Method and device for detecting leakage site in pipeline

FIELD: oil industry.

SUBSTANCE: method comprises receiving noise of discharging jet with the use of two acoustical pickups, converting the noise into voltage, digitization, filtering, and analyzing. The acoustical pickups are set at one site of the pipeline. One of the pickups receives acoustical waves, which propagate over the shell of the pipeline. The second one receives acoustical waves which propagate in the ambient fluid. The signal received are analyzed to determine co-spectra, and the values of the real and imaginary parts of the co-spectra indicate time lag between the signals which propagate in two fluids.

EFFECT: enhanced reliability of detecting.

3 cl, 1 dwg

 

The invention relates to a device for the detection of leakage of liquid or gas in pipelines and is intended to determine the coordinates of the leak in hard to reach areas of oil and gas pipelines.

The method for detection of holes in the pipe from Japan patent No. 4-184133, according to which the noise of the jet flowing out of the hole (the noise of the leak, take acoustic sensors located at both ends of the pipe, the signals from which visualize on the display and compare. If the signals are equal, then the hole is in the middle part between the sensors. If the signal from one of the sensors is significantly bigger than the other, the hole is located closer to the sensor.

A device that implements this method contains two tracts, each of the sequentially connected to the acoustic sensor, amplifier, display.

The disadvantages of the method and device of this analogy is not accurate determination of the leak, as well as the inability to install a second sensor in inaccessible places.

The closest in technical essence to the present proposal is U.S. patent No. 5.058.419 on method and apparatus for determining the location of the sound source. According to the method for determining coordinates of a leak in the pipeline detect the sound of this pipe leak in two remote from each other by 300 meters point is x and the delay time calculated location of the sound source. The required propagation velocity is calculated on the basis of the parameters of the liquid in the pipe, materials and shapes of the pipe by the standards of the American waterworks Association (AWWA With 401-77 and ANSG/AWWA With 403-78.

A device that implements the method-prototype contains two foster tract, each connected in series acoustic sensor, amplifier, filter, analog-to-digital Converter also includes a personal computer, the first and second inputs connected to the outputs of the analog-to-digital converters of the first and second paths.

The disadvantages of the method and device of the prototype are, firstly, the need to perform reception of signals in two remote locations, due to the need for creating special electrical communications, secondly, the calculation of the sound velocity in the pipe may not be accurate due to different fastening pipes on the highway, thirdly, there is provided the opportunity to determine where the leak unavailable for observation.

The objective of the invention is the provision determine where the leak from one point on the pipeline route.

The technical result of the invention is to simplify the method and device to determine the location of the leak due to the lack of need to carry out measurements at two points spaced apart a considerable distance and include the data among themselves or cable, any other means of conveying information. In addition, the second measurement point is not always available, you have the opportunity to determine the coordinates of the leak unavailable for observation.

This technical result is achieved in that in the method of determining the leak in the pipeline that contains the receive noise signals of the leak first and second acoustic sensors, conversion of these noise signals leak into electrical signals, filtering and binning electrical signals and determining the location of the leak on delay time leak noise signals, the received first and second acoustic sensors, introduced new features, namely the first and second acoustic sensors are installed on the pipeline near, so that the first acoustic transducer has an acoustic contact with the pipeline and acoustically screened from acoustic waves in the surrounding pipeline environment, and the second acoustically screened from acoustic waves propagating along the pipeline, at a fixed distance RHfrom sensors stir in the pipeline and its environment artificial noise signal, receive a noise signal propagating through the pipeline, the first acoustic sensor, a noise signal propagating around the pipeline environment, the second is an acoustic sensor, the electrical signals of the first and second acoustic sensors after filtering and sampling is subjected to inter spectral processing based on information about the real and imaginary parts of the mutual spectrum, the value of Randand the velocity of propagation of acoustic waves in the medium are the propagation velocity of a group of waves in the pipeline, in the presence of signal leak produce inter spectral processing is converted into electric signals filtered discretized signals of the leak, the received first and second acoustic sensors, time delay leak noise signals, the received first and second acoustic sensors, determine the data of the real and imaginary parts of the mutual spectrum of noise signals of the leak, and then determine the location of the leak, taking into account the velocity of propagation of acoustic waves in the medium and the speed of the group of waves in the pipeline.

The optimal result is obtained if the filtering is carried out in a frequency band of lower frequencyto the upper frequencywhere U is the stream velocity of the leak, and D is the minimum diameter of the hole of the leak to be detected.

To ensure this technical result in the device to determine where the leak in the pipeline, including the first and second reception paths, each of Kotor is x contains serially connected first and second acoustic sensor, respectively, amplifier, filter, and analog-to-digital Converter introduced the following new features, namely: the first sensor is an acoustic contact with the pipeline and acoustically screened from acoustic waves in the surrounding pipeline environment, and the second acoustic transducer acoustically screened from acoustic waves propagating through the pipeline, the device has connected in series analyzer mutual spectrum, the first and second inputs connected to the outputs of the analog-to-digital converters of the first and second receiving channels, respectively, the block distance calculation and display, also contains the memory block group velocity dispersion of the waves in the pipeline and the pipeline environment, the entrance of which connected with the second output block distance calculation, and output to the second input of the computing unit of the distance and velocity of a group of waves in the pipeline, also has a control unit, the state clock inputs and synchronicity which is connected to the analog-to-digital converters, with the analyzer mutual spectrum, with the computing unit of the distance and velocity of a group of waves in the pipeline, with the memory block group velocity dispersion of the waves in the pipeline and the pipeline environment and with the indicator also contains art the config source of the acoustic signal, acoustically associated with the first acoustic sensor on the pipeline, and a second acoustic sensor for surrounding the pipeline environment.

The invention is illustrated in the drawing, which shows a block diagram of the device for implementing the proposed method of determining the location of a leak in the pipeline.

A device for determining the leak in the pipeline has two tract containing connected in series acoustic sensors 1.1 and 1.2 amps 2.1 and 2.2, filters 3.1 and 3.2, analog-to-digital converters 4.1 and 4.2. Contains connected in series analyzer mutual spectrum of 5, the first and second inputs connected to the outputs of the analog-to-digital converters 4.1 and 4.2, unit 6, determine the distance and velocity of a group of waves in the pipeline, the indicator 7. Also contains the memory unit 8 of the group velocity dispersion of the waves in the pipeline and the pipeline environment, the input of which is connected with the second output unit 6, and the output is connected to the second input of the unit to determine the distance 6. The control unit 9 has a state clock inputs and synchronicity, United with blocks 4.1 and 4.2 blocks 5, 6, 8. 7. Also there is a source of artificial signal 10.

The method involves the following sequence of operations provided by the device. First, experimentally determine the group with the speed - U of propagation of the acoustic signal through the pipe. The nature of wave propagation in a cylindrical tube, substantially depends on the dimensionless frequency[Assocition. Acoustic design of ship structures. The Handbook. -Leningrad: sudostroenie, 1990.-c.l7]

where Rcf- the average radius of the pipe, Withppl- the speed of longitudinal waves in the plate is equal to the pipe thickness. For steel pipes. Typically, the radii of pipelines. Therefore, it is possible for steel piping with the same Rcfto take

i.e. at frequencies fkr>1330 Hz, the pipe can occur Flexural, longitudinal and shear waves. This Flexural vibrations have a velocity of propagation

The speed of propagation of longitudinal waves

where E, σ, ρ - young's moduli, Poisson distribution and the density of the pipe material. The speed of shear waves

where G is the shear modulus.

For steel: young's modulus E=21·1010PA, shear modulus G=8.14·1010PA, Poisson's ratio σ=0.29, density ρ=7.8·103kg m-3.

When the pipe fluid is acholeplasma weight of this liquid is added to the weight of the pipeline at a frequency below f 0equal to

where C0- the speed of sound in the fluid filling the pipeline.

When the pipeline is in fluid nicolepluscyle weight [E. Skocik. Fundamentals of acoustics. -M: IL, 1958, volume 1-s] isIt is seen that the frequency of large

the pipeline moving acoustic waves with different propagation velocity. Therefore, the group velocity of propagation of acoustic signal through the pipe it is necessary to determine experimentally, the more that the pipe may be a different mount pipe.

For this method you have entered the following operation: a known distance R0from the point of location of the acoustic sensors create an artificial acoustic excitation in a pipe and in an environment with frequencies ranging from fnto finthe filters.

Signals artificial noise sources accept the first and second acoustic sensors 1.1 and 1.2, the first - acoustically isolated from noise in the environment, and the second receiving noise in the environment.

Using filters 3.1 and 3.2 filter received signals artificial noise sources.

The filters are selected so as to provide the noise of a jet from a minimum of damage, for example, with a diameter D=5·10-3m is the Maximum of W is mA leak jet, coming out of the pipeline occurs when the Strouhal

where f is frequency in Hz, U is the flow rate of the jet in m/s-1. The main energy of the jet noise sources is concentrated in the range from fD=0,21 to

[Aghanim, M.A. Shepochkin. Range sound power subsonic jets. - Acoust journal, vol. XVIII, 1972, issue 2, s-298].

Therefore, the lower boundary of the filter, you can chooseand the upper edge of the filter

Increase adopted by the sensors 1.1 and 1.2 filtered signals through amplifiers 3.1 and 3.2, convert them into digital signals by the ADC 4.1 and 4.2.

Define mutual spectrum of these signalswhere G0(f) power spectrum of the artificial noise at a single distance; t3,andthe time delay of the artificial signal in the medium relative to the signal propagating along the pipe.

The delay time is determined by the frequency of zero values in real or imaginary parts of the mutual spectrum or in the form

where Im[•], Re[•] symbols of the imaginary and real parts.

Determine the velocity of propagation of a group of waves propagating through the pipeline. Given that the time delay between artificially with the data signals: whereTrWithcfrespectively the velocity of propagation of acoustic waves through the pipeline and the environment. According to the algorithm as a sequence of the above expressions(1), (2), (3), (4), (5), (6), (7), (8), (9) and with the known values of Ro, t3and Ccfit is easy to find:

as is carried out in block 6.

Stop the radiation of artificial signals, monitor signals adopted by the sensors 1.1 1 and 2, and when the signals leak produce procedures for sampling, filtering, amplification and inter spectral signal processing noise of the leak according to the same procedure as for signals of artificial radiation.

Determine the delay time by the frequency of the zero real or imaginary parts of the mutual spectrum or in the form

where Im[•], Re[•] symbols of the imaginary and real parts.

Find the distance r to the leak on the delay time t3between the acoustic signals propagating through the pipe and into the environment in the form

Inter spectral analysis performed in block 5. Determining a distance r expressions(10),(11),(12) in block 6. Data WithTrand Ccfrecorded in the memory unit 8. The results of measurements of the values of g violets is on the indicator 7. The control unit 9 provides synchronization operation.

The building blocks of devices known from practice. Shielding acoustic sensors are known, for example, from the book Weglassen. Shielding hydroacoustic antennas. -Leningrad: Sudostroenie, 1986. - 148 C.

As an artificial source can be used electrodynamic vibration source (see, for example, Wehowsky. Vibroacoustic car. -M engineering, 1988. -s) or hammer emitter - standard source of vibration (GOST 15116-79, ISO 140).

Thus, the claimed method and apparatus implement the required technical result.

1. The method of determining the leak in the pipeline that contains the receive noise signals of the leak first and second acoustic sensors, conversion of these noise signals leak into electrical signals, filtering and binning electrical signals and determining the location of the leak on delay time leak noise signals, the received first and second acoustic sensors, wherein the first and second acoustic sensors are installed on the pipeline next, the first acoustic transducer has an acoustic contact with the pipeline and acoustically screened from acoustic waves in the surrounding pipeline environment, and second acoustically screened from the aka the optical waves, propagating along the pipeline, at a fixed distance Rhfrom sensors stir in the pipeline and its environment artificial noise signal, take the artificial noise signal propagating through the pipeline, the first acoustic sensor, a noise signal propagating around the pipeline environment, the second acoustic sensor, the electrical signals of the first and second acoustic sensors after filtering and sampling is subjected to inter spectral processing based on information about the real and imaginary parts of the mutual spectrum, the value of Rhand the velocity of propagation of acoustic waves in the medium are the propagation velocity of a group of waves in the pipeline, in the presence of a leak produce inter spectral processing is converted into electric signals filtered discretized signals of the leak, the received first and second acoustic sensors, time delay leak noise signals, the received first and second acoustic sensors to determine data about the real and imaginary parts of the mutual spectrum of noise signals of the leak, and then determine the location of the leak, taking into account the velocity of propagation of acoustic waves in the medium and the speed of the group of waves in the pipeline.

2. The method of determining the location of the leak according to claim 1, otlichuy is the, that filtering is carried out in a frequency band of lower frequencyto the upper frequencywhere U is the stream velocity of the leak, and D is the minimum diameter of the hole of the leak to be detected.

3. Device for determination of the leak in the pipeline, including the first and second reception paths, each of which contains serially connected first and second acoustic sensor, respectively, amplifier, filter and analog-to-digital Converter, wherein the first acoustic transducer has an acoustic contact with the pipeline and acoustically screened from acoustic waves in the surrounding pipeline environment, and the second acoustic acoustically screened from acoustic waves propagating through the pipeline, the device is introduced successively United analyzer mutual spectrum, the first and second inputs connected to the outputs of the analog-to-digital converters of the first and second receiving channels, respectively, the computing unit of the distance and velocity of a group of waves in the pipeline and display, it also introduced the memory block group velocity dispersion of the waves in the pipeline and the pipeline environment, the input of which is connected with the second output and the output with the second input of the computing unit RA is standing and the propagation velocity of a group of waves in the pipe, it also introduced the control unit, the state clock inputs and synchronicity which is connected to the analog-to-digital Converter, with the analyzer mutual spectrum, with the computing unit of the distance and velocity of a group of waves in the pipeline, with the memory block group velocity dispersion of the waves in the pipeline and the pipeline environment and with the indicator, also introduced an artificial source of acoustic signal acoustically associated with the first acoustic sensor on the pipeline, and a second acoustic sensor for surrounding the pipeline environment.



 

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