Seismic source device and method for realizing artificial seismic waves

Abstract

The present invention proposes a seismic source device and a method for realizing artificial seismic waves. The seismic source device of the present invention includes a launch tube, which extends from bottom to top; a bomb, which is movably arranged in the launch tube so that the bomb has a launch position and an impact position, and the bomb is detachably connected to the launch tube so that bombs of different shapes and / or materials can be replaced in the launch tube, and the launch position is located above the impact position; and a launch device, which can drive the bomb from the launch position to the impact position so that the bomb impacts downward and forms an artificial seismic wave. Therefore, the seismic source device according to the present invention has the advantage of being able to control the waveform and frequency band of the artificial seismic wave so as to increase the amount of information carried by the artificial seismic wave.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial seismic waves, and in particular to a seismic source device and a method for realizing artificial seismic waves. Background Art

[0002] Coalfield seismic exploration refers to the process of converting various geological structural information within the coalfield into images using seismic exploration equipment and imaging algorithms. Currently, seismic source equipment used for coalfield seismic exploration primarily includes pulsed sources such as explosive and spark sources, and controllable sources such as source vehicles and drop-weight sources. These can generate waveforms from various subsurface structures at the surface and receive reflected waveforms for inversion imaging. They can also generate waveforms in wells and working faces, receiving reflected and transmitted waves for imaging.

[0003] A common limitation of seismic sources in related technologies is the difficulty in manually controlling the frequency band and waveform of the artificial seismic wavelets they generate. The frequency band and waveform of the artificial seismic wavelets generated by a specific seismic source are also essentially fixed, resulting in a low amount of information carried by the seismic signal from that source and low imaging precision. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, embodiments of the present invention provide a seismic source device and a method for realizing artificial seismic waves.

[0005] The source device of the embodiment of the present invention comprises

[0006] a launch tube extending from bottom to top;

[0007] an impact bullet, the impact bullet being movably disposed in the launch tube so that the impact bullet has a launch position and an impact position, the impact bullet being detachably connected to the launch tube so as to allow replacement of impact bullets of different shapes and / or materials in the launch tube, the launch position being located above the impact position;

[0008] A launching device, wherein the launching device can drive the impact bomb to move from the launching position to the impact position, so that the impact bomb impacts downward and forms an artificial seismic wave.

[0009] In some embodiments, the length direction of the impact bullet is the up-down direction;

[0010] The outer diameter of the impact bomb is consistent from bottom to top;

[0011] Alternatively, the entire body or the lower portion of the impact bullet is a first diameter-reducing portion whose outer diameter increases from bottom to top;

[0012] Alternatively, the lower portion of the impact bullet is a second diameter-changing portion whose outer diameter increases from bottom to top, and the upper portion of the impact bullet is a third diameter-changing portion whose outer diameter decreases from bottom to top.

[0013] In some embodiments, the entire or lower portion of the impact bullet is the first diameter-reducing portion whose outer diameter increases from bottom to top, and the ratio of the length of the first diameter-reducing portion to the length of the impact bullet is (0.9-1):1;

[0014] Alternatively, the lower part of the impact bullet is the second variable diameter part whose outer diameter increases from bottom to top, and the upper part of the impact bullet is the third variable diameter part whose outer diameter decreases from bottom to top, and the ratio of the sum of the length of the second variable diameter part and the length of the third variable diameter part to the length of the impact bullet is (0.9-1):1.

[0015] In some embodiments, the outer contour of the cross section of the impact bullet is circular;

[0016] The launching device is an air pump;

[0017] The top of the launch tube is closed, at least part of the circumference of the impact bullet is slidably connected to the inner wall of the launch tube, the top surface of the impact bullet and the inner wall of the launch tube define a launch chamber, and the air pump is connected to the launch chamber.

[0018] In some embodiments, a motor and a cable are provided in the firing chamber, the motor is located at the top of the firing chamber, one end of the cable is connected to the output shaft of the motor, and the other end of the cable is connected to the impact bullet;

[0019] The inner side wall of the launch tube has a groove, and a spring piece is arranged in the launch tube. The spring piece can be elastically deformed, and the spring piece is arranged at the top of the groove and at least part of the spring piece extends out of the groove. In the launch position, the spring piece is used to support the impact bomb;

[0020] The seismic source device also includes a fixing frame and an impact plate. The fixing frame is mounted on the outer peripheral side of the launch tube. A counterweight is provided on the fixing frame. The impact plate is connected to the bottom of the fixing frame. The thickness direction of the impact plate is the up and down direction. The lower opening of the launch tube faces the top of the impact plate.

[0021] The present invention also proposes a method for realizing artificial seismic waves using the source device of an embodiment of the present invention, comprising the following steps:

[0022] S1. Installing a bomb having a preset shape and a preset material into a launch tube;

[0023] S2. Use a launching device to drive the impact bomb to move from the generating position to the impact position, so that the impact bomb impacts downward and forms an artificial seismic wave with a preset waveform and a preset frequency band.

[0024] In some embodiments, in step S1, the impact bombs of different preset shapes are replaced and installed in the launch tube, so that the waveform of the artificial seismic wave generated by the impact bombs is one of a square wave, a triangle wave, and a quasi-sine wave;

[0025] And / or, the impact bomb having at least one of a different preset material, a different preset density and a different preset length is replaced and installed in the launch tube, so that the artificial seismic wave formed by the impact bomb has a different preset frequency band.

[0026] In some embodiments, the length direction of the impact bullet is the up-down direction;

[0027] In the step S1,

[0028] Replacing the impact bombs with the same outer diameter from bottom to top so that the waveform of the artificial seismic wave is a square wave;

[0029] Alternatively, the impact bomb is replaced as a whole or at its lower portion with a first diameter-reducing portion whose outer diameter increases from bottom to top, so that the waveform of the artificial seismic wave is a triangular wave;

[0030] Alternatively, the impact bomb is replaced with a second variable diameter portion having an increasing outer diameter from bottom to top and a third variable diameter portion having a decreasing outer diameter from bottom to top, so that the waveform of the artificial seismic wave is a quasi-sine wave.

[0031] In some embodiments, in step S1,

[0032] Replacing the impact bomb with a different material and increasing the wave velocity of the material so as to increase the center frequency of the frequency band of the artificial seismic wave;

[0033] and / or, replacing the impact bomb with a density increased so as to reduce the center frequency of the frequency band of the artificial seismic wave;

[0034] and / or, replacing the impact bomb with one having a longer length so as to reduce the center frequency of the frequency band of the artificial seismic wave;

[0035] The method for realizing artificial seismic waves further includes step S3: increasing the amplitude of the waveform of the artificial seismic wave by increasing at least one of the emission energy of the emission device and the impact stroke of the impact bomb.

[0036] In some embodiments, the distribution function of the radius of the impact bullet is

[0037] R(x)(i+1)=R(x)(i)+Gradient(x)(i)*k(i);

[0038] in, u1=u-u0, u0 is the waveform and frequency band of the required artificial seismic wave, u is the forward wave field obtained by the dynamic simulation of the impact process based on u0, u1 is the reverse wavelet obtained by u-u0, u2 is the accompanying wave field obtained by the dynamic simulation of the impact process based on u1, Gradient(x) is the cross-correlation formula between the forward wave field u and the accompanying wave field u2, and the optimization gradient of the impact bomb shape can be inferred, i is the number of optimizations based on Gradient(x), k is the i-th optimization constant, R(x)(i) is the distribution function of the radius of the impact bomb after the i-th optimization, and R(x)(i+1) is the distribution function of the radius of the impact bomb after the i+1-th optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of a seismic source device according to an embodiment of the present invention.

[0040] Reference numerals:

[0041] A source device 100;

[0042] Launch tube 1, launch cavity 11, groove 12;

[0043] Impact bullet 2, second diameter-reducing portion 21, third diameter-reducing portion 22, connecting portion 23;

[0044] Air pump tube 3;

[0045] Cable 4;

[0046] Shrapnel 5;

[0047] Fixed frame 6, counterweight 61;

[0048] Impact plate. DETAILED DESCRIPTION

[0049] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0050] The following describes the source device 100 according to an embodiment of the present invention with reference to the accompanying drawings. Figure 1 As shown, the seismic source device 100 according to an embodiment of the present invention includes a launch tube 1, an impact bomb 2 and a launch device.

[0051] Launch tube 1 extends from bottom to top. A projectile 2 is movably positioned within launch tube 1, defining a launch position and an impact position. Projectile 2 is detachably connected to launch tube 1 to facilitate replacement of projectiles 2 of different shapes within launch tube 1. The launch position is located above the impact position. A launching device drives projectile 2 from the launch position to the impact position, allowing projectile 2 to impact downward and generate artificial seismic waves.

[0052] The launch device of the seismic source device 100 according to an embodiment of the present invention can move the impact projectile 2 from a launch position to an impact position. This causes the impact projectile 2 to impact the ground downward, generating artificial seismic waves. The impact projectile 2 is detachably connected to the launch tube 1, allowing for replacement of impact projectiles 2 of different shapes and / or materials within the launch tube 1. Impact projectiles 2 of preset shapes and materials can generate artificial seismic waves with preset waveforms and frequency bands, thereby increasing the information carrying capacity of the artificial seismic waves. By replacing impact projectiles 2 with different shapes, the generated artificial seismic waves can have different waveforms and frequency bands, while by replacing impact projectiles 2 with different materials, the generated artificial seismic waves can have different frequency bands. In other words, by replacing impact projectiles 2 with preset shapes and / or materials, the frequency band and waveform of the artificial seismic waves can be controlled to generate artificial seismic waves with different waveforms and / or frequency bands, further increasing the information carrying capacity of the artificial seismic waves and, in turn, improving imaging accuracy and interpretability. This promotes the development of seismic imaging in applications such as underground mining design, underground disaster warning and prevention, and underground overburden structure quality monitoring.

[0053] Therefore, the seismic source device 100 according to the embodiment of the present invention has the advantage of being able to control the waveform and frequency band of the artificial seismic wave so as to increase the amount of information carried by the artificial seismic wave.

[0054] The present invention further proposes a method for realizing artificial seismic waves using the source device 100 according to an embodiment of the present invention. The method for realizing artificial seismic waves according to an embodiment of the present invention comprises the following steps:

[0055] S1. Installing a bomb 2 having a preset shape and made of a preset material into a launch tube 1.

[0056] S2. Use the launching device to drive the impact bomb 2 to move from the generating position to the impact position, so that the impact bomb 2 impacts downward and forms an artificial seismic wave with a preset waveform and a preset frequency band.

[0057] The method for achieving artificial seismic waves according to an embodiment of the present invention involves installing a projectile 2 having a preset shape and material within a launch tube 1, causing the projectile 2 to impact downward and generate artificial seismic waves with a preset waveform and frequency band. This allows the artificial seismic waves to carry a high amount of information, thereby improving imaging accuracy and interpretability, and promoting the development of seismic imaging in applications such as underground mining design, underground disaster warning and prevention, and underground overburden structure quality monitoring.

[0058] Therefore, the method for realizing artificial seismic waves according to an embodiment of the present invention has the advantage of being able to control the waveform and frequency band of the artificial seismic waves so as to increase the amount of information carried by the artificial seismic waves.

[0059] The method for realizing artificial seismic waves according to an embodiment of the present invention will be described in detail below with reference to the seismic source device 100 according to an embodiment of the present invention.

[0060] like Figure 1 As shown, the seismic source device 100 according to an embodiment of the present invention includes a launch tube 1, an impact bomb 2, a launch device, a fixing frame 6 and an impact plate 7.

[0061] The launch tube 1 extends from bottom to top. Specifically, the launch tube 1 is a hollow circular tube made of high-strength steel, and the extension direction of the launch tube 1 is perpendicular to the horizontal plane. The impact bomb 2 is movably arranged in the launch tube 1 so that the impact bomb 2 has a launch position and an impact position. The impact bomb 2 is detachably connected to the launch tube 1 so that impact bombs 2 of different shapes and / or materials can be replaced in the launch tube 1. The launching device can drive the impact bomb 2 to move from the launch position to the impact position. Impact bombs 2 of different shapes and / or materials include: a. Impact bombs 2 of different shapes; b. Impact bombs 2 of different materials; c. Impact bombs 2 of different shapes and materials. For example, the impact bomb 2 moves vertically downward, and the bottom surface of the impact bomb 2 impacts downward (the ground) and forms an artificial seismic wave. The up and down directions are as follows: Figure 1 As shown by the arrow in .

[0062] A fixed frame 6 is mounted on the outer periphery of the launch tube 1 and is equipped with a counterweight 61. Specifically, the fixed frame 6 is a steel frame comprising an upper annular frame and a lower support frame. The launch tube 1 is positioned between the annular frame and the support frame, allowing the fixed frame 6 to support the launch tube 1, with its lower opening facing the ground. The counterweight 61 is a counterweight ring. Multiple counterweight rings are mounted on the annular frame and press the support frame toward the ground, maintaining the stability of the fixed frame 6.

[0063] The impact plate 7 is connected to the bottom of the fixing frame 6. The thickness direction of the impact plate 7 is the vertical direction, and the lower opening of the launch tube 1 is toward the top of the impact plate 7. As a result, the impact bomb 2 can impact the impact plate 7 downward to generate artificial seismic waves, and the artificial seismic waves can be transmitted to the geology below the impact plate 7 through the impact plate 7. Compared to the impact bomb 2 directly impacting the ground to generate artificial shock waves, the impact bomb 2 impacting the impact plate 7 to generate artificial seismic waves can prevent the ground from breaking under the direct impact of the impact bomb 2, and artificial shock waves can be generated multiple times. For example, by passing through the support frame and inserting the fixing nut of the impact plate 7, the fixing frame 6 and the impact plate 7 are firmly connected.

[0064] In some embodiments, the launch device is an air pump. The top of the launch tube 1 is sealed, and at least a portion of the circumference of the impact projectile 2 is slidably connected to the inner wall of the launch tube 1. The top surface of the impact projectile 2 and the inner wall of the launch tube 1 define a launch chamber 11, and the air pump is in communication with the launch chamber 11. Specifically, the top of the launch tube 1 is provided with a cover connected to the annular frame. At least a portion of the circumference of the impact projectile 2 is slidably connected to the inner wall of the launch tube 1, forming a sliding seal, thereby preventing gas in the launch chamber 11 from leaking between the impact projectile 2 and the inner wall of the launch tube 1. The outlet of the air pump pipe 3 of the air pump passes through the cover and extends into the launch chamber 11. Thus, when the air pump introduces gas into the generating chamber 11 through the air pump pipe 3, it can propel the impact projectile 2 downward and generate artificial seismic waves. For example, the air pump is a fully automatic high-pressure air pump that can provide high-pressure gas to accelerate the impact projectile 2, generating the initial bullet kinetic energy required for excitation.

[0065] In some embodiments, the inner sidewall of the launch tube 1 has a groove 12. A spring clip 5 is disposed within the launch tube 1. The spring clip 5 is elastically deformable and positioned at the top of the groove 12, with at least a portion of the spring clip 5 extending beyond the groove 12. In the launch position, the spring clip 5 supports the projectile 2. Specifically, in the launch position, the spring clip 5 supports the projectile 2, preventing it from falling due to gravity. When the launch device drives the projectile 2 downward, the projectile 2 can press the spring clip 5 into the groove 12 to prevent the spring clip 5 from blocking the projectile 2's downward impact.

[0066] Optionally, a rotating device is provided in the groove to drive the spring piece 5 to rotate into or out of the groove 5. Specifically, in the firing position, the rotating device can drive the spring piece 5 to rotate out of the groove 5 so that the spring piece 5 can support the impact bullet 2. During firing, the rotating device can drive the spring piece 5 to rotate into the groove 5 to prevent the spring piece 5 from blocking the impact bullet 2 from impacting downward.

[0067] In some embodiments, a motor and a cable 4 are provided within the launch chamber. The motor is located at the top of the launch chamber. One end of the cable 4 is connected to the motor's output shaft, and the other end of the cable 4 is connected to the impact projectile 2. Specifically, a reel is provided on the motor's output shaft. One end of the cable 4 is connected to the reel and can be wound around the reel. The other end of the cable 4 is connected to the top of the impact projectile 2. After the impact projectile 2 completes its impact, the motor rotates forward and pulls the impact projectile 2 upward to the launch position via the cable 4. After the impact projectile 2 reaches the launch position and is supported by the shrapnel 5, the motor reverses to allow at least a portion of the cable 4 to disengage from the reel, allowing a portion of the cable 4 to fall onto the top of the impact projectile 2. This prevents the cable 4 from obstructing the impact projectile 2 as it falls.

[0068] The method for realizing artificial seismic waves according to an embodiment of the present invention comprises the following steps:

[0069] In step S1, the impact bullet 2 with a preset shape and a preset material is installed in the launch tube 1. Specifically, the impact bullet 2 with a preset shape and a preset material is installed in the launch tube 1 and connected to the cable 4.

[0070] In step S2, the launch device drives the impact projectile 2 from the generating position to the impact position, so that the impact projectile 2 impacts downward and forms an artificial seismic wave with a preset waveform and a preset frequency band. Specifically, the air pump fires to provide high-pressure gas to accelerate the impact projectile 2, generating the initial kinetic energy required for the projectile to meet the excitation requirements, causing the impact projectile 2 to strike the impact plate 7 downward and form the artificial seismic wave.

[0071] In some embodiments, in step S1 , a bomb 2 with a different preset shape is replaced and installed in the launch tube 1 so that the waveform of the artificial seismic wave formed by the bomb 2 is one of a square wave, a triangle wave and a quasi-sinusoidal wave.

[0072] The length of the impact projectile 2 is in the vertical direction. The impact projectile 2 can have various shapes, and the shape of the impact projectile 2 can affect the waveform of the generated artificial seismic wave. Specifically, the outer contour of the cross section of the impact projectile 2 is circular. For example, the impact projectile 2 can be conical or at least partially conical.

[0073] In some embodiments, the outer diameter of the impact bomb 2 is uniform from bottom to top. The uniform outer diameter of the impact bomb 2 can make the waveform of the artificial seismic wave a square wave. A square wave refers to the waveform of the artificial seismic wave having a substantially rectangular outline. In step S1, the impact bomb 2 is replaced with an outer diameter that is uniform from bottom to top, so that the waveform of the artificial seismic wave is a square wave. For example, the impact bomb 2 is cylindrical, and the outer circumference of the impact bomb 2 is uniform from bottom to top in a cross section perpendicular to the horizontal direction.

[0074] In some embodiments, the entirety or lower portion of the impact bomb 2 is a first reducing portion whose outer diameter increases from bottom to top. The entirety or lower portion of the impact bomb 2 is a first reducing portion whose outer diameter increases from bottom to top, which can make the waveform of the artificial seismic wave a triangular wave. A triangular wave refers to a waveform of an artificial seismic wave whose outline (roughly) is a triangle. In step S1, the impact bomb 2 is replaced with a first reducing portion whose outer diameter increases from bottom to top, so that the waveform of the artificial seismic wave is a triangular wave. For example, the impact bomb 2 is a truncated cone with a lower bottom surface area smaller than an upper bottom surface. In a cross section perpendicular to the horizontal direction, the size of the outer peripheral outline of the entirety or lower portion of the impact bomb 2 increases from bottom to top.

[0075] Optionally, the ratio of the length of the first reducing portion to the length of the impact projectile 2 is (0.9-1):1. Specifically, the impact projectile 2 includes a first reducing portion (lower portion) and a sliding portion, wherein the first reducing portion is located below the sliding portion, and the sliding portion is slidably connected to the inner wall surface of the launch tube 1. The ratio of the length of the first reducing portion to the length of the impact projectile 2 (the sum of the first reducing portion and the sliding portion) is (0.9-1):1. In other words, the large proportion of the first reducing portion can make the waveform of the artificial seismic wave a triangular wave.

[0076] like Figure 1 As shown, in some embodiments, the lower portion of the impact bomb 2 is a second variable diameter portion 21 whose outer diameter increases from bottom to top, and the upper portion of the impact bomb 2 is a third variable diameter portion 22 whose outer diameter decreases from bottom to top. The lower portion of the impact bomb 2 is the second variable diameter portion that increases from bottom to top, and the upper portion of the impact bomb 2 is the third variable diameter portion 22 that decreases from bottom to top, which can make the waveform of the artificial seismic wave a quasi-sinusoidal wave. A quasi-sinusoidal wave refers to an artificial seismic wave whose waveform profile is (substantially) a sine waveform. In step S1, the impact bomb 2 is replaced with a lower portion having a second variable diameter portion that increases from bottom to top and an upper portion having a third variable diameter portion that decreases from bottom to top, so that the waveform of the artificial seismic wave is a quasi-sinusoidal wave. For example, the lower portion of the impact bomb 2 is truncated cone-shaped, with a smaller bottom surface area than the upper bottom surface, while the upper portion of the impact bomb 2 is truncated cone-shaped, with a larger bottom surface area than the upper bottom surface. In the cross section perpendicular to the horizontal direction, the outer diameter of the lower part of the impact bullet 2 (the second diameter-changing portion 21) increases from bottom to top, and the outer diameter of the upper part of the impact bullet 2 (the third diameter-changing portion 22) decreases from bottom to top.

[0077] Optionally, the ratio of the sum of the lengths of the second reducing portion 21 and the third reducing portion 22 to the length of the impact bomb 2 is (0.9-1):1. Specifically, the impact bomb 2 includes a second reducing portion 21 (lower portion), a connecting portion 23 (middle portion), and a third reducing portion 22 (upper portion), and the connecting portion 23 is slidably connected to the inner wall surface of the launch tube 1. The ratio of the sum of the lengths of the second reducing portion 21 and the third reducing portion 22 to the length of the impact bomb 2 (the sum of the second reducing portion 21, the connecting portion 23, and the third reducing portion 22) is (0.9-1):1. In other words, the large proportion of the second reducing portion 21 and the third reducing portion 22 can make the waveform of the artificial seismic wave a quasi-sinusoidal wave.

[0078] The shape (outer contour) of the impact projectile 2 can affect the waveform of the artificial seismic wave. The desired shape of the impact projectile 2 can be designed and manufactured based on the desired waveform, so that the artificial seismic wave generated by the impact projectile 2 carries more information. In other words, the impact projectile 2 can be designed, manufactured, and replaced with a preset shape based on the desired waveform.

[0079] Specifically, the distribution function of the radius of the impact bullet 2 is R(x)(i+1)=R(x)(i)+Gradient(x)(i)*k(i).

[0080] in, u1=u-u0, u0 is the waveform and frequency band of the required artificial seismic wave, u is the forward wave field obtained by the dynamic simulation of the impact process based on u0, u1 is the reverse wavelet obtained by u-u0, u2 is the accompanying wave field obtained by the dynamic simulation of the impact process based on u1, Gradient(x) is the cross-correlation formula between the forward wave field u and the accompanying wave field u2, which can be used to infer the optimization gradient of the shape of the impact bomb 2, i is the number of optimizations based on Gradient(x), k is the i-th optimization constant, R(x)(i) is the distribution function of the radius of the impact bomb 2 after the i-th optimization, and R(x)(i+1) is the distribution function of the radius of the impact bomb 2 after the i+1-th optimization.

[0081] In some implementations, the percussion projectile 2 having at least one of a different preset material, a different preset density, and a different preset length is replaced and installed in the launch tube 1, so that the artificial seismic wave generated by the percussion projectile 2 has a different preset frequency band. For example, the percussion projectile 2 having at least one of a different preset material, a different preset density, and a different preset length, and a different preset shape, is replaced so that the artificial seismic wave generated by the percussion projectile 2 is one of a square wave, a triangular wave, and a quasi-sinusoidal wave, and has a different preset frequency band.

[0082] In step S1, the impact projectile 2 is replaced with a different material and an increased material velocity to increase the center frequency of the artificial seismic wave band. Specifically, the center frequency of the band can (roughly) represent the location of the frequency band. Different materials can result in different wave velocities C of the impact projectile 2, thereby affecting the lateral duration of the artificial seismic wave waveform (i.e., the center frequency of the frequency band). Different wave velocities C of different materials result in different center frequencies of the frequency band. As the wave velocity C of the impact projectile 2 increases, the center frequency of the frequency band increases. Therefore, replacing the impact projectile 2 with a different material and an increased material velocity increases the center frequency of the artificial seismic wave band. Conversely, replacing the impact projectile 2 with a different material and a decreased material velocity decreases the center frequency of the artificial seismic wave band. The elastic modulus E is the uniaxial compressive elastic modulus of the material used in the impact projectile 2 and is an inherent property of the material. The relationship between the elastic modulus E and the material velocity C is: C = (E / ρ)0.5, where ρ represents the density of the impact projectile material. It can be seen that an increase in the elastic modulus E leads to an increase in the velocity C, which in turn increases the center frequency.

[0083] In some embodiments, the density of the impact projectile 2 can be increased to reduce the center frequency of the artificial seismic wave's frequency band. Specifically, a higher density of the impact projectile 2 results in a greater mass, which in turn increases the energy required to accelerate the same volume of the impact projectile 2. Increasing the density of the impact projectile 2 reduces the lateral duration of the artificial seismic wave waveform. Therefore, the density of the impact projectile 2 can be increased to reduce the center frequency of the artificial seismic wave's frequency band. Conversely, the density of the impact projectile 2 can be decreased to increase the center frequency of the artificial seismic wave's frequency band.

[0084] In some embodiments, the impact bomb 2 is replaced with a longer one in order to reduce the center frequency of the frequency band of the artificial seismic wave. Specifically, the center frequency f of the frequency band is negatively correlated with the length L of the impact bomb 2 (f=0.5C / L). Increasing the length (in the vertical direction) of the impact bomb 2 can reduce the center frequency of the frequency band of the artificial seismic wave. Reducing the length of the impact bomb 2 can increase the center frequency of the frequency band of the artificial seismic wave. The elastic modulus E is the uniaxial compression elastic modulus of the material used for the impact bomb 2, which is an inherent property of the material. The relationship between the elastic modulus E and the material wave velocity C is: C=(E / ρ)0.5, where ρ represents the material density of the impact bomb 2. It can be seen that an increase in the elastic modulus E leads to an increase in the wave velocity C, thereby achieving an increase in the center frequency.

[0085] Therefore, the frequency band of the artificial shock wave can be changed by changing at least one of the material, density and length of the shock bomb 2 and installing the changed shock bomb 2 in the launch tube 1.

[0086] The method for realizing artificial seismic waves according to an embodiment of the present invention further includes step S3, which increases the amplitude of the waveform of the artificial seismic wave by increasing at least one of the emission energy of the emission device and the impact stroke of the impact bomb 2. Specifically, the amplitude of the waveform of the artificial seismic wave is related to the energy of the artificial shock wave generated by the impact bomb 2. Increasing the emission energy of the emission device can increase the impact energy of the impact bomb 2. Increasing the impact stroke of the impact bomb 2 means increasing the height of the position where the impact bomb 2 occurs, so that the impact bomb 2 converts more gravitational potential energy into impact energy during the impact (falling) process, thereby increasing the impact energy of the impact bomb 2 and then increasing the energy of the artificial shock wave, so as to improve the amplitude of the waveform of the artificial seismic wave.

[0087] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0089] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0090] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0091] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0092] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A seismic source device, characterized in that: include a launch tube extending from bottom to top; an impact bullet, the impact bullet being movably disposed in the launch tube so that the impact bullet has a launch position and an impact position, the impact bullet being detachably connected to the launch tube so as to allow replacement of impact bullets of different shapes and / or materials in the launch tube, the launch position being located above the impact position; a launching device, wherein the launching device can drive the impact bomb to move from the launching position to the impact position so that the impact bomb impacts downward and forms an artificial seismic wave; The shape of the impact bomb can affect the waveform of the artificial seismic wave. The distribution function of the radius of the impact bomb is: R(x)(i+1)=R(x)(i)+Gradient(x)(i)*k(i); in, u1=u-u0, u0 is the waveform and frequency band of the required artificial seismic wave, u is the forward wave field obtained by the dynamic simulation of the impact process based on u0, u1 is the reverse wavelet obtained by u-u0, u2 is the accompanying wave field obtained by the dynamic simulation of the impact process based on u1, Gradient(x) is the cross-correlation formula between the forward wave field u and the accompanying wave field u2, and the optimization gradient of the impact bomb shape can be inferred, i is the number of optimizations based on Gradient(x), k is the i-th optimization constant, R(x)(i) is the distribution function of the radius of the impact bomb after the i-th optimization, and R(x)(i+1) is the distribution function of the radius of the impact bomb after the i+1-th optimization.

2. The seismic source device according to claim 1, characterized in that: The length direction of the impact bullet is the up-down direction; The outer diameter of the impact bomb is consistent from bottom to top; Alternatively, the entire body or the lower portion of the impact bullet is a first diameter-reducing portion whose outer diameter increases from bottom to top; Alternatively, the lower portion of the impact bullet is a second diameter-changing portion whose outer diameter increases from bottom to top, and the upper portion of the impact bullet is a third diameter-changing portion whose outer diameter decreases from bottom to top.

3. The seismic source device according to claim 2, characterized in that: The entire or lower portion of the impact bullet is the first diameter-reducing portion whose outer diameter increases from bottom to top, and the ratio of the length of the first diameter-reducing portion to the length of the impact bullet is (0.9-1):1; Alternatively, the lower part of the impact bullet is the second variable diameter part whose outer diameter increases from bottom to top, and the upper part of the impact bullet is the third variable diameter part whose outer diameter decreases from bottom to top, and the ratio of the sum of the length of the second variable diameter part and the length of the third variable diameter part to the length of the impact bullet is (0.9-1):

1.

4. The seismic source device according to claim 2, characterized in that: The outer contours of the cross sections of the impact bombs are all circular; The launching device is an air pump; The top of the launch tube is closed, at least part of the circumference of the impact bullet is slidably connected to the inner wall of the launch tube, the top surface of the impact bullet and the inner wall of the launch tube define a launch chamber, and the air pump is connected to the launch chamber.

5. The seismic source device according to claim 4, characterized in that: A motor and a cable are provided in the launch chamber. The motor is located at the top of the launch chamber. One end of the cable is connected to the output shaft of the motor, and the other end of the cable is connected to the impact bullet. The inner side wall of the launch tube has a groove, and a spring piece is arranged in the launch tube. The spring piece can be elastically deformed, and the spring piece is arranged at the top of the groove and at least part of the spring piece extends out of the groove. In the launch position, the spring piece is used to support the impact bomb; The seismic source device also includes a fixing frame and an impact plate. The fixing frame is mounted on the outer peripheral side of the launch tube. A counterweight is provided on the fixing frame. The impact plate is connected to the bottom of the fixing frame. The thickness direction of the impact plate is the up and down direction. The lower opening of the launch tube faces the top of the impact plate.

6. A method for realizing artificial seismic waves using the source device according to any one of claims 1 to 5, comprising the following steps: S1. Installing a bomb having a preset shape and a preset material into a launch tube; S2. Use a launching device to drive the impact bomb to move from the generating position to the impact position, so that the impact bomb impacts downward and forms an artificial seismic wave with a preset waveform and a preset frequency band.

7. The method for realizing artificial seismic waves according to claim 6, In the step S1, the impact bombs of different preset shapes are replaced and installed in the launch tube, so that the waveform of the artificial seismic wave generated by the impact bombs is one of a square wave, a triangle wave and a quasi-sine wave; And / or, the impact bomb having at least one of a different preset material, a different preset density and a different preset length is replaced and installed in the launch tube, so that the artificial seismic wave formed by the impact bomb has a different preset frequency band.

8. The method for realizing artificial seismic waves according to claim 7, characterized in that: The length direction of the impact bullet is the up-down direction; In the step S1, Replacing the impact bombs with the same outer diameter from bottom to top so that the waveform of the artificial seismic wave is a square wave; Alternatively, the impact bomb is replaced as a whole or at its lower portion with a first diameter-reducing portion whose outer diameter increases from bottom to top, so that the waveform of the artificial seismic wave is a triangular wave; Alternatively, the impact bomb is replaced with a second variable diameter portion having an increasing outer diameter from bottom to top and a third variable diameter portion having a decreasing outer diameter from bottom to top, so that the waveform of the artificial seismic wave is a quasi-sine wave.

9. The method for realizing artificial seismic waves according to claim 7, characterized in that: In the step S1, Replacing the impact bomb with a different material and increasing the wave velocity of the material so as to increase the center frequency of the frequency band of the artificial seismic wave; and / or, replacing the impact bomb with a density increased so as to reduce the center frequency of the frequency band of the artificial seismic wave; and / or, replacing the impact bomb with one having a longer length so as to reduce the center frequency of the frequency band of the artificial seismic wave; The method for realizing artificial seismic waves further includes step S3: increasing the amplitude of the waveform of the artificial seismic wave by increasing at least one of the emission energy of the emission device and the impact stroke of the impact bomb.

10. The method for realizing artificial seismic waves according to claim 7, characterized in that: The distribution function of the radius of the impact bullet is R(x)(i+1)=R(x)(i)+Gradient(x)(i)*k(i); in, u1=u-u0, u0 is the waveform and frequency band of the required artificial seismic wave, u is the forward wave field obtained by the dynamic simulation of the impact process based on u0, u1 is the reverse wavelet obtained by u-u0, u2 is the accompanying wave field obtained by the dynamic simulation of the impact process based on u1, Gradient(x) is the cross-correlation formula between the forward wave field u and the accompanying wave field u2, and the optimization gradient of the impact bomb shape can be inferred, i is the number of optimizations based on Gradient(x), k is the i-th optimization constant, R(x)(i) is the distribution function of the radius of the impact bomb after the i-th optimization, and R(x)(i+1) is the distribution function of the radius of the impact bomb after the i+1-th optimization.

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