Solution to edge effect of two-phase gas-liquid flow capacitive sensor

Abstract

The present invention is solution to edge effect of two-phase gas-liquid flow capacitive sensor. The two-phase gas-liquid flow capactitive sensor is provided with protecting pole plates of optimal length L. The increase of length results in decreased influence of the edge effect but increased volume of the sensor, and the angle of the arced pole plate is 120-140 deg. The protecting plate length L and the angle of the arced pole plate, as the main parameters, are obtained via 3D electromagnetic field equi-parameter finite element algorithm including the steps of: start, unit separating, dielectric constant setting, rigid matrix synthesis, solving coupled equations and capacitor integration. The method of the present invention has simple structure, low cost, long life, high sensitivity and capacity of measuring flow rate, phase density and sliding ratio, and other advantages. The present invention is suitable for non-invasion measurement of two-phase gas-liquid flow in oil pipeline.

Description

technical field [0001] The invention relates to a capacitive sensor for oil field oil pipeline measurement, in particular to a method for solving the edge effect of a gas-liquid two-phase flow capacitive sensor. Background technique [0002] In the production of petroleum industry, the crude oil sprayed or extracted from oil wells is a multiphase flow, which contains crude oil, water, natural gas and mud sand, etc. Due to the different flow conditions of the pipeline, this multiphase flow may produce annular flow, Turbulent flow, core flow and other flow patterns, its metering problem is a very complicated problem. And its accurate measurement is an extremely important basis for oil production. For example, the measurement of oil-water content is the most important technical index for evaluating underground oil storage, extraction value, recovery degree and formulation of extraction plan. In the previous capacitive sensor research, the plate was assumed to be infinitely lon...

AI Technical Summary

Problems solved by technology

In the previous capacitive sensor research, the plate was assumed to be infinitely long, ignoring the edge effect, making the sensitive field uneven, affected by the flow pattern, making it difficult to determine the volume of the fluid sensitive space in the sensitive field, resulting in measurement errors; In the detection of multiphase flow, especially for the measurement of phase concentration, since the capacitance value of the capacitive sensor is small, between a few Pf to tens of Pf, the requirement for the uniformity of the electromagnetic field generated by the capacitive sensor is relatively high, so in the fluid The edge effect in the direction (sensor axial direction) and X, Y direction (sensor axis section) cannot be ignored, otherwise it will cause a large measurement error. In order to solve the problem of the edge effect of the capacitive sensor, a protective plate is added to the capacitive sensor and optimized Determining its length is one of the keys to solve the measurement accuracy of multiphase flow capacitive sensors

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