的跃迁.首先确定不同流型下对应的归一化能量阈值,阈值概率统计技术通过移动时间窗扫描中频带子信号的方式来监测流型状态变化.油气两相流的实验结果表明该方法是有效的,为两相流流型状态监测提供了新途径.     

基于小波神经网络的气液两相流流型识别方法

为了克服传统流型识别方法的特点,采用小波分解和RBF神经网络技术来实现气液两相流流型的智能识别。首先测量了水平管内气液两相流的差压波动信号,其次应用小波分解对流型的动态差压波动信号进行了分析并提取流型特征,最后将小波能量特征作为RBF神经网络的输入,从而实现对流型的智能识别。仿真结果表明:该方法能够较好地识别出4种流型,从而为流型的在线识别提供了一种定量的流型识别方法。     

电阻层析成像(ERT)技术在识别两相流流型中的应用

介绍TERT-Ⅱ系统样机在实验装置上进行气/液两相流的实验研究，提出了应用ERT系统进行流型识别的基本方法，通过重建图像和分析测量数据实现两相流流型的识别；证明了应用ERT系统实现两相流流型和参数测量的可能性。     

集流型流体电容仪测量井下油水两相流的含水率

对集流型流体电容含水率计在井下油水两相流高含水时应用的可行性进行了研究。建立了泡状流、水为连续相时传感器的等效电路模型。该模型认为在泡状流、高水矿化度、水为连续相的情况下，传感器只敏感于碰撞到内电极绝缘介质层上的油滴。在通常的测量条件下，传感器仍具有较高的灵敏度。为验证理论的正确性，设计了四个静态实验，并进行了模拟井动态实验。实验结果与理论预测完全一致。     

非线性时间序列的符号化分析方法研究

符号时间序列分析方法是近年来新兴的一种数据处理方法,已经被广泛的应用于各个领域．采用符号化分析方法能够从动力系统中快速有效地提取有用定量信息,计算简单快捷,而且能够有效的抑制噪声．本文采用三种统计量用于表征符号化时间序列的特性,用Henon方程作为算例验证了该方法的可靠性,并且将此方法应用于垂直上升管中油水两相流流型分析,结果表明从符号时间序列计算的统计量对油水两相流过渡流型变化敏感．     

一种新型三相流测量系统的研制

利用成熟的单相流测量仪的基本原理 ,研制了一种新的三相流在线检测仪及其系统。应用热扩散法来测量气液比 ,设计的灵巧电容探头来测量油水比 ,该仪器可适合各种不同生产条件的油田的三相流测量     

电磁相关法流量测量传感器检测电极距离研究

多相流流量测量在工业生产与科学研究中有着广泛的应用。针对石油生产测井狭小空间环境下的油气水多相流流量测量问题,提出了一种能扩大生产测井中多相流油气含率的量程范围并提高流量测量精度,且具有连续测量、无放射性、低成本等优点的油气水多相流电磁相关法流量测量传感器。电磁相关法流量测量传感器两对检测电极之间的距离设计是该类传感器设计的关键技术之一,通过传感器内部虚电流及其敏感场的仿真研究与分析,为电磁相关法流量测量传感器的两对检测电极之间的距离设计提供帮助,以促进新型多相流流量仪表的发展。     

Space-based detection of wetlands' surface water level changes from L-band SAR interferometry

Interferometric processing of JERS-1 L-band Synthetic Aperture Radar (SAR) data acquired over south Florida during 1993-1996 reveals detectable surface changes in the Everglades wetlands. Although our study is limited to south Florida it has implication for other large-scale wetlands, because south Florida wetlands have diverse vegetation types and both managed and natural flow environments. Our analysis reveals that interferometric coherence level is sensitive to wetland vegetation type and to the interferogram time span. Interferograms with time spans less than six months maintain phase observations for all wetland types, allowing characterization of water level changes in different wetland environments. The most noticeable changes occur between the managed and the natural flow wetlands. In the managed wetlands, fringes are organized, follow patterns related to some of the managed water control structures and have high fringe-rate. In the natural flow areas, fringes are irregular and have a low fringe-rate. The high fringe rate in managed areas reflects dynamic water topography caused by high flow rate due to gate operation. Although this organized fringe pattern is not characteristic of most large-scale wetlands, the high level of water level change enables accurate estimation of the wetland InSAR technique, which lies in the range of 5-10 cm. The irregular and low rate fringe pattern in the natural flow area reflects uninterrupted flow that diffuses water efficiently and evenly. Most of the interferograms in the natural flow area show an elongated fringe located along the transitional zone between salt- and fresh-water wetlands, reflecting water level changes due to ocean tides.     

基于水流分割的石油钻井水流异常检测

通过对钻井管道水流的智能监控技术实现,可以解决石油钻井污染气体的自动监测问题,最大程度的减少人工监测成本;但是依然有以下几个难点需要攻克:(1)传统的特征提取方式不能描述水流形态的变化过程;(2)因为异常情况发生的概率很低,所以异常样本稀少,全监督的方法不再适用;为解决特征提取问题,提出了一种基于图像分割的新特征特提取方式——形态流,形态流可以从时序上描述水流形态的变化;另一方面,为克服异常样本稀少的问题,通过无监督的方式——多元高斯建模,来判别水流数据是否正常;实验表明在水流异常数据检测任务中算法检测精度达到了93.6%,在使用GPU并行加速处理时可达到28帧每秒的处理速度,能够准确地检测出水流数据中的异常数据帧。     

Measurement of dynamic surface tension using helical flow of a viscous liquid in a pool of another viscous liquid inside a micro-channel

Measurement of surface tension (s.t.) and critical micelle concentration (c.m.c.) of a surfactant in dynamic condition is important for several engineering applications, for which, the interface between two or more different phases does not remain constant but alters and replenishes continuously with flow of the fluids so that equilibrium may not be reached between the bulk and the interface. There are however not many methods for measuring these quantities in dynamic experiments which mimics the real dynamic situations. In this report, we present a novel two-phase flow pattern inside a triple-helical micro-channel using which, we show that it may be possible to measure the dynamic s.t. of a liquid. When two immiscible liquids such as oil and water are pumped into it, at a certain range of flow rates, oil flows as the continuous phase, whereas water remains in it as a wavy filament, the wavelength of which varies with the flow rates of oil and water but also on the interfacial tension between these two liquids. We show that wavelength decreases with increase in concentration of a solute attaining a minima at the c.m.c. A simple scaling analysis captures most experimental observations.     

Numerical simulation of ground water mounding and its verification by Hele–Shaw model

Ground water mounding is the rise of the water table above its regional level in a local area of an aquifer in order to provide sufficient head to distribute the water supplied by a localized source to that area. The shape and height of the mound depend on many factors including recharge rate and distribution, geology, hydraulic conductivity, flow/head control locations, saturated thickness and regional flow in the aquifer in that area. In this work, an accurate and efficient numerical model for calculating ground water mounding was developed. Numerical calculations were done on a uniform rectangular grid, obtained by a transformation of the physical domain. Grid for computation were generated by a grid generation code, EagleView, which is developed by the Mississippi State University. Model predictions were verified with tests in a Hele–Shaw model for situations with and without a regional flow, with and without heterogeneity, and for two recharge rates. SAE#50 oil was used as the fluid in the Hele–Shaw. A peristaltic pump was used to supply the constant (and adjustable) recharge rate from the reservoir below the Hele–Shaw model. The results of experiments of estimating mounds and the numerical mounding model are in good agreement. However, mound height of the region below recharge of Hele–Shaw model can not be observed because the flow of this region combines vertical flow from recharge and the rising of the free surface (horizontal flow). Hence, an emulated perched aquifer was used so that mound height of the recharge region can be observed.