A reverse circulation milling system for horizontal wells

Abstract

The present application provides a horizontal well reverse circulation milling system, in which the upper conversion chamber and the lower conversion chamber respectively convert the first conversion joint and the second conversion joint inside to achieve the change of the circulating fluid circulation channel and the reverse circulation of the circulating fluid, so that the milling debris can be smoothly returned to the ground with the circulating fluid, which can effectively prevent accidents such as debris stuck in the drill, thereby improving the milling efficiency and reducing the construction risk. The setting of the adjustment part can effectively solve the connection at the turning point between the horizontal well section and the vertical well section, thereby avoiding the circulating fluid with milling debris from being affected by the horizontal well section, so that it can effectively return to the ground along the vertical well section. The pressure of the pumped circulating fluid drives the hydraulic motor in the hydraulic motor part to operate normally, thereby achieving the effective rotation speed and torque at the bottom, and the effective rotation torque acts on the hollow rotating shaft, driving the lower conversion chamber part to rotate, completing the sleeve milling work, and improving the milling efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of horizontal wells, and in particular to a reverse circulation milling system for a horizontal well. Background Art

[0002] With the continuous deepening of oilfield development, most oilfields have basically entered the middle and late stages of exploitation. Some oil and water wells are producing with problems due to falling objects, casing changes, etc., and in serious cases, the oil and water wells are scrapped. In recent years, drilling technology and production technology have gradually matured, and many high-angle wells and horizontal wells have been continuously developed, but the supporting well repair technology has not been improved, especially the horizontal well repair technology is a major problem in the well repair industry, especially in horizontal drilling and milling operations.

[0003] In traditional well repair and milling operations, the drill bit is connected to the drill and lowered into the well, and the ground equipment provides rotational torque to the drill in the well so that the drill can perform milling operations. Affected by the characteristics of horizontal wells, the drill bit is affected by the inflection point, resulting in most of the rotational torque provided by the ground equipment being consumed by friction resistance, and the milling effect is not obvious.

[0004] Based on this, a method of connecting a drilling tool, a hydraulic motor and a milling drill bit is adopted to carry out well repair milling construction, so that the torque provided by the hydraulic motor directly acts on the fish top of the falling objects, thereby improving the milling efficiency. Due to the hydraulic motor drive method, the circulation mode of the circulating fluid must adopt a positive circulation mode, that is, the circulating fluid reaches the milling drill bit from the inner hole of the drilling tool through the hydraulic motor, and returns through the water hole of the milling drill bit. As a result, the debris generated during milling is carried back to the ground from between the drilling tool and the casing through the circulating fluid. Due to the influence of grinding resistance, at the same time, the circulation channel changes from a small channel to a large channel, which reduces the flow rate of the circulating fluid and makes it impossible for large particles of debris to return. Then, a large amount of debris generated during milling is difficult to return to the ground from the well as the flow rate continues to decrease, resulting in the accumulation of some debris, causing the milling drill tool to be stuck and cannot be effectively handled, which will cause engineering accidents, and in severe cases, the oil well will be scrapped. Summary of the invention

[0005] The invention provides a horizontal well reverse circulation milling system to solve the problem of a large amount of debris accumulation in the horizontal well during the existing well repair milling construction process.

[0006] The present invention provides a horizontal well reverse circulation milling system, comprising an upper conversion cavity part, an adjustment part, a hydraulic motor part and a lower conversion cavity part; two ends of the adjustment part are respectively connected to the upper conversion cavity part and the hydraulic motor part through a first connection joint and a second connection joint; the hydraulic motor part and the lower conversion cavity part are connected through a connecting shaft;

[0007] The upper conversion cavity part includes a rubber cylinder seat sealing tube, a first conversion joint connected at the end, and a conversion center tube; a sealing rubber cylinder with a sealing sleeve is arranged outside the rubber cylinder seat sealing tube;

[0008] A first conversion cavity is provided at the end of the first conversion joint, and the first conversion cavity is connected to the conversion center tube;

[0009] A first conversion sleeve is provided on the outside of the end of the first conversion joint, and a first clamping cavity is formed between the first conversion sleeve, the first conversion joint and the conversion center tube;

[0010] The lower conversion cavity portion includes a hollow rotating shaft and a second conversion joint connected to each other; a second conversion cavity is provided at the end of the second conversion joint, and the second conversion cavity is connected to the hollow rotating shaft;

[0011] A second conversion sleeve is provided on the outer side of the connection between the hollow rotating shaft and the second conversion joint, and a second clamping cavity is formed between the second conversion sleeve, the hollow rotating shaft and the second conversion joint;

[0012] A stabilizing sleeve is disposed on the outer side of the hollow rotating shaft, a third clamping cavity is formed between the stabilizing sleeve and the hollow rotating shaft, and the second clamping cavity is communicated with the third clamping cavity.

[0013] Preferably, a fourth clamping cavity is formed between the sealing tube of the rubber cartridge seat and the conversion center tube; and the first clamping cavity is respectively communicated with the fourth clamping cavity and the interior of the first conversion joint.

[0014] Preferably, the regulating part comprises an adjusting sleeve, a switching switch and an extension tube located outside the switching central tube; a switch joint is provided between the adjusting sleeve and the switching switch;

[0015] A connecting sleeve is provided on the outside of the extension tube, and a fifth clamping chamber is formed between the connecting sleeve, the conversion switch, the extension tube, the hydraulic motor part, and the straightening sleeve;

[0016] A sixth clamping cavity is formed between the conversion switch and the conversion central tube; the fifth clamping cavity and the sixth clamping cavity are connected through a flow hole.

[0017] Preferably, a butt coupling is provided on the outer side of the extension tube.

[0018] Preferably, a switch locking ring is provided between the switch connector and the conversion switch.

[0019] Preferably, a rotating tube is provided outside the hollow rotating shaft, and the rotating tube is connected to the straightening sleeve bearing; a seventh clamping cavity is formed between the hollow rotating shaft and the rotating tube, and the seventh clamping cavity is communicated with the second clamping cavity and the third clamping cavity respectively.

[0020] Preferably, a pressing cap is provided between the end of the straightening sleeve and the rotating tube, and a locking ring is provided on the pressing cap.

[0021] Preferably, the hollow rotating shaft and the connecting shaft are connected via a connecting cap, and deep groove ball bearings are provided at the contact points of the hollow rotating shaft, the connecting shaft and the connecting cap.

[0022] The technical solution provided by the embodiments of the present invention may have the following beneficial effects:

[0023] In the horizontal well reverse circulation milling system provided by the present application, the upper conversion chamber part and the lower conversion chamber part respectively convert the internal parts of the first conversion joint and the second conversion joint to realize the change of the circulating channel of the circulating fluid and realize the reverse circulation of the circulating fluid, so that the milling debris can be smoothly returned to the ground with the circulating fluid, which can effectively prevent the occurrence of accidents such as debris stuck in the drill, thereby improving the milling efficiency and reducing the construction risk. The setting of the adjustment part can effectively solve the connection at the turning point between the horizontal well section and the vertical well section, thereby avoiding the circulating fluid with milling debris from being affected by the horizontal well section, so that it can effectively return to the ground along the vertical well section. The pressure of the pumped circulating fluid drives the hydraulic motor in the hydraulic motor part to operate normally, thereby realizing the effective speed and torque at the bottom, and applying the effective rotational torque to the hollow rotating shaft, driving the lower conversion chamber part to rotate, completing the sleeve milling work, and improving the milling efficiency.

[0024] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0026] Figure 1 A schematic diagram of the overall structure of a horizontal well reverse circulation milling system provided by an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the structure of an up-conversion cavity provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the structure of the adjustment unit provided by an embodiment of the present invention;

[0029] Figure 4 A schematic diagram of the structure of a down-conversion cavity provided by an embodiment of the present invention;

[0030] Symbols represent:

[0031] 01-upper conversion cavity part, 02-adjustment part, 03-hydraulic motor part, 04-lower conversion cavity part, 05-first connecting joint, 06-second connecting joint, 07-connecting shaft;

[0032] 1-rubber tube seat sealing tube, 2-first conversion joint, 3-conversion center tube, 4-sleeve, 5-sealing rubber tube, 6-first conversion cavity, 7-first conversion outer sleeve, 8-first clamping cavity, 9-hollow rotating shaft, 10-second conversion joint, 11-second conversion cavity, 12-second conversion outer sleeve, 13-second clamping cavity, 14-righting sleeve, 15-third clamping cavity, 16-fourth clamping cavity, 17-adjusting sleeve, 18-conversion switch, 19-extension tube, 20-switch joint, 21-connecting outer sleeve, 22-fifth clamping cavity, 23-sixth clamping cavity, 24-circulation hole, 25-butt coupling, 26-switch locking ring, 27-rotating tube, 28-seventh clamping cavity, 29-pressing cap, 30-locking ring, 31-connecting cap, 32-deep groove ball bearing, 33-center tube butt coupling. DETAILED DESCRIPTION

[0033] Please refer to the attached Figure 1 , attached Figure 1 The overall structure diagram of the horizontal well reverse circulation milling system provided in the embodiment of the present application is shown. Figure 1 It can be seen that the horizontal well reverse circulation milling system provided in the embodiment of the present application includes an upper conversion chamber part 01, an adjustment part 02, a hydraulic motor part 03 and a lower conversion chamber part 04, wherein the two ends of the adjustment part 02 are respectively connected to the upper conversion chamber part 01 and the hydraulic motor part 03 through a first connecting joint 05 and a second connecting joint 06, and the hydraulic motor part 03 and the lower conversion chamber part 04 are connected through a connecting shaft 07, thereby realizing the assembly of various parts in the horizontal well reverse circulation milling system.

[0034] Specifically, as attached Figure 2 As shown, the upper conversion cavity 01 is located at the top of the horizontal well reverse circulation milling system, and is the part for sealing the casing 4, pumping in the circulating fluid, and pumping out the circulating fluid. The upper conversion cavity 01 in the embodiment of the present application includes a rubber cylinder seat sealing tube 1, a first conversion joint 2, and a conversion center pipe 3, wherein the first conversion joint 2 is connected to the end of the conversion center pipe 3, and the conversion center pipe 3 is located inside the rubber cylinder seat sealing tube 1.

[0035] The rubber tube seat sealing tube 1 is used to set the sealing rubber tube 5 of the sealing sleeve 4, so that the sealing rubber tube 5 of the sealing sleeve 4 is set outside the rubber tube seat sealing tube 1. Since the sealing rubber tube 5 can seal the sleeve 4, the sealing rubber tube 5 divides the sleeve 4 into two parts, namely, the first conversion joint 2, the first conversion sleeve 7 and other components located at the upper end of the sealing rubber tube 5, and the adjustment part 02, the hydraulic motor part 03 and the lower conversion cavity part 04 located at the lower end of the sealing rubber tube 5.

[0036] The first conversion joint 2 is used to transfer the circulating fluid from the sleeve 4 into the conversion center tube 3, and then the conversion center tube 3 brings the circulating fluid into the adjustment part 02, the hydraulic motor part 03 and the lower conversion cavity part 04. Therefore, there is a certain gap between the first conversion joint 2 and the sleeve 4. One end of the first conversion joint 2 is a hollow structure, and the other end is provided with a first conversion cavity 6, and the first conversion cavity 6 is connected with the conversion center tube 3, so that the circulating fluid can enter the first conversion cavity 6 from the gap between the first conversion joint 2 and the sleeve 4, and then be converted into the conversion center tube 3, so as to realize the reverse circulation pumping of the circulating fluid. In addition, a first conversion sleeve 7 is provided on the outside of the end of the first conversion joint 2, and a first clamping cavity 8 is formed between the first conversion sleeve 7 and the first conversion joint 2 and the conversion center tube 3. A fourth clamping cavity 16 is formed between the rubber cylinder seat sealing tube 1 and the conversion center tube 3, and the first clamping cavity 8 is respectively connected with the fourth clamping cavity 16 and the inside of the first conversion joint 2. Thus, the returned circulating fluid enters the first clamping chamber 8 from the fourth clamping chamber 16 , returns from the first clamping chamber 8 to the hollow part of the first conversion joint 2 , and is then discharged from the first conversion joint 2 .

[0037] The adjusting part 02 is not only used for connecting the horizontal well section and the vertical well section, but also for supplying fluid to the hydraulic motor part 03. In the embodiment of the present application, the upper conversion chamber part 01 and the adjusting part 02 are connected through the first connecting joint 05. Since the adjusting part 02 is used for connecting the horizontal well section and the vertical well section, if the length of the conversion center pipe 3 is not enough, it can also be connected and extended through the center pipe butt coupling 34. The length of the conversion center pipe 3 is set according to the actual situation.

[0038] Please refer to the attached Figure 3 , attached Figure 3 FIG. 2 shows a schematic diagram of the structure of the adjustment unit 02 provided in the embodiment of the present application. Figure 3 It can be seen that the adjustment part 02 includes an adjustment sleeve 17, a conversion switch 18, and an extension tube 19 located outside the conversion center tube 3. Among them, the adjustment sleeve 17 and the rubber cylinder seat sealing tube 1 are connected through the first connecting joint 05 to realize the connection between the upper conversion cavity part 01 and the adjustment part 02. The first connecting joint 05 is usually set at the connection between the horizontal well section and the vertical well section, that is, at the inflection point. The setting of the first connecting joint 05 can prevent the rotation torque provided by the ground equipment from being consumed by friction resistance, thereby improving the milling effect.

[0039] A switch joint 20 is provided between the adjustment sleeve 17 and the conversion switch 18, and a switch lock ring 26 is provided between the switch joint 20 and the conversion switch 18 to facilitate the opening of the conversion switch 18. A sixth clamping cavity 23 is formed between the conversion switch 18 and the conversion center pipe 3 to facilitate the return of the circulating fluid. A connecting sleeve 21 is provided on the outside of the extension tube 19, and a fifth clamping cavity 22 is formed between the connecting sleeve 21 and the conversion switch 18, the extension tube 19, the hydraulic motor part 03, and the straightening sleeve 14. The fifth clamping cavity 22 is used for the return of the circulating fluid. A flow hole 24 is provided at the connection between the conversion switch 18 and the extension tube 19 to facilitate the circulating fluid to enter the inside of the extension tube 19 from the outside of the extension tube 19, that is, the circulating fluid enters the sixth clamping cavity 23 through the fifth clamping cavity 22 and the flow hole 24. Further, in order to enhance the structural strength of the extension tube 19 at the inflection point, a butt coupling 25 is provided on the outside of the extension tube 19.

[0040] The hydraulic motor unit 03 can provide milling torque for the horizontal well reverse circulation milling system provided in the embodiment of the present application, thereby overcoming the problem that the wellhead torque cannot be transmitted to the horizontal section. The hydraulic motor unit 03 in the embodiment of the present application is located in the horizontal well section, and the pressure of the pumped circulating fluid drives the hydraulic motor in the hydraulic motor unit 03 to operate normally, thereby achieving the effective rotation speed and torque at the bottom, and applying the effective rotation torque to the hollow rotating shaft 9, driving the lower conversion cavity unit 04 to rotate, and completing the sleeve milling work.

[0041] Please refer to the attached Figure 4 , attached Figure 4 FIG. 2 shows a schematic diagram of the structure of the down-conversion cavity portion 04 provided in an embodiment of the present application. Figure 4 It can be seen that the lower conversion cavity part 04 is located at the end of the horizontal well reverse circulation milling system, specifically at the horizontal well section. The lower conversion cavity part 04 is used to allow the circulating fluid to carry the milling debris from the milling device cavity to circulate. The circulating fluid does not pass through the drilling tool and the casing annulus, and the diameter of the circulation channel is not increased much, which solves the problem of circulating the milling debris and returning it to the ground smoothly, thereby realizing the reverse circulation milling process. The lower conversion cavity part 04 realizes the flow of the circulating fluid in the central cavity into the casing 4 through the second conversion joint 10, completes the flushing operation, and then brings the circulating fluid carrying the milling debris from the central cavity back to the clamping cavity of the system to complete the return of the circulating fluid.

[0042] Specifically, the lower conversion cavity 04 includes a hollow rotating shaft 9 and a second conversion joint 10, and the two ends of the hollow rotating shaft 9 are respectively connected to the connecting shaft 07 and the second conversion joint 10. A connecting cap 31 is provided on the outer side of one end of the hollow rotating shaft 9, and the connecting cap 31 is used to connect the hollow rotating shaft 9 and the connecting shaft 07. In order to realize the rotation of the hollow rotating shaft 9, a deep groove ball bearing 32 is provided at the contact point of the hollow rotating shaft 9, the connecting shaft 07 and the connecting cap 31.

[0043] A straightening sleeve 14 and a rotating tube 27 are provided on the outside of the hollow rotating shaft 9. The straightening sleeve 14 and the rotating tube 27 partially overlap, and the overlapping parts of the straightening sleeve 14 and the rotating tube 27 are connected by a bearing. The straightening sleeve 14 is in sealing contact with the end of the connecting sleeve 21 to achieve sealing between the connecting sleeve 21, the straightening sleeve 14 and the hollow rotating shaft 9. Since the straightening sleeve 14 is arranged on the outside of the hollow rotating shaft 9, a third clamping chamber 15 is formed between the straightening sleeve 14 and the hollow rotating shaft 9, and the third clamping chamber 15 is used for the return of the circulating fluid. A seventh clamping chamber 28 is formed between the hollow rotating shaft 9 and the rotating tube 27, and the seventh clamping chamber 28 is used for the return of the circulating fluid. The third clamping chamber 15 in the embodiment of the present application is respectively connected to the second clamping chamber 13 and the seventh clamping chamber 28, and the seventh clamping chamber 28 is respectively connected to the second clamping chamber 13 and the fifth clamping chamber 22. In addition, a pressing cap 29 is provided between the end of the straightening sleeve 14 and the rotating tube 27 , and a locking ring 30 is provided on the pressing cap 29 .

[0044] The end of the second conversion joint 10 is provided with a second conversion cavity 11, which is in communication with the hollow rotating shaft 9, so that the circulating fluid is discharged into the sleeve 4 after being converted by the hollow rotating shaft 9 through the second conversion cavity 11. A second conversion sleeve 12 is provided outside the connection between the hollow rotating shaft 9 and the second conversion joint 10, and a second clamping cavity 13 is formed between the second conversion sleeve 12, the hollow rotating shaft 9 and the second conversion joint 10, and the second clamping cavity 13 is in communication with the third clamping cavity 15.

[0045] The circulation process of the circulating fluid in the horizontal well reverse circulation milling system provided in the embodiment of the present application is as follows:

[0046] The circulating fluid is pumped in from the casing 4, and when passing through the horizontal well reverse circulation milling system provided by the embodiment of the present application, the circulating fluid enters between the casing 4 and the first conversion joint 2. After the circulating fluid enters between the casing 4 and the first conversion joint 2, it enters the conversion center pipe 3 after being converted by the first conversion cavity 6. The circulating fluid enters the hydraulic motor part 03 through the conversion center pipe 3 inside the regulating part 02. After the circulating fluid enters the hydraulic motor part 03, while providing power to the hydraulic motor part 03, the circulating fluid continues to move in the direction of the downward conversion cavity part 04 until it enters the inside of the hollow rotating shaft 9. After the circulating fluid inside the hollow rotating shaft 9 is converted by the second conversion cavity 11, it enters between the second conversion sleeve 12 and the casing 4, and then completely enters the casing 4, realizing the reverse circulation pumping of the circulating fluid, and then realizing the flushing of the milling part by the circulating fluid.

[0047] After the circulating fluid flushes the milling part, the circulating fluid carries the milling debris. The circulating fluid carrying the debris enters the second conversion joint 10 from the central hollow of the second conversion joint 10, and then enters the second clamping chamber 13 formed by the second conversion cavity 11 and the second conversion sleeve 12. Due to the constant pressure, the inner diameter of the second clamping chamber 13 is smaller than the inner diameter of the second conversion joint 10, that is, the passage of the circulating fluid becomes smaller, which ensures the flow rate of the circulating fluid. Since the second clamping chamber 13, the seventh clamping chamber 28, the third clamping chamber 15, the fifth clamping chamber 22, the flow hole 24, the sixth clamping chamber 23, and the fourth clamping chamber 16 are connected in sequence, the circulating fluid carrying the debris gradually enters the fourth clamping chamber 16 of the upper conversion cavity part 01. Since the first clamping chamber 8 in the upper conversion cavity part 01 is connected to the fourth clamping chamber 16 and the first conversion joint 2 respectively, the circulating fluid carrying the debris flows out through the central tube cavity of the first conversion joint 2, and then is discharged to the ground after the first conversion joint 2 is connected to the drill pipe, realizing the work of reverse circulation milling.

[0048] In the horizontal well reverse circulation milling system provided by the embodiment of the present application, the upper conversion chamber part 01 and the lower conversion chamber part 04 respectively convert the first conversion joint 2 and the second conversion joint 10 inside to realize the change of the circulating fluid circulation channel and the reverse circulation of the circulating fluid, so that the milling debris can be smoothly returned to the ground with the circulating fluid, which can effectively prevent the occurrence of accidents such as debris stuck in the drill, thereby improving the milling efficiency and reducing the construction risk. The setting of the adjustment part 02 can effectively solve the connection at the turning point between the horizontal well section and the vertical well section, thereby avoiding the circulating fluid with milling debris from being affected by the horizontal well section, so that it can effectively return to the ground along the vertical well section. The pressure of the pumped circulating fluid drives the hydraulic motor in the hydraulic motor part 03 to operate normally, thereby realizing the effective rotation speed and torque at the bottom, and applying the effective rotation torque to the hollow rotating shaft 9, driving the lower conversion chamber part 04 to rotate, completing the sleeve milling work, and improving the milling efficiency.

[0049] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the disclosure of the invention herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0050] It should be understood that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A horizontal well reverse circulation milling system, characterized in that: The invention comprises an upper conversion cavity part (01), an adjusting part (02), a hydraulic motor part (03) and a lower conversion cavity part (04); two ends of the adjusting part (02) are respectively connected to the upper conversion cavity part (01) and the hydraulic motor part (03) through a first connecting joint (05) and a second connecting joint (06); the hydraulic motor part (03) and the lower conversion cavity part (04) are connected through a connecting shaft (07); The upper conversion cavity part (01) comprises a rubber cartridge seat sealing tube (1), a first conversion joint (2) and a conversion center tube (3) connected at the ends; a sealing rubber cartridge (5) having a sealing sleeve (4) is arranged outside the rubber cartridge seat sealing tube (1); A first conversion cavity (6) is provided at the end of the first conversion joint (2), and the first conversion cavity (6) is connected to the conversion center pipe (3); A first conversion sleeve (7) is provided on the outside of the end of the first conversion joint (2), and a first clamping cavity (8) is formed between the first conversion sleeve (7), the first conversion joint (2) and the conversion center pipe (3); The lower conversion cavity part (04) comprises a hollow rotating shaft (9) and a second conversion joint (10) connected to each other; a second conversion cavity (11) is provided at the end of the second conversion joint (10), and the second conversion cavity (11) is connected to the hollow rotating shaft (9); A second conversion sleeve (12) is provided on the outer side of the connection between the hollow rotating shaft (9) and the second conversion joint (10), and a second clamping cavity (13) is formed between the second conversion sleeve (12), the hollow rotating shaft (9) and the second conversion joint (10); A stabilizing sleeve (14) is provided on the outer side of the hollow rotating shaft (9), a third clamping cavity (15) is formed between the stabilizing sleeve (14) and the hollow rotating shaft (9), and the second clamping cavity (13) and the third clamping cavity (15) are connected.

2. The horizontal well reverse circulation milling system according to claim 1, characterized in that: A fourth clamping cavity (16) is formed between the rubber cartridge seat sealing tube (1) and the conversion center tube (3); the first clamping cavity (8) is respectively connected to the fourth clamping cavity (16) and the interior of the first conversion joint (2).

3. The horizontal well reverse circulation milling system according to claim 1, characterized in that: The regulating part (02) comprises an adjusting sleeve (17), a switching switch (18), and an extension tube (19) located outside the conversion center tube (3); a switch connector (20) is provided between the adjusting sleeve (17) and the switching switch (18); A connecting sleeve (21) is disposed on the outside of the extension tube (19), and a fifth clamping chamber (22) is formed between the connecting sleeve (21), the conversion switch (18), the extension tube (19), the hydraulic motor unit (03), and the straightening sleeve (14); A sixth clamping chamber (23) is formed between the conversion switch (18) and the conversion central tube (3); the fifth clamping chamber (22) and the sixth clamping chamber (23) are connected via a flow hole (24).

4. The horizontal well reverse circulation milling system according to claim 3, characterized in that: A butt joint (25) is provided on the outer side of the extension tube (19).

5. The horizontal well reverse circulation milling system according to claim 3, characterized in that: A switch lock ring (26) is provided between the switch connector (20) and the conversion switch (18).

6. The horizontal well reverse circulation milling system according to claim 3, characterized in that: A rotating tube (27) is provided on the outside of the hollow rotating shaft (9), and the rotating tube (27) is connected to the bearing of the straightening sleeve (14); a seventh clamping cavity (28) is formed between the hollow rotating shaft (9) and the rotating tube (27), and the seventh clamping cavity (28) is respectively connected to the second clamping cavity (13) and the third clamping cavity (15).

7. The horizontal well reverse circulation milling system according to claim 6, characterized in that: A pressing cap (29) is provided between the end of the straightening sleeve (14) and the rotating tube (27), and a locking ring (30) is provided on the pressing cap (29).

8. The horizontal well reverse circulation milling system according to claim 1, characterized in that: The hollow rotating shaft (9) and the connecting shaft (07) are connected via a connecting cap (31), and a deep groove ball bearing (32) is provided at the contact points between the hollow rotating shaft (9), the connecting shaft (07) and the connecting cap (31).

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