CN115126438A

CN115126438A - Electrodeless variable-diameter leakage blocking device and method thereof

Info

Publication number: CN115126438A
Application number: CN202110318037.9A
Authority: CN
Inventors: 彭元超; 杨赟; 韦海防; 仵磊; 韩朝辉; 李婧; 李晓黎; 张弢; 赵恒�; 周文兵; 曹健伟; 王磊
Original assignee: China National Petroleum Corp; CNPC Chuanqing Drilling Engineering Co Ltd
Current assignee: China National Petroleum Corp; CNPC Chuanqing Drilling Engineering Co Ltd
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2022-09-30
Anticipated expiration: 2041-03-25
Also published as: CN115126438B

Abstract

The invention provides an electrodeless variable-diameter leakage blocking device and a method thereof, wherein the device comprises three hollow pipe columns which are concentrically sleeved, and a central pipe, an expansion rubber cylinder and a thin-wall metal pipe are sequentially arranged from inside to outside; the end annular spaces of any two adjacent tubular columns in the three tubular columns are sealed and closed. The stepless expansion rubber cylinder is realized through the stepless variable diameter support ring, the pressure of the central pipe and the annular cavity of the expansion rubber cylinder can be controlled through the ground pump truck, so that the expansion size of the expansion rubber cylinder is controlled, liquid in a shaft is prevented from entering a stratum, other underground complex conditions and major accidents caused by lost circulation, such as collapse, drilling sticking, blowout and the like, can be prevented, meanwhile, the cost of drilling fluid materials, drilling machines and personnel can be saved, and the drilling effect and efficiency are improved.

Description

Electrodeless variable-diameter plugging device and method

Technical Field

The invention belongs to the field of oil field downhole tools, and particularly relates to an electrodeless variable-diameter plugging device and a method thereof.

Background

The main lost liquid of the lost circulation is drilling fluid, cement slurry, completion fluid and other working fluids which are immersed into the stratum, the lost circulation with different degrees exists in most common drilling processes, the serious lost circulation can cause the pressure imbalance in the well, the normal drilling work is influenced, the instability of the well wall is caused, the stratum fluid is induced to flow into the shaft and generate the blowout phenomenon, even other underground complex conditions and major accidents such as well collapse, stuck drilling, blowout and the like can be caused, the damage to the drilling work is great, the well is even scrapped, the huge economic loss is caused, and the following problems are caused by the stratum lost circulation in the actual drilling and well cementation operation at present:

(1) and a large amount of slurry materials are consumed for plugging, so that the construction cost is increased.

(2) And (3) prolonging the construction period:

when the well is lost and cannot be continued, the well must be stopped to perform leaking stoppage, wherein the leaking stoppage is performed for a few hours, and the leaking stoppage is performed for a plurality of days or even months.

(3) The liquid level in the well is reduced by the lost circulation, the pressure of the liquid column is reduced, the pressure of the liquid column cannot balance the higher formation pressure, blowout occurs, well collapse and even drilling sticking occur, well blowout and drilling sticking accidents occur, if the treatment is improper, partial well sections or the whole well sections can be scrapped, and huge economic loss is caused.

(4) The well cementation quality is influenced:

the lost circulation well is often difficult to bear the cement slurry pressure, so that annular cement-free sealing is realized or the well cementation quality is not achieved during well cementation, the service life of the well is further shortened, and the problem that part of wells adopt graded well cementation with high cost cannot be solved.

According to statistics, the worldwide well leakage occurrence rate accounts for 20% -25% of the total number of drilled wells, while the treatment of well leakage is a difficult point in petroleum drilling, particularly the complex well leakage problem is troublesome, the malignant well leakage loss accounts for more than 50% of the total loss of well leakage, and the plugging is difficult to succeed, so that the prevention and treatment research for strengthening the malignant well leakage is urgently needed.

Disclosure of Invention

The invention aims to provide an electrodeless variable-diameter plugging device and a method thereof, which are used for overcoming the technical defects.

In order to solve the technical problems, the invention provides an electrodeless variable-diameter leakage blocking device which comprises three hollow tubular columns which are concentrically sleeved, wherein a central tube, an expansion rubber cylinder and a thin-wall metal tube are sequentially arranged from inside to outside;

the end annular spaces of any two adjacent tubular columns in the three tubular columns are sealed and closed.

Preferably, the outer pipe wall of the thin-walled metal pipe is sleeved with two support rings, namely an upper support ring and a lower support ring, wherein the upper support ring is close to the upper end part of the thin-walled metal pipe, and the lower support ring is close to the lower end part of the thin-walled metal pipe.

Furthermore, the support rings have the same structure and comprise an inner diameter-changing ring and an outer diameter-changing ring which can synchronously change diameters, the outer diameter-changing ring is of a circular ring structure formed by splicing a plurality of first arc-shaped pieces, two adjacent first arc-shaped pieces are connected or spaced, and first sawteeth are uniformly distributed on the inner arc surface of each first arc-shaped piece; the inner diameter-changing ring is of a circular ring structure formed by splicing a plurality of second arc-shaped pieces, two adjacent second arc-shaped pieces are connected or spaced, and second sawteeth are uniformly distributed on the outer arc surface of each second arc-shaped piece;

the second saw teeth of the inner reducing ring are meshed with the first saw teeth of the outer reducing ring.

Furthermore, the inner diameter changing ring is of a circular ring structure formed by splicing four first arc-shaped parts at uniform intervals, the outer diameter changing ring is of a circular ring structure formed by splicing four second arc-shaped parts at uniform intervals, each second arc-shaped part is over against the interval of two adjacent first arc-shaped parts, and the second saw teeth of each second arc-shaped part are meshed with the first saw teeth of the two adjacent first arc-shaped parts over against the second arc-shaped parts at the same time.

Preferably, the first saw teeth and the second saw teeth are oblique teeth which are obliquely arranged, and the same first arc-shaped piece or the same second arc-shaped piece is provided with the saw teeth in two oblique directions, and the oblique teeth are symmetrically arranged on two sides of the middle point by taking the middle point of the first saw teeth as a boundary or taking the middle point of the second saw teeth as a boundary.

Furthermore, a plurality of rivets are uniformly distributed on the peripheral surface of the outer reducing ring at intervals.

Preferably, the outer tube wall of the central tube is sleeved with at least two sealing elements, namely an upper sealing element at the top and a lower sealing element at the bottom, wherein the inner peripheral surfaces of the upper sealing element and the lower sealing element are tightly attached to the outer tube wall of the central tube, and the outer peripheral surfaces of the upper sealing element and the lower sealing element are tightly attached to the inner tube wall of the expansion rubber tube.

Preferably, the upper end and the lower end of the outer cylinder wall of the expansion rubber cylinder are respectively sleeved with an annular rubber cylinder top seat and an annular rubber cylinder base, wherein the inner circumferential surfaces of the annular rubber cylinder top seat and the annular rubber cylinder base are tightly attached to the outer cylinder wall of the expansion rubber cylinder, and the thin-wall metal pipe is clamped between the lower annular end surface of the annular rubber cylinder top seat and the upper annular end surface of the annular rubber cylinder base.

The invention also provides a stepless reducing leakage stopping method, which at least comprises a stepless reducing leakage stopping device, and specifically comprises the following steps:

acquiring a target leakage point;

placing the stepless variable diameter plugging device into a target well;

starting a ground pump truck, and pumping high-pressure liquid into the stepless variable-diameter plugging device;

high-pressure liquid is input into the central pipe and is discharged into the annular cavities of the central pipe and the expansion rubber cylinder through the liquid inlet hole;

the expansion rubber cylinder expands to extrude the thin-wall metal pipe, and the thin-wall metal pipe expands;

continuously pumping high-pressure liquid until the support ring is propped open and embedded into the wall of the target wellbore;

stopping the pump to release pressure, shrinking the expansion rubber cylinder, patching and plugging a target leakage point by the thin-wall metal pipe and separating from the expansion rubber cylinder;

and lifting the pipe column to lift the stepless variable diameter plugging device.

Further, thin wall metal pipe expands and opens, continues to pump high-pressure liquid, and the support ring struts and imbeds target wellbore wall, specifically includes:

the thin-wall metal tube expands, and the upper support ring and the lower support ring are opened at the same time;

the inner reducing ring and the outer reducing ring of each support ring are synchronously expanded in a reducing way;

and stabilizing the pressure for 5-10 minutes to wedge the rivet of the outer reducing ring into the wall of the target wellbore.

The invention has the following beneficial effects:

(1) the invention adopts the stepless expansion rubber cylinder, can control the pressure of the central pipe and the annular cavity of the expansion rubber cylinder through the ground pump truck, thereby controlling the expansion size of the expansion rubber cylinder, preventing liquid in a shaft from entering a stratum, preventing other underground complex conditions and major accidents caused by lost circulation, such as collapse, sticking, blowout and the like, simultaneously saving the cost of drilling fluid materials, drilling machines and personnel, and improving the drilling effect and efficiency.

(2) The stepless expansion rubber cylinder is mainly realized by the inner reducing ring and the outer reducing ring which are concentrically sleeved, the inner reducing ring and the outer reducing ring are expanded in a single direction by meshing, and the self-locking effect of the meshing helical teeth is combined, so that the purpose that the support ring can be expanded but cannot be reduced is achieved, the firmness of the repair leakage point of the thin-wall metal pipe is ensured, and the thin-wall metal pipe is not easy to separate.

In order to make the aforementioned and other objects of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a sectional view of a stepless variable diameter plugging device.

FIG. 2 is a schematic structural diagram of the support ring without diameter-changing expansion.

FIG. 3 is a schematic view of a structure of the support ring after diameter reduction and expansion.

Description of reference numerals:

1. a central tube; 2. expanding the rubber cylinder; 3. a thin-walled metal tube; 4. a liquid inlet hole; 5. an upper support ring; 6. a lower support ring; 7. an inner reducing ring; 8. an outer reducing ring; 9. riveting; 10. an upper seal member; 11. a lower seal member; 12. a ring-shaped rubber cylinder footstock; 13. an annular rubber cylinder base; 14. target miss points.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

In the invention, the upper, lower, left and right in the drawings are regarded as the upper, lower, left and right of the stepless variable diameter plugging device described in this specification.

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their context in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

First embodiment

The embodiment relates to an electrodeless variable-diameter plugging device, which comprises three hollow pipe columns concentrically sleeved with each other, wherein a central pipe 1, an expansion rubber cylinder 2 and a thin-wall metal pipe 3 are sequentially arranged from inside to outside, a plurality of liquid inlet holes 4 are formed in the wall of the central pipe 1, the axial center line of each liquid inlet hole 4 is perpendicular to the axial center line of the central pipe 1, at least one support ring capable of being changed in diameter and self-locked is sleeved on the outer pipe wall of the thin-wall metal pipe 3, and the annular spaces of the end parts of any two adjacent pipe columns in the three pipe columns are sealed and closed.

The working principle of the stepless variable diameter plugging device is as follows:

obtaining a target leakage point 14, lowering the stepless reducing plugging device into a target well, starting a ground pump truck, pumping high-pressure liquid into the stepless reducing plugging device, inputting the high-pressure liquid into the central pipe 1, discharging the high-pressure liquid into annular cavities of the central pipe 1 and the expansion rubber cylinder 2 through the liquid inlet hole 4, expanding the expansion rubber cylinder 2 by 20-40%, pushing and extruding the thin-wall metal pipe 3, expanding the thin-wall metal pipe 3, continuously pumping the high-pressure liquid until the support ring is expanded and embedded into the wall of the target well, stopping the pump for pressure relief, shrinking the expansion rubber cylinder 2, subsiding and plugging the target leakage point by the thin-wall metal pipe 3 and separating from the expansion rubber cylinder 2, lifting the pipe column, and taking out the stepless reducing plugging device.

Target leak-off point 14 as described above with reference to fig. 1, the thin-walled metal tube 3 completely covers the target leak-off point 14 to ensure leak-off integrity.

The high pressure liquid may be clear water, drilling mud or the like, preferably at a pressure such that the expansion bladder 2 gradually expands, e.g. 50 MPa.

The liquid inlet hole 4 is used for guiding high-pressure liquid into the annular cavities of the central tube 1 and the expansion rubber cylinder 2, and in order to enable the high-pressure liquid to fill the annular cavities quickly, the liquid inlet hole 4 can be formed in the middle of the central tube 1, but is not limited to this, and can also be formed in any other position of the central tube 1.

In order to ensure the pressure of the high-pressure liquid and the reasonable expansion of the expansion rubber sleeve 2, the upper end and the lower end of the annular cavities of the central pipe 1 and the expansion rubber sleeve 2 are required to be closed, so that the embodiment provides that the end annular spaces of any two adjacent pipe columns in the three pipe columns are sealed and closed.

After the expansion rubber sleeve 2 is expanded, the thin-wall metal pipe 3 is pushed to expand along the radial direction, meanwhile, the support ring on the thin-wall metal pipe 3 is expanded along the radial direction, along with the continuous expansion of the expansion rubber sleeve 2, the thin-wall metal pipe 3 is continuously expanded along the radial direction at the same time until the support ring is wedged into the wall of the target well bore, then the expansion is continued, the thin-wall metal pipe 3 is embedded into the wall of the target well bore, the target leakage point 14 is completely covered by the thin-wall metal pipe 3, and the leakage stoppage of the leakage point is completed.

The support ring not only guides and limits the thin-walled metal tube 3, but also has a self-locking function to prevent the thin-walled metal tube 3 from shrinking.

In practical application, a plurality of stepless variable-diameter leakage stopping devices can be connected in series in a drill rod string, leakage stopping of a plurality of leakage points is achieved simultaneously, and the stepless variable-diameter leakage stopping devices can be screwed in the drill rod string through threads.

Second embodiment

Referring to fig. 1, the outer tubular wall of the thin-walled metal tube 3 is sleeved with two support rings, an upper support ring 5 and a lower support ring 6, wherein the upper support ring 5 is close to the upper end of the thin-walled metal tube 3, and the lower support ring 6 is close to the lower end of the thin-walled metal tube 3.

The number of the support rings is not unique, and a corresponding number of support rings can be sleeved according to needs, and two support rings are preferred in the embodiment, on one hand, the balanced support of the thin-wall metal pipe 3 is considered, and on the other hand, the thin-wall metal pipe 3 can be ensured to be stably sealed and cover the target leakage point 14, so that the liquid in the shaft is prevented from being communicated with the formation liquid.

Referring to fig. 2 and 3, the support rings have the same structure and comprise an inner diameter-changing ring 7 and an outer diameter-changing ring 8 which can synchronously change diameters, wherein the outer diameter-changing ring 8 is a circular ring structure formed by assembling a plurality of first arc-shaped pieces, two adjacent first arc-shaped pieces are connected or spaced, and first sawteeth are uniformly distributed on the inner arc surface of each first arc-shaped piece; the inner reducing ring 7 is a circular ring structure formed by assembling a plurality of second arc-shaped parts, two adjacent second arc-shaped parts are connected or spaced, second sawteeth are uniformly distributed on the outer arc surface of each second arc-shaped part, and the second sawteeth of the inner reducing ring 7 are meshed with the first sawteeth of the outer reducing ring 8.

Thin wall metal pipe 3 is located to interior reducing ring 7 cover, and when thin wall metal pipe 3 expanded gradually, interior reducing ring 7 diameter increase, because inside and outside reducing ring passes through the sawtooth meshing and is in the same place, promotes inside and outside sawtooth meshing through the expanding force of interior reducing ring 7, and outer reducing ring 8 is also expanded in step, lasts the inflation until support ring embedding target wellbore wall, restriction thin wall metal pipe 3's radial activity.

The inner diameter changing ring 7 is a circular ring structure formed by splicing four first arc-shaped parts at uniform intervals, the outer diameter changing ring 8 is a circular ring structure formed by splicing four second arc-shaped parts at uniform intervals, each second arc-shaped part is just opposite to the interval of two adjacent first arc-shaped parts, and second saw teeth of each second arc-shaped part are meshed with the first saw teeth of the two adjacent first arc-shaped parts which are just opposite to the second arc-shaped parts at the same time.

As shown in fig. 3, if the second arc-shaped parts of the outer diameter-changing ring 8 are numbered clockwise, they are numbered ABCD in sequence, where a is the second arc-shaped part right above, and taking a and B as an example, the same first arc-shaped part is engaged with the second arc-shaped part a and the second arc-shaped part B at the same time, so that the inner diameter-changing ring and the outer diameter-changing ring can be connected, and the diameter-changing size can be controlled by adjusting the number of the arc-shaped parts.

The self-locking function of the support ring is realized by the following structure:

the first sawtooth and the second sawtooth are oblique teeth obliquely arranged, the same first arc-shaped piece or the same second arc-shaped piece is provided with sawteeth in two oblique directions, the middle point of the first sawtooth is used as a boundary or the middle point of the second sawtooth is used as a boundary, and the oblique teeth symmetrically arranged are arranged on two sides of the middle point.

Fig. 2 shows a state when the support ring is not expanded, when the expansion rubber sleeve 2 is expanded by high-pressure liquid, the thin-wall metal tube 3 is expanded together with the upper and lower support rings, and the support ring is expanded, as shown in fig. 3, the diameter of the support ring is increased, because the inner and outer variable diameter rings are meshed together with the teeth with certain inclination, the inner and outer teeth are pushed to be meshed by the expansion force of the inner variable diameter ring 7, the diameter of the support ring can only be increased and can not be contracted, namely, once the support ring is expanded and expanded, the support ring can not be retracted, and the self-locking function is realized.

In order to limit the expanded thin-wall metal pipe 3 and prevent the expanded thin-wall metal pipe from moving up and down along a shaft, the expanded thin-wall metal pipe 3 needs to be limited in the axial direction, therefore, a plurality of rivets 9 are uniformly distributed on the outer peripheral surface of the outer reducing ring 8 at intervals, the thin-wall metal pipe 3 is embedded into a well wall through the rivets 9 after the support ring is expanded, the up-and-down movement of the thin-wall metal pipe is limited, and the axial direction and the radial direction of the thin-wall metal pipe 3 are limited and well fixed.

The rivets 9 shown in figures 2 and 3, it can be seen that each rivet 9 is provided with barbs, the purpose of which is to guide the support ring into the target wellbore wall, the barbs preventing the support ring from backing out, i.e. further ensuring that the support ring is firmly embedded in the target wellbore wall.

Referring to fig. 1, the outer tube wall of the central tube 1 is sleeved with at least two sealing elements, which are an upper sealing element 10 located at the top and a lower sealing element 11 located at the bottom, wherein the inner circumferential surfaces of the upper sealing element 10 and the lower sealing element 11 are both tightly attached to the outer tube wall of the central tube 1, and the outer circumferential surfaces of the upper sealing element 10 and the lower sealing element 11 are both tightly attached to the inner tube wall of the expansion rubber tube 2.

High-pressure liquid gets into the annular cavity of center tube 1 and expansion packing element 2 through feed liquor hole 4, and because the sealed of two sealing members, the pressurize can be gathered to high-pressure liquid in the annular cavity, and then can promote expansion packing element 2, avoids releasing pressure in advance, influences the inflation effect of expansion packing element 2.

The upper end and the lower end of the outer cylinder wall of the expansion rubber cylinder 2 are respectively sleeved with an annular rubber cylinder top seat 12 and an annular rubber cylinder base 13, wherein the inner circumferential surfaces of the annular rubber cylinder top seat 12 and the annular rubber cylinder base 13 are tightly attached to the outer cylinder wall of the expansion rubber cylinder 2, and the thin-wall metal pipe 3 is clamped between the lower annular end surface of the annular rubber cylinder top seat 12 and the upper annular end surface of the annular rubber cylinder base 13.

The annular rubber sleeve top seat 12 and the annular rubber sleeve base seat 13 can provide a seat body for the expansion rubber sleeve 2, and simultaneously play a role in limiting the thin-wall metal pipe 3, so that the thin-wall metal pipe 3 is prevented from slipping in a normal state, and the thin-wall metal pipe 3 can be smoothly embedded into the target well bore wall when being pushed.

In the drilling and cementing process, the stratum leakage is in an open hole section, and the change range of the hole diameter size of the open hole section at the leakage position is large due to different hole diameter expansion rates.

Third embodiment

The embodiment protects a stepless reducing leakage blocking method, which at least comprises a stepless reducing leakage blocking device, and specifically comprises the following steps:

acquiring a target leakage point;

placing the stepless variable diameter plugging device into a target well;

continuously pumping high-pressure liquid until the support ring is unfolded and embedded into the wall of the target wellbore;

Wherein thin-walled metal pipe expands and opens, lasts the pump sending high-pressure liquid, and the support ring struts and imbeds target wellbore wall, specifically includes:

the inner reducing ring and the outer reducing ring of each support ring are synchronously subjected to reducing and expanding;

Electrodeless reducing plugging device, its characterized in that: the pipe comprises three hollow pipe columns which are concentrically sleeved, a central pipe 1, an expansion rubber cylinder 2 and a thin-wall metal pipe 3 are sequentially arranged from inside to outside, a plurality of liquid inlet holes 4 are formed in the pipe wall of the central pipe 1, the axial center line of each liquid inlet hole 4 is perpendicular to the axial center line of the central pipe 1, and at least one diameter-variable self-locking support ring is sleeved on the outer pipe wall of the thin-wall metal pipe 3;

The outer pipe wall of the thin-wall metal pipe 3 is sleeved with two support rings, namely an upper support ring 5 and a lower support ring 6, wherein the upper support ring 5 is close to the upper end part of the thin-wall metal pipe 3, and the lower support ring 6 is close to the lower end part of the thin-wall metal pipe 3.

The support rings have the same structure and comprise an inner diameter-changing ring 7 and an outer diameter-changing ring 8 which can synchronously change diameters, the outer diameter-changing ring 8 is a circular ring structure formed by assembling a plurality of first arc-shaped pieces, two adjacent first arc-shaped pieces are connected or spaced, and first sawteeth are uniformly distributed on the inner arc surface of each first arc-shaped piece; the inner diameter-changing ring 7 is a circular ring structure formed by splicing a plurality of second arc-shaped pieces, two adjacent second arc-shaped pieces are connected or spaced, and second sawteeth are uniformly distributed on the outer arc surface of each second arc-shaped piece;

the second saw teeth of the inner reducing ring 7 are meshed with the first saw teeth of the outer reducing ring 8.

The first sawtooth and the second sawtooth are oblique teeth which are obliquely arranged, the same first arc-shaped piece or the same second arc-shaped piece is provided with sawteeth in two oblique directions, the middle point of the first sawtooth is used as a boundary or the middle point of the second sawtooth is used as a boundary, and the oblique teeth are symmetrically arranged on two sides of the middle point.

The outer peripheral surface of the outer reducing ring 8 is evenly provided with a plurality of rivets 9 at intervals.

The outer pipe wall cover of center tube 1 is equipped with two at least sealing members, is located the upper seal 10 of top and is located the lower seal 11 of bottom respectively, and wherein the inner peripheral surface of upper seal 10 and lower seal 11 all hugs closely the outer pipe wall of center tube 1, and the outer peripheral surface of upper seal 10 and lower seal 11 all hugs closely the inner tube wall of inflation packing element 2.

The upper and lower ends of the outer cylinder wall of the expansion rubber cylinder 2 are respectively sleeved with an annular rubber cylinder top seat 12 and an annular rubber cylinder base 13, wherein the inner circumferential surfaces of the annular rubber cylinder top seat 12 and the annular rubber cylinder base 13 are tightly attached to the outer cylinder wall of the expansion rubber cylinder 2, and the thin-wall metal pipe 3 is clamped between the lower annular end surface of the annular rubber cylinder top seat 12 and the upper annular end surface of the annular rubber cylinder base 13.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of practicing the invention, and that various changes in form and detail may be made therein without departing from the spirit and scope of the invention in practice.

Claims

1. An electrodeless reducing plugging device is characterized in that: the pipe comprises three hollow pipe columns which are concentrically sleeved, a central pipe (1), an expansion rubber cylinder (2) and a thin-wall metal pipe (3) are sequentially arranged from inside to outside, the pipe wall of the central pipe (1) is provided with a plurality of liquid inlet holes (4), the axial center line of each liquid inlet hole (4) is perpendicular to the axial center line of the central pipe (1), and the outer pipe wall of the thin-wall metal pipe (3) is sleeved with at least one diameter-variable self-locking support ring;

2. The electrodeless variable-diameter plugging device as defined in claim 1, wherein: the outer pipe wall cover of thin-walled metal pipe (3) is equipped with two support rings, is last support ring (5) and lower support ring (6) respectively, wherein goes up support ring (5) and is close to the upper end of thin-walled metal pipe (3), and lower support ring (6) are close to the lower tip of thin-walled metal pipe (3).

3. The electrodeless variable diameter plugging device as defined in claim 2, wherein: the support rings have the same structure and comprise an inner diameter-changing ring (7) and an outer diameter-changing ring (8) which can synchronously change diameters, the outer diameter-changing ring (8) is of a circular ring structure formed by assembling a plurality of first arc-shaped pieces, two adjacent first arc-shaped pieces are connected or spaced, and first sawteeth are uniformly distributed on the inner arc surface of each first arc-shaped piece; the inner diameter-changing ring (7) is of a circular ring structure formed by splicing a plurality of second arc-shaped pieces, two adjacent second arc-shaped pieces are connected or spaced, and second sawteeth are uniformly distributed on the outer arc surface of each second arc-shaped piece;

the second saw teeth of the inner reducing ring (7) are meshed with the first saw teeth of the outer reducing ring (8).

4. The electrodeless variable diameter plugging device as defined in claim 3, wherein: the inner reducing ring (7) is a circular ring structure formed by splicing four first arc-shaped parts at uniform intervals, the outer reducing ring (8) is a circular ring structure formed by splicing four second arc-shaped parts at uniform intervals, wherein each second arc-shaped part is just opposite to the interval of two adjacent first arc-shaped parts, and the second saw teeth of each second arc-shaped part are simultaneously meshed with the first saw teeth of the two adjacent first arc-shaped parts which are just opposite to the second arc-shaped parts.

5. The electrodeless variable diameter plugging device according to claim 3 or 4, characterized in that: the first sawtooth with the second sawtooth is the skewed tooth that the slope set up, and same first arc spare or same second arc spare all are equipped with the sawtooth of two kinds of incline directions to the midpoint of first sawtooth is the border or uses the midpoint of second sawtooth as the border, is the skewed tooth that the symmetry and established in the both sides of midpoint.

6. The electrodeless variable diameter plugging device as defined in claim 3, wherein: the outer peripheral surface of the outer reducing ring (8) is evenly provided with a plurality of rivets (9) at intervals.

7. The electrodeless variable diameter plugging device as defined in claim 1 or 3, characterized in that: the outer pipe wall of the central pipe (1) is sleeved with at least two sealing elements, namely an upper sealing element (10) located at the top and a lower sealing element (11) located at the bottom, wherein the inner peripheral surfaces of the upper sealing element (10) and the lower sealing element (11) are tightly attached to the outer pipe wall of the central pipe (1), and the outer peripheral surfaces of the upper sealing element (10) and the lower sealing element (11) are tightly attached to the inner pipe wall of the expansion rubber cylinder (2).

8. The electrodeless variable diameter plugging device as defined in claim 7, wherein: the upper end and the lower end of the outer cylinder wall of the expansion rubber cylinder (2) are respectively sleeved with an annular rubber cylinder top seat (12) and an annular rubber cylinder base (13), wherein the inner circumferential surfaces of the annular rubber cylinder top seat (12) and the annular rubber cylinder base (13) are tightly attached to the outer cylinder wall of the expansion rubber cylinder (2), and the thin-wall metal pipe (3) is clamped between the lower annular end face of the annular rubber cylinder top seat (12) and the upper annular end face of the annular rubber cylinder base (13).

9. An electrodeless variable diameter plugging method is characterized by at least comprising the electrodeless variable diameter plugging device as claimed in any one of claims 1-8, and specifically comprises the following steps:

acquiring a target leakage point;

placing the stepless variable diameter plugging device into a target well;

10. The electrodeless variable diameter plugging method according to claim 9, wherein the thin-wall metal pipe is expanded, high-pressure liquid is continuously pumped, and the support ring is expanded and embedded into the wall of the target wellbore, specifically comprising:

expanding the thin-wall metal tube, and simultaneously opening the upper support ring and the lower support ring;