CN116345944A

CN116345944A - Plasma pulse generating device

Info

Publication number: CN116345944A
Application number: CN202111592321.1A
Authority: CN
Inventors: 崔晓杰; 朱和明; 侯乃贺; 马兰荣; 戴文潮; 谷磊; 秦金立; 尹慧博
Original assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Current assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2023-06-27

Abstract

The invention provides a plasma pulse generating device, which comprises a water storage tank, an energy storage capacitor, a charging loop for charging the energy storage capacitor and a discharging loop for releasing energy of the energy storage capacitor, wherein the charging loop and the discharging loop are connected with the energy storage capacitor; the discharging loop is provided with a trigger switch and a discharging load, and the discharging load is immersed in the water storage tank; the discharging loop is conducted when the charging voltage of the energy storage capacitor reaches the trigger voltage of the trigger switch; the discharge load vaporizes when the discharge loop is on to form a plasma channel. The invention has the advantages of generating high-amplitude pressure shock waves, achieving the aim of increasing the yield of oil and gas fracturing, and the like.

Description

Plasma pulse generating device

Technical Field

The invention relates to the field of fracturing yield increase of petroleum and natural gas, in particular to a plasma pulse generating device.

Background

In the development process of petroleum and natural gas resources, a hypotonic reservoir needs to be subjected to hydraulic fracturing to form enough cracks so as to obtain effective output; meanwhile, as development time increases, the yield of the oil and gas well gradually decreases and even is exhausted, and measures such as secondary hydraulic fracturing, hydraulic pulse, ultrasonic wave, electromagnetic heating, electric pulse blocking removal and the like are often needed to be adopted for yield increasing operation. The hydraulic fracturing process is complex, and the water resource and chemical additive are large in dosage, so that the ecological environment is influenced; the energy density of the yield increasing measures such as hydraulic pulse, ultrasonic wave, electromagnetic wave and the like is low, and the action range is only about a few meters; the hydraulic fracturing method by utilizing the plasma electric pulse can excite high-pressure shock waves to periodically act on the reservoir to generate a micro-fracture network, thereby greatly improving the seepage capability of the reservoir and increasing the yield of an oil and gas well. However, the existing plasma pulse generator has limited pressure amplitude of the impact wave, low energy conversion efficiency and high working voltage, which limits practical application.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a plasma pulse generating device capable of generating high-amplitude pressure shock waves and achieving the purpose of oil-gas fracturing and yield increase.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

the plasma pulse generating device comprises a water storage tank, an energy storage capacitor, a charging loop for charging the energy storage capacitor and a discharging loop for discharging energy of the energy storage capacitor, wherein the charging loop and the discharging loop are connected with the energy storage capacitor; the discharging loop is provided with a trigger switch and a discharging load, and the discharging load is immersed in the water storage tank; the discharging loop is conducted when the charging voltage of the energy storage capacitor reaches the trigger voltage of the trigger switch; the discharge load vaporizes when the discharge loop is on to form a plasma channel.

As a further improvement of the above technical scheme:

the discharge load comprises two groups of discharge electrodes and a load metal wire, the discharge electrodes are connected with the discharge loop, and a discharge gap for forming the plasma channel is reserved between the two groups of discharge electrodes; the load metal wire is arranged in the discharge gap, and two ends of the load metal wire are respectively connected with one discharge electrode.

The discharge electrode comprises an electrode connecting rod, a fixed electrode cap and a metal wire compacting component, one end of the electrode connecting rod is connected with the discharge loop, and the fixed electrode cap is arranged at the other end of the electrode connecting rod; the electrode connecting rod and the fixed electrode cap are provided with a through channel for a load metal wire to pass through, and the metal wire pressing component is arranged on one side of the through channel of the fixed electrode cap.

The metal wire compressing component comprises a compressing sheet and a fastening screw, wherein the fastening screw is horizontally screwed on the fixed electrode cap, and the compressing sheet is vertically arranged and compresses the load metal wire under the action of the fastening screw.

The device also comprises a piezoelectric probe for detecting the size of the plasma pulse and a probe mounting assembly for mounting the piezoelectric probe, wherein the piezoelectric probe is arranged in the water storage tank and is positioned at the horizontal side of the discharge load; the piezoelectric probe is arranged on the water storage tank through the probe installation component.

The two groups of discharge electrodes are arranged up and down correspondingly, the two groups of discharge electrodes are connected with the discharge loop through a conductive copper bar respectively, and the conductive copper bar positioned at the lower side is arranged at the bottom of the water storage tank through a fixed sleeve; the conductive copper bar positioned on the upper side is arranged at the top of the water storage tank through an insulating sleeve and extends out of the water storage tank to be connected with the discharge loop.

The charging loop is provided with a voltage regulator, a transformer, a rectifying silicon stack and a current-limiting resistor which are sequentially connected, and the output end of the current-limiting resistor is connected with the energy storage capacitor.

The energy storage capacitor energy measuring device further comprises an oscilloscope for measuring the energy size of the energy storage capacitor, and the oscilloscope is connected with the energy storage capacitor.

The trigger switch is a self-breakdown air switch, and the breakdown voltage of the self-breakdown air switch is regulated through a gap of the self-breakdown air switch.

The water storage tank comprises an upper cover plate and a lower cover plate, and the lower cover plate is provided with a maintenance hole which is convenient for replacing the internal components of the water storage tank; the upper cover plate is installed on the lower cover plate and covers the maintenance hole.

Compared with the prior art, the invention has the advantages that:

according to the invention, the trigger switch and the discharge load are arranged in the discharge loop, the discharge loop is conducted when the charging voltage of the energy storage capacitor reaches the trigger voltage of the trigger switch, a complex trigger circuit is not needed, and the structure is simple and the operation is convenient. Meanwhile, the discharge load is immersed in the water storage tank, and is gasified rapidly when the discharge loop is conducted, at this time, a large amount of energy is released, the water in the water storage tank breaks down to form a plasma channel, so that the current is released instantaneously, a large amount of bubbles are generated by the water, and pressure shock waves are generated after the bubbles break down. Therefore, the invention adopts the shock wave generation mode that the discharge load is immersed in water, greatly improves the energy conversion efficiency, so as to generate high-amplitude pressure shock waves, realize the conduction of the oil gas drainage and production channel in practical application, improve the rock breaking capacity and achieve the aim of oil gas fracturing and yield increase.

Drawings

The invention will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:

fig. 1 is a schematic structural diagram of a plasma pulse generator according to the present invention.

Fig. 2 is a schematic circuit diagram of a plasma pulse generating apparatus according to the present invention.

Fig. 3 is a schematic view of the positional relationship of the internal components of the water storage tank of the present invention.

FIG. 4 is a schematic diagram of the positional relationship between a discharge electrode and a load wire according to the present invention.

Fig. 5 is a schematic structural view of the lower cover plate of the present invention.

Fig. 6 is a schematic structural view of the upper cover plate of the present invention.

FIG. 7 is a graph showing the relationship between the discharge time and the shock wave size measured by the piezoelectric probe according to the present invention.

The reference numerals in the drawings denote:

1. a water storage tank; 11. an upper cover plate; 111. a through hole; 12. a lower cover plate; 121. a maintenance hole; 2. an energy storage capacitor; 3. a charging circuit; 31. a voltage regulator; 32. a transformer; 33. a rectifying silicon stack; 34. a current limiting resistor; 4. a discharge circuit; 41. triggering a switch; 42. a discharge load; 421. a discharge electrode; 422. loading a wire; 423. a discharge gap; 424. an electrode connecting rod; 425. fixing an electrode cap; 426. a through passage; 427. a compacting sheet; 428. a fastening screw; 5. a piezoelectric probe; 6. a probe mounting assembly; 61. mounting a cross bar; 62. mounting a vertical rod; 7. conductive copper bars; 71. a fixed sleeve; 72. an insulating sleeve; 73. a sleeve is led out; 8. an oscilloscope; 9. a series resistor; 10. and protecting the resistor.

Detailed Description

The invention will now be described in further detail with reference to the drawings and the specific examples, which are not intended to limit the scope of the invention.

As shown in fig. 1 to 3, the plasma pulse generating device of the present embodiment includes a water storage tank 1, an energy storage capacitor 2, a charging circuit 3 and a discharging circuit 4, wherein the charging circuit 3 and the discharging circuit 4 are connected with the energy storage capacitor 2, the charging circuit 3 charges the energy storage capacitor 2, and the discharging circuit 4 releases the energy of the energy storage capacitor 2 to provide the energy required by the pressure shock wave. In this embodiment, the discharging circuit 4 is provided with the trigger switch 41 and the discharging load 42, and the discharging circuit 4 is turned on when the charging voltage of the energy storage capacitor 2 reaches the trigger voltage of the trigger switch 41, so that a complex trigger circuit is not required, the trigger structure is simple, and the operation is convenient.

Meanwhile, the discharge load 42 is immersed in the water storage tank 1, and the discharge load 42 is gasified rapidly when the discharge loop 4 is turned on, and at this time, a large amount of energy is released, and the water in the water storage tank 1 breaks down to form a plasma channel, so that the current is released instantaneously, a large amount of bubbles are generated by the water, and pressure shock waves are generated after the bubbles break. It can be seen that the invention adopts the form of generating the shock wave of the discharge load 42 immersed in the water to greatly improve the energy conversion efficiency, so as to generate the pressure shock wave with high amplitude, thereby realizing the conduction of the oil gas drainage and production channel during practical application, improving the rock breaking capability and achieving the purpose of increasing the oil gas fracturing yield.

As shown in fig. 2 and 3, the discharge load 42 includes two sets of discharge electrodes 421 and a load wire 422. Wherein, the discharge electrodes 421 are connected with the discharge circuit 4, and a discharge gap 423 is left between the two groups of discharge electrodes 421; the load wire 422 is disposed in the discharge gap 423, and both ends of the load wire 422 are respectively connected to a discharge electrode 421. When the discharge loop 4 is turned on, the energy storage capacitor 2 discharges to the load wire 422 through the discharge loop 4, and huge energy is deposited to the load wire 422 in a very short time, so that the phase state of the load wire 422 is changed (solid-liquid-gas state), at this time, a plasma channel is formed at the discharge gap 423, and charging energy is instantaneously released into surrounding water through the plasma, so as to generate a high-amplitude pressure shock wave. The invention adopts the discharge form of the load wire 422, greatly improves the energy conversion efficiency and enhances the amplitude of the shock wave. In this embodiment, the load wire 422 is a load copper wire.

As shown in fig. 7, under the conditions that the working voltage is 6kV, the energy storage capacitor 2 is 200uF, the discharge gap 423 is 50mm, and the diameter of the load wire 422 is 0.8mm, a shock wave exceeding 80MPa can be detected at a position 50mm away from the load wire 422 through the piezoelectric probe 5, the impact strength of the shock wave greatly exceeds the breaking strength of rock, microscopic and macroscopic cracks can be generated in a petroleum well, and the conduction of an oil gas drainage channel is realized. That is, the present invention adopts a form in which the discharge electrode 421 and the load wire 422 are combined, and can generate high-amplitude pressure shock waves through low working pressure and high energy conversion efficiency, which improves rock breaking capacity while ensuring safety and reliability of the device. In other embodiments, the operating voltage, the energy storage capacitor 2, the discharge gap 423, and the diameter of the load wire 422 may be adjusted according to practical situations.

As shown in fig. 4, the discharge electrode 421 includes an electrode connecting rod 424, a fixed electrode cap 425, and a wire pressing member. One end of the electrode connecting rod 424 is connected with the discharge loop 4, and the electrode connecting rod 424 is a conductive member; a fixed electrode cap 425 is mounted to the other end of the electrode connecting rod 424, and the fixed electrode cap 425 is an insulating member. The electrode connecting rod 424 and the fixed electrode cap 425 are provided with a through passage 426 for the load wire 422 to pass through; the wire pressing member is provided at one side of the through passage 426 of the fixed electrode cap 425 to press the load wire 422. The discharge electrode 421 of the present invention can firmly fix the load wire 422 while ensuring effective discharge to the load wire 422, and ensure safe and reliable operation of the device.

Further, the wire compressing member includes a compressing piece 427 and a fastening screw 428. A fastening screw 428 is horizontally screwed to the fixed electrode cap 425; the pressing piece 427 is vertically disposed, and the pressing piece 427 presses the load wire 422 under the action of the fastening screw 428 to effectively fix the position of the load wire 422. Meanwhile, the wire pressing part of the present invention is simple in structure and facilitates the installation of the load wire 422. In this embodiment, the pressing piece 427 is a conductive member.

As shown in fig. 3, the plasma pulse generating device further includes a piezoelectric probe 5 and a probe mounting assembly. The piezoelectric probe 5 is arranged in the water storage tank 1, and the piezoelectric probe 5 is positioned on the horizontal side of the discharge load 42 to detect the size of the plasma pulse; meanwhile, since the piezoelectric probe 5 is arranged in the water storage tank 1, the shock wave is not disturbed after being generated until reaching the wall of the water storage tank 1, and at the moment, the shock wave directly acts on the piezoelectric probe 5, so that the accuracy of an ion pulse detection result is ensured.

Meanwhile, the piezoelectric probe 5 is mounted on the water storage tank 1 through the probe mounting assembly 6. Further, the probe mounting assembly 6 includes a mounting cross bar 61 and a mounting vertical bar 62, wherein the mounting cross bar 61 is mounted on the upper portion of the water storage tank 1; the mounting vertical rod 62 is horizontally movably mounted on the mounting cross rod 61 through a fastener, and the piezoelectric probe 5 can conveniently adjust the distance between the mounting vertical rod and the load wire 422 so as to test the ion pulse size under the same parameter and at different distances. In this embodiment, the distance between the piezoelectric probe 5 and the load wire 422 is 50mm, and fig. 7 shows the result of measurement when the distance between the piezoelectric probe 5 and the load wire 422 is 50mm, and in other embodiments, the distance between the piezoelectric probe 5 and the load wire 422 can be adjusted according to practical situations.

In this embodiment, two sets of discharge electrodes 421 are disposed up and down correspondingly, and the two sets of discharge electrodes 421 are connected to the discharge circuit 4 through a conductive copper bar 7, and the conductive copper bar 7 located at the lower side is mounted at the bottom of the water storage tank 1 through a fixing sleeve 71; the conductive copper bar 7 positioned on the upper side is arranged on the top of the water storage tank 1 through an insulating sleeve 72, and extends out of the water storage tank 1 to be connected with the discharge loop 4 through a lead-out sleeve 73. The layout structure is compact, the conductive copper bars 7 are convenient to detach, inductance and resistance of a loop are effectively reduced, and energy conversion efficiency is improved. Meanwhile, the electric connection of the invention adopts the conductive copper bars 7 for connection so as to reduce the inductance resistance of the loop.

In this embodiment, the charging circuit 3 is provided with a voltage regulator 31, a transformer 32, a rectifying silicon stack 33 and a current limiting resistor 34 which are sequentially connected, and an output end of the current limiting resistor 34 is connected with the energy storage capacitor 2. The commercial power is regulated by a voltage regulator 31, then is boosted by a transformer 32, is rectified by a rectifying silicon stack 33, and then charges an energy storage capacitor 2 through a current limiting resistor 34 to form an adjustable direct current high voltage source.

Further, the charging loop 3 further comprises an oscilloscope 8, the oscilloscope 8 is connected with the energy storage capacitor 2, the oscilloscope 8 is connected in series with a series resistor 9, and the oscilloscope 8 is used for measuring the energy of the energy storage capacitor 2, so that the follow-up judgment is convenient. Meanwhile, the discharging load 42 is connected in parallel with a protection resistor 10 to play a role of safety protection.

Further, the trigger switch 41 is a self-breakdown air switch. The breakdown voltage of the self-breakdown air switch is adjusted by the gap of the self-breakdown air switch, thereby changing the amplitude of the shock wave. When the amplitude of the shock wave needs to be reduced, the gap of the self-breakdown air switch is reduced, so that the working voltage is reduced; when the amplitude of the shock wave needs to be increased, the gap of the self-breakdown air switch is increased, so that the working voltage is increased. In the embodiment, the working voltage of the self-breakdown air switch is continuously adjustable from 0V to 6 kV; in other embodiments, the operating voltage of the self-breakdown air switch may be adjusted according to the actual situation.

As shown in fig. 3, the water storage tank 1 includes an upper cover plate 11 and a lower cover plate 12. As shown in fig. 5, the lower cover plate 12 is used for fixing the insulating sleeve 72, the probe mounting assembly and the conductive copper bar 7, the lower cover plate 12 is provided with three maintenance holes 121, the maintenance holes 121 are fan-shaped holes, and the three maintenance holes 121 are arranged along the circumferential direction of the lower cover plate 12 so as to facilitate the replacement of the internal components of the water storage tank 1; in other embodiments, the number and the structural form of the maintenance holes 121 may be adjusted according to practical situations, so long as the internal components of the water storage tank 1 can be replaced conveniently. As shown in fig. 6, the upper cover plate 11 is two semi-annular cover plates, the upper cover plate 11 is installed above the lower cover plate 12, and the upper cover plate 11 is covered on the maintenance hole 121 for shielding the sprayed water flow; meanwhile, the upper cover plate 11 is provided with a through hole 111 for leading out the lead of the piezoelectric probe 5. In this embodiment, the water storage tank 1, the upper cover plate 11 and the lower cover plate 12 are all metal conductive members to form a part of a circuit, and are also a part of the circuit for the backflow of the discharge pulse high current,

the working principle of the plasma pulse generating device of this embodiment is as follows: according to the required discharge parameters, the electrode gap of the self-breakdown air switch is adjusted, the circuit connection is checked, and the power supply of the voltage regulator 31 is switched on after the circuit connection is confirmed to be correct; after the commercial power is regulated by the voltage regulator 31, boosted by the transformer 32 and rectified by the rectifying silicon stack 33, the energy storage capacitor 2 is charged by the current limiting resistor 34, the voltage of the energy storage capacitor 2 slowly rises, and the oscilloscope 8 deflects; when the charging voltage of the energy storage capacitor 2 reaches the breakdown voltage of the self-breakdown air switch, the self-breakdown air switch breaks down and turns on, and the circuit transits to a discharging mode, at this time, the energy storage capacitor 2 discharges to the load wire 422 through the discharging loop 4, at this time, huge energy is deposited to the load wire 422 in an extremely short time, so that the phase transition (solid-liquid-gas) of the load wire 422 forms a plasma channel, the diameter of the load wire 422 expands sharply, so as to compress the surrounding aqueous medium, and finally extremely strong shock waves are generated.

While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims

1. The plasma pulse generating device is characterized by comprising a water storage tank, an energy storage capacitor, a charging loop for charging the energy storage capacitor and a discharging loop for discharging energy of the energy storage capacitor, wherein the charging loop and the discharging loop are connected with the energy storage capacitor; the discharging loop is provided with a trigger switch and a discharging load, and the discharging load is immersed in the water storage tank; the discharging loop is conducted when the charging voltage of the energy storage capacitor reaches the trigger voltage of the trigger switch; the discharge load vaporizes when the discharge loop is on to form a plasma channel.

2. The plasma pulse generating device according to claim 1, wherein the discharge load comprises two sets of discharge electrodes and a load wire, the discharge electrodes are connected with the discharge circuit, and a discharge gap for forming the plasma channel is left between the two sets of discharge electrodes; the load metal wire is arranged in the discharge gap, and two ends of the load metal wire are respectively connected with one discharge electrode.

3. The plasma pulse generating apparatus according to claim 2, wherein the discharge electrode comprises an electrode connecting rod, a fixed electrode cap and a wire pressing member, one end of the electrode connecting rod is connected with the discharge circuit, and the fixed electrode cap is mounted at the other end of the electrode connecting rod; the electrode connecting rod and the fixed electrode cap are provided with a through channel for a load metal wire to pass through, and the metal wire pressing component is arranged on one side of the through channel of the fixed electrode cap.

4. The plasma pulse generating device according to claim 3, wherein the wire pressing member comprises a pressing piece and a fastening screw horizontally screwed to the fixed electrode cap, the pressing piece being vertically disposed and pressing the load wire by the fastening screw.

5. The plasma pulse generating device according to any one of claims 1 to 4, further comprising a piezoelectric probe that detects a magnitude of a plasma pulse, and a probe mounting assembly that mounts the piezoelectric probe, wherein the piezoelectric probe is provided in the water storage tank and is located on a horizontal side of the discharge load; the piezoelectric probe is arranged on the water storage tank through the probe installation component.

6. The plasma pulse generating device according to any one of claims 2 to 4, wherein two sets of the discharge electrodes are disposed up and down correspondingly, and the two sets of the discharge electrodes are connected to the discharge circuit through a conductive copper bar, respectively, and the conductive copper bar located at the lower side is mounted at the bottom of the water storage tank through a fixing sleeve; the conductive copper bar positioned on the upper side is arranged at the top of the water storage tank through an insulating sleeve and extends out of the water storage tank to be connected with the discharge loop.

7. The plasma pulse generating device according to any one of claims 1 to 4, wherein the charging circuit is provided with a voltage regulator, a transformer, a rectifying silicon stack and a current limiting resistor which are sequentially connected, and an output end of the current limiting resistor is connected with the energy storage capacitor.

8. The plasma pulse generating device according to claim 6, further comprising an oscilloscope measuring the energy level of the storage capacitor, the oscilloscope being connected to the storage capacitor.

9. The plasma pulse generating device according to any one of claims 1 to 4, wherein the trigger switch is a self-breakdown air switch whose breakdown voltage is adjusted by a gap of the self-breakdown air switch.

10. The plasma pulse generating device according to any one of claims 1 to 4, wherein the water storage tank includes an upper cover plate and a lower cover plate, the lower cover plate being provided with a maintenance hole for facilitating replacement of an internal part of the water storage tank; the upper cover plate is installed on the lower cover plate and covers the maintenance hole.