基于超声层析成像技术的地下油气管道多相流检测方法研究

Many accidents were happened frequently in underground oil/gas pipeline of the industral field, it not only threatens the safety of industrial production, but also brings urban's life a potential of dangerous. We are proposing a ultrasonic computerized tomography based method for multiphase flow detection of underground gas pipeline, which can be used for protection of industrial production and the safety of residents. Early findings: Ultrasound technology is commonly used in pipeline defect deteciton, however, it is rarely reported in multiphase flow detection of the oil/gas pipeline. There are many advantages of this technology, such as low cost, wide detection of objects and high resolution. Considering the ultrasonic wave propagation characteristics and distribution of the sound field, ultrasonic computerized tomography can be used to detect multiphase flow distribution in the metal pipes, provide enough data to determine the health of the pipeline and gives the range information of defect location of abnormal pipeline, while the majority of processed tomography techniques are hard to do the same things on those pipelines. Research intends to use the effective theory, multi-scale model, simulation and platform such method to study the formation process of complex sound field of detecion area, establish a theoretical model of sound field distribution, analyze the key impact aspects of detection performance, build the influence weigh theoretical model to optimize the sensor, make a testing platform, propose a fast imaging algorithms to improve the imaging accuracy, and present inversion rules and calibration methods to identify the health of the pipe. The project will provide a strong support and guidance to detection of underground oil/gas pipelines and determination of the defect position range of the pipes.

地下油气管道事故频发，危及工业生产安全，对城市居民生活亦构成威胁。为此提出利用超声层析成像技术对地下油气管道进行多相流检测，对保障工业生产、居民生活安全有积极意义。前期研究发现：超声波技术具有成本低，检测对象广、分辨率高等特点，常用于管道缺陷检测而鲜见于管道多相流检测。依据超声波传播特性与声场分布特点，超声层析成像技术可弥补过程层析成像技术不便于检测金属材料管道的弱点，对地下油气管道多相流分布进行检测，判断管道运行状况并给出异常管道缺陷位置范围信息。项目拟采用有效理论、多尺度模型、模拟仿真、平台搭建等方法与手段，研究检测区域复杂声场形成机制，建立声场分布数学模型；探索分析影响检测性能的关键环节，建立影响要素的权重分析理论模型，制备最优化传感器；搭建检测试验平台，开发快速成像算法，建立管道运行状况反演规则与标定方法。项目将为地下油气管道工况检测、异常管道缺陷位置范围判断提供有力支持与指导。

地下油气管道事故频发，危及工业生产安全，对城市居民生活亦构成威胁。为此提出利用超声层析成像技术对地下油气管道进行多相流检测，对保障工业生产、居民生活安全有积极意义。前期研究发现：超声波技术具有成本低，检测对象广、分辨率高等特点，常用于管道缺陷检测而鲜见于管道多相流检测。依据超声波传播特性与声场分布特点，超声层析成像技术可弥补过程层析成像技术不便于检测金属材料管道的弱点，对地下油气管道多相流分布进行检测，判断管道运行状况并给出异常管道缺陷位置范围信息。本课题就此提出基于超声层析成像技术的油气管道多相流分布检测研究，主要研究内容包括：1. 超声波声场分布仿真，利用PZFlex完成了多物理模型的场分布仿真研究。利用椭圆算法对仿真模型进行成像验证，结果表明，仿真模型中管壁与边界条件设定对于接收信号及成像结果有明显影响。椭圆算法仅能确定气泡位置，而无法检测气泡尺寸。2. 传感器设计及实验系统研发，提出了传感器信号滤波结构，利用管壁外增加“滤波结构”，提升接收直达波信号的“信噪比”。完成了传感器设计参数的优化设计，研制PZT-5A压电直探头，直径为10mm，厚度为6.7mm，中心频率为300kHz，实验结果证明能够用于实际气泡检测。开发多通道检测硬件模块，包括16个检测通道，单通道检测频率100kHz-25MHz，采样率为250MS/s，能够满足本课题实验要求。3. 成像算法方面，提出了扇形区域线性反投影算法，将原始矩形灵敏度矩阵改为扇形波束矩阵，能够在不降低成像速度的同时改善成像质量。4. 管道损伤检测方面基于对固体中非线性波的分析与双谱方法的研究，提出了一种基于相位检测的可用于微裂纹检测方法。通过相位阈值的选择，提高非线性超声调制因子与裂纹长度之间关系的可靠性。本方法有一定裂纹检测适用范围，能够用于小裂纹的定量评估。