Milling fishing tool for oil pipe

Abstract

The invention provides a casing milling and fishing tool for an oil pipe, which comprises a fishing cylinder sleeved outside the oil pipe, a joint arranged at the upstream of the fishing cylinder and a casing milling cylinder arranged at the downstream of the fishing cylinder, and a plurality of convex teeth for milling the lug bosses are arranged on the lower end surface of the milling cylinder. According to the invention, the milling length can be accurately controlled, so that the milling cylinder can accurately reach a preset position. Compared with a conventional casing milling tool, the casing milling tool can control the casing milling precision so as to avoid the problem that underground faults are complicated.

Description

Technical Field

[0001] The present invention relates to the field of downhole operations, and particularly to a milling fishing tool for tubing. Background Art

[0002] Currently, during the major overhaul of oil production wells in downhole operations, the milling shoe assembly and the milling barrel are necessary milling tools for cleaning debris from the fallen fish. However, the following technical problems exist during the milling process:

[0003] Firstly, since the precise length of milling in the prior art cannot be controlled, the quality of milling cannot be guaranteed. Secondly, when milling the electric pump string, if the length of milling cannot be precisely controlled, it is extremely easy to damage the cable clamps of the electric pump string and create a more complex situation in the downhole of the oil production well, thereby increasing the difficulty and cost of downhole operations.

[0004] Therefore, in this field, it is desirable to provide a milling fishing tool for tubing to solve the above technical problems. Summary of the Invention

[0005] The object of the present invention is to provide a milling fishing tool for tubing, which can accurately control the length of milling through a limiting rod, thereby ensuring that the milling barrel can accurately reach the predetermined position. Compared with conventional milling tools, the present invention can control the milling accuracy to avoid the complication of downhole failures.

[0006] According to the present invention, there is provided a milling fishing tool for tubing, including a fishing barrel sleeved outside the tubing,

[0007] a joint provided upstream of the fishing barrel, and

[0008] a milling barrel provided downstream of the fishing barrel,

[0009] wherein, a raised portion is formed on the outer wall of the tubing, and a plurality of convex teeth for milling the raised portion are provided at the lower end surface of the milling barrel.

[0010] In one embodiment, the inner diameter of the milling barrel is larger than the outer diameter of the tubing.

[0011] In one embodiment, a plurality of inner fishing windows radially inwardly inclined and extending are provided on the outer wall of the fishing barrel, and a gap is left between the inner fishing windows and the tubing.

[0012] In one embodiment, the inner fishing window includes a first fishing tongue and a second fishing tongue configured as a trapezoidal structure, wherein the first fishing tongue is upstream of the second fishing tongue, and the cross-sectional area of the first fishing tongue is larger than the cross-sectional area of the second fishing tongue.

[0013] In one embodiment, engaging portions configured as arc surface structures are formed at the ends of the first fishing tongue and the second fishing tongue.

[0014] In one embodiment, a plurality of outer fishing windows that radially extend outwardly and are configured as rectangular structures are provided on the outer wall of the fishing barrel, and the outer fishing windows are downstream of the inner fishing windows.

[0015] In one embodiment, both the inner fishing windows and the outer fishing windows are spirally arranged on the outer wall of the fishing barrel.

[0016] In one embodiment, a drive pipe string for allowing the milling fishing tool to rotate unidirectionally is provided at the upper end face of the joint, and the opening direction of the outer fishing window is consistent with the rotation direction of the drive pipe string.

[0017] In one embodiment, an included angle of 10° to 30° is formed between the extending directions of both the inner fishing windows and the outer fishing windows and the central line direction of the fishing barrel.

[0018] In one embodiment, a plurality of limiting rods that are cross-arranged and used for abutting against the tubing are provided at the joint between the joint and the fishing barrel.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] First, the present invention can accurately control the milling length through the limiting rods, so as to ensure that the milling barrel can accurately reach the predetermined position. Compared with conventional milling tools, the present invention can control the milling accuracy to avoid the complication of downhole failures. In addition, the present invention has strong adaptability to the precise milling of tubing strings with packers and cable cast iron clamps, which is convenient for on-site processing and use.

[0021] Second, when the present invention performs fishing work while rotating and ascending the fishing barrel, it can simultaneously fish the waste attached to the outer surface of the tubing and the debris in the wellbore through the inner fishing windows and the outer fishing windows, thereby improving the carrying capacity of the debris or waste, and further improving the fishing efficiency and fishing quality of the milling fishing tool for the tubing, so as to further ensure that the tubing can obtain a better working environment after the fishing work.

[0022] Third, the present invention can protect the complete structure of the tubing, effectively meet the construction requirements of the site, can be used to guide downhole operation overhaul fishing, and has wide engineering application value and scientific research value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in detail below with reference to the drawings. In the drawings:

[0024] Figure 1 Schematically shows the structure of a milling fishing tool for tubing according to the present invention;

[0025] Figure 2 Schematically shows the first stage of the milling fishing operation of the milling fishing tool for tubing according to the present invention;

[0026] Figure 3 Schematically shows the second stage of the milling fishing operation of the milling fishing tool for tubing according to the present invention;

[0027] Figure 4 Schematically shows the third stage of the milling fishing operation of the milling fishing tool for tubing according to the present invention.

[0028] In the drawings, the same components are denoted by the same reference numerals. The drawings are not drawn to actual scale. Detailed Description of the Invention

[0029] In order to make the technical solutions and advantages of the present invention more clear and understandable, the exemplary embodiments of the present invention will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. And without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0030] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0031] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed" and other terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements.

[0032] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, the directional terms "upstream" or "above" or similar terms refer to the direction close to the wellhead, that is, Figure 1 the top direction in Figure 1 The directional terms "downstream" or "below" or similar terms refer to the direction away from the wellhead, that is,

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] Figure 1 Schematically shows the structure of a milling and fishing tool 100 for tubing according to the present invention;

[0036] Figure 2 Schematically shows the first stage of the milling and fishing operation of the milling and fishing tool 100 for tubing according to the present invention;

[0037] Figure 3 Schematically shows the second stage of the milling and fishing operation of the milling and fishing tool 100 for tubing according to the present invention;

[0038] Figure 4 Schematically shows the third stage of the milling and fishing operation of the milling and fishing tool 100 for tubing according to the present invention.

[0039] As Figure 1 shown, the milling and fishing tool 100 for tubing according to the present invention includes a fishing barrel 11 sleeved outside the tubing 101, a joint 12 provided upstream of the fishing barrel 11, and a milling barrel 13 provided downstream of the fishing barrel 11. In the present invention, the milling barrel 13 can perform a milling operation on the outer wall surface of the tubing 101, and the fishing barrel 11 can perform a fishing operation on the waste in the well, which will be specifically introduced below.

[0040] In one embodiment, a rotating string (not shown) is provided at the upper end face of the joint 12. Preferably, the rotating string is configured to be able to drive the fishing barrel 11 and the milling barrel 13 to perform rotational movement and axial movement simultaneously through the joint 12, thereby helping the milling barrel 13 to remove the raised portion 102 (introduced below).

[0041] In one embodiment, as Figure 1 shown, a plurality of raised portions 102 are formed on the outer wall surface of the tubing 101 in a staggered distribution, and a plurality of convex teeth 131 are provided at the lower end face of the milling barrel 13.

[0042] In the present invention, in combination with Figure 2 and 3 shown, the milling barrel 13 rotates and descends under the driving action of the rotating string, so that the raised portions 102 on the outer wall surface of the tubing 101 can be removed by the convex teeth 131 arranged on the milling barrel 13, thereby completing the milling work, and further ensuring that the milling and fishing tool 100 for tubing can achieve the purpose of accurate and efficient milling.

[0043] In an embodiment of the present invention, a plurality of convex teeth 131 are arranged at intervals in the circumferential direction at the lower end surface of the milling barrel 13. Preferably, the plurality of convex teeth 131 are arranged obliquely on the milling barrel 13 to form a petal-like layout, so as to be able to expand the contact area with the convex portion 102 and contribute to improving the milling efficiency of the milling and fishing tool 100 for the tubing.

[0044] In one embodiment, the inner diameter of the milling barrel 13 is larger than the outer diameter of the tubing 101. In this way, the milling barrel 13 can fully and comprehensively mill the convex portion 102 attached to the outer wall surface of the tubing 101 through the convex teeth 131, thereby contributing to the subsequent smooth waste fishing work of the inner fishing window 21 (introduced below).

[0045] According to the present invention, as Figure 1 shown, a plurality of inner fishing windows 21 extending radially inward and obliquely are provided on the outer wall of the fishing barrel 11. Combining Figure 3 and 4 shown, after the milling work of the milling barrel 13 is completed, the fishing barrel 11 rotates and moves upward while being driven by the rotating string, so as to uniformly fish the waste attached to the outer surface of the tubing 101 through the inner fishing window 21 to complete part of the fishing work in the wellbore 40.

[0046] In this way, not only can the working environment of the tubing 101 in the wellbore 40 be improved, but also the service life of the tubing 101 can be further extended.

[0047] In the present invention, since the opening directions of the inner fishing windows 21 all face the direction of the joint 12. Therefore, when the milling barrel 13 rotates and moves downward while being driven by the rotating string to perform milling work, the tubing 101 can always be in a centered position under the action of the inner fishing window 21, so as to ensure that the milling barrel 13 can fully and comprehensively mill the convex portion 102 on the outer surface of the tubing 101, thereby further improving the working efficiency and milling quality of the milling and fishing tool 100 for the tubing.

[0048] In one embodiment, there is a gap between the inner fishing window 21 and the tubing 101. Therefore, when the fishing barrel 11 rotates and moves upward while being driven by the rotating string to perform fishing work, it can effectively avoid the contact between the inner fishing window 21 and the outer wall surface of the tubing 101, thereby playing a good protective role for the tubing 101 to ensure that the tubing 101 can be effectively protected during the fishing process.

[0049] In an embodiment of the present invention, as Figure 1As shown, the internal fishing window 21 includes a first fishing tongue 211 and a second fishing tongue 212 disposed downstream of the first fishing tongue. Preferably, both the first fishing tongue 211 and the second fishing tongue 212 are configured as trapezoidal structures.

[0050] In the present invention, when the fishing barrel 11 rotates and moves upward under the driving action of the rotating string to perform the fishing operation, a larger contact area is formed between the first fishing tongue 211 and the waste, and between the second fishing tongue 212 and the waste. Thereby, the fishing efficiency and fishing quality of the milling fishing tool 100 for the oil pipe are improved.

[0051] Preferably, the first fishing tongue 211 and the second fishing tongue 212 can more fully fish the waste attached to the outer surface of the oil pipe 101, thereby ensuring that the oil pipe 101 can have a good working environment in the wellbore 40.

[0052] In one embodiment, the cross-sectional area of the first fishing tongue 211 is larger than the cross-sectional area of the second fishing tongue 212. In this way, when the fishing barrel 11 rotates and moves upward under the driving action of the rotating string, the internal fishing window 21 can perform staged fishing operations, the content of which will be introduced below.

[0053] Preferably, during the fishing operation of the fishing barrel 11, both the first fishing tongue 211 and the second fishing tongue 212 can selectively perform classified fishing. In other words, the first fishing tongue 211 with a larger cross-sectional area can fish the larger-volume waste attached to the outer surface of the oil pipe 101, while the second fishing tongue 212 with a smaller cross-sectional area can fish the smaller-volume waste attached to the outer surface of the oil pipe 101.

[0054] Therefore, under the combined action of the first fishing tongue 211 and the second fishing tongue 212, the internal fishing window 21 can take away more waste at one time during the fishing process to ensure that the oil pipe 101 can obtain a better working environment after the milling operation and the fishing operation.

[0055] In one embodiment, engaging portions (not shown) configured as arc surface structures are formed at the ends of both the first fishing tongue 211 and the second fishing tongue 212. Therefore, during the fishing process when the fishing barrel 11 rotates and moves upward under the driving action of the rotating string, even if the internal fishing window 21 accidentally touches the oil pipe 101, it can pass through the engaging portion of the first fishing tongue 211 or the second fishing tongue 212, thereby avoiding scratching or damaging the oil pipe 101 to further ensure the safety of the oil pipe 101 during the fishing process.

[0056] In one embodiment, the inner fishing window 21 is spirally arranged on the outer wall of the fishing barrel 11. Preferably, both the first fishing tongue 211 and the second fishing tongue 212 are spirally arranged on the outer wall of the fishing barrel 11.

[0057] In this way, the first fishing tongue 211 and the second fishing tongue 212 can more easily carry more waste during the rotation and rising processes, so as to ensure that the tubing 101 can obtain a better working environment after the milling and fishing operations.

[0058] According to the present invention, as Figure 1 shown, a plurality of outer fishing windows 31 extending radially outward and obliquely are provided on the outer wall of the fishing barrel 11. Therefore, after the milling operation of the milling barrel 13 is completed, the fishing barrel 11 rotates and ascends while being driven by the rotating string, so that sundries (such as scattered cables) in the wellbore 40 can be uniformly fished through the outer fishing windows 31 to complete part of the fishing work in the wellbore 40.

[0059] In this way, the working environment of the tubing 101 in the wellbore 40 can be effectively improved to further extend the service life of the tubing 101.

[0060] In one embodiment of the present invention, the outer fishing window 31 is downstream of the inner fishing window 21, and the outer fishing window 31 is configured as a rectangular structure. Thus, when the fishing barrel 11 rotates and ascends while being driven by the rotating string to perform the fishing operation, a larger contact area is formed between the outer fishing window 31 and the sundries, thereby improving the fishing efficiency and fishing quality of the tubing milling and fishing tool 100 for the tubing.

[0061] In one embodiment, the outer fishing window 31 is spirally arranged on the outer wall of the fishing barrel 11. In this way, the outer fishing window 31 can more easily carry more sundries during the rotation and rising processes, so as to ensure that the tubing 101 can obtain a better working environment after the milling and fishing operations.

[0062] In one embodiment of the present invention, the opening direction of the outer fishing window 31 is the same as the rotation direction of the driving string. Therefore, when the fishing barrel 11 rotates and ascends while being driven by the rotating string to perform the fishing operation, the outer fishing window 31 can more easily pick up the sundries, so as to increase the carrying amount of the sundries, and further improve the fishing efficiency and fishing quality of the tubing milling and fishing tool 100 for the tubing.

[0063] In one embodiment, the extending directions of the inner fishing window 21 and the outer fishing window 31 both form an angle of 10° to 30° with the central line direction of the fishing barrel 11. In this way, the grasping ability of the inner fishing window 21 and the outer fishing window 31 is effectively improved, so as to further improve the fishing efficiency and fishing quality of the milling fishing tool 100 for the oil pipe.

[0064] When the present invention is performing fishing work while rotating and ascending the fishing barrel 11, it can simultaneously perform unified fishing on the waste attached to the outer surface of the oil pipe 101 and the sundries in the wellbore 40 through the inner fishing window 21 and the outer fishing window 31, thereby improving the carrying capacity of the sundries or waste, and further improving the fishing efficiency and fishing quality of the milling fishing tool 100 for the oil pipe, so as to further ensure that the oil pipe 101 can obtain a better operating environment after the fishing work.

[0065] According to the present invention, as Figure 1 shown, a limiting rod 121 is provided at the joint of the joint 12 and the fishing barrel 11. Preferably, a plurality of limiting rods 121 are provided, and the plurality of limiting rods 121 are all arranged in a crossed manner, so as to be able to smoothly make axial contact with the oil pipe 101. In this way, the milling fishing tool 100 for the oil pipe can smoothly reach the predetermined position in the wellbore 40, so as to achieve the purpose of avoiding damaging the structure of the oil pipe 101.

[0066] The present invention can accurately control the milling length through the limiting rod 121, so as to ensure that the milling barrel 13 reaches the predetermined position. Compared with conventional milling tools, the present invention can control the milling accuracy to avoid the problem of complication of downhole failures. In addition, the present invention has strong adaptability to the precise milling of pipe strings with packers and cable cast iron clamps, which is convenient for on-site processing and use.

[0067] Compared with the prior art, the advantages of the present invention are:

[0068] Firstly, the present invention can accurately control the milling length through the limiting rod 121, so as to ensure that the milling barrel 13 can accurately reach the predetermined position. Compared with conventional milling tools, the present invention can control the milling accuracy to avoid the problem of complication of downhole failures. In addition, the present invention has strong adaptability to the precise milling of pipe strings with packers and cable cast iron clamps, which is convenient for on-site processing and use.

[0069] Second, when the fishing barrel 11 rotates and moves upward during the fishing operation, the inner fishing window 21 and the outer fishing window 31 can simultaneously carry out unified fishing for the waste attached to the outer surface of the oil pipe 101 and the sundries in the wellbore 40, thereby improving the carrying capacity of the sundries or waste, and further improving the fishing efficiency and fishing quality of the milling fishing tool 100 for the oil pipe, so as to further ensure that the oil pipe 101 can obtain a better working environment after the fishing operation.

[0070] Third, the present invention can protect the complete structure of the oil pipe 101, effectively meet the construction requirements on site, can be used to guide the overhaul fishing of downhole operations, and has extensive engineering application value and scientific research value.

[0071] The above is only the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can easily make changes or variations within the disclosure scope of the present invention, and such changes or variations should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A milling fishing tool for tubing, comprising: a fishing barrel (11) sleeved outside the tubing (101), a joint (12) provided upstream of the fishing barrel (11), and a milling barrel (13) provided downstream of the fishing barrel (11), wherein a raised portion (102) is formed on the outer wall of the tubing (101), and a plurality of convex teeth (131) for milling the raised portion (102) are provided at the lower end face of the milling barrel (13).

2. The milling fishing tool for tubing according to claim 1, characterized in that the inner diameter of the milling barrel (13) is larger than the outer diameter of the tubing (101).

3. The milling fishing tool for tubing according to claim 2, characterized in that a plurality of inner fishing windows (21) radially inclined inwardly are provided on the outer wall of the fishing barrel (11), and a gap is left between the inner fishing windows (21) and the tubing (101).

4. The milling fishing tool for tubing according to claim 3, characterized in that the inner fishing window (21) includes a first fishing tongue (211) and a second fishing tongue (212) configured in a trapezoidal structure, wherein the first fishing tongue (211) is upstream of the second fishing tongue (212), and the cross-sectional area of the first fishing tongue (211) is larger than that of the second fishing tongue (212).

5. The milling fishing tool for tubing according to claim 4, characterized in that arc-shaped joints are formed at the ends of the first fishing tongue (211) and the second fishing tongue (212).

6. The milling fishing tool for tubing according to claim 5, characterized in that a plurality of outer fishing windows (31) radially inclined outwardly and configured in a rectangular structure are provided on the outer wall of the fishing barrel (11), and the outer fishing windows (31) are downstream of the inner fishing windows (21).

7. The milling fishing tool for tubing according to claim 6, characterized in that both the inner fishing windows (21) and the outer fishing windows (31) are spirally arranged on the outer wall of the fishing barrel (11).

8. The milling fishing tool for tubing according to claim 7, characterized in that a drive pipe string for allowing the milling fishing tool to rotate unidirectionally is provided at the upper end face of the joint (12), and the opening direction of the outer fishing window (31) is consistent with the rotation direction of the drive pipe string.

9. The milling fishing tool for tubing according to claim 8, characterized in that both the inner fishing window (21) and the outer fishing window (31) form an angle of 10° to 30° with the central line direction of the fishing barrel (11).

10. The milling fishing tool for tubing according to any one of claims 1 to 9, characterized in that a plurality of limiting rods (121) arranged crosswise and used for abutting against the tubing (101) are provided at the joint between the joint (12) and the fishing barrel (11).

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