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Flow rate and holdup are two essential parameters to describe oil-water two-phase flow. The distribution of oil-water two-phase flow in the pipeline is very uneven, and there is a significant slippage between the phases. This makes it difficult to measure these two flow parameters. In this paper, a new measurement method of flow rate and holdup based on phase state regulation is proposed. The oil-water two-phase flow is adjusted to oil or water single-phase flow according to the time sequence by the phase state regulation, and the oil-water phase interface is measured with a conductance sensor. A wavelet transform based phase inflection point detection model is proposed to detect the oil-water phase change point. The experimental results show that the maximum measurement error of the flow rate of water is 3.73%, the maximum measurement error of the flow rate of oil is 3.68%, and the flow rate measurement repeatability is 0.0002. The accuracy of the measurement holdup is better than 3.23%, and the repeatability of the measurement holdup is 0.0003. The prototype designed based on this method has two advantages. One is that it is small in size, the other is that it does not depend on the accuracy of the sensor. Therefore, it can be widely used in oilfield ground measurement.

Methacrylate functional monomers containing polymerisable double bonds and sulphhydryl group were synthesised using (methyl) hydroxyethyl (propyl) acrylate and mercaptopropionic acid as precursors with benzene (toluene, ethyl acetate, ether) as solvent and aqueous agent, p-toluene sulphonic acid as catalyst, hydroquinone as polymerisation inhibitor. The yield of methacrylate functional monomers was more than 90%. The structure and purity of methacrylate functional monomers was characterised by proton nuclear magnetic resonance (1H-NMR) and liquid chromatography–mass spectrometry (LC-MS). The precursor material source is of low cost and widely available, and the product did not need to be purified by a special method, which means that it can be directly used for the synthesis of vinyl branched polymer. Therefore, the price of vinyl branched polymer can be greatly reduced and the application range of vinyl branched polymer can be greatly expanded. [ABSTRACT FROM AUTHOR]

Velocity is an important parameter for fluid flow characteristics in profile logging. Particle tracking velocimetry (PTV) technology is often used to study the flow characteristics of oil wells with low flow velocity and high water cut, and the key to PTV technology is particle matching. The existing particle matching algorithms of PTV technology do not meet the matching demands of oil drops in the oil phase velocity measurement of oil-water two-phase flow with low velocity and high water cut. To raise the particle matching precision, we improved the particle matching algorithm from the oriented FAST and the rotated BRIEF (ORB) feature description and the random sample consensus (RANSAC) algorithm. The simulation and experiment were carried out. Simulation results show that the improved algorithm not only increases the number of matching points but also reduces the computation. The experiment shows that the improved algorithm in this paper not only reduces the computation of the feature description process, reaching half of the computation amount of the original algorithm, but also increases the number of matching results, thus improving the measurement accuracy of oil phase velocity. Compared with the SIFT algorithm and the ORB algorithm, the improved algorithm has the largest number of matching point pairs. And the variation coefficient of this algorithm is 0.039, which indicates that the algorithm is stable. The mean error of oil phase velocity measurement of the improved algorithm is 1.20 %, and the maximum error is 6.16 %, which is much lower than the maximum error of PTV, which is 25.89 %. The improved algorithm overcomes the high computation cost of the SIFT algorithm and achieves the precision of the SIFT algorithm. Therefore, this study contributes to the improvement of the measurement accuracy of oil phase velocity and provides reliable production logging data for oilfield.

A flexible dual‐band efficient polarization converter is realized by both coupled mode theory (CMT) analysis and numerical simulation in the microwave regime. The proposed structure can convert linearly polarized electromagnetic waves into their orthogonal components in the two sidebands. Moreover, a specular reflection performance is obtained in the central frequency band. The polarization conversion ratio (PCR) and operating bandwidth of dual band is dynamically modulated by vanadium dioxide (VO2). In the simulation results, it is shown that the proposed metasurface can achieve linear polarization conversion in 8.17–12.87 and 14.63–18.92 GHz in the insulating phase. PCRs of the dual band are 97.06% and 98.13%, the corresponding relative bandwidths (RBs) are 44.68% and 25.58%. In the metallic phase, the PCRs in 6.81–13.95 and 16.23–18.16 GHz are 91.12% (RB = 68.79%) and 96.92% (RB = 11.22%). The analyses of the phase difference (u–v coordinate system) and the surface current are given to explain the mechanisms of dual‐band and high PCR. The simulation results are in good agreement with those of CMT. Furthermore, the structure has a robust response to the oblique incidence angle (up to 30°) and has polarization insensitivity. The proposed metasurface has great potential applications in antenna radiation, biosensing, and stealth technology. [ABSTRACT FROM AUTHOR]