阅读说明：本技术 一种油气井套管切割和锻铣系统的刀板组件 (Cutting board assembly of oil and gas well casing cutting and forging milling system ) 是由 刘伟 黄兵 张德军 王平安 胡超 连太炜 陈东 高林 汪洋 冯思恒 谭东 蔡强 于 2021-01-04 设计创作，主要内容包括：本发明提供了一种油气井套管切割和锻铣系统的刀板组件,所述套管切割锻铣系统包括壳体、活塞、可压缩弹性件、刀板组件以及扶正短接,所述刀板组件刀槽、刀板、受剪切力可断裂件和限位块,其中,刀槽设置在壳体的侧壁上；刀板具有彼此连接的小头端和大头端,小头端通过受剪切力可断裂件可转动连接在刀槽上,大头端包括设有第一切削齿的下端面、设有第二切削齿的外端面、设有突出部的内端面、以及扶正配合部；受剪切力可断裂件能够在刀板受到从上向下的预定力时断裂；限位块设置在刀槽中,并能够限制刀板的向上运动。本发明的油气井套管切割和锻铣系统的刀板组件的吃入能力强、进尺大,能够显著套管的切割和锻铣效率,降低套管切割和锻铣时间。(The invention provides a cutting board assembly of an oil and gas well casing cutting and forging milling system, wherein the casing cutting and forging milling system comprises a shell, a piston, a compressible elastic part, a cutting board assembly and a centralizing short circuit, wherein a cutter groove of the cutting board assembly, a cutting board, a part which can be broken under shearing force and a limiting block are arranged on the side wall of the shell; the cutter plate is provided with a small head end and a large head end which are connected with each other, the small head end is rotatably connected on the cutter groove through a breakable part subjected to shearing force, and the large head end comprises a lower end face provided with a first cutting tooth, an outer end face provided with a second cutting tooth, an inner end face provided with a protruding part and a righting matching part; the breakable part under the shearing force can be broken when the knife board is subjected to a preset force from top to bottom; the limiting block is arranged in the cutter groove and can limit the upward movement of the cutter plate. The cutting plate assembly of the oil and gas well casing cutting and forging milling system is strong in penetration capacity and large in size, can show the cutting and forging milling efficiency of the casing, and reduces the cutting and forging milling time of the casing.)

1. A cutting board component of a sleeve cutting and forging-milling system of an oil and gas well is characterized in that the sleeve cutting and forging-milling system comprises a shell, a piston, a compressible elastic part, a cutting board component and a centralizing short joint,

the shell is in a straight cylinder shape and is provided with an upper cavity and a lower cavity which are sequentially connected from top to bottom along a central axis, and the inner diameter of the upper cavity is larger than that of the lower cavity;

the piston comprises a piston head and a piston rod which are connected with each other, the piston head is arranged in the upper cavity and is provided with a first flow passage which is arranged in a penetrating manner along the vertical direction and an outer diameter which is equal to the inner diameter of the upper cavity, and the piston rod is provided with a second flow passage which is arranged in a penetrating manner along the vertical direction and is communicated with the first flow passage and an outer diameter which is equal to the inner diameter of the lower cavity;

the compressible elastic piece is sleeved at one end of the piston rod close to the piston head and is positioned in a space formed by the upper cavity, the piston head and the piston rod;

the knife plate assembly comprises a knife groove, a knife plate, a breakable part subjected to shearing force and a limiting block, wherein the knife groove is arranged on the side wall of the shell along the up-down direction and can accommodate the knife plate;

the knife plate is provided with a small head end and a large head end which are connected with each other, the small head end is rotatably connected to the shell through a breakable part subjected to shearing force, the large head end comprises a lower end face provided with first cutting teeth, an outer end face provided with second cutting teeth, an inner end face provided with a protruding part and a righting matching part which is positioned between the first cutting teeth and the central axis and protrudes downwards from the extension line of the lower end face, and the protruding part of the inner end face can be pressed by the other end of the piston rod under the condition that the compressible elastic part is compressed by the piston head, so that the first cutting teeth on the lower end face of the knife plate and the second cutting teeth on the outer end face of the knife plate are outwards expanded from the knife groove;

the limiting block is arranged in the cutter groove and can limit the upward movement of the cutter plate;

the breakable part under the shearing force can be broken when the knife board is subjected to a preset force from top to bottom so as to separate the small head end of the knife board from the shell;

the righting short circuit is provided with a third flow channel which penetrates through the righting short circuit in the vertical direction, the upper end of the righting short circuit is connected with the lower end of the shell, the limit of the maximum outward expansion degree of the cutter plate and the righting of the cutter plate can be realized through the mutual matching of the righting matching parts of the cutter plate, and the third flow channel can be communicated with the second flow channel.

2. The knife plate assembly of claim 1, wherein the knife plate assembly has a plurality of pockets and a number of knife plates corresponding to the number of pockets.

3. The cutting board assembly according to claim 2, wherein the plurality of cutting grooves include short cutting grooves and long cutting grooves arranged at intervals in the circumferential direction of the housing, the plurality of cutting boards include short cutting boards engaged with the short cutting grooves and long cutting boards engaged with the long cutting grooves and having a length in the up-down direction longer than that of the short cutting boards, and in the outwardly expanded state, the first cutting teeth of the respective lower end surfaces of the plurality of long cutting boards can be located at the same horizontal plane as the first cutting teeth of the respective lower end surfaces of the short cutting boards, and the second cutting teeth of the respective outer end surfaces of the plurality of long cutting boards can be located at the same circumferential plane as the second cutting teeth of the respective outer end surfaces of the short cutting boards.

4. The knife plate assembly of claim 3, wherein the number of short knife slots, long knife slots, short knife plates and long knife plates is 3.

5. The knife plate assembly of claim 1, wherein the first cutting tooth is a sharpened diamond-shaped tooth, the second cutting tooth is a concave rounded tooth, and the first cutting tooth and the second cutting tooth are carbide teeth.

6. The cutter plate assembly of claim 5, wherein the carbide teeth are sporulated carbide teeth or elliptical carbide teeth.

7. The cutter plate is characterized in that the cutter plate is provided with a small end and a large end which are connected with each other, the small end is rotatably connected to a shell through a shearing force breakable piece, the large end comprises a lower end face provided with first cutting teeth, an outer end face provided with second cutting teeth, an inner end face provided with a protruding portion and a righting matching portion located between the first cutting teeth and the central axis of the shell and protruding downwards to the extension line of the lower end face, and the protruding portion of the inner end face can be extruded by the other end of a piston rod under the condition that a compressible elastic piece is compressed by a piston head, so that the first cutting teeth on the lower end face of the cutter plate and the second cutting teeth on the outer end face of the cutter plate are outwards expanded from a cutter groove.

8. The cutting board according to claim 7, wherein the cutting board comprises a short cutting board and a long cutting board longer than the short cutting board in length in the up-down direction, and in the outwardly expanded state, the first cutting teeth of the lower end surface of the long cutting board can be located at the same level as the first cutting teeth of the lower end surface of the short cutting board, and the second cutting teeth of the outer end surface of the long cutting board can be located at the same circumferential surface as the second cutting teeth of the outer end surface of the short cutting board.

9. The cutter plate according to claim 7, wherein the first cutting teeth are sharpened diamond-shaped teeth, the second cutting teeth are concave circular teeth, and the first cutting teeth and the second cutting teeth are cemented carbide teeth.

10. The cutter plate of claim 9, wherein the carbide teeth are spore type carbide teeth or oval type carbide teeth.

Technical Field

The invention relates to the technical field of oil and gas well forging and milling tools, in particular to a cutting board assembly of an oil and gas well casing cutting and forging and milling system.

Background

With the development of exploration and development towards economy and high efficiency, the old well is excavated to generate a large amount of forging and milling workload. According to statistics, about 5% -7% of old wells need to be windowed, forged and milled on the basis of old well bores through special technological means every year, and then horizontal wells are sidetracked, so that residual oil gas resources beyond 400-500 m are developed, and the old wells are revived. In addition, along with the strength of the government to environmental protection is continuously enhanced, the old well with A, B annular pressure also needs to remove a cement sheath with poor cementation through forging and milling operation, then comprehensive plugging is realized, and the damage to personnel, property and ecology caused by harmful gas leakage is eliminated.

At present, the workload of the operation of abandoning wells at home and abroad is increasing day by day, and the annual workload of abandoning old wells in the world is estimated to reach 50 hundred million dollars by 2025 years. However, the casing forging and milling process and the tools which play the most critical role in the old well sidetracking and abandoned well operation are not matched in a mature mode, and especially the cutting and forging and milling of 127-215.9 mm casings have great challenges. The existing forging and milling tool cannot completely meet the requirements of actual working conditions, so that the forging and milling windowing efficiency is low, the drilling clamping risk is high, and the reliability is poor.

Therefore, the research on the forging, milling and windowing technology of the casing has important practical significance and development prospect.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, it is an object of the present invention to provide a cutting block assembly for an oil and gas well casing cutting and forge milling system that enables fast casing cutting, high speed long section forge milling. For another example, it is a further object of the present invention to provide a cutting plate suitable for use in oil and gas well casing cutting and forge milling systems.

In order to achieve the above object, an aspect of the present invention provides a cutting plate assembly of a casing cutting and forging-milling system for an oil and gas well, the casing cutting and forging-milling system comprising a housing, a piston, a compressible elastic member, a cutting plate assembly and a centralizing short joint, wherein the housing is in a straight cylinder shape and has an upper cavity and a lower cavity which are sequentially connected from top to bottom along a central axis, and an inner diameter of the upper cavity is larger than an inner diameter of the lower cavity; the piston comprises a piston head and a piston rod which are connected with each other, the piston head is arranged in the upper cavity and is provided with a first flow passage which is arranged in a penetrating manner along the vertical direction and an outer diameter which is equal to the inner diameter of the upper cavity, and the piston rod is provided with a second flow passage which is arranged in a penetrating manner along the vertical direction and is communicated with the first flow passage and an outer diameter which is equal to the inner diameter of the lower cavity; the compressible elastic piece is sleeved at one end of the piston rod close to the piston head and is positioned in a space formed by the upper cavity, the piston head and the piston rod; the knife plate assembly comprises a knife groove, a knife plate, a breakable part subjected to shearing force and a limiting block, wherein the knife groove is arranged on the side wall of the shell along the up-down direction and can accommodate the knife plate; the knife plate is provided with a small head end and a large head end which are connected with each other, the small head end is rotatably connected to the shell through a breakable part subjected to shearing force, the large head end comprises a lower end face provided with first cutting teeth, an outer end face provided with second cutting teeth, an inner end face provided with a protruding part and a righting matching part which is positioned between the first cutting teeth and the central axis and protrudes downwards from the extension line of the lower end face, and the protruding part of the inner end face can be pressed by the other end of the piston rod under the condition that the compressible elastic part is compressed by the piston head, so that the first cutting teeth on the lower end face of the knife plate and the second cutting teeth on the outer end face of the knife plate are outwards expanded from the knife groove; the limiting block is arranged in the cutter groove and can limit the upward movement of the cutter plate; the breakable part under the shearing force can be broken when the knife board is subjected to a preset force from top to bottom so as to separate the small head end of the knife board from the shell; the righting short circuit is provided with a third flow channel which penetrates through the righting short circuit in the vertical direction, the upper end of the righting short circuit is connected with the lower end of the shell, the limit of the maximum outward expansion degree of the cutter plate and the righting of the cutter plate can be realized through the mutual matching of the righting matching parts of the cutter plate, and the third flow channel can be communicated with the second flow channel.

In an exemplary embodiment of the knife plate assembly of the present invention, the knife plate assembly may have a plurality of knife grooves, and a plurality of knife plates corresponding to the number of the knife grooves.

In an exemplary embodiment of the blade assembly of the present invention, the plurality of blades may include short blades and long blades arranged at intervals in a circumferential direction of the housing, the plurality of blades may include short blades engaged with the short blades and long blades engaged with the long blades and having a length in an up-down direction longer than that of the short blades, and in an outwardly expanded state, the first cutting teeth of the respective lower end surfaces of the plurality of long blades may be located at the same horizontal plane as the first cutting teeth of the respective lower end surfaces of the short blades, and the second cutting teeth of the respective outer end surfaces of the plurality of long blades may be located at the same circumferential plane as the second cutting teeth of the respective outer end surfaces of the short blades.

In an exemplary embodiment of the knife plate assembly of the present invention, the number of the short knife grooves, the long knife grooves, the short knife plates and the long knife plates may be 3.

In an exemplary embodiment of the knife plate assembly of the present invention, the first cutting tooth may be a sharpened diamond-shaped tooth, the second cutting tooth may be an inwardly concave circular tooth, and the material of the first cutting tooth and the second cutting tooth may be a cemented carbide tooth.

In an exemplary embodiment of the knife plate assembly of the present invention, the cemented carbide teeth may be sporulated cemented carbide teeth or oval cemented carbide teeth.

Another aspect of the present invention provides a cutter plate suitable for an oil and gas well casing cutting and forging system, the cutter plate having a small end and a large end connected to each other, the small end being rotatably connected to a housing by a shear force breakable member, the large end including a lower end surface provided with first cutting teeth, an outer end surface provided with second cutting teeth, an inner end surface provided with a protrusion, and a centering engagement portion located between the first cutting teeth and a central axis of the housing and protruding downward from an extension line of the lower end surface, the protrusion of the inner end surface being capable of being pressed by the other end of the piston rod under compression of the piston head by a compressible elastic member, so that the first cutting teeth of the lower end surface of the cutter plate and the second cutting teeth of the outer end surface of the cutter plate are outwardly expanded from the cutter groove.

In an exemplary embodiment of the cutter plate of the present invention, the cutter plate includes a short cutter plate, and a long cutter plate longer in length in an up-down direction than the short cutter plate, and in the outwardly-expanded state, the first cutting teeth of the lower end surface of the long cutter plate can be located at the same level as the first cutting teeth of the lower end surface of the short cutter plate, and the second cutting teeth of the outer end surface of the long cutter plate can be located at the same circumferential surface as the second cutting teeth of the outer end surface of the short cutter plate.

In an exemplary embodiment of the cutter plate of the present invention, the first cutting teeth may be sharpened diamond-shaped teeth, the second cutting teeth may be concave circular teeth, and the material of the first cutting teeth and the second cutting teeth may be cemented carbide teeth.

In an exemplary embodiment of the cutting plate of the present invention, the cemented carbide teeth may be sporulated cemented carbide teeth or oval cemented carbide teeth.

Advantageous effects and advantages of the present invention compared to the prior art may include at least one of the following:

(1) the lower end face of the cutter plate is sharpened, and the surface contact between the lower end face of the cutter plate and the inner wall of the sleeve is converted into point contact, so that the cutting capability of the cutter plate is enhanced, and the cutting efficiency is improved;

(2) the lower end face of the cutter plate is provided with the concave circular teeth, so that the cutting of iron wires (or iron cuttings) formed by forging and milling is facilitated, the winding of the iron cuttings is prevented, and the forging and milling efficiency is improved;

(5) the invention has higher cutting efficiency on the casing, higher milling speed on the casing section and larger footage, can obviously improve the cutting and forging milling efficiency of the casing in the well abandoning and sidetracking functions, can greatly reduce the cutting and forging milling time of the casing in the well abandoning and sidetracking processes, and reduces the operation cost.

Drawings

FIG. 1 illustrates a schematic structural view of an exemplary embodiment of a cutter plate assembly of the oil and gas well casing cutting and forge milling system of the present invention;

FIG. 2 illustrates an installation schematic of an exemplary embodiment of a cutter plate assembly of the oil and gas well casing cutting and forge milling system of the present invention;

FIG. 3 illustrates a schematic view of a stop block in an exemplary embodiment of a cutter plate assembly of the oil and gas well casing cutting and forge milling system of the present invention;

FIG. 4a illustrates a top view of a structure of an exemplary embodiment of a cutter plate suitable for use in an oil and gas well casing cutting and forge milling system of the present invention;

FIG. 4b shows a structural left side view of an exemplary embodiment of a cutter plate suitable for use in an oil and gas well casing cutting and forge milling system of the present invention;

FIG. 4c illustrates a front view of the structure of an exemplary embodiment of a cutter plate suitable for use in an oil and gas well casing cutting and forge milling system of the present invention.

The reference numerals are explained below:

1-long cutter groove, 2-short cutter groove, 3-long cutter plate, 4-short cutter plate, 5-shearing pin, 6-limiting block, 7-first cutting tooth and 8-second cutting tooth.

Detailed Description

Hereinafter, the cutter plate assembly for cutting and forge milling of a sleeve according to the present invention will be described in detail with reference to exemplary embodiments. Herein, the terms "first," "second," and "third" are used merely for convenience of description and for convenience of distinction, and are not to be construed as indicating or implying relative importance or a strict order of magnitude.

One aspect of the invention provides a cutter plate assembly of an oil and gas well casing cutting and forging milling system, wherein the casing cutting and forging milling system comprises a shell, a piston, a compressible elastic piece, a cutter plate assembly and a centralizing short joint.

The shell is in a straight cylinder shape and is provided with an upper cavity and a lower cavity which are sequentially connected from top to bottom along a central axis, and the inner diameter of the upper cavity is larger than that of the lower cavity. Here, the housing functions to mount the piston, the compressible elastic member, and the knife board assembly therein to perform basic functions of opening and closing the knife board.

The piston comprises a piston head and a piston rod which are connected with each other, the piston head is arranged in the upper cavity and is provided with a first flow passage which is arranged in a penetrating mode along the vertical direction and an outer diameter which is equal to the inner diameter of the upper cavity, and the piston rod is provided with a second flow passage which is arranged in a penetrating mode along the vertical direction and is communicated with the first flow passage and an outer diameter which is equal to the inner diameter of the lower cavity. Here, the drilling fluid can flow from the first flow passage to the second flow passage in the up-down direction, thereby achieving circulation of the drilling fluid and carrying out cutting iron pieces (or iron pins).

The compressible elastic piece is sleeved at one end, close to the piston head, of the piston rod and is positioned in a space formed by the upper cavity, the piston head and the piston rod. After the pump is started, the hydraulic acting force of the drilling fluid acts on the upper end face of the piston rod to push the piston rod to move downwards, so that the compressible elastic part is in a compressed state; after the pump is stopped, the hydraulic acting force of the drilling fluid on the upper end surface of the piston rod is suddenly reduced, and the elastic acting force of the compressible elastic part pushes the piston rod to move upwards.

The knife plate assembly comprises a knife groove, a knife plate, a breakable part subjected to shearing force and a limiting block.

Wherein the knife groove is arranged on the side wall of the shell along the up-down direction and can accommodate a knife board. A knife board mounting hole and a limiting block mounting hole can be formed in the knife groove.

The cutting board is provided with a small head end and a large head end which are connected with each other, the small head end is rotatably connected to the shell through a breakable part subjected to shearing force, and the large head end comprises a lower end face provided with a first cutting tooth, an outer end face provided with a second cutting tooth, an inner end face provided with a protruding portion and a righting matching portion located between the first cutting tooth and the central axis and protruding downwards to the extension line of the lower end face. The protrusion of the inner end surface can be pressed by the other end of the piston rod under the condition that the compressible elastic piece is compressed by the piston head, so that the first cutting teeth of the lower end surface of the knife plate and the second cutting teeth of the outer end surface of the knife plate are outwards expanded from the knife groove. The terms "inner", "outer", and "inside-out" as used herein refer to relative orientations and generally refer to the rotation of the blade from a position "inside" the lower cavity of the housing to a position "outside" the housing during operation of the bushing cutting and milling system.

The first cutting teeth may be sharpened diamond-shaped teeth mounted on a lower end surface of the cutter plate for cutting the casing. The second cutting teeth can be concave circular teeth which are arranged on the outer end face of the cutter plate and used for sleeve forging and milling. The lower end face of the cutter plate is in point contact with the inner wall of the sleeve by sharpening the rhombic teeth, so that the sleeve can be efficiently cut; the concave circular teeth enable the cutting teeth to have certain internal chamfers, so that cutting of rock debris during forging and milling is facilitated, long iron pins and winding of the iron pins during sleeve forging and milling are prevented, and the forging and milling speed and the footage are improved. For example, the first cutting tooth may be a diamond-shaped tungsten carbide cutting tooth, and the second cutting tooth may be a concave circular tungsten carbide cutting tooth, and the concave circular tooth may be mounted on the outer end surface of the cutter plate with non-uniform teeth, that is, the concave circular teeth are not necessarily arranged according to a certain angle or size. The first cutting tooth and the second cutting tooth can be made of hard alloy teeth. For example, the cemented carbide teeth may be sporulated cemented carbide teeth or oval cemented carbide teeth.

The limiting block is arranged in the cutter groove and can limit the upward movement of the cutter plate. Here, the stopper is used to prevent the cutter plate from moving up or shearing off the sheared breakable piece when the sleeve cutting and milling system performs the cutting and milling operation.

The shearing force breakable piece can be broken when the knife board is subjected to a preset force from top to bottom so as to separate the small head end of the knife board from the shell. The sleeve cutting and forging-milling system comprises a sleeve cutting and forging-milling system, a cutter plate and a cutter groove, wherein the sleeve cutting and forging-milling system comprises a sleeve, a cutter plate and a cutter plate, wherein the sleeve is provided with a cutting part and a shearing part; after the operation of the casing cutting and forging-milling system is finished, if the cutter plate cannot be automatically folded, the cutter plate is folded or separated from the cutter groove and falls to the bottom of the well by shearing off the breakable part subjected to the shearing force, so that the casing cutting and forging-milling system is taken out. For example, the connecting element breakable by shearing force may be a shear pin which can be broken by the force from top to bottom, and if the condition that the cutter is to be lost is confirmed, the shear pin can be sheared by lifting the drill with a predetermined force larger than the maximum stress of the shear pin.

The righting short circuit is provided with a third flow channel which penetrates through the righting short circuit in the vertical direction, the upper end of the righting short circuit is connected with the lower end of the shell, the limit of the maximum outward expansion degree of the cutter plate and the righting of the cutter plate can be realized through the mutual matching of the righting matching parts of the cutter plate, and the third flow channel can be communicated with the second flow channel.

In an exemplary embodiment of the knife plate assembly of the present invention, the knife plate assembly may have a plurality of knife grooves, and a plurality of knife plates corresponding to the number of the knife grooves. The plurality of cutter grooves may include short cutter grooves and long cutter grooves arranged at intervals in the circumferential direction of the housing, the plurality of cutter plates may include short cutter plates engaged with the short cutter grooves and long cutter plates engaged with the long cutter grooves and having a length in the up-down direction longer than that of the short cutter plates, in an outwardly-expanded state, the first cutting teeth of the respective lower end surfaces of the plurality of long cutter plates may be located at the same horizontal plane as the first cutting teeth of the respective lower end surfaces of the short cutter plates, and the second cutting teeth of the respective outer end surfaces of the plurality of long cutter plates may be located at the same circumferential plane as the second cutting teeth of the respective outer end surfaces of the short cutter plates.

For example, the number of short sipes, long sipes, short blades, and long blades may each be 3. Wherein, 3 long tool grooves and 3 short tool grooves are arranged along the circumference of the lower cavity of the shell at intervals in a staggered manner, and the shapes of the 3 long tool plates and the 3 short tool plates are configured as follows: the combination position of 3 long cutting boards and long knife grooves is positioned above the combination position of 3 short cutting boards and short knife grooves, and under the extrusion action of the piston rod, the first cutting teeth of 3 long cutting boards and the first cutting teeth of 3 short cutting boards are positioned on the same circumferential surface, and the second cutting teeth of 3 long cutting boards and the second cutting teeth of 3 short cutting boards are positioned on the same horizontal plane. The long knife groove can be provided with a long knife plate mounting hole as the combination position of the long knife plate and the short knife groove, and the short knife groove is provided with a short knife plate mounting hole as the combination position of the short knife plate and the short knife groove. For a sleeve with the size of 127-215.9 mm, the 3 long knife boards and the 3 short knife boards are arranged, so that the situation that the wall thickness of the whole knife is too thin after the knife groove is formed and the torsional strength of the body is not favorable due to the fact that 6 knives are arranged on the same horizontal plane can be effectively avoided. The 3 long knife boards and the 3 short knife boards can be arranged in a vertically staggered mode at the combination positions of the 6 knife boards and the knife grooves, so that the wall thickness can be increased, and the 6 knife boards can be arranged. For a sleeve with the size of 127-215.9 mm, the effect is best when 6 knife boards are arranged, the number of the knife boards is more than 6, for example, 8, the cutting effect is not ideal, the number of the knife boards is less than 6, for example, 3, the knife boards are easy to break, and the good cutting effect cannot be achieved.

It should be noted that the terms "up", "down" and "from top to bottom" of the present invention are relative terms, and that the drilling fluid fed downhole from the surface generally passes through the term "up" and then through the term "down". That is, for vertical operation, the sleeve cutting and milling system is in the right direction from top to bottom as described herein. The terms "up", "down", and "top to bottom" as used herein correspond to "left", "right", and "left to right" if the casing cutting and milling system is used for lateral or horizontal drilling of an old well.

When no pump pressure is applied (i.e., in the installed state), the small end of the knife plate is connected in the knife groove, and the large end is located in the lower cavity of the shell.

During forging and milling operation (namely after a pump is started), drilling fluid flows through the first flow passage and the second flow passage of the piston and the third flow passage for centralizing the short circuit from the well head and then flows to the well bottom, so that circulation of the drilling fluid is realized. In the flowing process of the drilling fluid, the energy of the drilling fluid acts on the upper end face of the piston rod to push the piston rod to compress the spring to move downwards, and the lower end of the piston rod is in contact with the protruding part of the cutting board to push the cutting board to expand outwards. In the opening process of the cutting board, the righting matching part of the cutting board is matched with the upper end of the righting short circuit, so that the limitation on the maximum outward opening degree of the cutting board is realized. Then, the rotary drilling tool drives the tool to perform casing cutting, forging and milling operation, the first cutting teeth on the lower end face of the cutter plate are in point contact with the inner wall of the casing, and the drill column is rotated to realize continuous casing cutting; and after the sleeve is completely cut off, the second cutting teeth on the outer end face of the cutter plate contact the sleeve, and drilling pressure is applied to realize continuous forging and milling of the sleeve.

When the forging and milling operation is finished (namely after the pump is stopped), the piston rod moves upwards through the elastic restoring force of the compressible elastic part, meanwhile, the cutter plate can be pushed back to the cutter groove by utilizing the force generated by the contact of the drilling tool and the well wall, and if the cutter plate cannot be automatically retracted, the breakable part subjected to the shearing force can be sheared, so that the cutter plate is separated from the cutter groove and falls to the bottom of the well.

Another aspect of the invention provides a cutting plate suitable for use in an oil and gas well casing cutting and forge milling system. The cutting board is provided with a small head end and a large head end which are connected with each other, the small head end is rotatably connected to the shell through a breakable part subjected to shearing force, and the large head end comprises a lower end face provided with a first cutting tooth, an outer end face provided with a second cutting tooth, an inner end face provided with a protruding part and a righting matching part located between the first cutting tooth and the central axis of the shell and protruding downwards to the extension line of the lower end face. The protrusion of the inner end surface can be pressed by the other end of the piston rod under the condition that the compressible elastic member is compressed by the piston head, so that the first cutting teeth of the lower end surface of the knife plate and the second cutting teeth of the outer end surface of the knife plate are outwards expanded from the knife groove.

The first cutting teeth may be sharpened diamond-shaped teeth mounted on a lower end surface of the cutter plate for cutting the casing. The second cutting teeth can be concave circular teeth which are arranged on the outer end face of the cutter plate and used for sleeve forging and milling. The lower end face of the cutter plate is in point contact with the inner wall of the sleeve by sharpening the rhombic teeth, so that the sleeve can be efficiently cut; the concave circular teeth enable the cutting teeth to have certain internal chamfers, so that cutting of rock debris during forging and milling is facilitated, long iron pins and winding of the iron pins during sleeve forging and milling are prevented, and the forging and milling speed and the footage are improved. For example, the first cutting tooth may be a sharpened diamond-shaped tungsten carbide cutting tooth and the second cutting tooth may be a concave rounded tungsten carbide cutting tooth. The first cutting tooth and the second cutting tooth can be made of hard alloy teeth. For example, the cemented carbide teeth may be sporulated cemented carbide teeth or oval cemented carbide teeth.

In an exemplary embodiment of the cutter plate of the present invention, the cutter plate includes a short cutter plate, and a long cutter plate longer in length in an up-down direction than the short cutter plate, and in the outwardly-expanded state, the first cutting teeth of the lower end surface of the long cutter plate can be located at the same level as the first cutting teeth of the lower end surface of the short cutter plate, and the second cutting teeth of the outer end surface of the long cutter plate can be located at the same circumferential surface as the second cutting teeth of the outer end surface of the short cutter plate.

For a better understanding of the above-described exemplary embodiments of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings and specific examples.

As shown in fig. 1 and 2, a cutting board assembly of an oil and gas well casing cutting and forging milling system comprises a long cutter groove 1, a short cutter groove 2, a long cutting board 3, a short cutting board 4, a shearing pin 5 and a limiting block 6. The left-to-right direction in fig. 1 and 2 is the direction from top to bottom in the present invention.

Specifically, the casing cutting and forging system comprises a shell, a piston, a compressible elastic element, a knife board assembly and a centering short circuit. Wherein the housing has an upper cavity and a lower cavity connected in series from top to bottom along the central axis, and the piston has a piston head and a piston rod connected to each other. The piston head is disposed in the upper cavity of the housing and the piston rod is disposed in the lower cavity of the housing. The compressible elastic element is sleeved at one end of the piston rod close to the piston head and is positioned in a space formed by the upper cavity, the piston head and the piston rod. The lower extreme at the casing is connected to the short circuit of righting.

The number of the long cutter grooves 1 and the number of the short cutter grooves 2 are 3. The 3 long cutter grooves 1 and the 3 short cutter grooves 2 are arranged on the outer circumference of the shell and are arranged along the circumferential direction of the lower cavity at intervals in a staggered mode, and the opening positions of the long cutter grooves 1 are located above the opening positions of the short cutter grooves 2. The number of the long knife boards 3 and the short knife boards 4 is 3. 3 long cutter plates 3 and 3 short cutter plates 4 are respectively installed in the corresponding long cutter grooves 1 and short cutter grooves 2 through shearing pins 5. The limiting blocks 6 are respectively arranged in the long cutter groove 1 and the short cutter groove 2 and are positioned above the shearing pins 5.

The structure of the limiting block 6 is as shown in fig. 3, the limiting block 6 is provided with a concave platform for preventing the long cutter plate 3 and the short cutter plate 4 from moving upwards or shearing the shearing pin 5 when the sleeve cutting and forging milling tool is used for cutting and forging and milling the sleeve.

Fig. 4a, 4b and 4c show the structure of the knife plate, where the direction from left to right in fig. 4a is the direction from the upper end to the lower end in this example, and the direction from top to bottom in fig. 4a is the direction from the outer end to the inner end in this example. The cutting board is provided with a small head end and a large head end which are connected with each other, the small head end is rotatably connected to the shell through a shearing pin, and the large head end comprises a lower end face provided with a first cutting tooth 7, an outer end face provided with a second cutting tooth 8, an inner end face provided with a protruding portion and a righting matching portion which is located between the central axes of the first cutting tooth 7 and the shell and protrudes downwards from the extension line of the lower end face. The first cutting tooth 7 is a sharpened diamond-shaped tungsten carbide cutting tooth, and the second cutting tooth 8 is an inward concave circular tungsten carbide cutting tooth.

In summary, the advantages of the cutter plate assembly of the oil and gas well casing cutting and forge milling system of the present invention may include:

(1) the lower end face of the cutter plate is sharpened, and the surface contact between the lower end face of the cutter plate and the inner wall of the sleeve is converted into point contact, so that the cutting capability of the cutter plate is enhanced, and the cutting efficiency is improved;

(2) the outer end face of the cutter plate is provided with the concave circular teeth, so that the iron wire (or iron cutting) formed by forging and milling can be cut off, the iron cutting winding can be prevented, and the forging and milling efficiency can be improved;

(5) the invention has higher cutting efficiency on the casing, higher milling speed on the casing section and larger footage, can obviously improve the cutting and forging milling efficiency of the casing in the well abandoning and sidetracking functions, can greatly reduce the cutting and forging milling time of the casing in the well abandoning and sidetracking processes, and reduces the operation cost.

Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.