Radial windowing tool for underground casing pipe

Abstract

The invention relates to the technical field of oil exploitation, in particular to a radial windowing tool for an underground casing. The drill bit and the guide adjusting assembly are installed in a casing body, a drill rod is coaxially connected to the top of the drill bit, an installation groove is formed in the drill bit in a penetrating mode in the radial direction, and a pin is slidably connected into the installation groove; the guide adjusting assembly comprises a mounting base, a whipstock and a limiting arm, and the outer walls of the mounting base, the whipstock and the limiting arm are all attached to the inner wall of the sleeve body; after the drill bit breaks the damaged casing pipe body and reaches the oil field space on the outer side, two-point supporting on the drill rod is formed through the inclined face of the whipstock and the stable adjusting base, and drill jumping caused by lack of stable supporting of the drill bit is prevented. After the stable adjusting seat extends out of the third mounting groove, the levelness of the stable adjusting seat in the axial direction of the casing pipe body is not limited by the third mounting groove any more, the inclined plane of the whipstock and the stable adjusting seat rotating around the rotating shaft jointly support a drill rod, and the stability of a drill bit in the drilling process is ensured.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, and more specifically, to a radial windowing tool for downhole casing. Background Technology

[0002] After long-term production, the oil and gas reserves in the main producing layers gradually deplete, and the production of individual wells decreases significantly. By installing radial windowing tools in old oil wells, directional windows of the required specifications are formed at target locations in the downhole casing, such as damaged sections. Branch wells are then drilled into the remaining oil-rich areas and untapped thin-layer reservoirs around the wellbore, expanding the drainage area and effectively utilizing previously untapped oil and gas resources, thereby significantly improving the ultimate recovery rate of the oil and gas field. This method eliminates the need for drilling new wells, greatly reducing extraction costs, and is one of the core means of tapping the potential and increasing efficiency in old oil fields.

[0003] Currently, existing radial (also called lateral) windowing tools typically employ an oblique guiding structure, guiding the milling device, which originally moves axially along the casing, obliquely towards the casing's sidewall. However, after the milling device leaves the casing and reaches the oilfield space outside its sidewall, the resistance from the rock structure during drilling not only exists axially but also radially. Once the drill bit reaches the oilfield space outside the casing, the lack of stable axial support easily leads to vibration and drill skipping, preventing the drill bit from opening a window laterally at the preset angle. Furthermore, the angle of lateral windowing is generally determined by the inclination angle of the directional drilling tool, which fixes the angle between the drill bit's drilling direction and the casing. This limits the application scenarios of the directional drilling tool. When encountering hard rock formations that need to be bypassed, the drill bit must be withdrawn, and a new location must be found to reopen the window, thus reducing oil and gas extraction efficiency.

[0004] In view of this, we propose a radial windowing tool for downhole casing to improve the above-mentioned shortcomings. Summary of the Invention

[0005] This invention provides a radial windowing tool for downhole casing, which solves the problems of lack of stable axial support and fixed lateral windowing angle after the drill bit reaches the outer space of the casing.

[0006] To achieve the above objectives, the radial windowing tool for the downhole casing includes a drill bit and a guide adjustment assembly installed inside the casing body. A drill rod is coaxially connected to the top of the drill bit, and an installation groove is radially opened through the drill bit. A pin is slidably connected inside the installation groove. The guiding and adjusting assembly includes a mounting base, a directional tool, and a limiting arm. The outer walls of all three are in contact with the inner wall of the casing body. The directional tool is used to guide the drill bit, which moves along the axis of the casing body, to deviate from the axial direction. The mounting base and the limiting arm are used to fix the position of the directional tool. A fixing groove is provided inside the mounting base along the radial direction of the sleeve body. A stabilizing adjustment seat is provided on the side of the fixing groove near the inclined surface of the swashplate. The stabilizing adjustment seat moves radially along the sleeve body and can rotate around its own radial movement axis. The stabilizing adjustment seat, which moves radially along the casing body, is used to adjust the angle at which the drill bit deviates from the casing body axis. The stabilizing adjustment seat, together with the directional tool, forms at least two points of fixation on the drill rod to ensure the stability of the drill bit during the drilling process and prevent the drill bit from deviating from the preset drilling trajectory due to drill jumping.

[0007] Based on this, a widening head is coaxially provided on the drill rod. The widening head is located on the upstream side of the drill bit's drilling trajectory and is used to expand the diameter of its drilling channel after the drill bit has drilled.

[0008] The widening head is truncated cone in shape, and its radius gradually narrows along the drilling direction.

[0009] The radius of the narrowest part of the sizing head is less than or equal to the radius of the drill bit, and the radius of the widest part of the sizing head is greater than the radius of the drill bit.

[0010] This design allows for a smaller drill bit radius, reducing resistance during drilling within the rock formation.

[0011] The reamer is designed to be narrower at the front and wider at the back, allowing the narrower front section to easily enter the borehole created by the drill bit. The gradually widening rear section further enlarges the borehole, increasing oil and gas production in subsequent wells. It also reduces resistance during the process of the reamer penetrating the borehole to form a new well. In another technical solution, the mounting groove includes a first chamber, a second chamber, and a third chamber that are connected to each other. The second chamber is located between the first chamber and the third chamber, and the aperture of the second chamber is smaller than that of the other two. A pin is slidably connected to the first chamber.

[0012] The end of the pin facing the second chamber is connected to a drive rod, which is located in both the second and third chambers. The end of the drive rod away from the pin is fixedly connected to a limiting plate, which is in contact with the outer wall of the third chamber. A spring is fitted on the outer wall of the drive rod on the side of the limiting plate closest to the second chamber.

[0013] The side wall of the limiting arm is provided with an anchoring hole, and the drill rod is provided with a through hole. A pressure relief valve is provided in the through hole. The pin is provided with a pressure bearing platform at one end near the drive rod. The space where the pressure bearing platform is located is a pressure channel. The radius of the pressure channel is larger than the pressure bearing platform at all points. A pressure relief channel communicating with the through hole is provided above the pressure channel.

[0014] This technical solution involves separating the pin from the drive rod and inserting it into the anchoring hole to fix the position of the limiting arm.

[0015] In addition, a second mounting groove is provided in the mounting base along the radial direction of the sleeve body. A double-headed hydraulic rod is provided in the second mounting groove. Both ends of the double-headed hydraulic rod that are far apart along the radial direction of the sleeve body are provided with piston rods. One end of one of the piston rods is fixedly connected to a slip that moves only along the radial direction of the sleeve body, which is used to fix the mounting base to the inner wall of the sleeve body and form a two-point fixation of the directional device with the pin driven into the anchor hole.

[0016] The mounting base has a third mounting groove on the side of the sleeve body that is radially away from the slip, and the other piston rod is fixedly connected to a rotating shaft at the end away from the slip. The rotating shaft is rotatably connected to the stabilizing adjustment base.

[0017] When the stabilizing adjustment seat is located in the third mounting slot, the stabilizing adjustment seat can only slide radially along the sleeve body. When the stabilizing adjustment seat is disengaged from the third mounting slot, the stabilizing adjustment seat can also rotate around the pivot.

[0018] As can be seen from the above scheme, by controlling the distance that the piston rod connected to the stabilizing adjustment seat extends from inside the double-headed hydraulic rod, the tilt angle of the stabilizing adjustment seat from the axis of the casing body can be adjusted.

[0019] Furthermore, when the horizontality of the stabilizing adjustment seat along the axial direction of the casing body is no longer restricted by the third mounting groove, the inclined surface of the directional tool and the stabilizing adjustment seat rotating around the axis together support the drill rod, ensuring the stability of the drill bit during the drilling process.

[0020] Based on the above description, the beneficial effects of the present invention compared with the prior art are as follows: After the drill bit breaks through the damaged casing and reaches the outer oilfield space, the inclined surface of the directional drilling rig and the stabilizing adjustment seat form two-point support for the drill pipe, preventing the drill bit from jumping due to lack of stable support. When the stabilizing adjustment seat extends out of the third mounting slot, the horizontality of the stabilizing adjustment seat along the casing axis is no longer limited by the third mounting slot. The inclined surface of the directional drilling rig and the stabilizing adjustment seat rotating around the axis jointly support the drill pipe, ensuring the stability of the drill bit during drilling. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a side view schematic diagram of the overall structure of the present invention; Figure 2 This is a perspective view of the overall structure of the present invention; Figure 3 This diagram shows the positional connection between the drill pipe, drill collar, and drill bit in this invention. Figure 4 This is a side view schematic diagram illustrating the anchoring principle of the pin and the limiting arm in this invention; Figure 5 For the present invention Figure 4 Enlarged view of point A in the middle; Figure 6 This is a side view schematic diagram of the guide adjustment component of the present invention; Figure 7 For the present invention Figure 6 Enlarged view of point B in the middle; Figure 8 This is a side view of the drill rod where the directional guide and the stabilizing adjustment seat jointly limit its movement in this invention.

[0022] The meanings of the labels in the diagram are as follows: 100. Casing body; 101. Drill pipe; 102. Widening head; 103. Drill bit; 104. Through hole; 105. Pressure relief valve; 110. Mounting slot; 111. Drive rod; 112. Pin; 113. Limiting plate; 114. Spring; 115. Pressure relief channel; 116. Pressure bearing platform; 117. Pressure application channel; 200. Guide adjustment assembly; 210. Mounting base; 220. Incliner; 221. Limit arm; 222. Anchoring hole; 230. Double-headed hydraulic cylinder; 231. Piston rod; 232. Slip; 233. Rotary shaft; 234. Stabilizing adjustment base. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In existing technologies, a directional drilling rig is typically used to tilt the milling device, which originally moves axially along the casing, towards the sidewall of the casing. After the drill bit reaches the oilfield space outside the sidewall, it continues to drill forward. The resistance from the rock structure exists not only axially but also radially on the drill bit. Once the drill bit reaches the oilfield space outside the casing, the lack of stable axial support makes it prone to vibration and drill skipping, preventing it from opening a window laterally at the preset angle. Furthermore, the angle at which the drill bit opens a window is generally determined by the directional drilling rig's inclination angle, which fixes the angle between the drill bit's drilling direction and the casing. This limits the directional drilling rig's application scenarios. When encountering hard rock formations that need to be bypassed, the drill bit must be withdrawn, and a new window opened at a different location, thus slowing down oil and gas extraction efficiency.

[0025] Please see Figure 1 and Figure 2In order to solve the problems existing in the prior art, the present invention aims to provide a radial window opening tool for downhole casing. The window opening tool includes a drill bit 103 and a guide adjustment assembly 200 installed in the casing body 100. A drill rod 101 is coaxially connected to the top of the drill bit 103. An installation groove 110 is radially opened through the drill bit 103. A pin 112 is slidably connected inside the installation groove 110. The guide adjustment assembly 200 includes a mounting base 210, a directional tool 220, and a limiting arm 221. The outer walls of all three are in contact with the inner wall of the casing body 100. The directional tool 220 is used to guide the drill bit 103, which moves along the axis of the casing body 100, to deviate from the axial direction. The mounting base 210 and the limiting arm 221 are used to fix the position of the directional tool 220. A fixing groove is provided inside the mounting base 210 through the sleeve body 100 radially. A stabilizing adjustment seat 234 is provided on the side of the fixing groove near the inclined surface of the inclined device 220. The stabilizing adjustment seat 234 moves radially along the sleeve body 100 and can rotate around its own radial movement axis. The stabilizing adjustment seat 234, which moves radially along the casing body 100, is used to adjust the inclination angle of the drill bit 103 off the axis of the casing body 100. The stabilizing adjustment seat 234, together with the directional device 220, forms at least two points of fixation on the drill rod 101 to ensure the stability of the drill bit 103 during the drilling process and to prevent the drill bit 103 from deviating from the preset drilling trajectory due to drill jumping.

[0026] During implementation, firstly, the location of the damaged section of the casing body 100 inside the old oil well is determined, and the point where radial opening is required is located. Then, the mounting base 210 is installed near the point where radial opening is required, and the position of the directional drilling tool 220 is anchored by the mounting base 210 and the limiting arm 221. Next, the drill bit 103 is started and rotated under the drive of the drill pipe 101, and the drill bit 103 is advanced to move along the axial direction of the casing body 100. Under the guidance of the inclined surface of the directional drilling tool 220, the drill bit 103 deviates from its original movement trajectory along the axis of the casing body 100, and under the drilling action of the drill bit 103, the damaged casing body 100 is broken open, and a new oil and gas extraction channel is drilled out from the sidewall of the old oil well.

[0027] After drill bit 103 breaks through the damaged casing body 100 and reaches the outer oilfield space, the inclined surface of directional drilling tool 220 and stabilizing adjustment seat 234 form two-point support for drill pipe 101, preventing drill bit 103 from jumping due to lack of stable support. During the continuous drilling process of drill bit 103, the distance by which stabilizing adjustment seat 234 moves radially along casing body 100 is adjusted to change the inclination angle of drill bit 103's drilling trajectory deviating from the axis of casing body 100, adapting to the complex and varied rock formations and oil and gas resource layout underground in the oilfield.

[0028] To facilitate understanding of the above content, Figure 3The drilling structure with a side-opening drill bit 103 is shown. A widening head 102 is coaxially mounted on the drill rod 101. The widening head 102 is located upstream of the drilling trajectory of the drill bit 103 and is used to widen the diameter of its drilling channel after the drill bit 103 has drilled.

[0029] Further details are needed; please refer to the following: Figure 3 The widening head 102 is shaped like a frustum, and its radius gradually narrows along the drilling direction of the drill bit 103.

[0030] The radius of the narrowest part of the sizing head 102 is less than or equal to the radius of the drill bit 103, and the radius of the widest part of the sizing head 102 is greater than the radius of the drill bit 103.

[0031] It should be noted that setting the radius of drill bit 103 to be relatively small is to reduce its resistance during drilling within the rock formation. However, if the channel left by drill bit 103 is too small, it will be detrimental to the subsequent improvement of oil and gas production from the well. Therefore, the reamer 102, located upstream of the drilling trajectory of drill bit 103, needs to further enlarge the channel left by drill bit 103. Setting the reamer 102 to be smaller at the front and larger at the back allows the narrower front portion of the reamer 102 to easily enter the channel created by drill bit 103. The gradually increasing rear end of the reamer 102, on the one hand, further enlarges the channel created by drill bit 103, thereby increasing the oil and gas production of subsequent new oil wells; on the other hand, since the radius of the reamer 102 does not increase abruptly but gradually along the axis of drill pipe 101, it reduces the resistance of the reamer 102 during the process of expanding the channel drilled by drill bit 103 to form a new oil well.

[0032] Then as Figure 4 As shown, the mounting groove 110 includes a first chamber, a second chamber, and a third chamber that are connected to each other. The second chamber is located between the first chamber and the third chamber, and the aperture of the second chamber is smaller than that of the other two. The pin 112 is slidably connected to the first chamber.

[0033] A drive rod 111 is connected to one end of the pin 112 facing the second chamber. The drive rod 111 is located in both the second and third chambers. A limiting plate 113 is fixedly connected to the end of the drive rod 111 away from the pin 112. The limiting plate 113 is in contact with the outer wall of the third chamber. A spring 114 is sleeved on the outer wall of the drive rod 111 on the side of the limiting plate 113 near the second chamber.

[0034] Moreover, in Figure 5In the middle, the side wall of the limiting arm 221 is provided with an anchoring hole 222, the drill rod 101 is provided with a through hole 104, the through hole 104 is provided with a pressure relief valve 105, the pin 112 is provided with a pressure bearing platform 116 at one end near the drive rod 111, the space where the pressure bearing platform 116 is located is a pressure channel 117, the radius of the pressure channel 117 is larger than the pressure bearing platform 116 at all points, and a pressure relief channel 115 communicating with the through hole 104 is provided above the pressure channel 117.

[0035] When the drill bit 103 moves to the position corresponding to the anchor hole 222 in the first chamber, the pressure relief valve 105 releases the hydraulic oil stored in the through hole 104 and sprays it into the pressure application channel 117 through the pressure relief channel 115. Figure 7 The gray shaded area in the middle. Originally, the pin 112 was retracted in the first chamber. After the hydraulic oil entered the pressure channel 117, it applied pressure to the inclined surface of the pressure plate 116, causing the pin 112 to separate from the drive rod 111. Under the joint drive of the spring 114 which stores elastic potential energy, the pin was driven into the anchoring hole 222 to fix the position of the limiting arm 221.

[0036] Based on the above explanation, the following will further combine... Figures 6-8 The preferred effect of the stabilizing adjustment seat 234 is explained in the figure. The mounting seat 210 has a second mounting groove radially along the sleeve body 100. The second mounting groove is provided with a double-headed hydraulic rod 230. Both ends of the double-headed hydraulic rod 230 that are radially away from each other along the sleeve body 100 are provided with piston rods 231. One end of one of the piston rods 231 is fixedly connected to a slip 232 that moves only radially along the sleeve body 100. This is used to fix the mounting seat 210 to the inner wall of the sleeve body 100 and form a two-point fixation of the slanter 220 with the pin 112 that is driven into the anchoring hole 222.

[0037] The mounting base 210 has a third mounting groove on the side of the sleeve body 100 that is radially away from the slip 232. The other piston rod 231 is fixedly connected to a rotating shaft 233 at the end away from the slip 232. The rotating shaft 233 is rotatably connected to the stabilizing adjustment seat 234.

[0038] When the stabilizing adjustment seat 234 is located in the third mounting groove, the stabilizing adjustment seat 234 can only slide radially along the sleeve body 100. When the stabilizing adjustment seat 234 is disengaged from the third mounting groove, the stabilizing adjustment seat 234 can also rotate around the rotating shaft 233.

[0039] In other words, by controlling the distance by which the piston rod 231, connected to the stabilizing adjustment seat 234, extends from inside the double-ended hydraulic rod 230, the tilt angle of the stabilizing adjustment seat 234 off the axis of the casing body 100 is adjusted. Compared with the drill bit 103 with a fixed tilt angle window, the advantages are: Firstly, it improves the adaptability of oil and gas reservoir development. The window opening angle is dynamically adjusted according to the dip angle, strike and thickness of the oil and gas reservoir, and the drilling is accurately carried out into thin and poor reservoirs, areas with remaining oil accumulation or fracture development zones. This avoids target point deviation caused by the fixed angle of the drill bit 103, and improves the productivity and recovery rate of single wells. Secondly, by controlling the trajectory of the new wellbore, construction risks are reduced. By adjusting the inclination angle of drill bit 103 in stages, the curvature of the wellbore is optimized, reducing the risks of drill string wear, sticking, and pressure buildup, thereby improving drilling safety. Third, it reduces the cost of oil and gas extraction. A set of adjustable tilting directional drilling rig 220 can complete multiple branch wells at different angles, reducing the number of tripping operations, reducing the operation cycle and tool costs, and is especially suitable for high-day-cost operation scenarios such as offshore.

[0040] In addition, after the stabilizing adjustment seat 234 extends out of the third mounting slot, the horizontality of the stabilizing adjustment seat 234 along the axial direction of the casing body 100 is no longer restricted by the third mounting slot. The inclined surface of the swashplate 220 and the stabilizing adjustment seat 234 rotating around the rotating shaft 233 jointly support the drill rod 101, ensuring the stability of the drill bit 103 during the drilling process.

[0041] The working principle of the radial window opening tool will be explained in detail below: First, determine the location of the damaged section of the casing body 100 in the old oil well and locate the point where radial opening is required. Then, install the mounting base 210 near the point where radial opening is required, and fix it to the side wall of the casing body 100 by inserting the pin 112 into the anchoring hole 222 and the slip 232, thereby anchoring the position of the directional device 220.

[0042] Next, the drill bit 103 is started and rotated under the drive of the drill pipe 101, and the drill bit 103 is advanced to move along the axial direction of the casing body 100. Under the guidance of the inclined plane of the directional device 220, the drill bit 103 deviates from its original movement trajectory along the axis of the casing body 100, and under the drilling action of the drill bit 103, it breaks through the damaged casing body 100 and drills out a new oil and gas extraction channel on the sidewall of the old oil well.

[0043] After the drill bit 103 breaks through the damaged casing body 100 and reaches the outer oilfield space, the inclined surface of the directional actuator 220 and the stabilizing adjustment seat 234 form two-point support for the drill pipe 101, preventing the drill bit 103 from jumping due to lack of stable support. When the stabilizing adjustment seat 234 extends out of the third mounting slot, the horizontality of the stabilizing adjustment seat 234 along the axial direction of the casing body 100 is no longer restricted by the third mounting slot. The inclined surface of the directional actuator 220 and the stabilizing adjustment seat 234 rotating around the rotating shaft 233 jointly support the drill pipe 101, ensuring the stability of the drill bit 103 during drilling.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A radial windowing tool for downhole casing, comprising a drill bit (103) and a guide adjustment assembly (200) installed inside the casing body (100), a drill rod (101) coaxially connected to the top of the drill bit (103), and a mounting groove (110) radially penetrating the drill bit (103), wherein a pin (112) is slidably connected inside the mounting groove (110), characterized in that: The guide adjustment assembly (200) includes a mounting base (210), a slant (220), and a limiting arm (221). The outer walls of all three are in contact with the inner wall of the casing body (100). The slant (220) is used to guide the drill bit (103) moving along the axis of the casing body (100) to deviate from the axis. The mounting base (210) and the limiting arm (221) are used to fix the position of the slant (220). The mounting base (210) has a fixing groove that runs radially through the sleeve body (100). A stabilizing adjustment seat (234) is provided on the side of the fixing groove near the inclined surface of the inclined device (220). The stabilizing adjustment seat (234) moves radially along the sleeve body (100) and can rotate around its own radial movement axis. The stabilizing adjustment seat (234) that moves radially along the casing body (100) is used to adjust the angle of the drill bit (103) off the axis of the casing body (100), and the stabilizing adjustment seat (234) and the directional device (220) form at least two points of fixation on the drill rod (101) to ensure the stability of the drill bit (103) during the drilling process.

2. The radial windowing tool for downhole casing according to claim 1, characterized in that: An enlarging head (102) is coaxially arranged on the drill rod (101). The enlarging head (102) is located upstream of the drilling trajectory of the drill bit (103) and is used to expand the diameter of the drilling channel after the drill bit (103) has drilled.

3. The radial windowing tool for downhole casing according to claim 2, characterized in that: The widening head (102) is shaped like a frustum, and its radius gradually narrows along the drilling direction of the drill bit (103).

4. The radial windowing tool for downhole casing according to claim 2, characterized in that: The radius of the narrowest part of the widening head (102) is less than or equal to the radius of the drill bit (103), and the radius of the widest part of the widening head (102) is greater than the radius of the drill bit (103).

5. The radial windowing tool for downhole casing according to claim 1, characterized in that: The mounting groove (110) includes a first chamber, a second chamber and a third chamber that are connected to each other. The second chamber is located between the first chamber and the third chamber, and the aperture of the second chamber is smaller than that of the other two. The pin (112) is slidably connected to the first chamber.

6. The radial windowing tool for downhole casing according to claim 5, characterized in that: The pin (112) is connected to a drive rod (111) at one end facing the second chamber. The drive rod (111) is located in both the second and third chambers. A limiting plate (113) is fixedly connected to the end of the drive rod (111) away from the pin (112). The limiting plate (113) is in contact with the outer wall of the third chamber. A spring (114) is sleeved on the outer wall of the drive rod (111) on the side of the limiting plate (113) near the second chamber.

7. The radial windowing tool for downhole casing according to claim 6, characterized in that: The side wall of the limiting arm (221) is provided with an anchoring hole (222), the drill rod (101) is provided with a through hole (104), and a pressure relief valve (105) is provided in the through hole (104). The pin (112) is provided with a pressure bearing platform (116) at one end near the drive rod (111). The space where the pressure bearing platform (116) is located is a pressure channel (117). The radius of the pressure channel (117) is larger than that of the pressure bearing platform (116) at all points. A pressure relief channel (115) communicating with the through hole (104) is provided above the pressure channel (117).

8. The radial windowing tool for downhole casing according to claim 1, characterized in that: The mounting base (210) has a second mounting groove radially along the sleeve body (100). The second mounting groove is provided with a double-headed hydraulic rod (230). Both ends of the double-headed hydraulic rod (230) that are radially away from each other along the sleeve body (100) are provided with piston rods (231). One end of one of the piston rods (231) is fixedly connected to a slip (232) that moves only radially along the sleeve body (100), which is used to fix the mounting base (210) to the inner wall of the sleeve body (100) and form a two-point fixation of the inclined device (220) with the pin (112) nailed into the anchor hole (222).

9. The radial windowing tool for downhole casing according to claim 8, characterized in that: The mounting base (210) has a third mounting groove on the side of the sleeve body (100) that is radially away from the slip (232). The other piston rod (231) has a rotating shaft (233) fixedly connected to one end away from the slip (232). The rotating shaft (233) is rotatably connected to the stabilizing adjustment seat (234).

10. The radial windowing tool for downhole casing according to claim 1, characterized in that: When the stabilizing adjustment seat (234) is located in the third mounting groove, the stabilizing adjustment seat (234) can only slide radially along the sleeve body (100). When the stabilizing adjustment seat (234) is disengaged from the third mounting groove, the stabilizing adjustment seat (234) can also rotate around the rotating shaft (233).

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