Downhole segment milling tool and method

Abstract

The present invention provides a downhole segment milling tool and method, which belongs to the technical field of oil and gas well tools. Cutting fluid is injected into the inner hole of the moving tube of the telescopic component, and the cutting fluid enters the cutting component and is ejected along the circumference of the moving tube to cut the casing in the well. The driving component connected to the end of the moving tube away from the cutting assembly drives the moving tube to move axially, and controls the cutting assembly to perform rapid cutting in a limited area, thereby improving the cutting efficiency of the casing. In addition, the shoulder of the moving tube in the telescopic component moves the moving tube, which will compress the annular sealing space between the moving tube and the support tube. The annular sealing space is compressed and will exert a force on the annular elastic piston in the annular sealing space and provide a reaction force to the moving tube, thereby preventing the moving tube from moving too fast or too slow, and playing a certain buffering role in the movement of the moving tube and the cutting assembly, thereby effectively improving the cutting efficiency of the downhole segment milling tool while ensuring stable cutting of the downhole casing.

Description

Technical Field

[0001] The present disclosure relates to the technical field of oil and gas well tools, and in particular to a downhole segment milling tool and method. Background Art

[0002] Downhole section milling tools are commonly used in downhole maintenance of oil and gas wells. They are tools used to cut and mill away the casing on the well wall to form an open hole section, providing a channel from the casing to the formation for side drilling.

[0003] In the related art, the downhole milling tool includes a pipe joint, a rotating cylinder and a nozzle. One end of the pipe joint is used to connect a driving pump, and the other end of the pipe joint is coaxially and rotatably connected to one end of the rotating cylinder. The inner peripheral wall of the rotating cylinder has a plurality of spiral guide grooves. The other end of the rotating cylinder is fixedly connected to the nozzle, and the inner hole of the rotating cylinder is connected to the inner hole of the nozzle. The water flows through the guide groove to apply torque to the rotating cylinder and the nozzle to realize the rotation of the nozzle, and the water flow sprayed by the rotating nozzle rotates and cuts the casing.

[0004] When the nozzle of this downhole milling tool is working, it can only rely on the circumferential rotation of the nozzle to control the cutting work, and the cutting rate is slow. Manually controlling the rotation or axial movement of the nozzle is easy to cut the casing position outside the area to be cut, and the efficiency and accuracy of cutting the casing are difficult to guarantee. Summary of the invention

[0005] The embodiment of the present disclosure provides a downhole segment milling tool and method, which can ensure the accuracy of the casing cutting range and improve the casing cutting efficiency. The technical solution is as follows:

[0006] The present disclosure provides a downhole segment milling tool and method, wherein the downhole segment milling tool includes a telescopic component, a cutting component, and a driving component.

[0007] The telescopic component includes a moving tube, a supporting tube and an annular elastic piston. The moving tube has a first part and a second part that are coaxially connected. The outer diameter of the first part is larger than that of the second part. The moving tube is slidably and coaxially inserted in the supporting tube. An annular sealed space is provided between the supporting tube and the moving tube. A transition portion between the first part and the second part is located in the annular sealed space. The annular elastic piston is located at one end of the annular sealed space and is sleeved on the first part.

[0008] The cutting component is connected to one end of the moving tube and is used to spray the cutting fluid in the moving tube along the circumference of the moving tube.

[0009] The driving component is connected to the other end of the moving tube and is used to drive the moving tube to move axially.

[0010] Optionally, the annular sealed space is filled with hydraulic oil, the telescopic component further comprises an annular metering valve, the annular metering valve divides the annular sealed space into a first chamber and a second chamber along the axial direction of the annular sealed space, and the annular elastic piston fills the first chamber.

[0011] Optionally, the telescopic component also includes a return spring and an annular floating plate located in the second chamber, one end of the return spring is connected to the outer peripheral wall of the support tube, and the other end of the return spring is connected to the annular floating plate, the annular floating plate is coaxial with the moving tube and is slidably distributed in the annular sealing space, and the annular floating plate has a flow hole.

[0012] Optionally, an end of the inner circumferential wall of the moving tube away from the cutting component has a coaxial annular cutting fluid pushing groove.

[0013] Optionally, the cutting component includes a nozzle, which is rotatably connected to the moving tube, and has at least two first nozzles and at least one second nozzle connected to the inner hole of the moving tube, the at least two first nozzles and the at least one second nozzle are alternately spaced along the circumference of the moving tube, the axis of the first nozzle and the axis of the second nozzle are both skewed with the axis of the moving tube, the minimum distance between the axis of the first nozzle and the axis of the moving tube is equal to the minimum distance between the axis of the second nozzle and the axis of the moving tube, and the axis of the outlet of the first nozzle and the axis of the outlet of the second nozzle are respectively located on different planes.

[0014] Optionally, the nozzle further includes a guide hole coaxial with the moving tube, the diameter of the guide hole is smaller than the inner diameter of the moving tube, and the inlet of the first spray hole and the inlet of the second spray hole are both connected to the guide hole.

[0015] Optionally, the cutting component includes an annular straightening shell and a rotating tube, the annular straightening shell is coaxially connected to an end of the moving tube away from the driving component, the rotating tube is coaxially and rotationally connected to the annular straightening shell, and the rotating tube is connected to the nozzle.

[0016] The present disclosure provides a downhole segment milling method, the downhole segment milling method comprising:

[0017] Providing a downhole segment milling tool as described above;

[0018] Injecting cutting fluid into the moving tube of the downhole milling tool, the cutting fluid enters the cutting component and is ejected by the cutting component along the circumference of the moving tube to perform cutting;

[0019] The driving component in the downhole segment milling tool drives the moving tube to move axially, and the moving tube compresses the annular sealed space. The pressure in the annular sealed space increases, compressing the annular elastic piston in the downhole segment milling tool so that the moving tube and the cutting component move and cut evenly.

[0020] Optionally, the moving speed of the cutting component is 20-30 mm / min.

[0021] Optionally, the cutting fluid includes slick water and quartz sand, the volume concentration of the quartz sand is 5-9%, and the particle size of the quartz sand is 80-130 meshes.

[0022] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include at least:

[0023] The downhole milling tool includes a telescopic component, a cutting component and a driving component, wherein the telescopic component includes a moving tube, a supporting tube and an annular elastic piston. The moving tube has a first part and a second part which are coaxially connected, the outer diameter of the first part is larger than the second part, the moving tube can be slidably and coaxially inserted in the supporting tube, an annular sealing space for accommodating the transition part of the first part and the second part is provided between the supporting tube and the moving tube, and the annular elastic piston is coaxially connected to one end of the annular sealing space and is located in the first part. When used specifically, cutting fluid can be injected into the inner hole of the moving tube of the telescopic component, the cutting fluid enters the cutting component connected to one end of the moving tube from the moving tube, and the cutting component then sprays the cutting fluid along the circumference of the moving tube to cut the casing downhole. After the cutting component works stably, the driving component connected to the end of the moving tube away from the cutting component can drive the moving tube to move axially, and can control the cutting component to perform rapid cutting in a limited area, thereby improving the cutting efficiency of the casing. When the transition part between the first part and the second part of the moving tube in the telescopic component moves, the movement of the transition part can compress the annular sealing space between the moving tube and the supporting tube. The annular sealing space is compressed and exerts a force on the annular elastic piston in the annular sealing space and provides a reaction force to the moving tube, which can prevent the moving tube from moving too fast or too slow, and has a certain buffering effect on the movement of the moving tube and the cutting component, which can effectively improve the cutting efficiency of the downhole milling tool while ensuring the stable cutting of the downhole casing. In this structure, the volume of the annular elastic piston is compressed to provide an extension of the axial length of the annular sealing space, and the axial compression amount of the annular elastic piston is the axial movement distance of the moving tube. When the moving tube moves to the situation where the annular elastic piston cannot be compressed, the volume of the annular sealing space does not change, and the volume of the annular sealing space remains unchanged, resulting in the inability to move the transition part between the first part and the second part, and the moving tube. This structure can more accurately control the moving distance of the cutting component, so as to accurately control the cutting range of the cutting component, and stably and effectively cut the downhole casing within a certain range. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 It is a schematic diagram of the structure of a downhole segment milling tool provided by an embodiment of the present disclosure;

[0026] Figure 2 is a schematic diagram of the structure of a telescopic component provided in an embodiment of the present disclosure;

[0027] Figure 3 is a schematic structural diagram of an annular floating plate provided in an embodiment of the present disclosure;

[0028] Figure 4 is a cross-sectional view of a cutting component provided by an embodiment of the present disclosure;

[0029] Figure 5 is a simplified side view of a spray head provided by an embodiment of the present disclosure;

[0030] Figure 6 is a simplified schematic diagram of a spray head provided by an embodiment of the present disclosure;

[0031] Figure 7 is a schematic structural diagram of a cutting component provided by an embodiment of the present disclosure;

[0032] Figure 8 It is a structural schematic diagram of the downhole segment milling method provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0034] For ease of understanding, we first provide Figure 1 , Figure 1 Schematic diagram of the use of the downhole segment milling tool and method provided by the embodiment of the present disclosure, with reference to Figure 1 It can be seen that the embodiment of the present disclosure provides a downhole segment milling tool and method, and the downhole segment milling tool includes a telescopic component 1, a cutting component 2 and a driving component 3.

[0035] Figure 2 is a schematic diagram of the structure of the telescopic component provided in the embodiment of the present disclosure, with reference to Figure 2It can be seen that the telescopic component 1 includes a moving tube 11, a supporting tube 12 and an annular elastic piston 13. The moving tube 11 has a first part 111 and a second part 112 which are coaxially connected. The outer diameter of the first part 111 is larger than that of the second part 112. The moving tube 11 can be slidably and coaxially inserted in the supporting tube 12. There is an annular sealing space 4 between the supporting tube 12 and the moving tube 11. The transition part 113 between the first part 111 and the second part 112 is located in the annular sealing space 4. The annular elastic piston 13 is located at one end of the annular sealing space 4 and is sleeved on the first part 111.

[0036] The cutting member 2 is communicated with one end of the moving tube 11 , and is used to eject the cutting fluid in the moving tube 11 along the circumferential direction of the moving tube 11 .

[0037] The driving component 3 is connected to the other end of the moving tube 11 and is used to drive the moving tube 11 to move axially.

[0038] The downhole milling tool includes a telescopic component 1, a cutting component 2 and a driving component 3. The telescopic component 1 includes a moving tube 11, a supporting tube 12 and an annular elastic piston 13. The moving tube 11 has a first part 111 and a second part 112 which are coaxially connected. The outer diameter of the first part 111 is larger than that of the second part 112. The moving tube 11 can be slidably and coaxially inserted in the supporting tube 12. There is an annular sealing space 4 between the supporting tube 12 and the moving tube 11 to accommodate a transition part 113 of the first part 111 and the second part 112. The annular elastic piston 13 is coaxially connected to one end of the annular sealing space 4 and is located in the first part 111. When used, cutting fluid can be injected into the inner hole of the moving tube 11 of the telescopic component 1. The cutting fluid enters the cutting component 2 connected to one end of the moving tube 11 from the moving tube 11. The cutting component 2 then sprays the cutting fluid along the circumference of the moving tube 11 to cut the casing downhole. After the cutting component 2 works stably, the driving component 3 connected to the end of the moving tube 11 away from the cutting component 2 can drive the moving tube 11 to move axially, and can control the cutting component 2 to perform rapid cutting in a limited area, thereby improving the cutting efficiency of the casing. In addition, when the transition part 113 between the first part 111 and the second part 112 of the moving tube 11 in the telescopic component 1 moves, the movement of the transition part 113 can compress the annular sealing space 4 between the moving tube 11 and the support tube 12. The annular sealing space 4 is compressed and exerts a force on the annular elastic piston 13 in the annular sealing space 4 and provides a reaction force between the transition part 113 between the first part 111 and the second part 112 of the moving tube 11, thereby preventing the moving speed of the moving tube 11 from being too fast or too slow, and playing a certain buffering role in the movement of the moving tube 11 and the cutting component 2, thereby effectively improving the cutting efficiency of the downhole segment milling tool while ensuring the stable cutting of the downhole casing. In this structure, the annular elastic piston 13 is compressed at one end of the annular sealing space 4, and the compressed volume of the annular elastic piston 13 can be converted into the volume of the annular sealing space 4 pushed by the transition part 113 (essentially, the air normally stored in the annular elastic piston 13 is squeezed into the annular sealing space 4 by pressure), and the axial compression amount of the annular elastic piston 13 is correspondingly converted into the axial movement distance of the moving tube 11. When the moving tube 11 moves to the situation where the annular elastic piston 13 cannot be compressed, the volume of the annular sealing space 4 does not change. The unchanged volume of the annular sealing space 4 causes the transition part 113 between the first part 111 and the second part 112 to be unable to move, and the moving tube 11 cannot move. This structure can more accurately control the moving distance of the cutting component 2, so as to accurately control the cutting range of the cutting component 2, and stably and effectively cut the downhole casing within a certain range. The driving component 3 can also control the mobile tube 11 to be restored, and the annular elastic piston 13 to be restored by suction pressure.

[0039] It should be noted that the transition portion 113 between the first portion 111 and the second portion 112 can be made into a structure similar to a shaft shoulder, and the shaft shoulder can effectively push the annular sealing space 4. In other implementations provided by the present disclosure, the transition portion 113 between the first portion 111 and the second portion 112 can also be made into a form similar to a conical transition, and the present disclosure does not limit this.

[0040] Optionally, an end of the inner circumferential wall of the moving tube 11 away from the cutting component 2 has a coaxial annular cutting fluid pushing groove 114 .

[0041] The inner wall of the moving tube 11 is provided with an annular cutting fluid pushing groove 114 at one end away from the cutting component 2 . When the cutting fluid is pumped in, the cutting fluid acts on the bottom surface of the annular cutting fluid pushing groove 114 , thereby facilitating pushing the moving tube 11 .

[0042] Optionally, the annular elastic piston 13 may be made of materials such as rubber and nylon, etc. The present disclosure does not impose any limitation on this.

[0043] Exemplarily, the annular sealing space 4 is filled with hydraulic oil, the telescopic component 1 also includes an annular metering valve 14, the annular metering valve 14 divides the annular sealing space 4 into a first chamber 41 and a second chamber 42 along the axial direction of the annular sealing space 4, and the annular elastic piston 13 fills the first chamber 41.

[0044] The elastic modulus of hydraulic oil is smaller than that of air. The annular sealed space 4 is filled with hydraulic oil. When the hydraulic oil is under pressure, it is easier to flow to push and compress the moving tube 11. At the same time, the annular metering valve 14 can realize the pressure control of the hydraulic oil flowing between the first chamber 41 and the second chamber 42. When the hydraulic oil pressure is less than the back pressure of the annular metering valve 14, the annular metering valve 14 is closed, and there is no flow between the first chamber 41 and the second chamber 42, and the moving tube 11 is in a static state. When the hydraulic oil is pressurized to a certain extent, the pressure is greater than the back pressure of the annular metering valve 14, and the annular metering valve 14 is opened, and the hydraulic oil enters the first chamber 41 from the second chamber 42 to compress the annular elastic piston 13, so as to realize the movement of the moving tube 11 and the flow of the hydraulic oil.

[0045] It should be noted that the annular metering valve 14 may include a common metering valve structure and an annular plate with an opening connected to the outer shell of the metering valve structure, which together constitute the annular metering valve 14 .

[0046] Optionally, the annular elastic piston 13 may be slidably matched with the outer peripheral wall of the moving tube 11 , and the annular metering valve 14 is connected to the outer peripheral wall of the moving tube 11 .

[0047] The annular metering valve 14 clamps the annular elastic piston 13 at one end of the annular sealing space 4 , which is easy to install as a whole and can also realize stable movement of the moving tube 11 .

[0048] It should be noted that, under the premise that the annular sealed space 4 is divided into the first chamber 41 and the second chamber 42 , the transition portion 113 is located in the second chamber 42 .

[0049] Optionally, the telescopic component 1 also includes a return spring 15 and an annular floating plate 16 located in the second chamber 42, one end of the return spring 15 is connected to the outer peripheral wall of the support tube 12, and the other end of the return spring 15 is connected to the annular floating plate 16, the annular floating plate 16 is coaxial with the moving tube 11 and is slidably distributed in the annular sealing space 4, and the annular floating plate 16 has a flow hole 161.

[0050] The reset spring 15 and the annular floating plate 16 added in the second chamber 42, when the transition part 113 pushes the hydraulic oil in the second chamber 42 to flow, the reset spring 15 and the annular floating plate 16 with the flow hole 161 can play a certain damping and buffering role, reducing the shaking and impact caused by the movement of the moving tube 11. Ensure the stable movement of the moving tube 11 and the cutting component 2 and the stable injection of the water flow. When the hydraulic oil flows due to the force applied, although there is the flow hole 161, the annular floating plate 16 will still be pushed a certain distance by the hydraulic oil, and the reset spring 15 will be compressed. Therefore, during the resetting process of the moving tube 11, the reset spring 15 itself also has the need to reset, which can promote the rapid resetting of the moving tube 11.

[0051] For example, the return spring 15 may be a ring-shaped spring coaxially sleeved on the outer peripheral wall of the moving tube 11. The buffering effect is good.

[0052] In an implementation provided by the present disclosure, a plurality of reset springs 15 and annular floating plates 16 can be arranged in the axial direction of the moving tube 11 at intervals, so that the hydraulic oil can be pushed more evenly and stably, and the buffering effect is better.

[0053] In other implementations provided by the present disclosure, multiple return springs 15 and multiple annular floating plates 16 may be alternately distributed in the second chamber 42 of the annular sealed space 4, the return springs 15 and the annular floating plates 16 alternately abut against each other, and the total length of the multiple return springs 15 and the multiple annular floating plates 16 is equal to the total length of the second chamber 42, where the total length is the total axial length. The return spring 15 and the annular floating plate 16 are coaxially and slidably sleeved on the moving tube 11.

[0054] In the above structure, the sliding reset spring 15 and the annular floating plate 16 are convenient to disassemble and assemble, and there is no need to make additional connections between the reset spring 15 and the annular floating plate 16. The compression of each reset spring 15 is also relatively uniform, and the buffering effect is good, and the effect of controlling the moving speed is good. It should be noted that the total length of the multiple reset springs 15 and the multiple annular floating plates 16 is equal to the total length of the second chamber 42, then one of the multiple reset springs 15 or one of the multiple annular floating plates 16 is against the annular metering valve 14, and when the annular metering valve 14 moves axially with the moving tube 11, the reset spring 15 is compressed. When resetting is required, the reset spring 15 extends to push the annular metering valve 14 and the moving tube 11 to reset.

[0055] It should be noted that when the annular sealed space 4 is filled with hydraulic oil, the transition portion 113 applies pressure to the hydraulic oil and transmits it to the annular elastic piston 13, thereby compressing the annular elastic piston 13. When there is no hydraulic oil in the annular sealed space 4, the transition portion 113 applies pressure to the air in the annular sealed space 4, and finally transmits the pressure to the annular elastic piston 13.

[0056] Figure 3 is a schematic diagram of the structure of the annular floating plate provided in the embodiment of the present disclosure, with reference to Figure 3 It can be seen that the annular floating plate 16 may have a plurality of flow holes 161 spaced apart from each other in the circumferential direction, so as to improve the buffering and damping effect and ensure the stable movement of the moving pipe 11 .

[0057] Exemplarily, the telescopic component 1 further includes a first pipe joint 17 and a sealing connection ring 18, the wall thickness of the support tube 12 remains unchanged, one end of the first pipe joint 17 is connected to the driving component, the outer peripheral wall of the other end of the first pipe joint 17 is threadedly matched with the inner peripheral wall of the support tube 12, the first pipe joint 17 is coaxially connected to one end of the moving tube 11, the support tube 12 is sleeved on the moving tube 11, the other end of the support tube 12 is threadedly matched with the outer peripheral wall of the sealing connection ring 18, and the inner peripheral wall of the sealing connection ring 18 is slidably sealed with the outer peripheral wall of the moving tube 11. A sealed space is enclosed between the support tube 12 and the moving tube 11.

[0058] Adding the first pipe joint 17 and the sealing connection ring 18 can form a larger annular sealing space, which is also convenient for disassembly and assembly as a whole, and has low processing requirements for each structure, which can effectively control the preparation cost of the downhole segment milling tool.

[0059] In other implementations provided by the present disclosure, the fixed connection may also be fixed by adding bolts, and the present disclosure does not limit this.

[0060] It should be noted that in other implementation methods provided in the present disclosure, the outer diameter of the movable tube 11 and the inner diameter of the support tube 12 can also be set as a variable structure. For example, the outer circumferential wall of the movable tube 11 and the inner circumferential wall of the support tube 12 are slidably fitted through a sealing ring, and an annular groove is added to the outer circumferential wall of the movable tube 11, and an annular sealed space can be formed between the annular groove and the inner circumferential wall of the support tube 12.

[0061] In an implementation provided by the present disclosure, the maximum outer diameter of the support tube 12 can be 89 mm, the minimum inner diameter of the moving tube can be 29 mm, the maximum length of the telescopic component 1 is 1.42 m, the maximum moving distance of the moving tube 11 is 550 mm, the maximum moving speed of the moving tube 11 is 50 mm / min, and the upper limit of the pressure resistance of the annular sealing chamber 4 is 60 MPa. Stable and effective cutting of the casing can be achieved.

[0062] The type of pipe fittings provided in the present disclosure may be 2-3 / 8 inch EUE.

[0063] Figure 4 is a cross-sectional view of a cutting component provided in an embodiment of the present disclosure, with reference to Figure 4 It can be seen that the cutting component 2 includes a nozzle 21, which is rotatably connected to the moving tube 11. The nozzle 21 has at least two first nozzle holes 211 and at least one second nozzle hole 212 connected to the inner hole of the moving tube 11. The at least two first nozzle holes 211 and the at least one second nozzle hole 212 are alternately distributed along the circumference of the moving tube 11. The axis of the first nozzle hole 211 and the axis of the second nozzle hole 212 are not in the same plane as the axis of the moving tube 11. The minimum distance between the axis of the first nozzle hole 211 and the axis of the moving tube 11 is equal to the minimum distance between the axis of the second nozzle hole 212 and the axis of the moving tube 11. The axis of the outlet of the first nozzle hole 211 and the axis of the outlet of the second nozzle hole 212 are respectively located on different planes.

[0064] A first spray hole 211 and a second spray hole 212 are added to the spray head 21, at least two first spray holes 211 and at least one second spray hole 212 are alternately distributed along the circumference of the moving tube 11, the axis of the first spray hole 211 and the axis of the second spray hole 212 are not in the same plane as the axis of the moving tube 11, and the minimum distance between the axis of the first spray hole 211 and the axis of the moving tube 11 is equal to the minimum distance between the axis of the second spray hole 212 and the axis of the moving tube 11. Then, the position where the cutting fluid is sprayed is at the eccentric position of the spray head 21, and the self-reaction force generated when spraying the cutting fluid will provide a rotational power torque to drive the spray head 21 to rotate, thereby driving the spray head 21 to spray fluid, and realizing 360° circumferential cutting and destruction of the casing. The axis of the outlet of the first spray hole 211 and the axis of the outlet of the second spray hole 212 are located on different planes, which can form a torque on the spray head 21 to promote the rotation of the spray head 21, and on the other hand, the different positions of the outlets can increase the cutting area of ​​the spray head 21 in the axial direction of the mobile pipe 11. The overall structure is relatively simple, the space required is also small, and the rotary cutting of the downhole casing is realized with a relatively compact structure.

[0065] Optionally, the center of gravity of the spray head 21 may be located on the extension line of the axis of the moving tube 11. The rotation is more stable.

[0066] Optionally, the skew angle between the extended axis of the first spray hole 211 and the extended axis of the second spray hole 212 and the axis of the moving tube 11 may be in the range of 80-88°, which can ensure the stable rotation and spraying of the spray head.

[0067] It should be noted that the extended line of the axis of the first spray hole 211 and the second spray hole 212 refers to a line extending from the axis of the first spray hole 211 and the second spray hole 212 in the length direction.

[0068] Optionally, the nozzle 21 further includes a guide hole 213 coaxial with the moving tube 11 , the diameter of the guide hole 213 is smaller than the inner diameter of the moving tube 11 , and the inlet of the first spray hole 211 and the inlet of the second spray hole 212 are both connected to the guide hole 213 .

[0069] The guide hole 213 is coaxial with the mobile tube 11, and the cutting fluid can also enter the guide hole 213 from the mobile tube 11. In the case where the cutting fluid contains sand, the possibility of blockage of the nozzle 21 can be reduced, and the stable flow of the cutting fluid can be achieved to ensure stable cutting of the downhole casing. In the case that the nozzle 21 has been blocked, a fluid without sand can also be introduced into the nozzle 21, and the fluid flows out from the guide hole 213, the first nozzle 211 and the second nozzle 212 to clean the blocked position in the entire nozzle 21.

[0070] In an implementation provided by the present disclosure, the intersection of the axis of the inlet of the first spray hole 211 and the guide hole 213 and the intersection of the axis of the inlet of the second spray hole 212 and the guide hole 213 can be located on the same circumference of the inner circumferential wall of the guide hole 213. The inlet positions are controlled to be basically on the same circumference, which reduces the processing difficulty and makes the rotation of the nozzle 21 more stable.

[0071] Figure 5 is a simplified side view of a nozzle provided by an embodiment of the present disclosure, Figure 6 is a simplified schematic diagram of the nozzle provided in the embodiment of the present disclosure, refer to Figure 5 and Figure 6 It can be seen that on the plane perpendicular to the moving tube 11, the axes of the first spray hole 211 and the second spray hole 212 are not in the same plane as the axis of the moving tube 11 or the guide hole 213, and the distances from the axis of each first spray hole 211 and the axis of the second spray hole 212 to the axis of the guide hole 213 are the same. Figure 6 It can be seen that the first spray hole 211 and the second spray hole 212 have a certain height and slope.

[0072] It should be noted that, for ease of understanding, Figure 6 Only a perspective structural diagram of a first spray hole 211 and a second spray hole 212 is shown.

[0073] Optionally, the cutting component 2 includes an annular straightening shell 22 and a rotating tube 23, the annular straightening shell 22 is coaxially connected to one end of the moving tube 11 away from the driving component 3, the rotating tube 23 is coaxially and rotationally connected to the annular straightening shell 22, and the rotating tube 23 is connected to the nozzle 21.

[0074] The annular straightening shell can play a supporting and fixing role underground, and can reduce the possible shaking of the cutting component 2 in cooperation with the rotating tube 23, thereby ensuring the stable movement and rotation of the cutting component 2.

[0075] Figure 7 is a schematic diagram of the structure of the cutting component provided in the embodiment of the present disclosure, with reference to Figure 7 It can be known that the annular centralizing shell 22 may include a cylindrical body 221 and a plurality of support ribs 222. The plurality of support ribs 222 are spaced apart on the outer peripheral wall of the cylindrical body 221 along the circumferential direction of the cylindrical body 221, and the length direction of each support rib 222 is parallel to the axis of the cylindrical body 221.

[0076] This structure can ensure support while the annular straightening shell 22 itself has a small resistance to axial movement, thereby reducing the resistance to axial movement of the cutting component 2. In addition, a plurality of support ribs 222 are spaced apart along the circumference of the cylindrical body 221 on the outer peripheral wall of the cylindrical body 221, and the length direction of each support rib 222 is parallel to the axis of the cylindrical body 221. There is also enough space between the cylindrical body 221, the support ribs 222 and the casing of the well wall for liquid to be discharged from the wellhead.

[0077] It should be noted that at this time, the cutting fluid flows from the moving tube 11 into the rotating tube 23 and then into the cutting component 2 .

[0078] Optionally, the cutting component 2 also includes a second pipe joint 24, an annular sealing seat 25 and a ball bearing, one end of the second pipe joint 24 is sealed and coaxially connected to the movable tube 11, the outer circumferential wall of the other end of the second pipe joint 24 is sealed and connected to the inner circumferential wall of the annular straightening shell 22, the inner circumferential wall of the other end of the second pipe joint 24 is sealingly and slidingly matched with the outer circumferential wall of the rotating tube 23, one end of the annular sealing seat 25 is rotatably connected to the end face of the other end of the second pipe joint 24, the ball bearing is located between the annular sealing seat 25 and the end face of the second pipe joint 24, and the inner circumferential wall of the annular sealing seat 25 is sealingly matched with the outer circumferential wall of the rotating tube 23.

[0079] The second pipe joint 24 and the annular sealing seat 25 can improve the sealing performance of the rotating tube 23, and the ball bearings can reduce the wear between the various structures.

[0080] It should be noted that the sealing cooperation between the surfaces can be achieved through a sealing ring, and O-type sealing can be used in this application.

[0081] Optionally, the position where the rotating tube 23 extends out of the annular straightening shell 22 and the connection with the annular straightening shell 22 may also adopt a matching method similar to the second pipe joint, the annular sealing seat and the ball bearing to reduce friction, which will not be repeated here.

[0082] Exemplarily, the cutting component 2 also includes a support cylinder 26, a copper sleeve 27 and a rotating bearing 28. The copper sleeve 27 and the support cylinder 26 are coaxially covered on the outer peripheral wall of the rotating tube 23 in sequence. The copper sleeve 27 is connected to the rotating tube 23. The end of the support cylinder 26 is abutted against the second pipe joint 24. The two rotating bearings 28 are both located between the rotating tube 23 and the support cylinder 26, and the two rotating bearings 28 are distributed at both ends of the copper sleeve 27.

[0083] The copper sleeve 27 can reduce possible wear of the rotating tube 23, and cooperate with the support tube 26 and the rotating bearing 28 to reduce wear between the rotating tube 23 and the annular straightening shell 22, and is also easy to replace.

[0084] Optionally, the support tube 26 and the annular centralizing shell 22 may be connected by a square key and bolts to facilitate the connection.

[0085] In other implementations provided by the present disclosure, the cutting component 2 may also be configured to include a rotating cylinder and a nozzle, and the rotating cylinder has a spiral guide groove structure, which is not limited by the present disclosure.

[0086] Exemplarily, the driving component 3 may be a hydraulic pump, which can inject cutting fluid into the moving tube 11 and also push the moving tube 11 to move.

[0087] In other implementations provided by the present disclosure, the driving component 3 may also include a structure similar to a telescopic rod, one end of which is connected to the end surface of the moving tube 11. The movement of the moving tube 11 can be controlled without affecting the cutting fluid from entering the inner hole of the moving tube 11 and entering the cutting assembly.

[0088] Figure 8 is a schematic diagram of the structure of the downhole segment milling method provided by the embodiment of the present disclosure, with reference to Figure 8 It can be seen that the embodiment of the present disclosure provides a downhole segment milling method, and the downhole segment milling method includes:

[0089] S101: Provide a downhole segment milling tool as before.

[0090] S102: Inject cutting fluid into the moving tube of the downhole milling tool, the cutting fluid enters the cutting component and is ejected by the cutting component along the circumference of the moving tube to perform cutting.

[0091] S103: The driving component in the downhole milling tool drives the moving tube to move axially, and the moving tube compresses the annular sealing space. The pressure in the annular sealing space increases to compress the annular elastic piston, so that the moving tube and the cutting component move and cut evenly.

[0092] Figure 8 The technical effect of the downhole segment milling method shown in Figure 1 The technical effect of the downhole milling tool shown in FIG. Figure 8 The technical effects of the downhole segment milling method shown in are not described in detail.

[0093] It should be noted that before injecting cutting fluid into the downhole segment milling tool, the telescopic component and the cutting component in the downhole segment milling tool need to be lowered at a uniform speed into the casing to be cut in the downhole.

[0094] Optionally, the moving speed of the cutting component is 20-30 mm / min, which can ensure cutting accuracy and cutting efficiency.

[0095] Optionally, the cutting fluid includes slick water and quartz sand, the volume concentration of the quartz sand is 5-9%, and the particle size of the quartz sand is 80-130 meshes, which can ensure stable and effective cutting of the downhole casing.

[0096] For example, the displacement of the cutting fluid may be 400-600 L / min. The cutting efficiency is relatively high.

[0097] For example, before injecting the cutting fluid, the downhole milling method may also include injecting a fluid without sand into the moving pipe of the downhole milling tool, and checking the working condition of the downhole milling tool under the condition of a fluid displacement of 400-600 L / min. This can ensure the stability of subsequent cutting.

[0098] It should be noted that the working condition of the downhole milling tool can be judged by checking the pressure of the pump on the ground. After pumping for a period of time, if the pressure is stable at a certain threshold, it can be judged that the downhole milling tool can work normally.

[0099] Exemplarily, after the cutting fluid is injected, the downhole milling method may also include checking the sand content in the liquid discharged from the downhole. If the sand content in the cubic liquid is 0-3%, the injection of the cutting fluid is stopped; and the cutting fluid is injected after the sand-free fluid is passed to clean the downhole milling tool.

[0100] It should be noted that after the downhole milling tool completes a cutting stroke, the injection of cutting fluid is stopped and the downhole milling tool is cleaned; the downhole milling tool is controlled to move as a whole to the next casing to be cut, and the cutting is resumed. After all cutting work is completed, the downhole milling tool is taken out from the well.

[0101] The above does not limit the present disclosure in any form. Although the present disclosure has been disclosed as above through the embodiments, it is not used to limit the present disclosure. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present disclosure. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present disclosure without departing from the content of the technical solution of the present disclosure still falls within the scope of the technical solution of the present disclosure.

Claims

1. A downhole segment milling tool, characterized in that: The downhole segment milling tool comprises a telescopic component (1), a cutting component (2) and a driving component (3). The telescopic component (1) comprises a moving tube (11), a supporting tube (12) and an annular elastic piston (13); the moving tube (11) comprises a first part (111) and a second part (112) which are coaxially connected; the outer diameter of the first part (111) is larger than that of the second part (112); the moving tube (11) is slidably and coaxially inserted in the supporting tube (12); an annular sealing space (4) is provided between the supporting tube (12) and the moving tube (11); a transition part (113) between the first part (111) and the second part (112) is located in the annular sealing space (4); the annular elastic piston (13) is located at one end of the annular sealing space (4) and is sleeved on the first part (111); the annular sealing space (4) is filled with hydraulic oil. The telescopic component (1) further comprises an annular metering valve (14), wherein the annular metering valve (14) divides the annular sealed space (4) into a first chamber (41) and a second chamber (42) along the axial direction of the annular sealed space (4), wherein the annular elastic piston (13) fills the first chamber (41), and the telescopic component (1) further comprises a return spring (15) and an annular floating plate (16) located in the second chamber (42), wherein one end of the return spring (15) is connected to the outer peripheral wall of the support tube (12), and the other end of the return spring (15) is connected to the annular floating plate (16), wherein the annular floating plate (16) is coaxial with the moving tube (11) and is slidably distributed in the annular sealed space (4), and the annular floating plate (16) has a flow hole (161), The cutting component (2) is connected to one end of the moving tube (11) and is used to spray the cutting fluid in the moving tube (11) along the circumferential direction of the moving tube (11). The driving component (3) is connected to the other end of the moving tube (11) and is used to drive the moving tube (11) to move axially.

2. The downhole segment milling tool according to claim 1, characterized in that: An end of the inner peripheral wall of the moving tube (11) away from the cutting component (2) is provided with a coaxial annular cutting liquid pushing groove (114).

3. The downhole segment milling tool according to claim 1, characterized in that: The cutting component (2) comprises a nozzle (21), the nozzle (21) being rotatably connected to the moving tube (11), the nozzle (21) having at least two first nozzle holes (211) and at least one second nozzle hole (212) which are connected to the inner hole of the moving tube (11), the at least two first nozzle holes (211) and the at least one second nozzle hole (212) being alternately spaced and distributed along the circumference of the moving tube (11), the axis of the first nozzle hole (211) and the axis of the second nozzle hole (212) being both not in the same plane as the axis of the moving tube (11), the minimum distance between the axis of the first nozzle hole (211) and the axis of the moving tube (11) being equal to the minimum distance between the axis of the second nozzle hole (212) and the axis of the moving tube (11), and the axis of the outlet of the first nozzle hole (211) and the axis of the outlet of the second nozzle hole (212) being respectively located on different planes.

4. The downhole segment milling tool according to claim 3, characterized in that: The nozzle (21) further comprises a flow guide hole (213) coaxial with the moving tube (11); the diameter of the flow guide hole (213) is smaller than the inner diameter of the moving tube (11); and the inlet of the first spray hole (211) and the inlet of the second spray hole (212) are both connected to the flow guide hole (213).

5. The downhole segment milling tool according to claim 3, characterized in that: The cutting component (2) comprises an annular straightening shell (22) and a rotating tube (23); the annular straightening shell (22) is coaxially connected to an end of the moving tube (11) away from the driving component (3); the rotating tube (23) is coaxially and rotationally connected to the annular straightening shell (22); and the rotating tube (23) is connected to the nozzle (21).

6. A downhole segment milling method, characterized in that: The downhole segment milling method comprises: Provide a downhole segment milling tool as claimed in any one of claims 1 to 5; Injecting cutting fluid into the moving tube of the downhole milling tool, the cutting fluid enters the cutting component and is ejected by the cutting component along the circumference of the moving tube to perform cutting; The driving component in the downhole segment milling tool drives the moving tube to move axially, and the moving tube compresses the annular sealed space. The pressure in the annular sealed space increases, compressing the annular elastic piston in the downhole segment milling tool so that the moving tube and the cutting component move and cut evenly.

7. The downhole segment milling method according to claim 6, characterized in that: The moving speed of the cutting component is 20-30 mm / min.

8. The downhole segment milling method according to claim 6, characterized in that: The cutting fluid comprises slick water and quartz sand, the volume concentration of the quartz sand is 5-9%, and the particle size of the quartz sand is 80-130 meshes.

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