Study On Flow Characteristics Of Oil–water Two-Phase Flow By Terahertz Spectroscopy

The single-phase flow and oil–water two-phase flow and even oil–gas–water three phase flow widely exist in the process of oil and gas exploration,development and transportation.Because of the increasing technical requirements of pipeline transportation,it is necessary not only to clarify the specific phase distribution and friction pressure drop of oil–water two-phase flow in pipeline,but also to clarify the flow characteristics and mechanism of oil–water two-phase flow so as to guide the design and management of pipeline scientifically,which requires to develop practical and economical methods to improve and enrich the evaluation technology and the theoretical system of oil–water two-phase flow.In this paper,the flow characteristics of oil–water two-phase flow are studied and analyzed based on terahertz technology and computer simulation technology.The main obtained results are as following:1.The spectral characteristics of oil,gas,and water in terahertz band have been analyzed and studied.The spectral response of oil,gas and water in terahertz band are obviously different due to the difference of their molecular composition as well as polarity,and thus the terahertz spectral recognition of oil,gas,and water distribution is realized.2.The spectral response of diesel oil–water two-phase flow in a horizontal circular pipe are studied in terahertz band.The critical Reynold number from laminar flow to transition flow is obtained according to the turning point of its volume flow rate-time domain peak spectrum curve.It is confirmed that the absorption characteristics of twophase flow with different flow patterns are different in terahertz band.The variation law of the slip of two-phase flow under different flow patterns is analyzed,and the relationship between the slip and the terahertz spectral parameters are established.3.Terahertz spectroscopy is used to study the flow process of single-phase flow and oil–water two-phase flow in microchannel.The flow pattern is distinguished according to the variation law of terahertz spectral parameters at different flow rates and the transition velocity of single-phase flow from laminar flow to transition flow is determined.The flow process of oil–water two-phase flow in microchannel from liquid injection to stable flow is monitored as well.The results prove that THz technology provides a supplementary method for the study and analysis of flow characteristics of single-phase flow and two-phase flow in microchannels.4.A terahertz-band EIT-like metamaterial is designed and the mathematical models between the resonance frequencies and water content of emulsion are established,which helps to achieve the accurate prediction of water content for high water cut crude oil emulsion.A ‘+' metamaterial is applied to analyze the oil–water two-phase flow in the ‘T' microchannel,and to identify the flow pattern of two-phase flow.