Liquid flow non-immersive measuring device and sensing probe

Abstract

The invention discloses a liquid flow non-immersive measuring device and a sensing probe. The liquid flow non-immersive measuring device comprises the sensing probe and is characterized in that the sensing probe is connected with a circulator through an optical path, light emitted by a pump light source of 980nm is received by the circulator through a separator, optical signals output by the circulator is sent to a coupler through the separator, two optical signals are output by the coupler, one signal is sent to a first Faraday rotary mirror through a phase modulator, and the other signal is directly sent to a second Faraday rotary mirror; the optical signals output by the coupler are sent to a photoelectric detector, electric signals output by the photoelectric detector enter a phase carrier wave demodulating device, weak dynamic variation of the wave length of a DFB optical fiber laser is demodulated, and flow is calculated according to the variation of the wave length; the sensing probe relates to a section of asymmetric phase shifting optical fiber grating fixed on the outer wall of an oil pipe in the circumferential direction.

Description

technical field [0001] The invention relates to a flowmeter, in particular to a non-immersion measuring device for liquid flow. Background technique [0002] With the continuous progress of oilfield development, flow rate is an extremely important parameter to determine the characteristics of oil production and transmission. Long-term real-time monitoring of flow rate through advanced technical means can master the production performance of oil wells, evaluate production layers and analyze downhole technology of oil wells. It can provide a scientific basis for optimizing the oil and gas exploitation plan and improving the crude oil recovery rate. Due to the complex flow state changes in the production process of oil and gas, the gas content of the fluid is low under the condition of downhole high pressure, showing good homogeneous flow characteristics, and there is basically no slippage phenomenon, so the measurement of downhole flow under this condition is more More favora...

AI Technical Summary

Problems solved by technology

However, because electronic sensors cannot withstand high temperatures, they cannot work for a long time in underground high temperature, high pressure and corrosive environments

There are mainly the following types of optical fiber traditional sensors: turbine flowmeters, vortex flowmeters, Doppler flowmeters, etc., but these types of flowmeters have certain problems when used in oil wells: turbine-type easy card Blocking; vortex and Doppler type of sticky oil

[0003] The application number is 201210070213.2 "Non-immersed downhole optical fiber flow monitoring system" has disadvantages: 1. The manufacturing process of the sensor module is relatively complicated, especially the 105m length of optical fiber winding, and according to the pipe wall vibration test theory, the monitoring position is approximately one point, but the sensing unit is designed to have a width of 5cm, and the number of layers is 3 layers, not a cross-sectional point

2. The high accuracy of the flow test requires a long sensing fiber, but according to the test principle, its length cannot be too long, so the minimum range of energy flow is limited, and the minimum flow during the experiment is 10m3 / h

3. When completing the simultaneous test of multiple flow fields, because the same wavelength laser source is used, the signals between the sensor modules are susceptible to mutual interference

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