RU132571U1 - HYDRAULIC DETECTION OF LOCATION OF THE SOURCE OF THE GAS LEAKAGE OF THE UNDERWATER GAS PIPELINE - Google Patents

Abstract

1. A sonar for detecting the location of a gas leak source of an underwater gas pipeline, comprising a master oscillator, a transmission receiving switch, an antenna, a system for generating a static fan of directivity characteristics, a multi-channel system for receiving and processing echo signals, a threshold selection unit in each channel, an echo signal start and end determination unit in each channel, an echo identification unit between channels, a unit for determining a correlation coefficient between echo signals in adjacent channels, a decision block on Ichii shroud bubbles, if two adjacent channels are the same beginning and end of the echo, and if the correlation coefficient between the echo is less than 0.5, and upravleniya.2 monitor system. The sonar according to claim 1, characterized in that an additional unit for measuring the distance at the beginning and end of the echo signal and a unit for calculating the depth of the source of depressurization of the pipeline according to the formula are introduced, where H is the depth of the depressurization point; D is the distance corresponding to the end of the echo signal; D- distance corresponding to the beginning of the echo.

Description

This utility model relates to the field of exploitation of subsea gas pipelines and is designed to detect hidden gas leaks.

Currently, gas pipelines, which are laid at great distances under water, are becoming very common. They can be located both on the bottom of the seas, and in underwater position in a floating state at a certain depth. During operation, situations arise that can break the seal between the pipes, which will lead to the formation of a leak through which the gas will leak. A gas leak can be detected by reducing the pressure in the line. However, this is not always possible because the pressure in the system depends on consumption, which is almost always random and depends on the randomness of switching on and off the sources of consumption. It is difficult to detect a gas leak from the water surface, since gas bubbles will be observed on the sea surface, the nature of the formation of which will be masked by the vibrating water mass with foamy crests of waves.

Known sonar, which can detect local objects located under water and at the bottom. Sonar operation is based on the reflection of acoustic energy from a local object having a metal shell that reflects the acoustic signal, or rocky rocks that are mirrored relative to the incident wave and reflect well. According to the results of acoustic studies conducted by American experts, data were obtained that acoustic energy is well reflected not only by metal and rock objects, but gas bubbles, which can be created when the object is moving or set intentionally. In the monograph “Physical foundations of underwater acoustics” edited by V. Myasishchev ed. Owls of radio M 1955. Page 604 questions of reflection of acoustic energy from individual bubbles and from a veil of bubbles are considered. The paper indicates that the equivalent radius of the reflector, consisting of a veil of bubbles, will depend on their size. When the radiation frequency coincides with the resonant frequency of the bubble, the echo signal increases sharply. The size of the bubbles depends on the depth of their location, since the pressure at the installation site of the gas pipeline is large, then the diameter of the bubble will be small, as it will be compressed by hydrostatic pressure. As the bubble rises to the surface, its size will increase. Thus, practically when the sonar is operating at any frequency, it will be possible to obtain an echo signal from a bubble sheet formed when the bubbles move from depth to surface. On this basis, fish-finding sonars have been developed that detect echo signals reflected from swimming bladders of fish, both single and in their clusters, E.V. Shiishkova, Physical fundamentals of field acoustics, M. 1977. There are known sonars designed to search and detect fish clusters. jambs considered in Yu.S. Kobyakov, NNKudryavtsev V.I. Timoshenko "Design of hydroacoustic fish-finding equipment." Shipbuilding L. 1986, pp. 5-27. The closest analogue is the all-round sonar, considered in the book by A. S. Kolichedantsev “Hydroacoustic stations” Shipbuilding L. 1982, page 60. The sonar contains a stationary antenna, a master oscillator, a transmission reception switch, a preliminary amplifier, a scanning device, a reception system and echo processing and indicator. Also known is the fish echo sonar “Eel”, which has a simultaneous all-round view mode A. Tikunov “Fish Finding Devices and Complexes” L. Shipbuilding 1989, pp. 140-153. The composition of the sonar includes a receiving and emitting sonar antenna, a transmission receiving switch, a generator device, a receiving path, including equipment for the preliminary processing of the received signals and a control panel with an electronic indicator. In the "Eel" sonar in the mode of simultaneous circular viewing, the antenna does not emit acoustic sounding signals in the horizontal plane, in the receiving mode an electronic circular scanning of the radiation pattern in the horizontal plane is carried out.

The disadvantage of sonar is that it can not detect and classify the veil of gas bubbles that are formed when the tightness of the gas pipe joints is broken.

The prior art did not reveal a tool for the same purpose, therefore, the technical result of the invention is the creation of a sonar to detect the location of the source of a gas leak of an underwater gas pipeline.

To this end, it is proposed to create a sonar to detect the location of the gas leak source of the underwater gas pipeline, which contains a master oscillator, a transmission reception switch, an antenna, a system for generating a static fan of directional characteristics, a multi-channel system for receiving and processing echo signals, a threshold selection unit in each channel, a start detection unit and the end of the echo in each channel, the unit for identifying echoes between the channels, the unit for determining the correlation coefficient between echoes in adjacent channels, the decision block on the presence of a veil of bubbles, if the beginning and end of the echo signals coincide in two adjacent channels, if the correlation coefficient between the echo signals is less than 0.5, the monitor and the control system. In addition, a unit for measuring the distance at the beginning of the echo signal, a unit for determining the distance at the time of the end of the echo signal, and a unit for calculating the depth of the position of the source of depressurization of the pipeline were introduced.

Let us explain the essence of the proposed utility model. Existing sonars are not able to distinguish a veil of bubbles from a metal platform installed at the bottom or from lifting the soil at the bottom. The aim of this proposal is to develop a sonar that would be able to detect a veil of bubbles formed due to the release of gas. Here, one should proceed from several obvious premises: the source of gas output is located on the pipe, the gas rises only up and its volume increases due to expansion up to the surface, therefore the gas sheet is located vertically, when the bubbles rise, their size increases, and there will always be bubbles whose resonance sizes coincide with the frequency of sonar radiation. The presence of the pipeline does not preclude the receipt of an echo from the pipe body, since the pipe is a hollow space filled with gas, the density of which differs from the density of water. To detect the classification of the bubble veil, it is necessary to use a sonar containing a receiving and emitting antenna, a switch, a probe signal generator and a static fan of directional characteristics during reception. Since the probe signal propagates in an aqueous medium according to a spherical law, when emitted from a surface ship, acoustic energy will propagate in the direction of increasing depth, expanding. The first echo will come from the part of the veil of bubbles that has already reached the surface, and the last echo will come from the part that is in the non-sealed pipe and from the pipe itself. Reception of the echo signal is carried out by a static fan of directivity and the processing of the received echo signal occurs autonomously and independently in each directional characteristic. In each directional characteristic, an echo signal is detected, the amplitude of the echo signal and the moment of the beginning of the echo signal and the moment of the end of the echo signal are measured. Since the veil of bubbles is continuous all the way to the surface and expands, the echo signal will represent a continuous time function, where the beginning and end of the echo signal will be clearly observed. Such a temporary function will be observed in two adjacent spatial channels, since the spatial channels of the static fan of directivity characteristics overlap, and the width of the gas cloud expands. Thus, the obtained estimates of the echo signals in two adjacent spatial channels will have close temporal characteristics, but their amplitude characteristics will differ. The amplitude parameters of the echo signals are necessary for identification between the channels and lowering the detection threshold at the time of measurement. Therefore, it is necessary to ensure the detection of the echo signal in the adjacent directivity characteristics, the measurement of the start time of the echo reflected from the object, the measurement of the end time of the echo reflected from the object in the adjacent directivity characteristics. The moment of the end of the echo signal will correspond to the moment of exit of the gas that is on the pipe. By measuring the distance to the place where the gas escapes to the surface, which corresponds to the beginning of the echo signal, and by measuring the distance corresponding to the end of the echo signal, you can determine the depth of the source of depressurization of the gas pipeline by the formula

, где

where

H is the depth of the location of the depressurization point;

D _finish. - distance corresponding to the end of the echo signal,

_First - distance corresponding to the beginning of the echo signal.

Echoes from the veil of bubbles are formed by independent sources of reflection and therefore the echoes from them will not be coherent. This means that energetically the amplitudes of the echo signals will exceed the detection threshold, but in space they will be different and therefore the correlation coefficient between the signals received in the neighboring directivity characteristics will be small.

The essence of the utility model is illustrated in Fig 1, which shows the structural diagram of a sonar to determine the location of the source of depressurization of the pipeline.

Claims (2)

1. A sonar for detecting the location of a gas leak source of an underwater gas pipeline, comprising a master oscillator, a transmission receiving switch, an antenna, a system for generating a static fan of directivity characteristics, a multi-channel system for receiving and processing echo signals, a threshold selection unit in each channel, an echo signal start and end determination unit in each channel, an echo identification unit between channels, a unit for determining a correlation coefficient between echo signals in adjacent channels, a decision block on Ichii shroud bubbles, if two adjacent channels are the same beginning and end of the echo, and if the correlation coefficient between the echo is less than 0.5, the monitor and control system. 2. The sonar according to claim 1, characterized in that an additional unit for measuring the distance at the beginning and end of the echo signal and a unit for calculating the depth of the position of the source of depressurization of the pipeline according to the formula are introduced: $$H=\sqrt{D_{\mathrm{about}\mathrm{to}\mathrm{about}nh}^2-D_{n\mathrm{but}h}^2}$$

, where H is the depth of the location of the depressurization point; D _over - the distance corresponding to the end of the echo signal; D _beg - distance corresponding to the beginning of the echo signal.

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