Exponential curve type cylindrical milling shoe

Abstract

The index curve type cylindrical milling shoe comprises a main body axially extending in the vertical direction, the main body is provided with a cylinder structure and a gourd body structure, a cylindrical milling layer is laid on the cylinder part, an index curve type grinding and milling layer is laid on the whole gourd body part, and a finishing milling cutter is arranged between the cylindrical milling layer and the index curve type grinding and milling layer. The cylindrical milling layer, the outer edge of the finishing milling cutter and the index curve type milling layer are in smooth transition in an arc form; the continuous micro-cambered surface milling capacity is formed by arranging the index curve type milling surface, so that good continuity of the milling surface is ensured while the milling resistance is reduced; the index curve cambered surface and the axial index curve arc cutting edge are combined, the whole milling process is gradually changed according to the index curve to form micro-arc cutting and gradually increases, and the cutting and trimming efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield oil and gas well repairing equipment, and in particular relates to an exponential curve type cylindrical milling shoe. Background Art

[0002] During the development of oil and gas fields, the number of casing damage and casing change wells has continued to increase due to reasons such as formation pressure drop, increased water production, sand production, and operation construction. When using conventional milling cones and milling shoes, if the operating pipe string is not configured properly or when encountering complex situations, accidents such as well tool jamming and casing window opening will seriously affect the construction progress. The radial milling surface of existing conventional milling cones and milling shoes is basically a cone structure, and the axial tangent is a straight line. The contact angle with the casing change pipe wall during milling is fixed, which is linear milling. It is easy to form an overall guide in the well section with serious casing changes, and the milling efficiency is low. Summary of the invention

[0003] The purpose of the present invention is to provide an exponential curve type cylindrical milling shoe, which has the characteristics of high-efficiency milling.

[0004] The technical solution adopted in the present invention is an exponential curve cylindrical milling shoe, comprising a main body extending axially in the up and down directions, the main body having a cylindrical structure and a gourd body structure, the cylindrical part is paved with a cylindrical milling layer, the gourd body part is paved with an exponential curve grinding and milling layer, a trimming milling cutter is arranged between the cylindrical milling layer and the exponential curve grinding and milling layer, and a smooth transition in the form of an arc is adopted between the cylindrical milling layer, the outer edge of the trimming milling cutter, and the exponential curve grinding and milling layer.

[0005] The present invention is also characterized in that

[0006] The radial dimension of the gourd body is not greater than the radial dimension of the cylindrical body.

[0007] The gourd body comprises at least two gourd bellies, and the maximum radial dimensions of the gourd bellies gradually decrease from top to bottom, with the gourd mouths facing outwards.

[0008] The exponential curve grinding layer includes exponential curve grinding segments arranged in sequence along the axial direction on the outer periphery of each gourd belly, each exponential curve grinding segment has an exponential curve grinding surface, and any two adjacent exponential curve grinding surfaces are smoothly transitioned in the form of an arc, and the exponential curve grinding surface close to the dressing milling cutter is flush and smoothly transitioned with the outer edge of the dressing milling cutter. After the first layer of exponential curve grinding surface is cut and milled, the subsequent exponential curve grinding surface mills and expands the repair position of the first layer of exponential curve grinding surface, and the next layer of exponential curve grinding surface expands and trims the position milled by the former again, and the transition is sequentially formed into continuous trimming and grinding.

[0009] The finishing milling cutter includes two carbide blade blocks laid in the transition section between the cylindrical milling layer and the exponential curve grinding milling layer. The laying surfaces at the bottom of the two carbide blade blocks are not in the same horizontal plane and the angle between the two laying surfaces is 5° to 10°. The ends of the two carbide blade blocks smoothly transition with the cylindrical milling layer and the exponential curve grinding milling layer respectively.

[0010] The cylindrical milling layer is a hard alloy particle layer laid on the outer peripheral surface of the cylinder, and a cylindrical milling surface is formed on the surface of the cylindrical milling layer.

[0011] A fluid channel is arranged inside the main body, a plurality of liquid return grooves are opened along the axial direction on the side wall of the main body, and injection holes are opened in the liquid return grooves, and the injection holes are communicated with the fluid channel.

[0012] The inner diameter of the fluid channel decreases from top to bottom, and the injection holes in each return liquid groove are located at different positions.

[0013] A detachable drill rod is arranged at one end of the main cylindrical part away from the gourd body.

[0014] The drill rod and the main body are connected by thread.

[0015] The beneficial effects of the present invention are that the exponential curve cylindrical milling shoe forms a continuous micro-arc milling capability by setting an exponential curve milling surface, while reducing the milling resistance, ensuring that the milling surface maintains good continuity; the exponential curve milling surface, the dressing milling cutter and the cylindrical milling surface are combined in the grinding and cutting form, and the exponential curve arc surface and the axial exponential curve arc cutting edge are combined, which has the combined cutting functions of exponential curve arc surface grinding and axial exponential curve arc cutting edge, and the milling contact angle can change with the exponential curve of the milling surface, gradually contact the milling casing wall, and greatly reduce the cutting torque. The entire milling process is a gradual micro-arc cutting according to the exponential curve and is progressive in sequence, and the cutting and dressing efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of an exponential curve type cylindrical milling shoe of the present invention;

[0017] Figure 2 It is a schematic structural diagram of the main body of the exponential curve type cylindrical milling shoe of the present invention;

[0018] Figure 3 It is a structural schematic diagram of the finishing milling cutter in the exponential curve type cylindrical milling shoe of the present invention.

[0019] In the figure, 1. main body, 2. cylindrical milling layer, 3. cylindrical milling surface, 4. finishing milling cutter, 5. third exponential curve type grinding surface, 6. second exponential curve type grinding surface, 7. first exponential curve type grinding surface, 8. exponential curve type grinding layer, 9. injection hole, 10. return liquid groove. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The exponential curve cylindrical milling shoe of the present invention has a structure as follows Figure 1 and Figure 2 As shown, it includes a main body 1 extending axially in the up-down direction, the main body 1 has a cylindrical structure and a gourd body structure, the radial dimension of the gourd body part is not larger than the radial dimension of the cylindrical part, the gourd body part includes at least two gourd bellies, and the maximum radial dimension of each gourd belly gradually decreases from top to bottom, the gourd mouth faces outward, and a fluid channel with an inner diameter decreasing from top to bottom is provided inside the main body 1, a plurality of liquid return grooves 10 are opened axially on the side wall of the main body 1, and a spray hole 9 connected to the fluid channel is opened in the liquid return groove 10, and the positions of the spray holes 9 in each liquid return groove 10 are different, and a detachable drill rod is threadedly connected to one end of the cylindrical part of the main body 1 away from the gourd body.

[0022] The outer circumference of the cylindrical part is paved with a hard alloy particle layer to form a cylindrical milling layer 2, and the surface of the cylindrical milling layer 2 forms a cylindrical milling surface 3. The gourd body is paved with an exponential curve milling layer 8, and the exponential curve milling layer 8 includes exponential curve milling segments arranged in sequence along the axial direction on the outer circumference of each gourd belly, each exponential curve milling segment is composed of hard alloy particle materials, and each exponential curve milling segment has an exponential curve milling surface, and any two adjacent exponential curve milling surfaces are smoothly transitioned in the form of arcs. After the multi-level exponential curve milling surface is processed by CNC, the surface transition section smoothly transitions under the condition of forming the lower-level surface processing.

[0023] like Figure 3 As shown, two carbide blade blocks are laid in the transition section between the cylindrical milling layer 2 and the exponential curve grinding and milling layer 8 as finishing milling cutters 4, the laying surfaces of the bottom of the two carbide blade blocks are not in the same horizontal plane and the transition inclination angle between the two laying surfaces is 5°~10°, the top edge of the left carbide blade block is flush with one end of the cylindrical milling layer 2, the right side of the edge of the carbide blade block laid at the transition inclination angle is flush with the left end of the exponential curve grinding and milling layer 8, and the left outer edge is basically flush with the left edge of the carbide blade block.

[0024] The cylindrical milling layer 2, the outer edge of the finishing milling cutter 4, and the exponential milling layer 8 are all smoothly transitioned in the form of arcs to form a smooth transition milling surface. After the first layer of the exponential milling surface is cut and milled, the subsequent exponential milling surface mills and expands the repair position of the first layer of the exponential milling surface, and the next layer of the exponential milling surface expands and trims the position milled by the former again. This process is repeated until the last layer of the exponential milling surface is milled. Then, the milling is sequentially transitioned to the finishing milling cutter 4, and the transition forms continuous trimming and milling, forming a continuous micro-arc milling capability, while reducing the milling resistance, ensuring that the milling surface maintains good continuity. The casing damage and casing change well channel are repaired by the combined milling of the exponential milling layer 8, the finishing milling cutter 4, and the cylindrical milling layer 2.

[0025] The working principle of the index curve cylindrical milling shoe of the present invention is as follows: during the overhaul of oil and gas wells, the working pipe string is connected with the main body thread, and is lowered into the well to the sleeve change casing section for milling. The hard alloy surface welded on the index curve section surface selected during processing cuts the inner wall of the sleeve change at the curve change rate, which is a gradual micro-arc cutting according to the index curve and is progressive in sequence. A finishing milling cutter 4 is set at the transition section between the index curve milling surface and the cylindrical milling surface 3, which is a finishing cutter to form a target size after the initial shaping is complete. In further milling, the cylindrical The milling surface 3 is repaired and expanded by dressing. An exponential curve milling surface, a dressing milling cutter and a cylindrical milling surface are used to combine the exponential curve arc surface and the axial exponential curve arc cutting edge. It has the combined functions of exponential curve arc surface grinding and axial exponential curve arc cutting edge cutting. The milling contact angle can change with the milling surface exponential curve, gradually contact the milling casing wall, and greatly reduce the cutting torque. Since the exponential curve arc surface in contact with the pipe wall can continuously form a cutting edge surface, the cutting and dressing efficiency is improved.

[0026] The working process of the exponential curve cylindrical milling shoe of the present invention is as follows: the main body 1 is connected to the drill pipe thread, the exponential curve cylindrical milling shoe is lowered into the well to reach above the casing change section, and the casing change section is pressurized and milled. The circulating fluid is ejected from the side wing injection hole 9 and carries the milling debris back to the ground from the annulus. First, the first exponential curve milling surface 7 contacts the casing wall and starts to mill the sudden change pipe wall. Since the outer diameter of the end of the exponential curve milling surface 7 is much smaller than the inner diameter of the casing and is a curved surface, it plays a stabilizing and guiding role during milling. The milling is milled to the maximum outer diameter of the milling surface. When the outer diameter of the second exponential curve type milling surface 6 is the maximum, after the transition, the casing wall contacts the second exponential curve type milling surface 6 and continues to cut and mill. When the second exponential curve type milling surface 6 is milled to the maximum outer diameter, the casing wall transitions again and contacts the third exponential curve type milling surface 5. When the third exponential curve type milling surface 5 is the maximum outer diameter, the dressing milling cutter 4 takes over to contact the casing wall and starts milling to the target size. The cylindrical milling surface 3 is further milled and trimmed to establish a channel for continuously repeating the above-mentioned cutting and milling process until the diameter expansion repair of the sleeve change casing is completed.

[0027] When repairing the sleeve during overhaul operations, the exponential curve cylindrical milling shoe is lowered into the well in the above-mentioned connection form. On the basis of the exponential curve milling surface successively trimming the sleeve inner wall, the trimming milling cutter 4 quickly completes the target repair size, and then the cylindrical milling surface 3 is further ground and rounded to achieve stable guided grinding and rapid sleeve repair effects.

[0028] Example 1

[0029] The exponential curve cylindrical milling shoe of the present invention has a structure as follows Figure 1 As shown, the main body 1 has a cylindrical structure and a gourd body structure. The material of the main body 1 is 42CrMo or above. The radial dimension of the gourd body part is not greater than the radial dimension of the cylindrical part. The gourd body part includes three gourd bellies, and the maximum radial dimension of each gourd belly gradually decreases from top to bottom. The gourd mouth faces outward, and a fluid channel with an inner diameter decreasing from top to bottom is provided inside the main body 1. Three liquid return grooves 10 are provided on the side wings of the main body 1. The bottom of the three liquid return grooves 10 respectively provides a spray hole 9 connected to the fluid channel. The positions of the three spray holes 9 are different. A detachable drill rod is threadedly connected to one end of the cylindrical part of the main body 1 away from the gourd body.

[0030] The outer circumference of the cylindrical part is paved with a layer of carbide particles to form a cylindrical milling layer 2, and the surface of the cylindrical milling layer 2 forms a cylindrical milling surface 3. Carbide particles are laid on the outer circumference of the three gourd bellies to form exponential milling segments. The three exponential milling segments form an exponential milling layer 8. Each exponential milling segment has an exponential milling surface, which are the third exponential milling surface 5, the second exponential milling surface 6, and the first exponential milling surface 7 from left to right. The two adjacent exponential milling surfaces are smoothly transitioned in the form of arcs. Figure 3 As shown, two carbide blade blocks are laid in the transition section between the cylindrical milling surface 3 and the third exponential curve type grinding and milling surface 5 as finishing milling cutters 4, the top edge of the left carbide blade block is flush with one end of the cylindrical milling surface 3, and the top edge of the right carbide blade block is flush with one end of the third exponential curve type grinding and milling surface 5, and the angle between the laying surfaces of the bottom of the two carbide blade blocks is 5°, and the cylindrical milling layer 2, the outer edge of the finishing milling cutter 4, and the exponential curve type grinding and milling layer 8 are all smoothly transitioned in the form of arcs to form a smooth transition grinding and milling surface.

[0031] Example 2

[0032] The exponential curve cylindrical milling shoe of the present invention has a structure as follows Figure 1As shown, the main body 1 has a cylindrical structure and a gourd body structure. The material of the main body 1 is 42CrMo or above. The radial dimension of the gourd body part is not greater than the radial dimension of the cylindrical part. The gourd body part includes two gourd bellies, and the maximum radial dimension of each gourd belly gradually decreases from top to bottom, and the gourd mouth faces outward. A fluid channel with an inner diameter that decreases from top to bottom is provided inside the main body 1. Three liquid return grooves 10 are opened on the side wings of the main body 1. The bottom of the three liquid return grooves 10 respectively opens a spray hole 9 connected to the fluid channel, and the positions of the three spray holes 9 are different.

[0033] A layer of carbide particles is laid on the outer circumference of the cylindrical part to form a cylindrical milling layer 2, a cylindrical milling surface 3 is formed on the surface of the cylindrical milling layer 2, and carbide particles are laid on the outer circumference of the two gourd bellies to form exponential curve grinding segments. The two exponential curve grinding segments constitute an exponential curve grinding layer 8, and each exponential curve grinding segment has an exponential curve grinding surface, which are respectively a third exponential curve grinding surface 5 and a second exponential curve grinding surface 6 from left to right. A smooth transition between the third exponential curve grinding surface 5 and the second exponential curve grinding surface 6 is achieved in the form of an arc. Two carbide blade blocks are laid in the transition section between the cylindrical milling surface 3 and the third exponential curve grinding surface 5 as finishing milling cutters 4. The right outer edge of the left carbide blade block is basically flush with the left outer edge of the right carbide blade block. The top edge of the left carbide blade block is flush with one end of the cylindrical milling surface 3. The top edge of the right carbide blade block is flush with one end of the third exponential curve grinding surface 5. The angle between the laying surfaces of the bottom of the two carbide blade blocks is 8°. The cylindrical milling layer 2, the outer edge of the finishing milling cutter 4 and the exponential curve grinding layer 8 are all smoothly transitioned in the form of arcs to form a smooth transition grinding surface.

[0034] Example 3

[0035] The exponential curve cylindrical milling shoe of the present invention has a structure as follows Figure 1 As shown, the main body 1 has a cylindrical structure and a gourd body structure. The material of the main body 1 is 42CrMo or above. The radial dimension of the gourd body part is not greater than the radial dimension of the cylindrical part. The gourd body part includes two gourd bellies, and the maximum radial dimension of each gourd belly gradually decreases from top to bottom, and the gourd mouth faces outward. A fluid channel with an inner diameter that decreases from top to bottom is provided inside the main body 1. Three liquid return grooves 10 are opened on the side wings of the main body 1, and the bottom of the three liquid return grooves 10 respectively opens a spray hole 9 connected to the fluid channel.

[0036] A layer of carbide particles is laid on the outer circumference of the cylindrical part to form a cylindrical milling layer 2, a cylindrical milling surface 3 is formed on the surface of the cylindrical milling layer 2, and carbide particles are laid on the outer circumference of the two gourd bellies to form exponential curve grinding segments. The two exponential curve grinding segments constitute an exponential curve grinding layer 8, and each exponential curve grinding segment has an exponential curve grinding surface, which are respectively a third exponential curve grinding surface 5 and a second exponential curve grinding surface 6 from left to right. A smooth transition between the third exponential curve grinding surface 5 and the second exponential curve grinding surface 6 is achieved in the form of an arc. Two carbide blade blocks are laid in the transition section between the cylindrical milling surface 3 and the third exponential curve grinding surface 5 as finishing milling cutters 4. The right outer edge of the left carbide blade block is basically flush with the left outer edge of the right carbide blade block. The top edge of the left carbide blade block is flush with one end of the cylindrical milling surface 3. The top edge of the right carbide blade block is flush with one end of the third exponential curve grinding surface 5. The angle between the laying surfaces of the bottom of the two carbide blade blocks is 10°. The cylindrical milling layer 2, the outer edge of the finishing milling cutter 4 and the exponential curve grinding layer 8 are all smoothly transitioned in the form of arcs to form a smooth transition grinding surface.

Claims

1. Exponential curve cylindrical milling shoe, characterized in that: The invention comprises a main body (1) extending axially in the up-down direction, the main body (1) having a cylindrical structure and a gourd body structure, the cylindrical part being paved with a columnar milling layer (2), the gourd body being paved with an exponential curve milling layer (8), a trimming milling cutter (4) being arranged between the columnar milling layer (2) and the exponential curve milling layer (8), and a smooth transition in the form of an arc is adopted between the columnar milling layer (2), the outer edge of the trimming milling cutter (4) and the exponential curve milling layer (8).

2. The exponential curve cylindrical milling shoe according to claim 1, characterized in that: The radial dimension of the gourd body part is not greater than the radial dimension of the cylindrical body part.

3. The exponential curve cylindrical milling shoe according to claim 1, characterized in that: The gourd body portion includes at least two gourd bellies, and the maximum radial dimensions of the gourd bellies gradually decrease from top to bottom, with the gourd mouths facing outwards.

4. The exponential curve cylindrical milling shoe according to claim 3, characterized in that: The exponential curve milling layer (8) comprises exponential curve milling segments arranged in sequence along the axial direction on the outer periphery of each gourd belly, each exponential curve milling segment has an exponential curve milling surface, and any two adjacent exponential curve milling surfaces are smoothly transitioned in the form of an arc, and the exponential curve milling surface close to the trimming milling cutter (4) is flush and smoothly transitioned with the outer edge of the trimming milling cutter (4). When the first layer of exponential curve milling surface is cut and milled, the subsequent exponential curve milling surface mills and expands the repair position of the first layer of exponential curve milling surface, and the next layer of exponential curve milling surface expands and trims the position milled by the former again, and the transition is sequentially formed to form continuous trimming and milling.

5. The exponential curve cylindrical milling shoe according to claim 4, characterized in that: The finishing milling cutter (4) comprises two hard alloy blade blocks laid on the transition section between the cylindrical milling layer (2) and the exponential curve type grinding milling layer (8), the laying surfaces of the bottoms of the two hard alloy blade blocks are not on the same horizontal plane and the angle between the two laying surfaces is 5° to 10°, and the ends of the two hard alloy blade blocks are smoothly transitioned to the cylindrical milling layer (2) and the exponential curve type grinding milling layer (8) respectively.

6. The exponential curve cylindrical milling shoe according to claim 1, characterized in that: The cylindrical milling layer (2) is a hard alloy particle layer laid on the outer peripheral surface of the cylinder, and a cylindrical milling surface (3) is formed on the surface of the cylindrical milling layer (2).

7. The exponential curve cylindrical milling shoe according to claim 1, characterized in that: A fluid channel is provided inside the main body (1), and a plurality of liquid return grooves (10) are provided on the side wall of the main body (1) along the axial direction. A spray hole (9) is provided in the liquid return groove (10), and the spray hole (9) is connected to the fluid channel.

8. The exponential curve cylindrical milling shoe according to claim 7, characterized in that: The inner diameter of the fluid channel decreases from top to bottom, and the injection holes (9) in each of the liquid return grooves (10) are located at different positions.

9. The exponential curve cylindrical milling shoe according to claim 1, characterized in that: A detachable drill rod is provided at one end of the cylindrical part of the main body (1) away from the gourd body.

10. The exponential curve cylindrical milling shoe according to claim 9, characterized in that: The drill rod and the main body (1) are connected by thread.

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