RU2628672C1 - Method for leak tightness control and determining leak point coordinate in product pipeline and device for its implementation - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: acoustic signals are received in the first and the second pipelines (13, 14) located in parallel to each other by means of four acoustic sensors (1-4). Wherein the acoustic sensors (1-4) are arranged in pairs on each pipeline at a given distance (h1) along their length. Correlative processing of the acoustic signals from the acoustic sensors (1-4) is performed. The distances to the correlation function peaks are determined. Based on the difference in the correlation function peaks of the first pipeline (13) containing a leak (12) and the second pipeline (14) not containing a leak, the leak point coordinates in the pipeline are determined. The device for implementing the method comprises four acoustic sensors (1-4), and the first, second, third and fourth receiving paths located in the housing (10), a processing unit, an adder. Each receiving path contains a series-connected amplifier, a filter, an analog-to-digital converter. The receiving paths are connected to the acoustic sensors (1-4) and the processing unit. The processing unit is connected to the adder.

EFFECT: increasing the accuracy of determining a leak point in a pipeline.

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Description

FIELD OF TECHNOLOGY

The group of inventions relates to a method and apparatus for monitoring tightness and determining the coordinates of the location of a liquid or gas leak in pipelines, for example, gas pipelines and oil pipelines.

BACKGROUND

A known method for determining the coordinates of a leak in pipelines and a device for its implementation, disclosed in SU 1283566 A1, publ. 01/15/1987. The method for determining the coordinates of leaks in pipelines, which consists in the fact that they receive acoustic signals at two points along the length of the pipeline, measure the difference in the time of arrival of signals at these points in a correlation way by discretely delaying the signals of one receiving channel relative to another, and the magnitude of the coordinates of the leak is determined by the maximum curve, in this case, the signal delay step is measured until two adjacent peaks of equal value are obtained on the correlation curve, and the determination of the leak coordinate is Produce taking into account the distance between the points of reception of acoustic signals, the magnitude, number and number of delay steps of the signals. A device for determining the coordinates of a leak in pipelines contains electro-acoustic transducers, amplifiers, shapers, shift registers with a shift signal generator, coincidence circuits, pulse counters, a switch and an indicator.

A disadvantage of the known technical solution is that the false peaks of the correlation function associated with the geometry of the pipeline and the presence of supports and jumpers are not eliminated.

The closest analogue of the claimed invention is a method for monitoring the tightness and determining the coordinates of the leak in the product pipeline and a device for its implementation, disclosed in RU 2181881 C2, publ. 04/27/2002. The method of tightness control and determining the location of the leak in the product pipeline consists in receiving acoustic signals at two points along the length of the product pipeline, detecting the leak, and then correlating the received acoustic signals, which determines the difference in the arrival times of the acoustic signals and the coordinate of the leak location, while before the correlation by processing the received acoustic signals, discrete components are rejected in each of the signals, followed by spectral analysis m and last spectra of the received signals is isolated long-term spectral components exceeding a duration of 30 seconds and with an amplitude exceeding the background by 3-6 dB and the spectral components according to the presence of a leak is judged. In this case, an additional reception of acoustic signals at a third point along the length of the product pipeline is carried out, spectral analysis is performed and spectral components are selected that correspond to the vibration spectrum of the transfer pumps at compressor stations, and discrete components are cut in each of the first two signals taking into account the obtained spectral components corresponding to vibration spectrum of transfer pumps at compressor stations of a product pipeline. The device contains three sensors connected to the signal processing unit, which is connected with the recorder.

The disadvantage of the closest analogue is that the false peaks of the correlation function associated with the geometry of the pipeline and the presence of supports and jumpers are not eliminated.

SUMMARY OF THE INVENTION

The objective of the claimed group of inventions is to develop a method and device for monitoring the tightness and determining the coordinates of the leak in the product pipeline, ensuring the accuracy of determining the tightness and the place of leak in the pipeline.

The technical result of the claimed group of inventions is to increase the accuracy and reliability of determining the location of a leak in the pipeline.

The specified technical result is achieved due to the fact that the method of monitoring the tightness and determining the coordinates of the leak in the product pipeline includes receiving acoustic signals in the first and second pipelines parallel to each other using four acoustic sensors in pairs located on each pipeline at a given distance their length, followed by correlation processing of acoustic signals from acoustic sensors and determining the distances to the peaks of the correlation function, while Based on the difference of the peaks of the correlation function of the first pipeline containing the leak and the second pipeline that does not contain the leak, the coordinates of the leak in the pipeline are determined.

A device for determining a leak in a product pipeline contains a housing and four acoustic sensors, while an adder, a first, second, third and fourth receiving paths are located in the housing, each of which is connected to an acoustic sensor, and an amplifier, a filter, are connected in series in each receiving path , an analog-to-digital converter (ADC), which are connected to the processing unit, the processing unit being connected to the adder.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clear from the description, which is not restrictive and given with reference to the accompanying drawings, which depict:

in FIG. 1 is a block diagram of a device;

in FIG. 2 - location on the pipeline of acoustic sensors;

in FIG. 3 - callerograms of correlation functions: a) along the first pipeline; b) through the second pipeline.

1 - the first acoustic sensor; 2 - second acoustic sensor; 3 - the third acoustic sensor; 4 - fourth acoustic sensor; 5 - amplifier; 6 - filter; 7 - ADC; 8 - processing unit; 9 - adder; 10 - housing correlation leak detector; 11 - soil level; 12 - leak; 13 - the first pipeline; 14 - the second pipeline; 15 - peak correlation function of the acoustic leak signal; 16 - peak correlation function of the acoustic signal of the first turn of the first pipeline; 17 - peak correlation function of the acoustic signal of the second turn of the first pipeline; 18 - peak correlation function of the acoustic signal of the first rotation of the second pipeline; 19 - peak correlation function of the acoustic signal of the second rotation of the second pipeline.

DETAILED DESCRIPTION OF THE INVENTION

A device for determining the place of a leak in the product pipeline (correlation leak detector) contains a housing (10) and four acoustic sensors (1-4), while an adder (9), first, second, third and fourth receiving paths are located in the housing of the correlation leak detector (10) , each of which is connected to an acoustic sensor (1-4), and in each receiving path there are series-connected amplifier (5), filter (6), ADC (7), which are connected to the processing unit (8), and the processing unit ( 8) connected to the adder (9).

The method of tightness control and determining the coordinates of the leak in the product pipeline using a correlation leak detector containing a housing (10) and four sensors (1-4), is as follows. The first (1) and second (2) acoustic sensors are located on the first pipeline (13) located in the ground and located at a predetermined distance (h ₁ ) from each other along the length of the first pipeline (13), and on the second pipeline (14) located in the soil parallel to the first pipeline (13), fix the third (3) and fourth (4) acoustic sensors located at a given distance (h ₁ ) from each other along the length of the second pipeline (14). Then, the acoustic sensors (1-4) are connected via wires to the receiving path of the body of the correlation leak detector (10), located above the ground level (11), corresponding to each sensor. In accordance with FIG. 2 acoustic sensors (1-4) are installed in sections of pipelines (13, 14) between two turns of pipelines (13, 14) located at an unknown distance h ₂ from acoustic sensors (1, 3). After placing acoustic sensors (1-4) on pipelines (13, 14), they receive acoustic signals arising from the collision of the pumped liquid against the walls of pipelines (13, 14) both in the straight section and in the turns of pipelines (13, 14) . The received acoustic signals are amplified in the amplifier (5), filtered by a filter (6), the ADCs (7) are digitized and fed to the processing unit (8). When a leak (12) occurs in the first pipeline (13) at an unknown distance h ₃ , acoustic signals appear at the leak location (12), which are received by acoustic sensors (1, 2). Accepted acoustic signals from leakage (12) are amplified in the amplifier (5), filtered by a filter (6), the ADCs are digitized (7) and fed to the processing unit (8). Previously, data on the pipeline are entered into the processing unit (8): diameter, pipeline material, fluid pressure in the pipeline. Additionally, information about the distance between the sensors (h ₁ ) is entered. The parameter "distance between the sensors (h1)" is directly used in the calculations and when visualizing the results, the parameters "diameter" and "material" are used to select the value of the speed of sound (v) in the pipeline in a tabular manner. An empirical data table is used.

The processing unit (8) measures the received and digitized signals from the sensors. Moreover, the number of measurements is selected automatically, depending on the distance between the sensors. A spectral analysis of the source data is performed, for this, the Fourier transform is performed, the amplitudes are calculated, and histograms of the dependence of the signal amplitude on frequency are plotted. The presence of narrow-band interference and mismatch of the spectra of paired sensors is determined. Filters are adjusted. And a new dimension is being taken. Based on the adjusted data, the correlation function is calculated and linked to the pipeline section being examined. The binding is as follows:

- the maximum possible delay time of the signal on one sensor relative to the signal on the other is calculated. It is equal to the time the sound wave travels a distance equal to the length of the pipeline section being examined (the length of the section divided by the speed of sound);

- the number of measurements “2⋅N _max ” is calculated, which is done during this time (the calculated transit time multiplied by the sampling frequency (q));

- the leak signal that came to the sensors at the same time corresponds to a leak in the center of the section.

Thus, the entire section is divided into two segments. The segment from the center of the plot to the first (1) or third (3) sensors corresponds to the points of the correlation function calculated when the signal is delayed at the first (1) or third (3) sensors, changing from 0 to N _max . The segment from the center of the plot to the second (2) or fourth (4) sensors corresponds to the correlation function with the delay of the signal at the second (2) or fourth (4) sensor, varying from 0 to N _max ;

- the obtained resolution (A) (distance on the ground, between adjacent points of the correlation function) is calculated by the formula A = v / 2⋅q (the correlation function along the entire length of the section has 2 times more points than N _max ).

The correlation function is calculated for digital sequences of signals from one and the other sensors.

The calculation is made according to the formulas below.

where U _r (n), Ur (n + τ) are samples of digital sequences of signals from the first (third) sensor;

U _b (n), U _b (n + τ) - samples of digital sequences of signals from the second (fourth) sensor;

- среднеарифметическое значение отсчетов цифровых последовательностей сигналов с первого (третьего) датчика или со второго (четвертого) датчика соответственно;

- the arithmetic mean of the samples of digital sequences of signals from the first (third) sensor or from the second (fourth) sensor, respectively;

τ - the number of samples of digital signal sequences, showing the difference in the samples of the propagation of the signal from the leak to the installation location of the sensors

N _max - the number of samples of digital signal sequences, the range for calculating the correlation function 0≤τ≤ (N _max -1);

- нормализованная (диапазон принимаемых значений от -1 до +1) корреляционная функция на отрезке между двумя датчиками, расположенными по длине трубопровода, от центра обследуемого участка трубопровода до первого (1) или третьего (3) датчика.

- normalized (range of accepted values from -1 to +1) correlation function in the interval between two sensors located along the length of the pipeline, from the center of the pipeline section to the first (1) or third (3) sensor.

- нормализованная корреляционная функция на отрезке между двумя датчиками, расположенными по длине трубопровода, от центра обследуемого участка трубопровода до второго (2) или четвертого (4) датчика.

- the normalized correlation function on the segment between two sensors located along the length of the pipeline, from the center of the pipeline section to the second (2) or fourth (4) sensor.

The correlation function is displayed as graphs a) and b) in FIG. 3. The left edge of the graph corresponds to the position of the first (1) or third (3) sensor, the right edge corresponds to the position of the second (2) or (4) sensor, the center of the graphs a) and b) corresponds to the center of the pipeline section being examined. The graph shows the peaks of the correlation function, which can be caused by noise in the pipeline. These peaks can be caused both by leakage, and by the presence of bends and jumpers in the pipeline. The following peaks are shown in graph a): the peak of the correlation function of the acoustic signal of the leak (15), the peak of the correlation function of the acoustic signal of the first turn of the first pipeline (16) and the peak of the correlation function of the acoustic signal of the second turn of the first pipeline (17), and in graph b) - the peak of the correlation function of the acoustic signal of the first turn of the second pipeline (18) and the peak of the correlation function of the acoustic signal of the second turn of the second pipeline (19).

, где

- количество отсчетов цифровых последовательностей сигналов, соответствующих пику корреляционной функции), наиболее вероятно соответствующего утечке, и рассчитанной скорости звука в трубопроводе (скорость, умноженная на время задержки, дает расстояние от центра между датчиками до утечки). Вычитая из половины расстояния между первым (1) и вторыми (2) (третьим (3) и четвертым (4)) датчиками расстояние до центра, получаем расстояние от датчика до утечки.The calculation data of the correlation function in the first and second sections of the pipeline are fed to the adder (9), where the peaks of the correlation function are subtracted. In places where both pipelines have the same structural elements that are at the same distance from the sensors, generating acoustic signals (turns, supports, jumpers, etc.), the peaks of the correlation function (16-19) corresponding to the first and second turns of the pipelines compensate each other friend. As a result of processing (subtracting) the peaks (15-19) of the correlation function in the adder (9), the remaining peak (15) of the correlation function corresponding to the leak point (12) from the adder (9) goes to the processing unit (8), where the distance is calculated to the leak (12) and is displayed on the indicator (not shown) of the correlation leak detector (10). The distance to the leak location is calculated based on the determined signal delay time to the peak of the correlation function (

where

- the number of samples of digital sequences of signals corresponding to the peak of the correlation function), most likely corresponding to the leak, and the calculated speed of sound in the pipeline (the speed multiplied by the delay time gives the distance from the center between the sensors to the leak). Subtracting the distance from the center from the half of the distance between the first (1) and second (2) (third (3) and fourth (4)) sensors, we obtain the distance from the sensor to the leak.

The use of four sensors and calculation of the correlation function in two identical sections of the pipeline can significantly reduce the number of “false” leaks due to the presence of peaks of the correlation function at the same distance from the sensors in both pipelines, which improves the accuracy and reliability of determining the location of a leak in the pipeline.

Thus, the present invention improves the accuracy and reliability of determining the location of a leak in the pipeline.

The invention has been disclosed above with reference to a specific embodiment. Other specialists may be obvious to other embodiments of the invention, without changing its essence, as it is disclosed in the present description. Accordingly, the invention should be considered limited in scope only by the following claims.

Claims (2)

1. A method of monitoring the tightness and determining the coordinates of the leak in the product pipeline, including receiving acoustic signals in the first and second pipelines parallel to each other using four acoustic sensors in pairs located on each pipeline at a given distance along their length, followed by correlation processing the acoustic signals from the acoustic sensors and determining the distances to the peaks of the correlation function, while based on the difference of the peaks of the correlation function of the first the pipeline containing the leak, and the second pipeline that does not contain the leak, determine the coordinates of the leak in the pipeline. 2. A device for determining the place of a leak in the product pipeline for implementing the method according to claim 1, comprising a housing and four acoustic sensors, wherein an adder, first, second, third and fourth receiving paths are located in the housing, each of which is connected to an acoustic sensor, and in each receiving path there are series-connected amplifier, filter, analog-to-digital converter, which are connected to the processing unit, and the processing unit is connected to the adder.

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