油气水多相流相含率超声测试机理与方法研究

Multiphase flow has the inter-phase interface with spatial and temporal non-uniform distribution, the inter-phase slip, the inter-phase relative velocity, the nonlinearity response and other flow characteristics, so parameter measurement of multiphase flow is still a relatively difficult subject. With the advancement of science and industry, accurate measurement of multiphase flow parameter has significance on the optimization of production process and equipment. It is of great importance to ensure the security and stability of multiphase flow production process. Phase fraction of multiphase flow is a significant indicator to characterize multiphase flow. Aiming at the problems of non-linear ultrasonic response and low measuring range due to the complexity of multiphase flow (oil-water two-phase flow or oil-gas-water three-phase flow) flow, the interaction between ultrasound and multiphase flow will have been analyzed. Based on studying the ultrasound propagation mechanism in typical flow patterns of multiphase flow, the ultrasound transmission and multiple scattering characteristics in multiphase flow will have been explored and explained theoretically. A prediction model based on the ultrasound attenuation and transit time principle will have been presented to estimate the phase fraction in oil-gas-water three-phase flow. A corresponding ultrasonic technology testing method and system will have been established to accurately measure the phase fraction in oil-gas-water multiphase flow. The method could improve the nonlinear response and expand the application range of ultrasound measurement. The further development of the project research work and results could promote the application of ultrasonic technology in petroleum industry.

多相流具有时空非均匀性分布的相间界面、相间滑脱、相间相对速度、响应非线性等流动特征，对其参数的准确测量仍然是检测领域的挑战性课题。随着科学进步和工业发展，准确获取多相流流动参数，进而实现对复杂工业过程的有效控制，对保障多相流生产过程的安全、稳定运行十分重要。多相流相含率是表征多相流特性的重要指标之一。项目针对多相流体（油水两相流和油气水三相流）流动的复杂性导致超声信号响应非线性和测量范围低等问题，从分析超声波与多相流体相互作用出发，研究超声波在多相介质中的透射及复散射现象，探索和揭示非乳化油气水多相流典型流型中超声衰减规律和传播机理，提出基于超声衰减和渡越时间原理的油气水多相流相含率预测模型，建立相应的超声技术测试方法与系统，实现油气水多相流相含率的准确测量，改善超声测试响应非线性并且拓宽测试方法的应用范围。项目提出的相含率预测模型和超声测试方法有助于促进超声技术应用于多相流测试领域。

多相流相含率超声测试机理与方法研究是随着工业生产对测量、控制和节能等方面的要求和过程参数检测的要求日益提高形成和发展起来的一个基础的前沿研究问题。多相流具有时空非均匀性分布的相间界面、相间相对速度、相间滑脱、响应非线性等流动特征，对相关参数的准确测量一直是检测领域的挑战性课题之一。.本项目为实现相含率的准确测量，从超声波在油气水多相流典型流型中的传播机理出发，研究超声波在多相介质中的透射以及复散射现象，提出了基于超声衰减和渡越时间机理的油气水多相流相含率预测模型，建立了相应的超声技术测试方法与系统，实现油气水多相流相含率的准确测量，改善了超声测量响应非线性并且拓宽了测量方法的应用范围。.针对油水两相流典型流型中相分布及相含率变化对超声波衰减的影响问题，通过对非乳化油水两相流中典型流型，不同油相含率条件下超声衰减特性进行有限元数值模拟，分析超声衰减随相含率变化的规律。通过对超声波与多相流体相互作用，及超声波的衰减机制和传播机理分析，建立包含超声散射、吸收和扩散等传播衰减特性的机理模型，解决超声衰减系数与相含率之间的非线性关系问题。.针对多相流超声测试依赖于流型问题，提出一种超声透射衰减和反射回波结合的流型识别方法，作为油水两相流相含率测量的先验信息。针对超声法在实现油气水多相流相含率测量时，响应非线性及测量范围受限的问题，提出从研究超声波在多相流中的衰减特性和传播机理出发，通过建立相含率机理预测模型的方法，以实现油水两相流相含率测量。实验结果表明所建立的相含率预测模型，基本满足实际测试的要求，扩大了相含率测量的范围。.针对油气水三相流相含率测量问题，从水平流动过程中，气、液两相的实际分布出发，利用超声在气液界面反射的超声渡越时间计算液面高度；根据超声衰减预测反射路径中的油相含率；建立了三相相含率预测模型，并进行模型优化和修正，实现基于透射衰减和渡越时间的油气水三相流相含率的测量。