Calculating method of propagation speed of leakage dynamic pressure waves in in-pipe gas

Abstract

The invention discloses a calculating method of the propagation speed of leakage dynamic pressure waves in in-pipe gas. A pipe section where gas flows stably is selected as a pipe section to be measured, and dynamic pressure sensors are installed at the two ends of the pipe section to be measured. A point on the upstream portion or the downstream portion of the pipe section to be measured is selected as a leakage point, and the leakage point is made to leak. Amplitude values of two leakage signals are obtained through signal processing, then sampling points corresponding to the amplitude values are selected, the difference value which is obtained by subtracting the two sampling points is divided by the sampling frequency, and a time difference is obtained. The distance between the sensors is divided by the time difference so that the apparent propagation speed of the dynamic pressure waves can be obtained, and finally, the propagation speed of the dynamic pressure waves is obtained by taking the gas flow speed into consideration. According to the calculating method of the propagation speed of the leakage dynamic pressure waves in in-pipe gas, the theoretical calculating formula of the propagation speed of the leakage dynamic pressure waves can be verified and corrected, the calculation precision of the propagation speed of the dynamic pressure waves is improved, and accordingly a foundation is provided for improving the leakage positioning precision.

Description

technical field [0001] The invention relates to the technical field of oil and gas pipeline leakage monitoring by dynamic pressure wave method, in particular to a method for calculating the propagation speed of leakage dynamic pressure wave in the gas in the pipeline. Background technique [0002] At present, there are many leakage monitoring methods that can be applied to oil and gas pipelines. Among them, the dynamic pressure wave method has many advantages compared with the traditional mass balance method, negative pressure wave method, and transient model method: high sensitivity, high positioning accuracy, Low false alarm rate, short detection time, and strong adaptability; the dynamic pressure wave method measures the weak dynamic pressure change in the pipeline fluid, which has nothing to do with the absolute value of the pipeline operating pressure. The response frequency is wider and the detection range is wider. [0003] In the research on leak detection and locati...

AI Technical Summary

Problems solved by technology

[0008] It has certain deficiencies in the calculation and processing of the propagation velocity of the leakage dynamic pressure wave in the gas in the pipe. The existing patents are less involved in the calculation method of the propagation velocity of the leakage dynamic pressure wave in the gas in the pipe, and the improvement of the leak location accuracy is more It is achieved by accurately calculating the time difference between the dynamic pressure wave reaching the sensors at both ends of the pipeline. The calculation method of the propagation velocity generally adopts the traditional sound velocity calculation formula, and the specific performance is: the pressure in the traditional sound velocity calculation formula is the average pressure of the pipeline , but the pressure of gas decreases during pipeline transportation, which makes the calculation of sound velocity inaccurate, which reduces the accuracy of leak location. To accurately calculate the sound velocity, a large number of pressure sensors need to be installed, which results in a large investment scale. Reduced the feasibility and applicability of the dynamic pressure wave method

[0009] To sum up, in the prior art, there is still no effective solution for the calculation of the propagation velocity of the leakage dynamic pressure wave in the gas in the pipe

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