CN113811062A

CN113811062A - Plasma generating device and well milling method

Info

Publication number: CN113811062A
Application number: CN202010544705.5A
Authority: CN
Inventors: 陈培培; 高锐; 方易剑
Original assignee: ENN Science and Technology Development Co Ltd
Current assignee: ENN Science and Technology Development Co Ltd
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2021-12-17
Anticipated expiration: 2040-06-15

Abstract

The invention provides a plasma generating device and a well milling method. The device comprises: the cathode body, the anode body with a hollow interior and the air inlet mechanism; the first end of the cathode body is connected with the air inlet mechanism, the second end of the cathode body is provided with a bulge, and the radial size of the bulge is larger than that of the cathode body so as to form a convex structure; the anode body is sleeved outside the cathode body, a gap is formed between the anode body and the cathode body to form a discharge chamber, the first end of the anode body is connected with the air inlet mechanism, the second end of the anode body is a free end, the radial size of the second end of the anode body is not larger than that of the bulge, and a preset distance is reserved between the second end of the anode body and the bulge to form an annular discharge port communicated with the discharge chamber; the air inlet mechanism conveys working medium gas into the discharge chamber. In the invention, the plasma arcs generated in the discharge chamber are distributed in a circumferential shape after being output, so that the action area is enlarged, and when the plasma arcs are applied to well milling, the plasma arcs distributed in the circumferential shape cut well cementing materials, so that the well cementing materials can be conveniently taken out.

Description

Plasma generating device and well milling method

Technical Field

The invention relates to the technical field of drilling, in particular to a plasma generating device and a well milling method.

Background

Currently, the number of useless wells in the petroleum industry worldwide that are no longer producing oil is very large. However, the cement materials of the useless wells can be reused, but the cement materials are placed underground and are not convenient to take out.

Disclosure of Invention

In view of this, the invention provides a plasma generating device, which aims to solve the problem that the cementing material in the useless well in the prior art is not convenient to take out. The invention further provides a well milling method.

In one aspect, the present invention provides a plasma generating apparatus, comprising: the cathode body, the anode body with a hollow interior and the air inlet mechanism; the cathode body is of a columnar structure, the first end of the cathode body is connected with the air inlet mechanism, the second end of the cathode body is provided with a protruding part, and the radial size of the protruding part is larger than that of the cathode body so as to form a convex structure; the anode body is sleeved outside the cathode body, a gap is formed between the anode body and the cathode body to form a discharge chamber, the first end of the anode body is connected with the air inlet mechanism, the second end of the anode body is a free end, the radial size of the second end of the anode body is not larger than that of the bulge, and a preset distance is reserved between the second end of the anode body and the bulge to form an annular discharge port communicated with the discharge chamber; the air inlet mechanism is used for conveying working medium air into the discharge chamber.

Furthermore, in the plasma generating device, the second end of the cathode body and the convex part are in smooth transition; the anode body is of a cylindrical structure, and the inner diameter of the anode body is gradually increased from the first end to the second end, so that the second end of the anode body is of a horn-shaped structure.

Further, in the plasma generating apparatus, the air intake mechanism includes: a body; wherein, the body is all connected with the first end of the negative pole body and the first end of the positive pole body, and the inside of body is provided with the gas chamber, and the body is seted up air inlet and at least two gas outlets that communicate with the discharge chamber, and air inlet and each gas outlet all are linked together with the gas chamber.

Furthermore, in the plasma generating device, at least two spiral air outlet holes communicated with the gas cavity are formed in the body close to the discharge chamber, and an air outlet is formed at the outlet of each spiral air outlet hole.

Further, the plasma generating apparatus further includes: a cathode cooling mechanism; wherein, the cathode cooling mechanism is used for cooling the cathode body.

Further, in the plasma generator, the cathode cooling mechanism includes: the device comprises an outer pipe, an inner pipe for conveying cathode cooling water and an annular connecting piece; the outer pipe sleeve is arranged outside the inner pipe, a gap is reserved between the outer pipe sleeve and the inner pipe to form an annular space, the first end of the inner pipe is arranged outside the outer pipe, and the connecting piece is covered in the annular space; the outer tube is connected with the first end of the cathode body, the first end of the cathode body is provided with a cathode cooling channel which is sunken towards the second end, the second end of the inner tube is suspended in the cathode cooling channel, and a preset gap is formed between the second end of the inner tube and the inner wall of the cathode cooling channel; the side wall of the outer pipe is provided with an output port for outputting cathode cooling water; the air inlet mechanism is annular and is sleeved outside the outer pipe.

Further, the plasma generating apparatus further includes: an anode cooling mechanism; the anode cooling mechanism is arranged outside the anode body and used for cooling the anode body.

Further, in the plasma generator, the anode cooling mechanism includes: the device comprises a shell with openings at two ends, a partition plate and a cover body which are annular; the shell is sleeved outside the anode body, the first end of the shell is connected with the second end of the anode body, and the cover body is sleeved outside the first end of the anode body and connected with the second end of the shell; the partition plate is arranged in the shell, a first end of the partition plate is connected with the cover body, and a preset distance is reserved between a second end of the partition plate and a second end of the anode body; the cover body is provided with a cooling water inlet corresponding to the space between the partition plate and the anode body, and a cooling water outlet corresponding to the space between the partition plate and the shell.

In the invention, the gap between the anode body and the cathode body forms a discharge chamber, the first end of the discharge chamber corresponds to the air inlet mechanism, and the second end is in an open state to form an annular discharge port, thus, after being electrified, the cathode body and the anode body generate plasma electric arcs under the action of working medium gas and are output by the second end of the discharge chamber and then are distributed in a circumferential shape, the action area of the plasma electric arcs is effectively expanded, when the plasma generating device is applied to well milling, the plasma electric arcs distributed in the circumferential shape act on well cementing materials on a well wall, the well cementing materials are cut by using the high temperature of the plasma electric arcs, the well cementing materials are conveniently taken out and then are reused, and the problem that the well cementing materials in useless wells in the prior art are not convenient to take out is solved.

In another aspect, the present invention further provides a method for milling a well by using the plasma generating apparatus, including the following steps: a conveying step of conveying working medium gas into a discharge chamber between the cathode body and the anode body; the anode body is hollow and sleeved outside the cathode body, a discharge chamber is formed by a gap between the anode body and the cathode body, a bulge part with the radial dimension larger than that of the cathode body is arranged at one end of the cathode body, the radial dimension of the end part of the anode body close to the bulge part is not larger than that of the bulge part, and a preset distance is reserved between the end part of the anode body and the bulge part to form an annular discharge port communicated with the discharge chamber; an arc generating step of energizing the cathode body and the anode body to generate a plasma arc in the discharge chamber; a dividing step, namely dividing the well cementing material of the well wall after the plasma arc is output from the discharge port; and a taking-out step, in which the divided well cementing material is taken out.

Further, in the above well milling method, the arc generating step further includes: cooling the anode body; the cathode body is cooled.

In the invention, plasma electric arcs generated by the cathode body and the anode body after being electrified and under the action of the working medium gas are distributed in a circumferential shape after being output by the discharge chamber, so that the action area of the plasma electric arcs is effectively expanded, and the plasma electric arcs act on well cementing materials on a well wall to cut the well cementing materials, thereby facilitating the taking out and reutilization of the well cementing materials.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a schematic structural diagram of a plasma generating apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic view of working medium gas flow of the plasma generator according to the embodiment of the present invention;

FIG. 3 is a schematic view illustrating the flow of cooling water in the plasma generator according to the embodiment of the present invention;

fig. 4 is a flowchart of a method for milling a well according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Plasma generation device embodiment:

referring to fig. 1, fig. 1 is a schematic structural diagram of a plasma generation apparatus according to an embodiment of the present invention. As shown in the drawing, the plasma generating apparatus includes: cathode body 1, anode body 2, and air intake mechanism 3. The cathode body 1 is a columnar structure, the second end (the right end shown in fig. 1) of the cathode body 1 is provided with a protrusion 7, the radial dimension of the protrusion 7 is larger than that of the cathode body 1, and the cathode body 1 and the protrusion 7 form a convex structure. Preferably, the projection 7 is integrally formed with the cathode body 1. Preferably, the second end of the cathode body 1 and the convex portion 7 are in smooth transition. More preferably, the cathode body 1 has a cylindrical structure, the protrusions 7 also have a cylindrical structure, and the axial center line of the cathode body 1 and the axial center line of the protrusions 7 are aligned with each other.

The air inlet mechanism 3 is disposed on one side of the cathode body 1, and on the right side shown in fig. 1, the air inlet mechanism 3 is connected to the first end of the cathode body 1, and the connection may be a detachable connection or a fixed connection, which is not limited in this embodiment.

The anode body 2 is hollow, the anode body 2 is sleeved outside the cathode body 1, and a certain gap is formed between the anode body 2 and the cathode body 1, and the gap forms a discharge chamber 4. The first end (left end shown in fig. 1) of the anode body 2 is connected to the air inlet mechanism 3, the second end (right end shown in fig. 1) of the anode body 2 is a free end, the radial dimension of the second end of the anode body 2 is not greater than (i.e., not greater than) the radial dimension of the protrusion 7, and a preset distance is provided between the second end of the anode body 2 and the protrusion 7, which can be determined according to actual conditions, and this embodiment does not limit this. The distance between the second end of the anode body 2 and the boss 7 forms an annular discharge opening 8, the discharge opening 8 communicates with the discharge chamber 4, and the central axis of the discharge opening 8 is in the radial direction of the anode body 2, i.e. the discharge opening 8 is oriented in the radial direction of the anode body 2. Here, the radial direction is a direction in fig. 1, that is, a direction perpendicular to the longitudinal direction of the anode body 2.

Specifically, the cross section of the anode body 2 is circular, a gap is formed between the first end of the anode body 2 and the first end of the cathode body 1, the outer wall surface of the second end of the anode body 2 is arranged in the ring of the outer wall surface of the protrusion 7, or the two rings are overlapped, and the second end of the anode body 2 and the protrusion 7 are also provided with a gap, so that the discharge chamber 4 extends from the first end of the anode body 2 to the second end of the anode body 2. Since the cathode body 1 has a columnar structure, the discharge chamber 4 is annular as a whole. The discharge chamber 4 corresponding to the first end of the anode body 2 is denoted as a first end (right end shown in fig. 1) of the discharge chamber 4, and the discharge chamber 4 corresponding to the second end of the anode body 2 is denoted as a second end (left end shown in fig. 1) of the discharge chamber 4, and the annular space at the first end of the discharge chamber 4 is small and the annular space at the second end is large. The first end of the discharge chamber 4 is blocked by the air inlet mechanism 3, the second end of the discharge chamber 4 is in an open state to be communicated with the bottom of the well, and the open ends of the second end of the discharge chamber 4 are circularly distributed for one circle to form a discharge opening 8.

Preferably, the anode body 2 is a cylindrical structure, and the inner diameter of the anode body 2 gradually increases from the first end to the second end, so that the second end of the anode body 2 is in a horn-shaped structure. Specifically, the inner wall of the anode body 2 is in smooth transition, i.e. tapered, and the discharge chamber 4 is in an annular shape as a whole and has an arc-shaped wall surface.

The air inlet mechanism 3 is used for conveying working medium gas into the discharge chamber 4, and in the discharge chamber 4, the anode body 2 and the cathode body 1 are electrified to generate plasma arc under the action of the working medium gas.

The plasma generating device can be applied to well milling and can also be applied to other fields, and the embodiment does not limit the application. When the plasma generating device is applied to well milling, the plasma arc is conveyed to the well wall from the discharge chamber 4 and acts on the well wall, and then the plasma arc can divide the well cementing material of the well wall, so that the well cementing material can be taken out for reutilization.

It can be seen that, in this embodiment, the gap between the anode body 2 and the cathode body 1 forms the discharge chamber 4, the first end of the discharge chamber 4 corresponds to the air inlet mechanism 3, and the second end is in an open state to form an annular discharge port, so that the plasma arc generated by the cathode body 1 and the anode body 2 after being electrified and under the action of the working medium gas is output by the second end of the discharge chamber 4 and distributed in a circumferential shape, thereby effectively enlarging the action area of the plasma arc.

Referring to fig. 1 and 2, in the above embodiment, the intake mechanism 3 may include: a body 31. Wherein the body 31 is connected to both the first end of the cathode body 1 and the first end of the anode body 2, and there is a certain distance between the position of the first end of the cathode body 1 corresponding to the body 31 and the position of the first end of the anode body 2 corresponding to the body 31, the portion of the body 31 disposed between the first end of the cathode body 1 and the first end of the anode body 2 corresponds to the discharge chamber 4. The body 31 is provided with a gas chamber 32 inside, and the side wall of the body 31 is opened with a gas inlet which is communicated with the gas chamber 32. The body 31 is provided with at least two gas outlets corresponding to the discharge chamber 4, each gas outlet is communicated with both the gas cavity 32 and the discharge chamber 4, and the working medium gas is conveyed into the gas cavity 32 through the gas inlet and then conveyed into the discharge chamber 4 through each gas outlet.

Preferably, the gas outlets are uniformly distributed in the body 31 corresponding to the discharge chamber 4, so that the working medium gas can be uniformly distributed and delivered into the discharge chamber 4.

Preferably, at least two spiral air outlets 33 are arranged inside the body 31 near the discharge chamber 4, each spiral air outlet 33 is communicated with the gas cavity 32, and an outlet of each spiral air outlet 33 forms an air outlet, that is, an outlet of each spiral air outlet 33 is an air outlet. Specifically, each spiral air outlet 33 is disposed inside the body 31 and near the discharge chamber 4, an outlet of each spiral air outlet 33 is disposed at a position of the body 31 corresponding to the discharge chamber 4, and each spiral air outlet 33 is used for conveying the working medium gas in the gas cavity 32 to the discharge chamber 4. The setting of spiral venthole 33 can make in working medium gas carries to discharge chamber 4 evenly, especially when the quantity of spiral venthole 33 is at least two, the export of each spiral venthole 33 is circumference evenly distributed at body 31 corresponding to discharge chamber 4 department, not only is convenient for the transport of working medium gas, can also guarantee the evenly distributed of working medium gas in the discharge chamber, and then guarantees the stable production of plasma arc.

It can be seen that, in this embodiment, the working medium gas is conveyed to the gas cavity 32 for storage, and then conveyed to the discharge chamber 4 through the plurality of gas outlets, so that the working medium gas is stably and dispersedly conveyed to the discharge chamber 4, and the generated plasma arc is distributed more uniformly.

Referring to fig. 1 and 3, in the above embodiments, the plasma generation apparatus may further include: and a cathode cooling mechanism 5. The cathode cooling mechanism 5 is used for cooling the cathode body 1. Preferably, the cathode cooling mechanism 5 is provided with a cathode cooling water flow passage, and the temperature of the cathode body 1 is lowered and the temperature of the cathode cooling water is raised by heat exchange between the cathode cooling water and the cathode body 1, and then the cathode cooling water is output.

The cathode cooling mechanism 5 may include: an outer tube 51, an inner tube 52 and an annular connector 53. The outer tube 51 is sleeved outside the inner tube 52, and a certain gap is formed between the outer tube 51 and the inner tube 52, and the gap forms an annular space. A first end (right end shown in fig. 1) of the inner tube 52 is disposed outside the outer tube 51, and a second end (left end shown in fig. 1) of the inner tube 52 extends inside the outer tube 51. The connecting piece 53 covers the annular space, specifically, the connecting piece 53 is sleeved outside the inner tube 52, and the connecting piece 53 is connected with both the inner tube 52 and the outer tube 51, and the annular space is sealed by the connecting piece 53. In particular, the outer peripheral wall of the connector 53 is connected to the end of the outer tube 51.

The outer tube 51 is attached to the first end of the cathode body 1, and preferably, the outer tube 51 is detachably attached to the first end of the cathode body 1. The cathode body 1 has a cathode cooling channel 11 recessed toward the second end at the first end, the inner tube 52 is disposed inside the cathode cooling channel 11, and the second end of the inner tube 52 is suspended in the cathode cooling channel 11, i.e., a distance is provided between the second end of the inner tube 52 and the bottom (left end in fig. 1) of the cathode cooling channel 11. The inner tube 52 has a predetermined gap with the inner wall of the cathode cooling channel 11, which can be determined according to practical situations, and the embodiment does not limit this.

The inner pipe 52 is used for conveying cathode cooling water, the side wall of the outer pipe 51 is provided with an output port 511 for outputting the cathode cooling water, and then the cathode cooling water is conveyed into the cathode cooling channel 11 along the inner pipe 52, flows along the gap between the cathode cooling channel 11 and the inner pipe 52 after reaching the bottom of the cathode cooling channel 11, flows along the gap between the inner pipe 52 and the outer pipe 51, and is finally output through the output port 511. The cooling water can exchange heat with the cathode body 1 while flowing in the cathode cooling passage 11, so that the temperature of the cathode body 1 is lowered. Thus, the inside of the inner tube 52, the gap between the cathode cooling passage 11 and the inner tube 52, and the gap between the inner tube 52 and the outer tube 51 together constitute a cathode cooling water flow passage.

The air inlet mechanism 3 is annular, and the air inlet mechanism 3 is sleeved outside the outer tube 51. Specifically, the body 31 is hollow inside to form a ring shape, and the body 31 is sleeved outside the outer tube 51.

It can be seen that, in this embodiment, cool off negative pole body 1 through negative pole cooling mechanism 5, avoid negative pole body 1 high temperature and damage, and then the influence produces plasma arc to, cool down simple structure through negative pole cooling water to negative pole body 1.

Referring to fig. 1 and 3, in the above embodiments, the plasma generation apparatus may further include: and an anode cooling mechanism 6. The anode cooling mechanism 6 is provided outside the anode body 2, and the anode cooling mechanism 6 is used for cooling the anode body 2. Preferably, the anode cooling mechanism 6 is provided with an anode cooling water flow passage, and the anode cooling water exchanges heat with the anode body 2, so that the temperature of the anode body 2 is lowered, the temperature of the anode cooling water is raised, and the anode cooling water is output.

The anode cooling mechanism 6 may include: a case 61, a partition plate 62, and a cover 63. Both ends of the casing 61 are open ends, the casing 61 is sleeved outside the anode body 2, and a first end (a left end shown in fig. 3) of the casing 61 is connected to a second end of the anode body 2. Since the inner diameter of the first end of the anode body 2 is smaller than the inner diameter of the second end, a certain distance is provided between the second end (the right end shown in fig. 3) of the casing 61 and the first end of the anode body 2, the cover 63 is annular, and the cover 63 is sleeved outside the first end of the anode body 2 and connected with the second end of the casing 61, so that the casing 61, the anode body 2 and the cover 63 enclose a conical space.

The partition plate 62 is annular, and the partition plate 62 is disposed in the housing 61, that is, the partition plate 62 is disposed in the conical space. The first end (right end shown in fig. 3) of the partition plate 62 is connected to the cover 63, and a preset distance is formed between the second end (left end shown in fig. 3) of the partition plate 62 and the second end of the anode body 2, and the preset distance may be determined according to actual conditions, which is not limited in this embodiment. The partition plate 62 divides the tapered space into two spaces, and the two spaces communicate at the end of the second end of the partition plate 62.

The cover 63 has a cooling water inlet 631 corresponding to the space between the partition plate 62 and the anode body 2, and the cover 63 has a cooling water outlet 632 corresponding to the space between the partition plate 62 and the casing 61, so that the anode cooling water is delivered to the space between the partition plate 62 and the anode body 2 through the cooling water inlet 631, flows to the space between the partition plate 62 and the casing 61 through the gap between the second end of the partition plate 62 and the second end of the anode body 2, and is output through the cooling water outlet 632. The anode cooling water exchanges heat with the anode body 2 when flowing in the conical space to cool the anode body 2. Thus, the space between the separator 62 and the anode body 2, the gap between the second end of the separator 62 and the second end of the anode body 2, and the space between the separator 62 and the case 61 together constitute an anode cooling water flow passage.

It can be seen that, in this embodiment, cooling of anode body 2 through anode cooling mechanism 6 avoids anode body 2 high temperature and damage, and then the influence produces plasma arc to, cool down anode body 2 through anode cooling water, simple structure.

Referring to fig. 1, in order to make the structure of each component more compact and the whole structure more beautiful, the body 31 of the air inlet mechanism 3 is sleeved outside the outer tube 51, and the first end (the left end shown in fig. 1) of the body 31 contacts with the first end of the cathode body 1, the outside of the second end (the right end shown in fig. 1) of the body 31 is provided with an annular body 34, the overall cross-sectional shape of the annular body 34 connected with the body 31 is T-shaped, the annular body 34 is provided with an air inlet channel 35, and the air inlet channel 35 is communicated with the air inlet of the body 31 and further communicated with the air cavity 32. Preferably, the body 31 is integrally formed with the annular body 34.

In specific implementation, the cover 63 may contact and connect with the annular body 34, and then the annular body 34 has corresponding communication ports 633 at the position corresponding to the cooling water input port 631 and the cooling water output port 632 of the cover 63, so that the anode cooling water is sequentially transmitted to the space between the partition plate 62 and the anode body 2 through one of the communication ports 633 and the cooling water input port 631, and the anode cooling water flowing out from the space between the partition plate 62 and the housing 61 is sequentially output through the cooling water output port 632 and the other corresponding communication port 633.

In summary, in the embodiment, the first end of the discharge chamber 4 corresponds to the gas inlet mechanism 3, and the second end is in an open state to form an annular discharge port, so that the plasma arc generated by the cathode body 1 and the anode body 2 after being electrified and under the action of the working medium gas is output by the second end of the discharge chamber 4 and distributed in a circumferential shape, thereby effectively enlarging the action area of the plasma arc.

The embodiment of the well milling method comprises the following steps:

the embodiment also provides a well milling method, and referring to fig. 4, fig. 4 is a flowchart of the well milling method provided by the embodiment of the invention. As shown in the figure, the well milling method comprises the following steps:

and a conveying step S1, conveying working medium gas into the discharge chamber between the cathode body and the anode body. The cathode body is hollow inside and sleeved outside, a discharge chamber is formed by a gap between the anode body and the cathode body, a protruding portion with the radial size larger than that of the cathode body is arranged at one end of the cathode body, the radial size of the end portion, close to the protruding portion, of the anode body is not larger than (namely smaller than or equal to) that of the protruding portion, and a preset distance is reserved between the end portion of the anode body and the protruding portion to form an annular discharge port communicated with the discharge chamber.

Specifically, referring to fig. 1, the cathode body 1 is a columnar structure, and the second end (the right end shown in fig. 1) of the cathode body 1 is provided with a protruding portion 7, and the radial dimension of the protruding portion 7 is larger than that of the cathode body 1, so that the cathode body 1 and the protruding portion 7 form a convex structure. Preferably, the projection 7 is integrally formed with the cathode body 1. Preferably, the second end of the cathode body 1 and the convex portion 7 are in smooth transition. More preferably, the cathode body 1 has a cylindrical structure, the protrusions 7 also have a cylindrical structure, and the axial center line of the cathode body 1 and the axial center line of the protrusions 7 are aligned with each other.

The anode body 2 is hollow, the anode body 2 is sleeved outside the cathode body 1, and a certain gap is formed between the anode body 2 and the cathode body 1, and the gap forms a discharge chamber 4. The first end (left end shown in fig. 1) of the anode body 2 corresponds to the first end of the cathode body 1, the second end (right end shown in fig. 1) of the anode body 2 is a free end, the radial dimension of the second end of the anode body 2 is not greater than the radial dimension of the boss 7, and a predetermined distance is provided between the second end of the anode body 2 and the boss 7 to form an annular discharge port 8, the discharge port 8 is communicated with the discharge chamber 4, and the central axis of the discharge port 8 is along the radial direction of the anode body 2, that is, the discharge port 8 is oriented in the radial direction of the anode body 2. Here, the radial direction is a direction in fig. 1, that is, a direction perpendicular to the longitudinal direction of the anode body 2.

The first end of the cathode body 1 and the first end of the anode body 2 are both connected with an air inlet mechanism 3, and the air inlet mechanism 3 is used for conveying working medium gas into the discharge chamber 4. The specific implementation process of the cathode body 1, the anode body 2 and the air inlet mechanism 3 may refer to the above description, and the detailed description of this embodiment is omitted here.

An arc generating step S2, energizing the cathode body and the anode body to generate a plasma arc within the discharge chamber.

Specifically, the cathode body and the anode body are electrified to generate plasma arc under the action of the working medium gas.

When the plasma arc is generated, the temperatures of the cathode body and the anode body are increased, and then the anode body and the cathode body are cooled. Preferably, the anode body is cooled by anode cooling water; and/or cooling the cathode body by cathode cooling water.

And a dividing step S3, wherein the plasma arc is output by the discharge port and then the well cementing material of the well wall is divided.

Specifically, the plasma arc is also distributed in a circumferential shape after being output from the discharge port, and further acts on the well cementing material on the well wall, so that the well cementing material is separated.

And a taking-out step S4, wherein the divided cementing material is taken out.

It can be seen that, in the embodiment, after the cathode body and the anode body are electrified and the plasma arc generated under the action of the working medium gas is output by the discharge chamber and distributed in a circumferential shape, the action area of the plasma arc is effectively enlarged, and the plasma arc acts on the well cementing material on the well wall to cut the well cementing material, so that the well cementing material can be conveniently taken out and reused.

It should be noted that the principle of the plasma generating apparatus and the method of milling a well by using the plasma generating apparatus in the present invention is the same, and the related points can be referred to each other.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A plasma generating apparatus, comprising: a cathode body (1), an anode body (2) with a hollow interior and an air inlet mechanism (3); wherein the content of the first and second substances,

the cathode body (1) is of a columnar structure, the first end of the cathode body (1) is connected with the air inlet mechanism (3), the second end of the cathode body (1) is provided with a protruding part, and the radial size of the protruding part is larger than that of the cathode body (1) so as to form a convex structure;

the anode body (2) is sleeved outside the cathode body (1) and has a gap with the cathode body (1) to form a discharge chamber (4), the first end of the anode body (2) is connected with the air inlet mechanism (3), the second end of the anode body (2) is a free end, the radial size of the second end of the anode body is not larger than that of the bulge, and a preset distance is reserved between the second end of the anode body (2) and the bulge to form an annular discharge port (8) communicated with the discharge chamber (4);

the air inlet mechanism (3) is used for conveying working medium gas into the discharge chamber (4).

2. The plasma generating apparatus according to claim 1,

the second end of the cathode body (1) is in smooth transition with the lug boss;

the anode body (2) is of a cylindrical structure, and the inner diameter of the anode body (2) is gradually increased from a first end to a second end, so that the second end of the anode body (2) is of a horn-shaped structure.

3. The plasma generating apparatus according to claim 1, wherein the gas inlet mechanism (3) comprises: a body (31); wherein the content of the first and second substances,

the body (31) is connected with the first end of the cathode body (1) and the first end of the anode body (2), a gas cavity (32) is formed in the body (31), an air inlet and at least two air outlets communicated with the discharge chamber (4) are formed in the body (31), and the air inlet and the air outlets are communicated with the gas cavity (32).

4. A plasma-generating device according to claim 3, characterized in that the body (31) near the discharge chamber (4) is internally provided with at least two spiral gas outlets (33) communicating with the gas cavity (32), the outlet of each spiral gas outlet (33) forming one gas outlet.

5. The plasma generating apparatus according to claim 1, further comprising: a cathode cooling mechanism (5); wherein the content of the first and second substances,

the cathode cooling mechanism (5) is used for cooling the cathode body (1).

6. Plasma-generating device according to claim 5, characterized in that said cathode cooling means (5) comprise: an outer pipe (51), an inner pipe (52) for conveying cathode cooling water, and an annular connecting piece (53); wherein the content of the first and second substances,

the outer pipe (51) is sleeved outside the inner pipe (52) and has a gap with the inner pipe (52) to form an annular space, the first end of the inner pipe (52) is arranged outside the outer pipe (51), and the connecting piece (53) is covered in the annular space;

the outer tube (51) is connected with a first end of the cathode body (1), a cathode cooling channel (11) which is concave towards a second end is formed in the first end of the cathode body (1), the second end of the inner tube (52) is suspended in the cathode cooling channel (11), and a preset gap is formed between the second end of the inner tube and the inner wall of the cathode cooling channel (11);

an output port (511) for outputting the cathode cooling water is formed in the side wall of the outer pipe (51);

the air inlet mechanism (3) is annular and is sleeved outside the outer pipe (51).

7. The plasma generating apparatus according to claim 1, further comprising: an anode cooling mechanism (6); wherein the content of the first and second substances,

the anode cooling mechanism (6) is arranged outside the anode body (2) and used for cooling the anode body (2).

8. The plasma generating apparatus according to claim 7, wherein the anode cooling mechanism (6) comprises: a shell (61) with two open ends, a partition plate (62) and a cover body (63) which are annular; wherein the content of the first and second substances,

the shell (61) is sleeved outside the anode body (2), a first end of the shell (61) is connected with a second end of the anode body (2), and the cover body (63) is sleeved outside the first end of the anode body (2) and connected with the second end of the shell (61);

the separation plate (62) is arranged in the shell (61), a first end of the separation plate (62) is connected with the cover body (63), and a preset distance is reserved between a second end of the separation plate (62) and a second end of the anode body (2);

the cover body (63) is provided with a cooling water inlet (631) corresponding to the space between the partition plate (62) and the anode body (2), and the cover body (63) is provided with a cooling water outlet (632) corresponding to the space between the partition plate (62) and the shell (61).

9. A method of milling a well, comprising the steps of:

a conveying step of conveying working medium gas into a discharge chamber between the cathode body and the anode body; the anode body is hollow and sleeved outside the cathode body, a gap between the anode body and the cathode body forms the discharge chamber, a bulge part with the radial dimension larger than that of the cathode body is arranged at one end of the cathode body, the radial dimension of the end part of the anode body close to the bulge part is not larger than that of the bulge part, and a preset distance is reserved between the end part of the anode body and the bulge part to form an annular discharge port communicated with the discharge chamber;

an arc generating step of energizing the cathode body and the anode body to generate a plasma arc in the discharge chamber;

a cutting step, wherein the plasma arc is output by the discharge port and then is used for cutting the well cementation material of the well wall;

and a taking-out step, in which the divided well cementing material is taken out.

10. The well milling method of claim 9, wherein the arc producing step further comprises:

cooling the anode body;

and cooling the cathode body.