A downhole tool for drilling through the core to fish out the oil pipe in a large well repair

Abstract

The utility model relates to the technical field of oil and gas downhole salvage devices, specifically a downhole tool for salvaging oil pipes through the core of a well during overhaul, comprising: a central shaft, an elastic member and slips sleeved on the central shaft, a piston extension cylinder, a piston, and a guide cone connected in sequence and all connected to the central shaft; the elastic member is arranged at the tail of the central shaft, and the top of the elastic member is connected to the bottom of the slip; the top of the slip abuts against the piston extension cylinder; the guide cone is arranged at the top of the central shaft, and an adjusting screw is arranged at the top of the guide cone; the size of the water hole in the middle of the adjusting screw satisfies that the pressure under the preset displacement of the liquid flow is sufficient to push the piston; the inner wall of the slip is arranged as a stepped inner inclined surface, and the outer periphery of the part where the central shaft contacts the inner wall of the slip is arranged with an outer inclined surface matching the inner inclined surface; under the action of the piston thrust, the piston extension cylinder pushes the slip to move toward the tail of the central shaft, and the slip expands and separates from the central shaft. The utility model can effectively salvage corroded pipe strings during overhaul, thereby improving operation efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of downhole fishing devices for petroleum and natural gas, in particular to a downhole tool for fishing oil pipes through the core of a well for repair. Background Art

[0002] As oilfield development enters the middle and late stages, with the adjustment of production systems and the implementation of production-increasing measures, the performance degradation of production tubing due to corrosion and erosion has become increasingly prominent. These tubings are eroded by complex geological environments and fluid media during long-term oil and gas production, resulting in a significant reduction in their tensile strength. During salvage operations, even a slight overlift may cause a fracture due to the weakness of the tubing, making it impossible to salvage only part of the fish section, and not the entire fish section at once.

[0003] Corrosion and erosion at the breakpoints cause the fish top area to become weak and the cross section of the tubing to present an irregular shape, which greatly increases the difficulty of salvage. Traditional salvage tools, such as retractable salvage spears, face many challenges when trying to grab these damaged pipes. First, the grabbing position is usually located a certain distance below the fish top, and the degree of corrosion in this area may be extremely high, making it difficult for the tool to firmly grasp the pipe, and multiple attempts may further damage the fish top structure, making the salvage work more complicated. Secondly, if the overall corrosion of the tubing is serious, traditional tools can only be used for segmented salvage, which not only prolongs the operation time, but also increases the risk of operation. In addition, some salvage tools, such as long-pole salvage spears, are limited by size and torque when in use, making it difficult to operate without hands. Utility Model Content

[0004] The purpose of the utility model is to provide a downhole tool for drilling through the core and fishing out the oil pipe during a major well repair in order to solve at least one of the above technical problems.

[0005] The utility model achieves the above-mentioned purpose through the following technical scheme: a downhole tool for drilling through the core to fish out the oil pipe in a major well repair, comprising: a central shaft, an elastic member and slips sleeved on the central shaft, a piston extension cylinder, a piston, and a guide cone which are sequentially connected and all connected to the central shaft;

[0006] The elastic member is arranged at the tail of the central shaft, the top end of the elastic member is connected to the bottom end of the slip, and the elastic member is used to provide a pre-tightening force for the slip; the top end of the slip abuts against the piston extension cylinder;

[0007] The guide cone is arranged at the top of the central shaft, and an adjusting screw is arranged at the top of the guide cone; the size of the water hole in the middle of the adjusting screw satisfies that the pressure under the preset displacement of the liquid flow is sufficient to push the piston;

[0008] The inner wall of the slip is arranged as a stepped inner slope, and the outer periphery of the portion where the central axis contacts the inner wall of the slip is arranged with an outer slope matching the inner slope;

[0009] Under the action of the piston thrust, the piston extension cylinder pushes the slip to move toward the tail of the central shaft, and the slip expands and separates from the central shaft.

[0010] Further, the elastic member comprises: a spring and a spring sleeve;

[0011] One end of the spring is fixed to the bottom of the spring sleeve, and the other end is connected to the bottom end of the slip; in the initial state, the spring is in a compressed state.

[0012] Furthermore, the outer diameter of the central axis joint is smaller than the outer diameter of the slip after expansion, and the outer diameter of the slip after expansion is not smaller than the inner diameter of the oil pipe.

[0013] Furthermore, the outer diameter of the central shaft is 60 mm, and the joint is buckle type BD50.

[0014] Furthermore, the diameter of the water hole in the middle of the adjusting screw is 5 mm.

[0015] The beneficial effects of the utility model are:

[0016] The utility model realizes efficient and reliable salvage of corroded oil pipes; the utility model can penetrate through the fish top and penetrate deep into the pipe column to salvage, and release the hands through hydraulic pressure, and has the advantages of simple structure, easy maintenance, low cost, etc., which significantly improves the success rate and timeliness of salvage operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a schematic diagram of a downhole tool structure for drilling through the core to fish for oil pipes in a major well repair according to an embodiment of the present invention.

[0018] In the figure: 1, center shaft, 2, spring, 3, slip, 4, piston extension cylinder, 5, piston, 6, spring sleeve, 7, guide cone, 8, adjusting screw. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] Figure 1 This is a schematic diagram of the structure of a downhole tool for drilling through the core to fish the oil pipe in a large well repair according to an embodiment of the utility model. Figure 1 As shown, according to an embodiment of the utility model, a downhole tool for drilling through the core and fishing the oil pipe in a major well repair comprises: a central shaft 1, an elastic member and a slip 3 sleeved on the central shaft 1, a piston extension cylinder 4, a piston 5, and a guide cone 7 which are sequentially connected and all connected to the central shaft 1;

[0021] The elastic member is arranged at the tail of the central shaft 1, the top of the elastic member is connected to the bottom of the slip 3, and the elastic member is used to provide a pre-tightening force for the slip 3; the top of the slip 3 is in contact with the piston extension cylinder 4;

[0022] The guide cone 7 is arranged at the top of the central shaft 1, and an adjusting screw 8 is arranged at the top of the guide cone 7; the size of the water hole in the middle of the adjusting screw 8 is sufficient to ensure that the pressure under the preset displacement of the liquid flow is sufficient to push the piston 5;

[0023] The inner wall of the slip 3 is arranged as a stepped inner slope, and the outer periphery of the portion where the central axis 1 contacts the inner wall of the slip 3 is arranged with an outer slope matching the inner slope;

[0024] Under the action of the thrust of the piston 5 , the piston extension cylinder 4 pushes the slips 3 to move toward the tail of the central shaft 1 , and the slips 3 expand and separate from the central shaft 1 .

[0025] In the present embodiment, the downhole tool for drilling and fishing oil pipes for overhauling wells comprises: a central shaft 1, on which an adjusting screw 8, a guide cone 7, a piston 5, a piston extension tube 4, a slip 3, and an elastic member are sequentially arranged from the top to the tail of the central shaft 1; the elastic member is arranged at the tail of the central shaft 1, one end of which supports the main body and the other end pushes the slip 3, giving the slip 3 a pre-tightening force; the inner wall of the slip 3 matches the outer wall of the central shaft 1, and the inclined surface outside the central shaft 1 contacts the inclined surface inside the slip 3, so that the slip 3 can expand during the mutual movement; the water hole in the middle of the adjusting screw 8 discharges water outward, and under the liquid flow with a water discharge volume that meets the preset discharge volume, there is sufficient pressure to push the piston 5 to move, and the piston 5 is connected to the piston extension tube 4. Driven by the piston 5, the piston extension tube 4 pushes the slip 3 toward the tail of the central shaft, and the slip 3 expands and separates from the central shaft 1.

[0026] The utility model realizes efficient and reliable salvage of corroded oil pipes; the utility model can penetrate through the fish top and penetrate deep into the pipe column to salvage, and release the hands through hydraulic pressure, and has the advantages of simple structure, easy maintenance, low cost, etc., which significantly improves the success rate and timeliness of salvage operations.

[0027] According to an embodiment of the present utility model, the elastic member includes: a spring 2 and a spring sleeve 6;

[0028] One end of the spring 2 is fixed to the bottom of the spring sleeve 6, and the other end is connected to the bottom of the slip 3; in the initial state, the spring 2 is in a compressed state.

[0029] In this embodiment, the elastic member is a combination of a spring 2 and a spring sleeve 6. The spring 2 and the spring sleeve 6 cooperate to provide a pre-tightening force for the slips 3 to ensure that the slips 3 are in contact with the central shaft 1 in the initial state.

[0030] The utility model has simple structural design and low manufacturing cost.

[0031] According to an implementation of the utility model, the outer diameter of the joint of the central shaft 1 is smaller than the outer diameter of the slips 3 after expansion, and the outer diameter of the slips 3 after expansion is not smaller than the inner diameter of the oil pipe.

[0032] In this embodiment, the outer diameter of the joint on the central shaft 1 is smaller than the outer diameter of the slip 3 to achieve through-hole fishing.

[0033] According to an implementation mode of the present utility model, the outer diameter of the central shaft 1 is 60 mm, and the joint adopts the buckle type BD50.

[0034] In this embodiment, based on the common oil pipe size in oil field operations, the outer diameter of the central shaft 1 is set to 60 mm to ensure that the tool can smoothly pass through the inside of the oil pipe and enter the position to be salvaged. The buckle type BD50 is a common oil field equipment connection buckle type. The central shaft adopts the BD50 buckle type to make it compatible with other oil field equipment, which is convenient for rapid installation and replacement on site.

[0035] The central axis design selection of the utility model ensures the strength, stability and ease of operation of the tool while maintaining the compatibility of the downhole tool with the oilfield equipment, thereby improving the efficiency of oilfield operations, reducing risks and having good cost-effectiveness.

[0036] According to an embodiment of the present invention, the diameter of the water hole in the middle of the adjusting screw 8 is 5 mm.

[0037] In this embodiment, the diameter of the water hole in the middle of the adjusting screw 8 is 5 mm, which ensures that sufficient liquid flow pressure is generated to push the piston 5 under a specific displacement.

[0038] The utility model realizes efficient and reliable salvage of corroded oil pipes; the utility model can penetrate through the fish top and penetrate deep into the pipe column to salvage, and release the hands through hydraulic pressure, and has the advantages of simple structure, easy maintenance, low cost, etc., which significantly improves the success rate and timeliness of salvage operations.

[0039] How it works

[0040] A downhole tool for fishing oil pipes through the core of a well for repair and has a hydraulic release function, which can pass through a production pipe string for fishing. The tool comprises a central shaft 1, a spring 2, a spring sleeve 6, a slip 3, a piston extension tube 4, a piston 5, a guide cone 7, and an adjusting screw 8. The spring 2, the spring sleeve 6, and the slip 3 are sleeved on the central shaft 1, and the piston 5 is on the upper part of the guide cone 7 and connected to the central shaft 1.

[0041] The spring 2 cooperates with the spring sleeve 6, supporting the main body from above and pushing the slip 3 from below to give the slip 3 a pre-tightening force; the central shaft 1 and the slip 3 match each other, and the inclined surface outside the central shaft 1 contacts the inclined surface inside the slip 3, which can make the slip 3 expand during the mutual movement; under the action of pressure, the piston 5 can push the piston extension cylinder 4 to push the slip 3 upward, so as to realize the disengagement of the slip 3 from the central shaft 1; the water eye size of the adjustment screw 8 is designed to ensure that there is enough pressure to push the piston 5 under a certain displacement of liquid flow; the outer diameter of the joint on the central shaft 1 is smaller than the outer diameter of the slip 1 grabbing, so as to realize through-the-core salvage.

[0042] The utility model overcomes the limitation of the original fishing spear for fishing corroded pipes, has a higher success rate and timeliness for fishing corroded pipes, adopts a tool with simple structure, convenient use and reliable performance, can effectively fish corroded pipes during overhaul, and improves working efficiency.

[0043] The utility model can pass through the top of the fish, penetrate into the inside of the production pipe column to grab, and can be released by hydraulic pressure; the utility model has a simple structure and is easy to replace related wearing parts; the utility model has a simple principle, low cost and is easy to use.

[0044] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0045] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A downhole tool for drilling through the core to fish out the oil pipe during a major well repair, characterized in that: include: A central shaft (1), an elastic member and a slip (3) sleeved on the central shaft (1), a piston extension cylinder (4), a piston (5), and a guide cone (7) which are sequentially connected and all connected to the central shaft (1); The elastic component is arranged at the tail end of the central shaft (1), the top end of the elastic component is connected to the bottom end of the slip (3), and the elastic component is used to provide a pre-tightening force for the slip (3); the top end of the slip (3) is in contact with the piston extension cylinder (4); The guide cone (7) is arranged at the top of the central shaft (1), and an adjusting screw (8) is arranged at the top of the guide cone (7); the size of the water hole in the middle of the adjusting screw (8) satisfies that the pressure under the preset displacement of the liquid flow is sufficient to push the piston (5); The inner wall of the slip (3) is arranged as a stepped inner bevel, and the outer periphery of the portion where the central axis (1) contacts the inner wall of the slip (3) is arranged with an outer bevel matching the inner bevel; Under the thrust of the piston (5), the piston extension cylinder (4) pushes the slip (3) to move toward the tail of the central shaft (1), and the slip (3) expands and separates from the central shaft (1).

2. The downhole tool for drilling through the core and fishing the oil pipe during a major well repair according to claim 1, characterized in that: The elastic component comprises: a spring (2) and a spring sleeve (6); One end of the spring (2) is fixed to the bottom of the spring sleeve (6), and the other end is connected to the bottom of the slip (3); in the initial state, the spring (2) is in a compressed state.

3. The downhole tool for drilling through the core and fishing the oil pipe during a major well repair according to claim 1, characterized in that: The outer diameter of the joint of the central shaft (1) is smaller than the outer diameter of the slip (3) after expansion, and the outer diameter of the slip (3) after expansion is not smaller than the inner diameter of the oil pipe.

4. The downhole tool for drilling through the core and fishing the oil pipe during a major well repair according to claim 1, characterized in that: The central shaft (1) has an outer diameter of 60 mm and a buckle-type BD50 joint.

5. The downhole tool for drilling through the core and fishing the oil pipe during a major well repair according to claim 1, characterized in that: The diameter of the water hole in the middle of the adjusting screw (8) is 5 mm.

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