A high-pressure gas detector

Abstract

The present invention relates to the technical field of oil well liquid level detection, and in particular to a high-pressure gas geophone, comprising an outer shell and a geophone arranged in the outer shell, wherein a through hole penetrating the interior of the outer shell is provided on a side wall of the outer shell, and a plug is detachably provided on the through hole, and the geophone comprises a bracket, an inner shell, and a disc-shaped piezoelectric ceramic element arranged in the inner shell, wherein two inner shells are installed, and the two inner shells are symmetrically arranged on the bracket, and the disc-shaped piezoelectric ceramic elements in the two inner shells are arranged oppositely in the bracket, and a gap is provided between the two disc-shaped piezoelectric ceramic elements, and the inner shell is provided with a wire outlet hole and a wiring groove. The present invention is suitable for air gun geophones operating under high pressure, wherein the sensitive element thereof is a piezoelectric ceramic, and has the characteristics of reasonable structure and easy assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of oil well liquid level detection, and specifically relates to a high-pressure gas detector. Background Art

[0002] The oil well level meter is an important device for automatically monitoring the oil well liquid level. It is mainly composed of a main unit, a high-pressure air gun, a pressure reducing valve, a control cable, and a host computer display and control software. The high-pressure air gun mainly includes an air cavity and a detector. The air cavity is used to transmit pulse sound signals, and the detector is used to receive the sound wave signal reflected back from the oil well liquid surface. The collected signal is processed by the back-end algorithm and transmitted to the computer for real-time monitoring. Therefore, the structure of the detector in the high-pressure air gun has a significant impact on the accuracy of the level meter in monitoring the oil well liquid level. The pulse echo frequency is usually a low-frequency pulse sound signal of several hertz to tens of hertz. The detector is designed to withstand high-pressure pulse echoes and effectively receive low-frequency pulse signals.

[0003] In the existing technology, circular tube-type geophones or box-shaped geophones are used for well logging:

[0004] Circular tube geophones are a common structure for piezoelectric geophones. They primarily consist of a piezoelectric tube and a sheet-like transducer with fixed supports around its perimeter. The piezoelectric tube itself primarily withstands pressure. The low-frequency receiving sensitivity of a piezoelectric tube is directly proportional to its average radius and inversely proportional to its wall thickness. That is, the larger the radius and the thinner the tube wall, the higher the sensitivity. Therefore, it's difficult to achieve both size and receiving sensitivity in a piezoelectric circular tube geophone. To achieve a highly sensitive geophone, the tube must be larger, making installation difficult. To reduce the tube's size while maintaining sensitivity, the wall thickness must be reduced, which affects the tube's pressure resistance.

[0005] The main sensitive element of the box-shaped structure detector and the sheet-shaped detector is a piezoelectric ceramic disc. The piezoelectric ceramic disc is formed with a metal or non-metallic structure to form a fixed boundary condition on all sides, and the above structure is bonded to the metal box body. A damping tube or valve is set on the metal box body to achieve the effect of balancing the internal and external air pressure difference. The box-shaped structure detector needs to achieve internal and external pressure balance through an external structure, and the structure is more complex; devices such as damping tubes or valves are easily infiltrated with oil during operation and are not easy to clean. Long-term use may cause the detector to fail; in addition, the wall thickness of the metal box body is usually thin, and there may be a risk of deformation after long-term use, resulting in improper structural connection and varying degrees of blocking effect on sound waves, thereby reducing performance. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a high-pressure gas detector. By rationally designing the detector structure, the detector has the performance characteristics of high sensitivity, good pressure resistance and the structural advantage of easy cleaning.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a high-pressure gas detector, comprising an outer shell and a detector arranged in the outer shell, a through hole penetrating the interior of the outer shell being provided on the side wall of the outer shell, a plug being detachably provided on the through hole, the detector comprising a bracket, an inner shell and a disc-shaped piezoelectric ceramic element arranged in the inner shell, two inner shells being installed, and the two inner shells being symmetrically arranged on the bracket, and the disc-shaped piezoelectric ceramic elements in the two inner shells being located opposite to each other in the bracket, a gap being provided between the two disc-shaped piezoelectric ceramic elements, a wire outlet hole and a wiring groove being provided on the inner shell, the wire outlet hole being provided in the wiring groove, the electrode connecting wire of the disc-shaped piezoelectric ceramic element being led out through the wire outlet hole, and the electrode connecting wire being placed in the wiring groove, an acoustic wave through hole being provided on the bracket corresponding to the gap between the two disc-shaped piezoelectric ceramic elements, and the acoustic wave through hole being provided corresponding to the through hole on the outer shell.

[0008] Preferably, the bracket is a nylon bracket.

[0009] Preferably, the shell is a stainless steel shell made of austenitic stainless steel.

[0010] Preferably, the inner shell is an aluminum alloy inner shell.

[0011] Preferably, an insulating sleeve is provided on the wire outlet hole, and the electrode connecting wire of the disc-shaped piezoelectric ceramic element extends out after passing through the insulating sleeve and is placed outside the shell.

[0012] Preferably, a sealing ring is provided between the connection surface of the detector and the housing.

[0013] Compared with the prior art, the present invention has the following advantages: the air gun detector is suitable for working under high pressure, and its sensitive element is piezoelectric ceramic, which has the characteristics of reasonable structure and easy assembly;

[0014] The detector features a stainless steel housing with a regular shape, facilitating installation and connection with other parts of the high-pressure airgun. Openings are designed at the front and rear ends to facilitate airflow, and airflow channels are designed internally. Furthermore, the double-ended openings facilitate cleaning of the detector, preventing internal oil accumulation from affecting performance. The received sound waves have a low frequency, and the piezoelectric ceramic discs under clamped boundary conditions have an inherently low operating frequency, making them suitable for receiving low-frequency sound waves. To increase receiving sensitivity, two piezoelectric ceramic discs are electrically mounted in series within the housing and mechanically clamped by non-metallic parts. Furthermore, they are separated from the stainless steel housing by non-metallic parts, forming electrical insulation between the ceramic and the outer shell. Each ceramic disc has a through-hole above it, which primarily connects the interior and exterior of the detector housing and balances the internal and external pressures when the detector receives sound waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a structural schematic diagram of the present invention;

[0016] Figure 2 The detector structure of the present invention Figure 1 ;

[0017] Figure 3 The detector structure of the present invention Figure 2 ;

[0018] Figure 4 It is a cross-sectional structural diagram of the present invention;

[0019] Figure 5 An exploded diagram of the geophone of the present invention;

[0020] Figure 6 The cross-sectional structure of the detector of the present invention Figure 1 ;

[0021] Figure 7 The cross-sectional structure of the detector of the present invention Figure 2 .

[0022] In the figure: 1. Outer shell; 2. Through hole; 3. Plug; 4. Bracket; 5. Inner shell; 6. Disc-shaped piezoelectric ceramic element; 7. Wire outlet hole; 8. Wire routing groove; 9. Acoustic wave through hole; 10. Sealing ring; 11. Insulating sleeve. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] The following is an explanation of the relevant terms:

[0025] Pulse echo: When a sound wave pulse propagates in a certain medium, it will produce reflection and scattering when encountering an obstacle. The reflected and scattered sound waves will propagate back in the opposite direction of the original sound wave, which is called a pulse echo.

[0026] Simply supported boundary condition: A type of boundary condition where the deflection and curvature on the boundary are both 0.

[0027] Mechanical clamping: Fixing the periphery of the original part through special components is called clamping in mechanics.

[0028] Intrinsic operating frequency: also known as natural frequency, when a structure vibrates under external excitation, the specific frequency determined only by the nature of the system itself;

[0029] A high-pressure level meter for oil wells detects the liquid level within an oil well. It primarily consists of a main unit, a high-pressure air gun, a pressure reducing valve, a control cable, and host computer display and control software. The air gun primarily contains an air chamber and a detector. The air chamber stores gas, and the detector emits acoustic pulses under the action of external structures such as valves and pistons. The sound waves reflect off the oil-air interface in the oil well, where they are received by the detector. The detector converts the acoustic signal into an electrical signal, which is then transmitted to subsequent algorithms and software for processing and display.

[0030] Therefore, as a component that receives sound waves and provides electrical signals to the back-end system, the design of the detector should meet the following requirements: 1. Low resonant frequency (the frequency of the air gun echo signal is low); 2. High low-frequency sensitivity; 3. Good pressure resistance of the detector structure; 4. The detector structure is easy to clean oil stains.

[0031] See Figures 1 to 7 The present invention provides a technical solution: a high-pressure gas detector comprising a housing and a detector disposed within the housing. The housing is made of austenitic stainless steel, and a through hole extending through the interior of the housing is provided on the sidewall of the housing. The through hole is a central through hole in the housing. A removable plug is provided on the through hole, which may also be provided with a small sealing ring. When the detector is in operation, a plug is inserted into one end of the housing through hole, facilitating the sensitive element to receive sound waves. When the detector needs to be cleaned, the plug can be removed to facilitate water rinsing.

[0032] The detector includes a bracket, an inner shell and a disc-shaped piezoelectric ceramic element arranged in the inner shell. The disc-shaped piezoelectric ceramic element serves as a sensitive element of the detector. Two inner shells are installed, and the two inner shells are symmetrically arranged on the bracket. The disc-shaped piezoelectric ceramic elements in the two inner shells are located in the bracket and arranged opposite to each other. A gap is provided between the two disc-shaped piezoelectric ceramic elements. The inner shell is provided with a wire outlet hole and a wiring groove. The wire outlet hole is provided in the wiring groove. The electrode connecting wire of the disc-shaped piezoelectric ceramic element is led out through the wire outlet hole, and the electrode connecting wire is placed in the wiring groove. The bracket is provided with an acoustic wave through hole corresponding to the gap between the two disc-shaped piezoelectric ceramic elements. The acoustic wave through hole is provided corresponding to the through hole on the outer shell. The bracket is a nylon bracket, and the inner shell is an aluminum alloy inner shell.

[0033] The piezoelectric ceramic disc is bonded to the electrode sheet and then to the aluminum alloy inner shell. The disc is clamped on all sides. When receiving sound waves, the piezoelectric ceramic operates in a state of bending vibration, resulting in high low-frequency sensitivity. The upper and lower piezoelectric ceramic discs are separated by a nylon bracket, forming the detector's sensitive structure.

[0034] The piezoelectric disc achieves pressure resistance by balancing the internal and external pressures. The wire outlet holes and wiring grooves on the aluminum alloy inner shell are connected to the through-holes on the detector bracket. When sound waves are transmitted, the internal and external pressures of the detector can be quickly balanced through these holes and grooves, thereby realizing the pressure resistance of the detector.

[0035] An insulating sleeve is provided on the wire outlet hole, and the electrode connecting wire of the disc-shaped piezoelectric ceramic element extends out after passing through the insulating sleeve and is placed outside the shell.

[0036] In order to facilitate the connection of the piezoelectric ceramic electrode leads and ensure the firmness of the solder joints, a copper core is used as a lead adapter component, and an insulating sleeve is used to separate the copper core from the stainless steel shell of the detector. A nylon gasket is used to separate the copper core from the aluminum alloy inner shell to avoid short circuit between the copper core and metal parts. One side of the copper core is connected to the electrode wire connected from the piezoelectric ceramic, and the other side leads the electrode wire out through the wire outlet hole of the detector shell.

[0037] A sealing ring is provided between the connection surface of the detector and the shell.

[0038] The detector side cover seals the detector by installing a rubber sealing ring. The side cover is connected to the detector housing by screws, and the connection is relatively tight.

[0039] A geophone is a device used on a level meter for oil well logging to receive sound waves reflected from the oil well liquid surface. Piezoelectric elements are widely used in well logging geophones due to their strong pressure resistance, large dynamic range, and high sensitivity. Therefore, the present invention uses piezoelectric elements as geophone sensitive elements. The geophone housing serves to withstand pressure and protect the internal piezoelectric sensitive elements. Therefore, it must have pressure resistance and resistance to oil corrosion. Therefore, AISI304 stainless steel is used as the housing material. After the piezoelectric ceramic disc is bonded to the copper electrode sheet, it is bonded to the inside of the geophone inner shell. The geophone bracket serves to separate and support the two inner shells. The two geophone inner shells are bonded to the bracket to form the main part of the geophone sensitive structure.

[0040] The electrode lead of the piezoelectric ceramic disc is connected to one side of the copper core through the two outlet holes on the inner shell and the gasket. The other electrode lead is connected to the other side of the copper core and passes through the insulating pad and the two outlet holes on the detector shell to connect to the external circuit.

[0041] After installing the detector bracket, inner shell, and piezoelectric ceramic disc into the detector housing, seal the detector with a sealing ring, side cover, and screws, and tighten the internal components to complete the detector installation. When the detector is operating, block one side of the detector through-hole with a sealing ring and plug to facilitate receiving pulse echoes. When cleaning the detector, remove the plug and sealing ring to rinse the detector.

[0042] Through this technical solution, the present invention is a detector used in oil well logging technology to receive sound waves and convert sound signals into electrical signals. In order to increase the low-frequency receiving sensitivity of the detector, a bending vibration form is adopted and the detector is designed with a piezoelectric ceramic disc as a sensitive element. The sensitivity is further increased by connecting two groups of upper and lower piezoelectric discs in series. A dual piezoelectric disc series method is adopted to utilize the bending vibration of the piezoelectric discs to improve the low-frequency sensitivity of the detector.

[0043] In order to solve the problem that the detector is prone to oil pollution after long-term use, the through hole of the shell is designed to facilitate the flushing of the detector, extend the service life and ensure the test accuracy. The through hole is set in the detector shell to provide a channel for the propagation of sound waves and provide a flushing channel for cleaning the oil pollution of the detector.

[0044] Through the wiring holes, grooves and through-holes on the inner shell and the bracket, the internal and external pressures of the piezoelectric ceramic disc can be balanced to achieve pressure resistance performance. By connecting the through-holes on the inner shell and the bracket, the internal and external pressures of the piezoelectric disc can be quickly balanced, so that the pressure resistance performance of the detector is guaranteed.

[0045] The detector side cover can be connected to the air gun by screws, which is a simple and firm connection. The inner side of the side cover is fixed with the inner shell and bracket through a sealing ring, which increases the reliability of the structure.

[0046] Regarding the internal and external pressure balancing of the piezoelectric ceramic disc, the pressure sound waves reflected from the oil well liquid surface enter through the sound wave hole and act on the outer surface of the piezoelectric ceramic. At the same time, the structure quickly balances the internal and external pressures of the piezoelectric ceramic through the air pressure hole, wiring groove and outlet hole, so that the piezoelectric ceramic can withstand the pressure.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-pressure gas detector, characterized in that: The invention comprises an outer shell and a detector arranged in the outer shell, wherein a through hole penetrating the interior of the outer shell is provided on the side wall of the outer shell, and a plug is detachably provided at one end of the through hole, and the detector comprises a bracket, an inner shell and a disc-shaped piezoelectric ceramic element arranged in the inner shell, two inner shells are installed, and the two inner shells are symmetrically arranged on the bracket, and the disc-shaped piezoelectric ceramic elements in the two inner shells are arranged oppositely in the bracket, and a gap is provided between the two disc-shaped piezoelectric ceramic elements, and a wire outlet hole and a wiring groove are provided on the inner shell, the wire outlet hole is provided in the wiring groove, the electrode connection line of the disc-shaped piezoelectric ceramic element is led out through the wire outlet hole, and the electrode connection line is placed in the wiring groove, and the bracket An acoustic through hole is provided on the upper surface corresponding to the gap between the two disc-shaped piezoelectric ceramic elements. The acoustic through hole corresponds to the through hole on the outer shell. The wire outlet hole and the wiring groove on the inner shell are connected to the acoustic through hole on the bracket. The bracket is a nylon bracket, the outer shell is a stainless steel shell made of austenitic stainless steel, and the inner shell is an aluminum alloy inner shell. An insulating sleeve is provided on the wire outlet hole. The electrode connecting wire of the disc-shaped piezoelectric ceramic element extends out after passing through the insulating sleeve and is placed outside the outer shell. A sealing ring is provided between the connecting surface of the detector and the outer shell. After the piezoelectric ceramic disc is bonded to the electrode sheet, it is bonded to the aluminum alloy inner shell. The piezoelectric ceramic disc is in a boundary condition of being fixed on all sides.

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