Underwater electric explosion plasma source device

Abstract

The invention discloses an underwater electric explosion plasma source device, and the device comprises a pulse power device which is used for generating a large-current pulse, and transmitting the large current to a metal wire target; the metal wire target is connected with the pulse power device through a cable; the metal wire target is arranged in the water container and used for rapidly heating the metal wire target to perform wire explosion to generate plasma when large current passes through the metal wire target, and the plasma interacts with surrounding water to heat and gasify water near the metal wire target to form high-pressure bubbles; bubbles formed by the plasma and the water vapor generate pressure waves in the water body in the expansion and contraction process, and the bubbles serve as artificial focuses. Compared with an existing plasma source, large bubbles can be formed more easily; compared with an existing high-pressure air gun seismic source, the high-pressure air gun seismic source is short in bubble oscillation period, clean in signal, large in initial bubble ratio and capable of being used without a large water body, has the advantages of being simple in device design, convenient to operate, environmentally friendly and the like and can be widely applied to geological exploration.

Description

Technical Field

[0001] The invention relates to the technical field of underwater artificial seismic sources, and in particular to an underwater electric explosion plasma seismic source device. Background Art

[0002] Using artificial seismic sources in water is an important method of seismic exploration. The most commonly used artificial seismic sources in water include air guns, plasma seismic sources, electric spark seismic sources, and explosive underwater explosions.

[0003] Traditional air gun seismic sources require the injection of high-pressure air into the water, and the oscillation process of the bubbles repeatedly expanding and shrinking in the water is relatively long. During the oscillation process, the bubbles continue to float up until they burst after reaching the water surface. The pressure signal generated is also a multi-pulse oscillation signal. On the one hand, this affects the bubbles' ability to quickly transfer energy to the water body. On the other hand, the subsequent oscillation signal is an interference signal for geological exploration, which affects the analysis of the exploration results and makes it difficult to obtain a higher resolution.

[0004] Although plasma and spark sources do not inject air into the water, their bubbles also have many oscillation cycles, and the diameter of a single bubble is very small, requiring a large number of bubbles to form an emission array. Their signal interference and small energy limit their use. In addition to water vapor, the bubbles produced by the explosion of explosives in water also have a large amount of detonation gas products. The bubble oscillation is also very strong, and they have been abandoned due to environmental and safety issues.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The purpose of the present invention is to provide an underwater electric explosion plasma source device. The present invention is a brand-new electric explosion plasma source, which reduces the problem of multi-pulse oscillation of bubbles. After the first large bubble is formed, the second and third bubbles are very small, and there is almost no excessive bubble oscillation in the subsequent period. Therefore, when used, the seismic signal generated by a single gun is relatively clean and has a high bubble ratio. In addition, the radius of a single bubble is much larger than that of an existing plasma source, the energy is large, and it is safe to use and has little pollution to the water body.

[0007] The present invention is achieved through the following technical solutions:

[0008] An underwater electric explosion plasma seismic source device, the electric explosion plasma seismic source comprising:

[0009] a pulse power device for generating a high current pulse and transmitting the high current to the wire target;

[0010] A metal wire target is connected to a pulse power device through a cable; the metal wire target is arranged in a water container, and when the large current passes through the metal wire target, the metal wire target is rapidly heated to generate plasma through wire explosion; the plasma interacts with the surrounding water body to heat and vaporize the water near the metal wire target to form high-pressure bubbles; the bubbles formed by the plasma and water vapor generate pressure waves in the water body during the expansion and contraction process, which serve as artificial seismic sources.

[0011] The basic principle of the underwater electric explosion plasma seismic source device of the present invention is: a pulse power device is used to generate a large current pulse. When the current passes through a metal wire target, the metal wire is rapidly heated and exploded to generate plasma. The plasma interacts with the surrounding water body to heat and vaporize the water near the metal wire target to form high-pressure bubbles. The bubbles formed by the plasma and water vapor generate pressure pulses (i.e., pressure waves) in the water body during expansion and contraction, which can be used as an artificial seismic source. This seismic source is designed based on a new principle. Compared with the existing plasma seismic source, it is easier to form large bubbles. Compared with the existing high-pressure air gun seismic source, the bubble oscillation period is short, the signal is clean, the initial bubble ratio is large, and it can be used without a large water body. It has the characteristics of simple device design, convenient operation, environmental protection, etc., and can be widely used in geological exploration.

[0012] Furthermore, the pulse power device includes a control console, a trigger, a charging trigger component, a charging unit and an energy storage and switch module, the control console is connected to the trigger, the trigger is connected to the charging unit, the trigger is connected to the charging trigger component, the charging unit is connected to the charging trigger component, and the charging trigger component is connected to the energy storage and switch module; the energy storage and switch module includes an energy storage module and a switch module;

[0013] The console sends a trigger signal through a trigger, and the trigger signal triggers the charging trigger component to control the charging unit to enter a charging state. When the charging unit charges the energy storage module to reach a set threshold, the switch module is controlled to be turned on, and the energy storage module discharges to the metal wire target through a cable.

[0014] Furthermore, the energy storage module adopts a capacitor bank.

[0015] Furthermore, the metal wire target includes an electrode fixing insulator, a cathode body, an anode body and a metal connector. The cathode body and the anode body are arranged on the electrode fixing insulator for connecting with a cable; the cathode body and the anode body are connected via a metal connector.

[0016] Furthermore, the metal connector is a metal wire, and the metal wire includes a single metal wire or a wire array formed by multiple metal wires.

[0017] Furthermore, the metal connector is a metal foil.

[0018] Furthermore, the metal wire is made of aluminum wire, copper wire, tungsten wire or iron wire.

[0019] Furthermore, the large current ranges from 50 kA to 5 MA.

[0020] Furthermore, the radius of the high-pressure bubble is greater than 20 cm.

[0021] Furthermore, the cable is a coaxial cable, and the coaxial cable is connected to the cathode body and the anode body correspondingly.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. The present invention is an underwater electric explosion plasma source device. Different from the principles of traditional air gun sources, plasma sources and electric spark sources in the prior art, the present invention proposes a source with a completely new principle for use in water; the source uses a pulse power source as an energy system, and transmits a large electric current to a metal wire target through a cable. The metal wire target undergoes an electric explosion under the action of a large current to form plasma. The plasma energy generated by the electric explosion quickly heats the surrounding water, causing the water to vaporize to form high-pressure bubbles. The expansion and contraction of the bubbles form pressure pulses in the water, which can be used as an artificial source. This source designs a new source based on a new principle, which is easier to form large bubbles than the existing plasma source; compared with the existing high-pressure air gun source, the bubble oscillation period is short, the signal is clean, the initial bubble ratio is large, and it does not require a large water body to use. It has the characteristics of simple device design, convenient operation, and environmental protection, and can be widely used in geological exploration.

[0024] 2. The present invention provides an underwater electric explosion plasma source device, which reduces the problem of multiple pulse oscillations of bubbles. After the first large bubble is formed, the second and third bubbles are very small, and there is almost no excessive bubble oscillation afterwards. Therefore, when used, the seismic signal generated by a single gun is relatively clean and has a higher bubble ratio. In addition, the radius of a single bubble is much larger than that of an existing plasma source, the energy is large, and it is safe to use and has little pollution to the water body.

[0025] 3. Compared with existing plasma sources or spark sources, the diameter of a single bubble produced by the present invention is larger (easily more than 20 times); the bubble shape is almost a perfect sphere, and the bubble size and shape have good repeatability; it is easy to achieve coherent design of multiple bubbles, and the time synchronization is much higher than that of existing air gun sources.

[0026] 4. The bubbles generated by the present invention have fewer oscillation cycles: the substance in the bubbles is mainly water vapor, and no other gas is injected into the water. During the expansion and compression process, a phase change will occur at the interface between the bubbles and the water, so that the water vapor in the bubbles is converted back into water. Instability will also occur at the interface, which can accelerate the mixing of gas and water and the phase change conversion. Therefore, the bubbles will disappear in about three cycles.

[0027] 5. The size of the bubbles produced by the present invention is relatively easy to control and the energy conversion efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0029] Figure 1 This is a schematic diagram of the structure of an underwater electric explosion plasma source device of the present invention;

[0030] Figure 2 It is a schematic diagram of the structure of the metal wire target of the present invention;

[0031] Figure 3 This is a diagram of bubbles and three cycle processes generated by the seismic source device in the experimental water pool of the present invention.

[0032] Reference numerals and corresponding component names:

[0033] 1-metal wire target, 11-electrode fixing insulator, 12-cathode body, 13-anode body, 14-metal connector, 2-control console, 3-trigger, 4-charging trigger assembly, 5-charging unit, 6-energy storage and switch module, 7-cable. DETAILED DESCRIPTION

[0034] Hereinafter, the term "include" or "may include" used in various embodiments of the present invention indicates the presence of the invented function, operation or element, and does not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present invention, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0035] In various embodiments of the present invention, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the words listed at the same time. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0036] The expressions (such as "first", "second", etc.) used in various embodiments of the present invention may modify the various constituent elements in various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing an element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of various embodiments of the present invention, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0037] It should be noted that if it is described that one component element is “connected” to another component element, the first component element may be directly connected to the second component element, and a third component element may be “connected” between the first component element and the second component element. Conversely, when one component element is “directly connected” to another component element, it can be understood that there is no third component element between the first component element and the second component element.

[0038] The terms used in various embodiments of the present invention are only used for the purpose of describing specific embodiments and are not intended to limit various embodiments of the present invention. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meaning generally understood by those of ordinary skill in the art to which the various embodiments of the present invention belong. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in various embodiments of the present invention.

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0040] Different from the principles of traditional airgun seismic sources, plasma seismic sources and electric spark seismic sources in the prior art, the present invention proposes a seismic source with a completely new principle for use in water. The entire seismic source of the present invention includes a console 2, a trigger 3, a charging trigger component 4, a charging unit 5, an energy storage and switch module 6, a cable 7, a metal wire target 1, etc. The seismic source uses a pulse power source as an energy system, and transmits a large electric current to the metal wire target 1 through a transmission line (cable 7). The metal wire target 1 undergoes an electric explosion under the action of a large current to form plasma. The plasma energy generated by the electric explosion quickly heats the surrounding water, causing the water to vaporize to form high-pressure bubbles. The expansion and contraction of the bubbles form pressure pulses in the water, which can be used as an artificial seismic source. This seismic source designs a new seismic source based on a new principle. Compared with the existing plasma seismic source, it is easier to form large bubbles; compared with the existing high-pressure airgun seismic source, the bubble oscillation period is short, the signal is clean, the initial bubble ratio is large, and it does not require a large water body to use. It has the characteristics of simple device design, convenient operation, and environmental protection, and can be widely used in geological exploration.

[0041] Example 1

[0042] like Figure 1 As shown, Figure 1 The schematic diagram of the source device designed according to the new principle of underwater electric explosion is a schematic diagram of the source device designed according to the new principle of underwater electric explosion. The present invention is an underwater electric explosion plasma source device, and the electric explosion plasma source comprises:

[0043] A pulse power device, used to generate a high current pulse and transmit the high current to the metal wire target 1;

[0044] A metal wire target 1 is connected to a pulse power device via a cable 7; the metal wire target 1 is arranged in a water container, and when the large current passes through the metal wire target 1, the metal wire target 1 is rapidly heated to generate plasma by wire explosion, and the plasma interacts with the surrounding water body to heat and vaporize the water near the metal wire target to form high-pressure bubbles; the bubbles formed by the plasma and the water vapor generate pressure waves in the water body during the expansion and contraction process, which serve as an artificial seismic source; wherein the cable 7 is a coaxial cable, and the coaxial cable is correspondingly connected to the cathode body 12 and the anode body 13.

[0045] It should be noted that the water container is filled with water, and the metal wire target 1 extends into the water.

[0046] In this embodiment, the pulse power device includes a control console 2, a trigger 3, a charging trigger component 4, a charging unit 5 and an energy storage and switch module 6, the control console 2 is connected to the trigger 3, the trigger 3 is connected to the charging unit 5, the trigger 3 is connected to the charging trigger component 4, the charging unit 5 is connected to the charging trigger component 4, and the charging trigger component 4 is connected to the energy storage and switch module 6; the energy storage and switch module 6 includes an energy storage module and a switch module; wherein the charging unit 5 is composed of a plurality of chargers.

[0047] In this embodiment, the energy storage module adopts a capacitor bank.

[0048] In this embodiment, the metal wire target 1 includes an electrode fixing insulator 11, a cathode body 12, an anode body 13 and a metal connector 14. The cathode body 12 and the anode body 13 are arranged on the electrode fixing insulator 11 for connecting to the cable 7; the cathode body 12 and the anode body 13 are connected via the metal connector 14.

[0049] Specifically, the metal connector 14 is a metal wire or a metal foil, and the metal wire includes a single metal wire or a wire array formed by multiple metal wires, wherein the metal wire is made of aluminum wire, copper wire, tungsten wire or iron wire.

[0050] It should be noted that any seismic source that uses metal wire or metal foil to cause electric explosion under the action of large current as a liquid medium is within the scope of the present invention, wherein the large current ranges from 50kA to 5MA.

[0051] The basic principle of the underwater electric explosion plasma seismic source device of the present invention is: a pulse power device is used to generate a large current pulse. When the current passes through a metal wire target, the metal wire is rapidly heated and exploded to generate plasma. The plasma interacts with the surrounding water body to heat and vaporize the water near the metal wire target to form high-pressure bubbles. The bubbles formed by the plasma and water vapor generate pressure pulses (i.e., pressure waves) in the water body during expansion and contraction, which can be used as an artificial seismic source. This seismic source is designed based on a new principle. Compared with the existing plasma seismic source, it is easier to form large bubbles. Compared with the existing high-pressure air gun seismic source, the bubble oscillation period is short, the signal is clean, the initial bubble ratio is large, and it can be used without a large water body. It has the characteristics of simple device design, convenient operation, environmental protection, etc., and can be widely used in geological exploration.

[0052] The working process is as follows: the console 2 sends a trigger signal through the trigger 3, and the trigger signal triggers the charging trigger component 4 to control the charging unit 5 to enter the charging state. When the charging unit 5 charges the energy storage module to reach the set threshold, the switch module is controlled to be turned on, and the capacitor group discharges to the metal wire target 1 through the cable 7. The metal connector 14 (metal wire or metal foil) undergoes an electric explosion under the action of large current heating to form plasma, and the plasma quickly vaporizes water to form high-temperature and high-pressure bubbles. In the subsequent process, the bubble expansion does work on the water body, and the pressure inside the bubble itself decreases. Under the action of inertia, the pressure inside the bubble will be lower than the water pressure until the bubble interface velocity is zero; then it enters the contraction process, shrinks to a very small value, and enters the expansion and contraction process again. In addition to the first expansion process, in the subsequent expansion and contraction process, water vapor and the water interface mix and change phases, and water vapor is continuously converted into water until the bubble disappears. Generally speaking, after about three cycles, the bubbles basically disappear. If Figure 2 shown.

[0053] Compared with the existing plasma source, the bubble generation principle is different. The existing plasma source mainly discharges water in water after breaking down electricity. There is no wire explosion process in the present invention, and less plasma is generated. The wire explosion process of the present invention allows energy to be first deposited on the wire plasma in large quantities. After the explosion, the plasma can fully exchange energy with water, so that more water can be vaporized, and bubbles much larger than those of the existing plasma source can be obtained.

[0054] like Figure 2 This is an image of bubbles generated by the source in the experimental pool. Currently, bubbles with a radius greater than 20 cm have been generated in the laboratory. The source has the following advantages:

[0055] (1) Compared with existing plasma sources or spark sources, the diameter of a single bubble is larger (easily more than 20 times);

[0056] (2) The bubble shape is almost a perfect sphere, and the bubble size and shape have good repeatability;

[0057] (3) It is easy to realize the coherent design of multiple bubbles, and the time synchronization is much higher than that of existing airgun seismic sources;

[0058] (4) The bubble oscillation cycle is short: the substance in the bubble is mainly water vapor. No other gas is injected into the water. During the expansion and compression process, a phase change will occur at the interface between the bubble and the water, causing the water vapor in the bubble to be converted back into water. Instability will also occur at the interface, which can accelerate the mixing of gas and water and the phase change transformation. Therefore, the bubble will disappear in about three cycles.

[0059] (5) Bubble size is easier to control and energy conversion efficiency is high;

[0060] (6) The cost is relatively moderate.

[0061] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An underwater electric explosion plasma source device, characterized in that: The electric explosion plasma source comprises: a pulse power device for generating a high current pulse and transmitting the high current to the wire target; A metal wire target is connected to a pulse power device through a cable; the metal wire target is arranged in a water container, and when the large current passes through the metal wire target, the metal wire target is heated to generate plasma by wire explosion; the plasma interacts with the surrounding water body, heats and vaporizes the water near the metal wire target, and forms high-pressure bubbles; the bubbles formed by the plasma and water vapor generate pressure waves in the water body during the expansion and contraction process, which serve as artificial seismic sources.

2. The underwater electric explosion plasma source device according to claim 1, characterized in that: The pulse power device comprises a control console, a trigger, a charging trigger component, a charging unit and an energy storage and switch module, the control console is connected to the trigger, the trigger is connected to the charging unit, the trigger is connected to the charging trigger component, the charging unit is connected to the charging trigger component, and the charging trigger component is connected to the energy storage and switch module; the energy storage and switch module comprises an energy storage module and a switch module; The console sends a trigger signal through a trigger, and the trigger signal triggers the charging trigger component to control the charging unit to enter a charging state. When the charging unit charges the energy storage module to reach a set threshold, the switch module is controlled to be turned on, and the energy storage module discharges to the metal wire target through a cable.

3. The underwater electric explosion plasma source device according to claim 2, characterized in that: The energy storage module adopts a capacitor group.

4. The underwater electric explosion plasma source device according to claim 1, characterized in that: The metal wire target comprises an electrode fixing insulator, a cathode body, an anode body and a metal connector. The cathode body and the anode body are arranged on the electrode fixing insulator for connecting with a cable. The cathode body and the anode body are connected via the metal connector.

5. The underwater electric explosion plasma source device according to claim 4, characterized in that: The metal connecting body is a metal wire, and the metal wire includes a single metal wire or a wire array formed by multiple metal wires.

6. The underwater electric explosion plasma source device according to claim 4, characterized in that: The metal connecting body is a metal foil.

7. The underwater electric explosion plasma source device according to claim 5, characterized in that: The metal wire is made of aluminum wire, copper wire, tungsten wire or iron wire.

8. The underwater electric explosion plasma source device according to claim 1, characterized in that: The large current ranges from 50 kA to 5 MA.

9. The underwater electric explosion plasma source device according to claim 1, characterized in that: The radius of the high pressure bubble is greater than 20 cm.

10. The underwater electric explosion plasma source device according to claim 1, characterized in that: The cable is a coaxial cable.

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