Multi-diameter while-drilling underreamer

Abstract

A multi-diameter reaming while drilling tool, the tool, the drill collar includes a main body with a hollow channel for introducing fluid, the side wall of the main body is provided with a sink groove recessed towards the hollow channel, the bottom of the sink groove is provided with a through hole communicating with the hollow channel; a primary cutting block is movably connected to the sink groove from the direction perpendicular to the hollow channel, the primary cutting block includes a pair of cutting bodies approaching or moving away from each other, the cutting body includes a block movably contained in the through hole, the block includes a plurality of side cavities extending from the direction perpendicular to the hollow channel and a first cutting surface provided on the outer surface of the block away from the hollow channel; a secondary cutting tooth is movably connected to the side cavity, the secondary cutting tooth includes a second cutting surface on the outer surface away from the hollow channel; a throttle guide rail piston cylinder is arranged in the hollow channel to introduce fluid, and the throttle guide rail piston cylinder covers the through hole. The tool controls the extension length of the cutting tooth by the displacement size, and realizes the purpose of variable-diameter reaming.

Description

Technical Field

[0001] This invention relates to the field of drilling reaming technology, and more particularly to a multi-diameter reaming tool for drilling. Background Technology

[0002] Existing reaming tools are broadly classified into two types: those for hard formations and those for loose formations. Reaming tools for hard formations are typically designed with fixed, non-retractable cutting teeth, resulting in a single reaming diameter. Due to the fixed cutting teeth, the cutting angle is usually relatively smooth to prevent stuck drill bit, leading to weak cutting ability and low reaming efficiency. Reaming tools for loose formations are typically designed with retractable cutting teeth, allowing for variable reaming diameters. They are activated by dropping steel balls of different sizes to extend and retract the cutting teeth, but this extension and retraction is not repeatable. If stuck drill bit occurs during reaming, the cutting teeth must be retracted to prematurely end the reaming operation. Furthermore, the cutting teeth are blade-type, resulting in low strength of the cutting tooth support structure and low reaming efficiency. During large-diameter reaming operations, they are prone to damage when encountering geological interlayers, increasing the risk of cutting teeth falling to the bottom of the well. The safety, functionality, and application range of current reaming tools are insufficient to meet the current technical requirements for variable-diameter reaming in drilling.

[0003] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-diameter reaming tool that controls the extension length of the cutting teeth by adjusting the displacement, avoiding jamming of the reaming tool's cutting teeth due to changes in formation hardness. It enables long-section variable-diameter reaming in complex formations and features an anti-jamming design. For segmented reaming and reaming of different well diameters, this reaming tool can achieve reaming of different well diameters in a single drilling run. The strength of the cutting tooth support design meets the technical requirements for reaming in both hard and soft formations, improving the problem of low reaming efficiency. Furthermore, the well wall is smoother after reaming, avoiding the need for reaming repair work due to micro-steps. By controlling the extension and retraction of multi-stage cutting teeth multiple times through displacement, it effectively avoids premature termination of reaming operations due to jamming, allowing segmented reaming and reaming of different well diameters to be completed in a single drilling run.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A multi-diameter reaming tool of the present invention includes:

[0007] A drill collar includes a body having a hollow channel for introducing fluid, the sidewall of the body having a recessed groove toward the hollow channel, and the bottom of the recessed groove having a through hole communicating with the hollow channel.

[0008] A primary cutting block is movably connected to the countersink in a direction perpendicular to the hollow channel. The primary cutting block includes a pair of cutting bodies that are close to or far apart from each other. Each cutting body includes at least a portion of a block that is movably accommodated in the through hole. Each block includes a plurality of side cavities extending in a direction perpendicular to the hollow channel and a first cutting surface disposed on the outer surface of the block that is far away from the hollow channel.

[0009] At least one pair of limiting threaded sleeves, which are threadedly connected to the inner side cavity;

[0010] At least one pair of secondary cutting teeth, the secondary cutting teeth being movably connected to the side cavity, the secondary cutting teeth including a second cutting surface on the outer surface away from the hollow channel;

[0011] At least one pair of cutting tooth springs, wherein the cutting tooth springs are disposed in the space formed by the limiting screw sleeve and the secondary cutting tooth to elastically connect the secondary cutting tooth;

[0012] A throttling guide piston cylinder, disposed in the hollow channel to introduce fluid, covers the through hole.

[0013] The main spring, the top of which is connected to the bottom end of the throttling guide piston cylinder,

[0014] A spring base, the bottom of which is sealed to the bottom of the drill collar, supports the main spring.

[0015] In the aforementioned multi-diameter drilling reaming tool, when the fluid flow is greater than a predetermined flow rate, the throttling guide piston cylinder moves downward and squeezes the primary cutting block outward; when the fluid flow is less than a predetermined flow rate, the main spring force causes the throttling guide piston cylinder to move upward.

[0016] In the aforementioned multi-diameter drilling reaming tool, the predetermined flow rate is 20-25 L / S.

[0017] In the aforementioned multi-diameter drilling reaming tool, a step is formed at the connection between the through hole and the countersink.

[0018] In the aforementioned multi-diameter drilling reaming tool, support portions extend from both ends of the block, and the support portions are movably disposed in the settling groove in conjunction with the step.

[0019] In the aforementioned multi-diameter reaming tool, the periphery of the countersink is provided with a guide portion protruding from the side wall of the drill collar.

[0020] In the aforementioned multi-diameter drilling reaming tool, the guide portion has an arc-shaped outer surface.

[0021] In the aforementioned multi-diameter drilling reaming tool, the second outer surface is further away from the hollow channel than the first outer surface.

[0022] In the aforementioned multi-diameter drilling reaming tool, the bottom end of the throttling guide piston cylinder is provided with a stepped boss, and the top end of the main spring is sleeved on the stepped boss.

[0023] In the aforementioned multi-diameter drilling reaming tool, the central axes of the drill collar and the throttling guide piston cylinder are collinear.

[0024] In the above technical solution, the multi-diameter reaming tool provided by the present invention has the following beneficial effects: the multi-diameter reaming tool achieves the function of reaming while drilling by controlling the drilling pump displacement in multiple stages and extending and retracting the cutting teeth. The large-size cutting block has high torsional strength and serves as the main force to perform initial reaming of the well wall. The small-size cutting teeth perform subsequent correction of the well wall to keep it smooth. The design of the cutting block and multiple cutting teeth can achieve the purpose of reaming by segmented grinding of hard and soft formations. It can effectively solve the problem of unstable well wall after reaming caused by a single cutting method, which can lead to block falling and subsequent stuck drill bit and broken cutting teeth. It greatly improves the downhole safety and reaming quality of reaming operations while drilling. It can perform multiple reaming operations during drilling, with the reaming diameter controlled according to the displacement. It has a large reaming diameter range and high strength in the design of the cutting tooth structure, avoiding the breakage and fall of the cutting teeth caused by changes in formation hardness during the reaming process. It has the function of unsticking the drill bit due to damage or deformation of the cutting blade, and has the function of finely repairing the well wall. It can meet the technical requirements of reaming during drilling in one trip, in different segments, and in different diameters. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0026] Figure 1 This is a schematic diagram of the extended state of a multi-diameter drilling reaming tool provided in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the retracted state of a multi-diameter drilling reamer provided in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the structure of the first-stage cutting block of a multi-diameter drilling reamer provided in an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the throttling guide piston cylinder of a multi-diameter drilling reaming tool provided in an embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the side cavity of the first-stage cutting block of a multi-diameter drilling reamer provided in an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of 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, 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.

[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] See Figure 1-5 As shown, in one embodiment, a multi-diameter reaming tool of the present invention includes,

[0040] Drill collar 1 includes a body having a hollow channel for introducing fluid, the side wall of the body having a recessed groove that is recessed toward the hollow channel, and the bottom of the recessed groove having a through hole communicating with the hollow channel;

[0041] A primary cutting block 2 is movably connected to the countersink in a direction perpendicular to the hollow channel. The primary cutting block 2 includes a pair of cutting bodies that are close to or far apart from each other. Each cutting body includes at least a portion of a block 9 that is movably accommodated in the through hole. The block 9 includes a plurality of side cavities 12 extending in a direction perpendicular to the hollow channel and a first cutting surface 10 provided on the outer surface of the block 9 away from the hollow channel.

[0042] At least one pair of limiting screw sleeves 4, the limiting screw sleeves 4 are threadedly connected to the side inner cavity 12;

[0043] At least one pair of secondary cutting teeth 3, the secondary cutting teeth 3 being movably connected to the side cavity 12, the secondary cutting teeth 3 including a second cutting surface 11 on the outer surface away from the hollow channel;

[0044] At least one pair of cutting tooth springs 5, the cutting tooth springs 5 ​​are disposed in the space formed by the limiting screw sleeve 4 and the secondary cutting tooth 3 to elastically connect the secondary cutting tooth 3;

[0045] A throttling guide piston cylinder 6 is disposed in the hollow channel to introduce fluid, and the throttling guide piston cylinder 6 covers the through hole.

[0046] The main spring 7, the top of which is connected to the bottom end of the throttling guide piston cylinder 6,

[0047] The spring base 8 has its bottom end sealed to the bottom of the drill collar 1, and the spring base 8 supports the main spring 7.

[0048] In a preferred embodiment of the multi-diameter reaming tool, when the fluid flow is greater than a predetermined flow rate, the throttling guide piston cylinder 6 moves downward and squeezes the first-stage cutting block 2 outward. When the fluid flow is less than a predetermined flow rate, the main spring 7 causes the throttling guide piston cylinder 6 to move upward.

[0049] In a preferred embodiment of the multi-diameter reaming tool described above, the predetermined flow rate is 20-25 L / S.

[0050] In a preferred embodiment of the multi-diameter reaming tool described above, a step is formed at the connection between the through hole and the countersink.

[0051] In a preferred embodiment of the multi-diameter reaming tool, the block 9 extends support portions at both ends, and the support portions are movably disposed in the sinker in conjunction with the step.

[0052] In a preferred embodiment of the multi-diameter reaming tool described above, the periphery of the countersink is provided with a guide portion protruding from the side wall of the drill collar 1.

[0053] In a preferred embodiment of the multi-diameter reaming tool described above, the guide portion has an arc-shaped outer surface.

[0054] In a preferred embodiment of the multi-diameter reaming tool, the second outer surface is further away from the hollow channel than the first outer surface.

[0055] In a preferred embodiment of the multi-diameter drilling reaming tool, the bottom end of the throttling guide piston cylinder 6 is provided with a stepped boss, and the top end of the main spring 7 is sleeved on the stepped boss.

[0056] In a preferred embodiment of the multi-diameter reaming tool described above, the central axes of the drill collar 1 and the throttling guide piston cylinder 6 are collinear.

[0057] In one embodiment, a multi-diameter reaming tool includes,

[0058] Drill collar 1 includes a body having a hollow channel for introducing fluid, the side wall of the body having a recessed groove that is recessed toward the hollow channel, the bottom of the recessed groove having a through hole communicating with the hollow channel, and a step being formed at the connection between the through hole and the recessed groove;

[0059] A primary cutting block 2 is slidably and sealingly connected to the recess from a direction perpendicular to the hollow channel. The primary cutting block 2 includes a pair of cutting bodies that are close to or far apart from each other. Each cutting body includes at least a portion of a block 9 that is movably accommodated in the through hole and support portions extending at both ends of the block 9. The support portions are movably disposed in the recess in cooperation with the step. The block 9 includes a plurality of side cavities 12 extending from a direction perpendicular to the hollow channel and a first cutting surface 10 disposed on the outer surface of the block 9 away from the hollow channel.

[0060] At least one pair of limiting screw sleeves 4, the limiting screw sleeves 4 are threadedly connected to the side inner cavity 12;

[0061] At least one pair of secondary cutting teeth 3, the secondary cutting teeth 3 slidingly sealingly connecting the side cavity 12, the secondary cutting teeth 3 including a second cutting surface 11 on the outer surface away from the hollow channel;

[0062] At least one pair of cutting tooth springs 5, the cutting tooth springs 5 ​​are disposed in the space formed by the limiting screw sleeve 4 and the secondary cutting tooth 3 to elastically connect the secondary cutting tooth 3;

[0063] A throttling guide piston cylinder 6 is disposed in the hollow channel to introduce fluid, and the throttling guide piston cylinder 6 covers the through hole.

[0064] The main spring 7, the top of which is connected to the bottom end of the throttling guide piston cylinder 6,

[0065] The spring base 8 has its bottom end sealed to the bottom of the drill collar 1, and the spring base 8 supports the main spring 7.

[0066] When the fluid flow exceeds the predetermined flow rate, the throttling guide piston cylinder 6 moves downward and squeezes the first-stage cutting block 2 outward. When the fluid flow is less than the predetermined flow rate, the main spring 7 causes the throttling guide piston cylinder 6 to move upward.

[0067] In one embodiment, the variable diameter reaming tool uses the mud pump displacement to achieve the extension and retraction of the primary cutting block 2 and the secondary cutting teeth 3. When the variable diameter reaming tool is assembled and ready for well entry, the throttle guide piston cylinder 6, under the force of the main spring 7, restricts the primary cutting block 2 step to be positioned within the tool body's inner cavity 12 via the guide rail. The secondary cutting teeth 3, under the force of the cutting tooth spring 5, are also positioned within the primary cutting block 2's inner cavity 12.

[0068] The variable-diameter reaming tool can unclog the water hole at any time during drilling with a small displacement. When the tool reaches the reaming position, the mud pump displacement is increased to 20-25 L / s. This displacement pushes the throttling guide piston cylinder 6 downward, and the guide rail pushes out the first-stage cutting block 2. The rotary table is then activated for the initial step-building stage of reaming. Subsequently, stable drilling pressure and accelerated reaming operations are performed. After reaming is completed, the mud pump is turned off, and the throttling guide piston cylinder 6 retracts the first-stage cutting block 2 due to the elasticity of the main spring 7, completing the reaming operation. If it is necessary to increase the reaming diameter, [further details can be added]. Increase the mud pump displacement to 30-32 L / s. The current displacement first pushes the throttling guide piston cylinder 6 downward, the guide rail pushes out the first-stage cutting block 2, and then pushes the second-stage cutting teeth 3 radially out. The turntable is turned on to start the initial step-building stage of hole enlargement. Subsequently, the hole enlargement operation is carried out with stable drilling pressure and increased speed. After the hole enlargement is completed, the mud pump is turned off. The throttling guide piston cylinder 6 retracts the first-stage cutting block 2 by the elastic force of the main spring 7. The second-stage cutting teeth retract into the side cavity of the first-stage cutting block 2 by the elastic force of the cutting tooth spring 5, completing the overall hole enlargement operation.

[0069] like Figure 1 As shown, the primary cutting block 2 is slidably and sealed to the short drill collar 1. Its lower step is constrained by the throttling guide piston cylinder 6. The secondary cutting teeth 3 are slidably and sealed to the inner cavity 12 on the side of the primary cutting block 2. The limiting sleeve 4 is threadedly connected to the inner cavity 12 on the side of the primary cutting block 2. The cutting tooth spring 5 is placed in the space formed by the limiting sleeve 4 and the secondary cutting teeth 3, elastically connecting the secondary cutting teeth 3. The throttling guide piston cylinder 6, the main spring 7, and the spring base 8 are placed on the drill collar 1. The spring base 8 is sealed to the bottom of the drill collar 1. The throttling guide piston cylinder 6 is moved downward by the mud pump discharge, and the throttling guide piston cylinder 6 is moved upward by the elastic force of the main spring 7.

[0070] In one embodiment, during the reaming operation, a small-volume pump can be used to unclog the water hole at any time during the tool's drilling process. When the tool is lowered to reaming position A, the reaming section A is 100m long, and the reaming diameter is required to be 220mm. The mud pump's displacement is increased to 20-25L / S. The current displacement can push the choke guide piston cylinder 6 downward, and the guide rail pushes out the first-stage cutting block 2, achieving a reaming diameter of 220mm. The rotary table is then turned on to 55-60r / min for the initial step-building stage of reaming. Subsequently, stable drilling pressure and accelerated reaming operations are performed. After the reaming of section A is completed, the mud pump is turned off, and the choke guide piston cylinder 6 retracts the first-stage cutting block 2 due to the elasticity of the main spring 7, completing the overall reaming operation of section A. Subsequent... When drilling down to the reaming position B, the reaming diameter is required to be increased to 310mm. Increase the mud pump displacement to 30-32L / S. The current displacement first pushes the choke guide piston cylinder 6 downward, the guide rail pushes out the first-stage cutting block 2, and then pushes the second-stage cutting tooth 3 radially out. The reaming diameter reaches 310mm. Turntable is turned on to 40-50r / min to carry out the initial step-building stage of reaming. Subsequently, stable drilling pressure and speed-up reaming operations are carried out. When the reaming of section B is completed, the mud pump is turned off. The choke guide piston cylinder 6 relies on the elastic force of the main spring 7 to retract the first-stage cutting block 2. The second-stage cutting tooth 3 retracts into the side cavity of the first-stage cutting block 2 through the elastic force of the cutting tooth spring 5, completing the overall reaming operation of section B.

[0071] like Figure 3 , 5 As shown, the blocks 9 of the primary cutting block 2 are arrayed with multiple side cavities 12 at intervals. Each side cavity 12 is a hollow cavity that is narrower inside and wider outside. The outer wide portion of the cavity is threaded. The limiting screw sleeve 4 is threadedly connected to the outer wide portion of the side cavity 12. The secondary cutting teeth 3 are movably arranged in the side cavity 12. Each secondary cutting tooth 3 is a protrusion structure that is wider inside and narrower outside. It can be seen that the limiting screw sleeve 4 can resist the inner wide portion of the secondary cutting tooth 3 to prevent the secondary cutting tooth 3 from dislodging from the side cavity 12. The cutting tooth spring 5 is located between the inner wide portion of the secondary cutting tooth 3 and the side cavity 12 and is blocked by the limiting screw sleeve 4. The cutting tooth spring 5 elastically presses the secondary cutting tooth 3 towards the hollow channel, so that when the fluid flow is less than the predetermined flow rate, the secondary cutting tooth 3 retracts into the primary cutting block 2. When the fluid flow is greater than the predetermined flow rate, it overcomes the elastic force of the cutting tooth spring 5, and the secondary cutting tooth 3 extends out of the primary cutting block 2 away from the hollow channel. Furthermore, the secondary cutting tooth 3 is provided with a stepped portion that abuts against the cutting tooth spring 5.

[0072] Finally, it should be noted that the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0073] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A multi-diameter reaming tool for drilling, characterized in that, It includes, A drill collar includes a body having a hollow channel for introducing fluid, the sidewall of the body having a recessed groove toward the hollow channel, and the bottom of the recessed groove having a through hole communicating with the hollow channel. A primary cutting block is movably connected to the countersink in a direction perpendicular to the hollow channel. The primary cutting block includes a pair of cutting bodies that are close to or far apart from each other. Each cutting body includes at least a portion of a block that is movably accommodated in the through hole. Each block includes a plurality of side cavities extending in a direction perpendicular to the hollow channel and a first cutting surface disposed on the outer surface of the block that is far away from the hollow channel. At least one pair of limiting threaded sleeves, which are threadedly connected to the inner side cavity; At least one pair of secondary cutting teeth, the secondary cutting teeth being movably connected to the side cavity, the secondary cutting teeth including a second cutting surface on the outer surface away from the hollow channel; At least one pair of cutting tooth springs, wherein the cutting tooth springs are disposed within the space formed by the limiting screw sleeve and the secondary cutting tooth to elastically connect the secondary cutting tooth; A throttling guide piston cylinder, disposed in the hollow channel to introduce fluid, covers the through hole. The main spring, the top of which is connected to the bottom end of the throttling guide piston cylinder, A spring base, the bottom of which is sealed to the bottom of the drill collar, supports the main spring.

2. The multi-diameter reaming tool according to claim 1, characterized in that, When the fluid flow exceeds the predetermined flow rate, the throttling guide piston cylinder moves downward and squeezes the first-stage cutting block outward. When the fluid flow is less than the predetermined flow rate, the main spring force causes the throttling guide piston cylinder to move upward.

3. The multi-diameter reaming tool according to claim 2, characterized in that, The planned flow rate is 20-25 L / s.

4. The multi-diameter reaming tool according to claim 1, characterized in that, A step is formed at the connection between the through hole and the sink.

5. A multi-diameter reaming tool according to claim 4, characterized in that, Support portions extend from both ends of the block, and the support portions are movably disposed in the sinkhole in conjunction with the step.

6. A multi-diameter reaming tool according to claim 1, characterized in that, The periphery of the settling tank is provided with a guide portion that protrudes from the side wall of the drill collar.

7. A multi-diameter reaming tool according to claim 6, characterized in that, The guide portion has an arc-shaped outer surface.

8. A multi-diameter reaming tool according to claim 1, characterized in that, The second cutting surface is further away from the hollow channel than the first cutting surface.

9. A multi-diameter reaming tool according to claim 1, characterized in that, The bottom end of the throttling guide piston cylinder is provided with a stepped boss, and the top end of the main spring is sleeved on the stepped boss.

10. A multi-diameter reaming tool according to claim 1, characterized in that, The central axes of the drill collar and the throttling guide piston cylinder are collinear.

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