Transverse wave seismic source excitation device based on high-pressure gas explosion and application method thereof

Abstract

The invention relates to a shear wave seismic source excitation device based on high-pressure gas explosion and an application method of the shear wave seismic source excitation device. The first cover plate and the second cover plate are arranged at the two ends of the accelerating tube and used for sealing the accelerating tube, and an igniter connecting hole and a gas injection hole are formed in the first cover plate; the detonation tube is arranged in an inner cavity of the accelerating tube, and one end of the detonation tube is fixedly connected with the first cover plate; the third cover plate is arranged at the other end of the detonation tube and used for sealing the detonation tube, the area of the third cover plate is smaller than the cross sectional area of the accelerating tube, and the detonation tube has the advantages of being strong in transverse wave signal, environmentally friendly, good in economical efficiency and good in field adaptability. The problems that a transverse wave source is easily limited by the driving capacity and the ground coupling efficiency and the field operation capacity is poor are solved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of seismic exploration, and in particular to a shear wave source excitation device based on high-pressure gas explosion and an application method thereof. Background Art

[0002] Shear wave exploration is an important means of geological exploration. Shear waves have the characteristics of low wave velocity and high resolution, and their propagation is only related to the rock skeleton. Therefore, shear wave exploration can not only obtain data with higher resolution than longitudinal waves, but also solve the problem of no imaging of gas cloud areas in longitudinal wave exploration.

[0003] In the related technology, a gas explosion shear wave source excitation device is disclosed, the excitation device includes a gas storage cavity, an ignition element and a reflection block are arranged in the gas storage cavity, the reflection block is obliquely placed at the bottom of the gas storage cavity, a gas release port is arranged on the outer wall of the cavity opposite to the oblique surface of the reflection block, the gas release port is provided with a sealed bursting diaphragm, the gas storage cavity is connected to a gas injection pipe, the gas injection pipe is provided with a stop valve, the ignition element is excited by the current output by the ignition line to perform ignition explosion, the high-temperature and high-pressure gas is reflected by the reflection block, the bursting diaphragm is instantly ruptured from the gas release port, the gas is released, thereby generating shear waves in the surrounding medium for propagation, the shear wave energy obtained by this method is relatively strong, and combined with longitudinal wave exploration, the Poisson's ratio of geological layer materials can be intuitively judged, and then oil, gas and mineral species can be directly explored, in addition, the device is small in size, which not only reduces the cost, but also is convenient to carry and easy to carry and explore in the field, the Poisson's ratio of materials can be intuitively judged, and then oil, gas and mineral species can be directly explored, in addition, the device is small in size, which not only reduces the cost, but also is easy to carry and easy to carry and explore in the field, the Poisson's ratio of materials can be intuitively judged, and then oil, gas and mineral species can be directly explored.

[0004] In the related technology, a shear wave source device and a seismic data acquisition method based on a gas explosion source cavity are also disclosed. A central axis is provided at the vertical center of a rectangular steel plate, and gas explosion source cavities are fixed on two vertical sides respectively. The two gas explosion source cavities are respectively located on both sides of the rectangular steel plate; one side of the gas explosion source cavity is cut into a thinner cavity surface, and the opposite surface of the thin cavity surface is fixed on the surface of the rectangular steel plate; an electronic ignition gun is installed in the center of the gas explosion source cavity, and the gas explosion source cavity is connected to an explosion-proof metal gas tank. At each source point, a shear shear wave source signal parallel to the source line direction and propagating downward and a shear shear wave source signal perpendicular to the source line direction and propagating downward are sequentially excited. The three-component detector on the ground sequentially records the two mutually orthogonal and parallel to the ground shear wave data excited by this shear wave source device, and the seismic converted longitudinal wave data perpendicular to the ground, truly realizing pure shear wave and converted longitudinal wave seismic exploration parallel to the ground.

[0005] The gas explosion source in the related technology releases energy through the gas explosion reaction, generates vibrations in the ground, and can obtain a good longitudinal wave signal, but the generated shear wave signal is very weak and cannot be used for geological detection. The first type of gas explosion shear wave source excitation device has a low shear wave generation efficiency due to the weak gas product constraint. The second type of gas explosion shear wave source excitation device relies on the source of shear waves generated by torsion. This device is not only complex in structure, but also has low shear wave conversion efficiency. Therefore, when these two types of gas explosion shear wave source excitation devices are used, the shear wave source is easily limited by the driving capacity and ground coupling efficiency, the generated shear wave energy is limited, the shear wave signal is weak, the effective range and depth of detection are limited, and during use, it is required that the source vehicle can pass, which also limits its field operation capability to a certain extent. Summary of the invention

[0006] In order to solve the above technical problems or at least partially solve the above technical problems, the embodiments of the present disclosure provide a shear wave source excitation device based on high-pressure gas explosion and an application method thereof.

[0007] In a first aspect, an embodiment of the present disclosure provides a shear wave source excitation device based on high-pressure gas explosion, the device comprising:

[0008] Accelerator tube;

[0009] A first cover plate and a second cover plate are provided at both ends of the accelerating tube for sealing the accelerating tube, wherein the first cover plate is provided with an igniter access hole and a gas injection hole;

[0010] A detonation tube disposed in the inner cavity of the accelerating tube, wherein one end of the detonation tube is fixedly connected to the first cover plate;

[0011] A third cover plate is arranged at the other end of the detonation tube and is used to seal the detonation tube, wherein the area of ​​the third cover plate is smaller than the cross-sectional area of ​​the accelerating tube.

[0012] In a possible implementation manner, an igniter access hole tube is provided on the igniter access hole for connecting to an external ignition device.

[0013] In a possible implementation, a double-ended gas injection pipe is provided on the gas injection hole for respectively communicating with the methane storage device and the oxygen storage device through a gas conduit.

[0014] In a possible implementation manner, the detonation tube is made of iron or stainless steel, and the wall thickness of the detonation tube is determined according to the pressure of the gas to be injected and the detonation pressure generated.

[0015] In a possible implementation manner, the accelerating tube is made of iron or stainless steel.

[0016] In a possible implementation manner, the first cover plate, the second cover plate and the third cover plate are made of steel.

[0017] In a possible implementation manner, the area of ​​the first cover plate is larger than the cross-sectional area of ​​the accelerating tube.

[0018] In a possible implementation, the device further includes a coupling plate connected to the second cover plate in parallel.

[0019] In a second aspect, an embodiment of the present disclosure provides an application method of the shear wave source excitation device based on high-pressure gas explosion, which is applied to a rock environment, and the method comprises:

[0020] Connect the external ignition device to the igniter of the shear wave source excitation device of the high-pressure gas explosion through the sealing bolt, and connect it to the hole tube, so that the external ignition device can perform ignition work, and then communicate with the methane storage device and the oxygen storage device through the double-headed gas injection pipe of the shear wave source excitation device of the high-pressure gas explosion;

[0021] The shear wave source excitation device for high-pressure gas explosion is buried in the ground, and a soil layer of a preset thickness is covered above the shear wave source excitation device for high-pressure gas explosion;

[0022] Opening the valves of the methane storage device and the oxygen storage device, and injecting a predetermined amount of gas in the methane storage device and the oxygen storage device into the shear wave source excitation device of the high-pressure gas explosion;

[0023] After the gas injection is completed, the ignition operation is carried out. After the gas in the shear wave source excitation device of the high-pressure gas explosion is ignited, an explosion reaction occurs. The shock wave generated by the explosion reaction will break open the first cover plate, and the high-temperature gas after the explosion reaction will be released from the direction of the first cover plate. At the same time, the third cover plate and the detonation tube are pushed to accelerate toward the second cover plate, and the second cover plate and the coupling plate are hit at high speed in the acceleration tube, forming a directional energy release, and generating high-intensity shear waves in the earth.

[0024] In a second aspect, an embodiment of the present disclosure provides an application method of the shear wave source excitation device based on high-pressure gas explosion, which is applied to a soil environment, and the method includes:

[0025] Connect the external ignition device to the igniter of the shear wave source excitation device of the high-pressure gas explosion through the sealing bolt, and connect it to the hole tube, so that the external ignition device can perform ignition work, and then communicate with the methane storage device and the oxygen storage device through the double-headed gas injection pipe of the shear wave source excitation device of the high-pressure gas explosion;

[0026] The shear wave source excitation device for high-pressure gas explosion is buried in the ground, and a soil layer of a preset thickness is covered above the shear wave source excitation device for high-pressure gas explosion;

[0027] Opening the valves of the methane storage device and the oxygen storage device, and injecting a predetermined amount of gas in the methane storage device and the oxygen storage device into the shear wave source excitation device of the high-pressure gas explosion;

[0028] After the gas injection is completed, the ignition operation is carried out. After the gas in the shear wave source excitation device of the high-pressure gas explosion is ignited, an explosion reaction occurs. The shock wave generated by the explosion reaction will break open the first cover plate, and the high-temperature gas after the explosion reaction will be released from the direction of the first cover plate. At the same time, the third cover plate and the detonation tube are pushed to accelerate toward the second cover plate, and the second cover plate and the coupling plate are hit at high speed in the acceleration tube, forming a directional energy release, and generating high-intensity shear waves in the earth.

[0029] The above technical solution provided by the embodiment of the present disclosure has at least some or all of the following advantages compared with the prior art:

[0030] The shear wave source excitation device based on high-pressure gas explosion described in the embodiment of the present disclosure includes an accelerating tube; a first cover plate and a second cover plate arranged at both ends of the accelerating tube for sealing the accelerating tube, wherein the first cover plate is provided with an igniter access hole and a gas injection hole; a detonation tube arranged in the inner cavity of the accelerating tube, wherein one end of the detonation tube is fixedly connected to the first cover plate; and a third cover plate arranged at the other end of the detonation tube for sealing the detonation tube, wherein the area of ​​the third cover plate is smaller than the cross-sectional area of ​​the accelerating tube. The device has the advantages of strong shear wave signal, environmental protection, good economy and good field adaptability, and solves the problem that the shear wave source is easily limited by driving capacity and ground coupling efficiency and has poor field operation ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 The schematic diagram of the structure of the shear wave source body in the shear wave source device based on high-pressure gas explosion according to the embodiment of the present disclosure is shown;

[0034] Figure 2 The schematic diagram of the structure of the shear wave source device based on high-pressure gas explosion according to the embodiment of the present disclosure is shown;

[0035] Figure 3 The schematic diagram of the application structure of the shear wave source device based on high-pressure gas explosion according to the embodiment of the present disclosure is schematically shown;

[0036] Figure 4 The following schematically shows a flow chart of an application method of a shear wave source excitation device based on high-pressure gas explosion according to an embodiment of the present disclosure.

[0037] In the attached drawings, 1-earth; 2-coupling plate; 3-transverse wave source body; 4-accelerating tube; 5-third cover plate; 6-detonation tube; 7-first cover plate; 8-double-headed gas injection tube; 9-igniter access hole tube; 10-third cover plate. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0039] See also Figure 1 The embodiment of the present disclosure provides a shear wave source excitation device based on high-pressure gas explosion, the device comprising:

[0040] An accelerating tube 4; a first cover plate 7 and a second cover plate 10 provided at both ends of the accelerating tube for sealing the accelerating tube, wherein the first cover plate is provided with an igniter access hole and an air injection hole, and the accelerating tube can be fixedly installed between the first cover plate and the second cover plate by bolts;

[0041] A detonation tube 6 is arranged in the inner cavity of the accelerating tube, wherein one end of the detonation tube is fixedly connected to the first cover plate;

[0042] A third cover plate 10 is arranged at the other end of the detonation tube for sealing the detonation tube, wherein the area of ​​the third cover plate is smaller than the cross-sectional area of ​​the accelerating tube, so that the third cover plate is movably connected with the inner cavity of the accelerating tube in the inner cavity of the accelerating tube, and the detonation tube can be fixedly installed between the third cover plate and the first cover plate by bolts.

[0043] The shear wave seismic source device based on high-pressure gas explosion disclosed in the present invention can increase the kinetic energy generated by the detonation tube by providing an acceleration tube, thereby increasing the impact force generated by the device.

[0044] The shear wave source device based on high-pressure gas explosion disclosed in the present invention can seal the inside of the acceleration tube by providing a first cover plate, and at the same time, it is convenient for the double-head gas injection pipe and the igniter to be connected to the hole tube for installation.

[0045] The shear wave source device based on high-pressure gas explosion disclosed in the present invention can drive the detonation tube to move by providing a third cover plate, so as to transfer kinetic energy to the coupling plate.

[0046] See also Figure 1 An igniter access hole tube 9 is provided on the igniter access hole for connecting with an external ignition device, and the external ignition device can be an electric spark generator.

[0047] See also Figure 1 A double-headed gas injection pipe 8 is provided on the gas injection hole, which is used to communicate with the methane storage device and the oxygen storage device through the gas conduit respectively. Both the methane storage device and the oxygen storage device can use gas tanks with gas pressure gauges.

[0048] The shear wave source device based on high-pressure gas explosion disclosed in the present invention is conveniently connected to gas storage equipment for methane and oxygen by setting up a double-head gas injection pipe so as to inject the two gases into the device, thereby ensuring that the device can work normally.

[0049] In this embodiment, the material of the detonation tube is iron or stainless steel, and the wall thickness of the detonation tube is determined according to the pressure of the gas to be injected and the detonation pressure generated, so as to ensure the integrity of the acceleration tube cavity during the gas detonation process.

[0050] In this embodiment, the accelerating tube may be made of iron or stainless steel.

[0051] In this embodiment, the first cover plate, the second cover plate and the third cover plate may be made of steel.

[0052] In this embodiment, the area of ​​the first cover plate is larger than the cross-sectional area of ​​the accelerating tube. Preferably, the area of ​​the first cover plate is slightly larger than the cross-sectional area of ​​the accelerating tube.

[0053] See also Figure 2 The device further comprises a coupling plate, which is connected in parallel with the second cover plate. It should be noted that the coupling plate and the second cover plate can be fixedly connected together, or they can be independent of each other and are only placed together when collecting seismic data. The coupling plate can be a steel plate. When the shear wave source excitation device based on high-pressure gas explosion is applied to the seismic data collection link of oil and gas earth exploration, the connection between the coupling plate and the earth and the second cover plate is tightly connected.

[0054] When the above-mentioned shear wave seismic source excitation device based on high-pressure gas explosion is applied to the seismic data acquisition link of oil and gas earth exploration, it is judged whether to use the coupling plate in the shear wave seismic source excitation device based on high-pressure gas explosion according to the working environment of the shear wave seismic source excitation device based on high-pressure gas explosion, wherein, when the working environment is a rock environment, there is no need to use the coupling plate in the shear wave seismic source excitation device; when the working environment is a soil environment, it is necessary to use the coupling plate in the shear wave seismic source excitation device.

[0055] In the case where the working environment is a soil environment, the shear wave source excitation device includes a coupling plate, such as Figure 2 and Figure 3 As shown, when the working environment is a soil environment, the application method of the shear wave source excitation device includes:

[0056] Fill the two ends of the coupling plate with soil, then connect the external ignition device to the igniter through the closing bolts, so that the external ignition device can perform normal ignition work, and the user connects it with the methane and oxygen storage tanks through the double-headed gas injection pipe;

[0057] After the preparation is completed, the shear wave source body 3 of the shear wave source excitation device except the coupling plate is buried in the earth 1, and at the same time, the left side of the shear wave source body can be in close contact with the right side of the coupling plate, so that the arrangement angle between the coupling plate and the shear wave source body can be similar to the working angle of the shear wave source vehicle, and then a certain thickness of soil layer is covered above the shear wave source body to ensure that the coupling plate passes through the top of the earth. Preferably, when the shear wave source body is buried in the earth, the position where the igniter on the shear wave source body is connected to the hole tube is above the double-headed gas injection pipe;

[0058] After installation, open the valves on the methane and oxygen storage tanks, and then inject a certain amount of gas in the two storage tanks into the shear wave source body according to the pressure displayed on the gas pressure gauge, so that the two gases can be mixed in the shear wave source body to form high-pressure combustible gas;

[0059] After the gas injection is completed, the ignition equipment is remotely controlled to perform the ignition operation at a safe distance. After the gas in the shear wave source body is ignited, the gas will undergo an explosion reaction. The shock wave generated by the explosion will break open the first cover plate, and the high-temperature gas after the reaction will be released from the right end, while pushing the third cover plate and the detonation tube to accelerate to the left, gaining a high speed in the acceleration tube and finally hitting the coupling plate, forming a directional energy release, generating high-intensity shear waves in the earth, thereby conducting geological exploration.

[0060] See also Figure 4 , when the working environment is a rock environment, the application method of the shear wave source excitation device comprises:

[0061] S1, connect the external ignition device to the igniter of the shear wave source excitation device of the high-pressure gas explosion through the sealing bolt, connect it to the hole tube, so that the external ignition device can perform ignition work, and then connect it with the methane storage device and the oxygen storage device through the double-headed gas injection pipe of the shear wave source excitation device of the high-pressure gas explosion;

[0062] S2, burying the shear wave source excitation device for high-pressure gas explosion into the ground, and covering the shear wave source excitation device for high-pressure gas explosion with a soil layer of a preset thickness;

[0063] S3, opening the valves of the methane storage device and the oxygen storage device, and injecting a predetermined amount of gas in the methane storage device and the oxygen storage device into the shear wave source excitation device of the high-pressure gas explosion;

[0064] S4, after the gas injection is completed, the ignition operation is carried out. After the gas in the shear wave source excitation device of the high-pressure gas explosion is ignited, an explosion reaction occurs. The shock wave generated by the explosion reaction breaks open the first cover plate, and the high-temperature gas after the explosion reaction is released from the direction of the first cover plate. At the same time, the third cover plate and the detonation tube are pushed to accelerate toward the second cover plate, and the second cover plate and the coupling plate are hit at high speed in the acceleration tube, forming a directional energy release, and generating high-intensity shear waves in the earth.

[0065] The shear wave source device based on high-pressure gas explosion disclosed in the present invention, through the cooperation of the earth, coupling plate, acceleration tube, first cover plate, detonation tube, second cover plate, double-head gas injection tube and igniter access hole tube, makes it possible for the shear wave source device to generate a strong shear wave source excitation signal when working, and also has certain environmental protection and good economy when in use, and at the same time has good adaptability when used in the field, thereby solving the problems of insufficient signal strength of shear wave seismic equipment, insufficient detection depth and poor field operation capability caused by the shear wave source being easily limited by driving capacity and ground coupling efficiency.

[0066] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0067] The foregoing is merely a specific embodiment of the present disclosure, which enables those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A shear wave source excitation device based on high-pressure gas explosion, characterized in that: The device comprises: Accelerator tube; A first cover plate and a second cover plate are provided at both ends of the accelerating tube for sealing the accelerating tube, wherein the first cover plate is provided with an igniter access hole and a gas injection hole; A detonation tube disposed in the inner cavity of the accelerating tube, wherein one end of the detonation tube is fixedly connected to the first cover plate; A third cover plate is arranged at the other end of the detonation tube and is used to seal the detonation tube, wherein the area of ​​the third cover plate is smaller than the cross-sectional area of ​​the accelerating tube.

2. The shear wave source excitation device based on high-pressure gas explosion according to claim 1 is characterized in that: An igniter access hole tube is arranged on the igniter access hole for connecting with an external ignition device.

3. The shear wave source excitation device based on high-pressure gas explosion according to claim 1 is characterized in that: A double-ended gas injection pipe is provided on the gas injection hole, which is used to communicate with the methane storage device and the oxygen storage device respectively through the gas conduit.

4. The shear wave source excitation device based on high-pressure gas explosion according to claim 1 is characterized in that: The material of the detonation tube is iron or stainless steel, and the wall thickness of the detonation tube is determined according to the pressure of the gas to be injected and the detonation pressure generated.

5. The shear wave source excitation device based on high-pressure gas explosion according to claim 1 is characterized in that: The accelerating tube is made of iron or stainless steel.

6. The shear wave source excitation device based on high pressure gas explosion according to claim 1 is characterized in that: The first cover plate, the second cover plate and the third cover plate are made of steel.

7. The shear wave source excitation device based on high pressure gas explosion according to claim 1 is characterized in that: The area of ​​the first cover plate is larger than the cross-sectional area of ​​the accelerating tube.

8. The shear wave source excitation device based on high pressure gas explosion according to claim 1, characterized in that: The device further comprises a coupling plate connected to the second cover plate in parallel.

9. An application method of a shear wave source excitation device based on high pressure gas explosion according to any one of claims 1 to 7, characterized in that: Applied to a rock environment, the method comprises: Connect the external ignition device to the igniter of the shear wave source excitation device of the high-pressure gas explosion through the sealing bolt, and connect it to the hole tube, so that the external ignition device can perform ignition work, and then communicate with the methane storage device and the oxygen storage device through the double-headed gas injection pipe of the shear wave source excitation device of the high-pressure gas explosion; The shear wave source excitation device for high-pressure gas explosion is buried in the ground, and a soil layer of a preset thickness is covered above the shear wave source excitation device for high-pressure gas explosion; Opening the valves of the methane storage device and the oxygen storage device, and injecting a predetermined amount of gas in the methane storage device and the oxygen storage device into the shear wave source excitation device of the high-pressure gas explosion; After the gas injection is completed, the ignition operation is carried out. After the gas in the shear wave source excitation device of the high-pressure gas explosion is ignited, an explosion reaction occurs. The shock wave generated by the explosion reaction will break open the first cover plate, and the high-temperature gas after the explosion reaction will be released from the direction of the first cover plate. At the same time, the third cover plate and the detonation tube are pushed to accelerate toward the second cover plate, and the second cover plate and the coupling plate are hit at high speed in the acceleration tube, forming a directional energy release, and generating high-intensity shear waves in the earth.

10. An application method of the shear wave source excitation device based on high pressure gas explosion according to any one of claims 1 to 8, characterized in that: Applied to a soil environment, the method comprises: Connect the external ignition device to the igniter of the shear wave source excitation device of the high-pressure gas explosion through the sealing bolt, and connect it to the hole tube, so that the external ignition device can perform ignition work, and then communicate with the methane storage device and the oxygen storage device through the double-headed gas injection pipe of the shear wave source excitation device of the high-pressure gas explosion; The shear wave source excitation device for high-pressure gas explosion is buried in the ground, and a soil layer of a preset thickness is covered above the shear wave source excitation device for high-pressure gas explosion; Opening the valves of the methane storage device and the oxygen storage device, and injecting a predetermined amount of gas in the methane storage device and the oxygen storage device into the shear wave source excitation device of the high-pressure gas explosion; After the gas injection is completed, the ignition operation is carried out. After the gas in the shear wave source excitation device of the high-pressure gas explosion is ignited, an explosion reaction occurs. The shock wave generated by the explosion reaction will break open the first cover plate, and the high-temperature gas after the explosion reaction will be released from the direction of the first cover plate. At the same time, the third cover plate and the detonation tube are pushed to accelerate toward the second cover plate, and the second cover plate and the coupling plate are hit at high speed in the acceleration tube, forming a directional energy release, and generating high-intensity shear waves in the earth.

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