Coaxial conductivity sensor, measurement system and measurement method for oil content of oil-water two-phase flow

Abstract

The invention belongs to the technical field of measurement of oil-water two-phase flow and relates to a coaxial conductivity sensor for detecting oil content of the oil-water two-phase flow. The coaxial conductivity sensor comprises an annular outer electrode, an inner electrode and two protection electrodes which are coaxial, wherein the two protection electrodes are fixed to two ends of the inner electrode respectively; insulated gaskets are arranged among the two protection electrodes and the inner electrode; and the radiuses of the two protection electrodes are equal to that of the inner electrode. Meanwhile, the invention provides a measurement system employing the coaxial conductivity sensor and a measurement method realized employing the measurement system. The measurement system comprises an excitation module, a coaxial conductivity sensor, a measurement module, a demodulation module, an acquisition module and a calculation unit. The coaxial conductivity sensor and the measurement system provided by the invention are improved in measurement accuracy, particularly measurement accuracy under the condition of high water content.

Description

technical field [0001] The invention relates to a coaxial conductance sensor and a measuring system thereof, which can realize on-line precise measurement of oil content in oil-water two-phase flow. Background technique [0002] In the process of crude oil extraction and transportation, the online accurate measurement of the holdup of oil-water two-phase fluid is of great value. The conductivity method has the advantages of simple structure and principle, fast response, low price and no radiation, and is widely used in the measurement and research of multiphase flow. The conductometric method is a method of measuring according to the different conductivity of oil and water. Many researchers have done a lot of research on the relationship between the phase separation ratio and the conductivity of the mixture. Among them, the Maxwell model is more widely used [1，12，13] with the Bruggeman model [2，14，15] . [0003] In order to obtain better measurement results, researchers...

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Problems solved by technology

[0003] In order to obtain better measurement results, researchers have designed many forms of conductivity sensors, conductivity probes [3，4，5] Mainly used for the measurement of phase holdup distribution; parallel plate [6，7] The structure has the advantage of uniform electric field distribution. Due to its structural limitations, it is mainly used in the measurement of square pipes; arc electrodes [8] , in order to be suitable for the measurement of circular pipelines, the parallel plate electrode is changed into a semicircular structure, although it can be used for the measurement of circular pipelines, but the cross-sectional electric field distribution is uneven; the cross-sectional multi-electrode structure [9，10] , the structure is mainly used in electrical resistance tomography (ERT) and longitudinal ring multi-electrode [11]

In addition to the parallel plate structure of the traditional conductivity sensor, the uneven electric field distribution of other sensors affects the measurement accuracy of the holdup. Although the parallel plate electrode has the advantage of uniform electric field distribution, it is limited to the measurement of square pipes, and the actual application pipes are mostly round. shaped pipes, which limits its wide application

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