Hydraulic reducing milling shoe mechanism

Abstract

The utility model provides a hydraulic variable diameter milling shoe mechanism, which belongs to the technical field of oil and gas field well repair, and comprises an upper joint, a body, a piston, a spring and telescopic grinding heads, the left end of the body is in threaded connection with the upper joint, a plurality of uniformly distributed notches are milled at the right end of the body, one telescopic grinding head is arranged in each notch, the piston is arranged in the body, and the spring is arranged in the body. A space is formed between the outer wall of the piston and the inner wall of the body, a spring is arranged in the space, the piston is sleeved with the spring, meanwhile, the spring is pre-compressed between the body and the piston, and certain pre-tightening force is provided. According to the telescopic milling shoe tool, the problem that a conventional milling shoe tool cannot be normally used in a special well with the diameter shrinkage condition of the upper portion of a fish is effectively solved, the telescopic milling shoe tool can normally pass through the diameter shrinkage section of the upper portion to reach the fish top position of the fish, and in the milling operation process, the telescopic milling head is opened, and the milling diameter is enlarged. And after the operation is finished, the telescopic grinding head is forcibly retracted into the body, so that the safety of the workover pipe string is ensured.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas field well repair technology, and in particular to a hydraulic variable diameter grinding shoe mechanism. Background Technology

[0002] With the continuous increase in reserves and production in the offshore oil and gas industry and the rapid development of the deepwater industry, in the current well workover operations, for fish that cannot be pulled out from the bottom of the well, milling tools are generally used to grind them off. However, for special wells where the fish has a narrowed diameter above it, using traditional small-diameter milling shoes is not feasible because of their small milling diameter. For tools with larger fish, small-diameter milling shoes cannot grind the fish cleanly, while large-diameter milling shoes will get stuck at the narrowed diameter and cannot reach the fish. Utility Model Content

[0003] To address the problem of conventional grinding tools being unable to function properly in special wells with a reduced diameter at the top of the wellhead, this invention provides a hydraulic variable diameter grinding shoe mechanism. This mechanism can pass through the reduced diameter section at the top to reach the top of the wellhead. During the milling operation, the telescopic grinding head opens to increase the milling diameter. After the operation is completed, the telescopic grinding head can be forcibly retracted into the main body to ensure the safety of the well workover string.

[0004] To achieve the above objectives, the technical solution of this utility model is as follows: A hydraulic variable diameter grinding shoe mechanism includes an upper connector, a body, a piston, a spring, and a telescopic grinding head. The left end of the body is threadedly connected to the upper connector, and the right end is milled with multiple evenly distributed slots. A telescopic grinding head is installed in each slot. The piston is installed inside the body, and a space is formed between the outer wall of the piston and the inner wall of the body. A spring is installed in this space, and the spring is sleeved on the outside of the piston. At the same time, the spring is pre-compressed between the body and the piston and provides a pre-tightening force.

[0005] Furthermore, the end of the upper connector away from the main body is provided with an oil drill pipe thread for connection with the milling and grinding string, the end of the upper connector connected to the main body is provided with an O-ring groove, an O-ring is installed in the O-ring groove, and the interior of the upper connector is provided with a first through hole.

[0006] Furthermore, the left end face of the piston contacts the right end face of the upper connector, and an annular groove is provided on the right end. A limiting step is provided at the middle position of the piston's outer side, and a second through hole is provided inside. At the same time, the diameter of the second through hole is smaller than the diameter of the first through hole.

[0007] Furthermore, the main body has three slots, each slot has a mounting hole, and a pin is installed in each mounting hole. The telescopic grinding head is detachably connected to the main body through the pin. Multiple water grooves are evenly arranged on the right end of the main body, and the water grooves are connected to the through holes in the main body. The right end face of the main body has a bottom wear-resistant area, which is covered with YD alloy or wear-resistant material.

[0008] Furthermore, the body has an inner bore step. When the piston moves to the right under the action of hydraulic force, the inner bore step can abut against the piston's limiting step, thereby limiting the piston's position.

[0009] Furthermore, the telescopic grinding head is elongated and has a wear-resistant zone on its outer side, which is covered with YD alloy or wear-resistant material.

[0010] Furthermore, the inner side of the telescopic grinding head is provided with a ramp, which contacts the right end of the piston. The left end of the telescopic grinding head is provided with a protruding structure, which is placed in the annular groove of the piston. When the piston moves to the right under the action of hydraulic force, its right end can push the ramp of the telescopic grinding head, causing each telescopic grinding head to rotate outward along the pin axis and open. When the hydraulic force disappears, the spring pushes the piston to move to the left. During the leftward movement of the piston, the right step of the annular groove on the piston can drive the protruding structure of the telescopic grinding head, forcibly rotating and retracting the telescopic grinding head into the groove inside the body.

[0011] Compared to existing technologies, the hydraulic variable-diameter grinding shoe mechanism of this invention has the following advantages: This invention effectively solves the problem of not being able to use conventional grinding shoe tools normally in special wells where the upper diameter of the workpiece is reduced. This invention can pass through the upper reduced-diameter section normally, thereby reaching the top of the workpiece. During the milling operation, the telescopic grinding head opens, and the opening angle of the grinding head is adjusted by controlling the flow rate of the fluid pumped into the inner cavity of the main body, thereby controlling the milling diameter, making it suitable for workpieces of different sizes. After the operation is completed, the telescopic grinding head is forcibly retracted into the main body, thereby ensuring the safety of the workover string. Attached Figure Description

[0012] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0013] Figure 1 This is a structural schematic diagram (rear view) of a hydraulic variable diameter shoe grinding mechanism according to an embodiment of the present utility model;

[0014] Figure 2 for Figure 1 AA section view in the middle;

[0015] Figure 3 This is a schematic diagram of the structure of the main body described in an embodiment of the present utility model (tail view);

[0016] Figure 4 for Figure 3 BB section view in the middle;

[0017] Figure 5 for Figure 4 CC section view in the middle;

[0018] Figure 6 for Figure 4 DD section view in the middle;

[0019] Figure 7 This is a schematic diagram of the piston structure according to an embodiment of the present invention;

[0020] Figure 8 This is a schematic diagram of the telescopic grinding head described in an embodiment of the present invention;

[0021] Figure 9 This is a front view of the telescopic grinding head described in an embodiment of the present utility model;

[0022] Figure 10 This is a left view of the telescopic grinding head described in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Upper connector; 2. Body; 3. Piston; 4. Spring; 5. Pin; 6. Telescopic grinding head;

[0025] 11. First through hole; 21. Groove; 22. Mounting hole; 23. Inner hole step; 24. Bottom wear-resistant zone; 25. Water groove; 31. Limiting step; 32. Second through hole; 33. Annular groove; 61. Protruding structure; 62. Slope; 63. Wear-resistant zone. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0027] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] like Figures 1-9As shown, a hydraulic variable-diameter grinding shoe mechanism is a tool used to grind downhole objects, such as drill bits, roller cones, gauges, slips, pipe punches, drill string fittings, deep well pump accessories, packers, water distributors, and longer drill strings, using YD alloy or wear-resistant materials. Specifically, the hydraulic variable-diameter grinding shoe mechanism includes an upper connector 1, a body 2, a piston 3, a spring 4, and a telescopic grinding head 6. The left end of the upper connector 1 is threaded with an oil drill pipe and connected to the milling string, while the right end is threaded to the body 2. The piston 3 and the spring 4 are installed inside the body 2. A space is formed between the outer wall of the piston 3 and the inner wall of the body 2, and the spring 4 is placed in this space. The spring 4 is sleeved on the outside of the piston 3 and is pre-compressed between the body 2 and the piston 3, providing a certain preload. The right end of the main body 2 is milled with multiple evenly distributed slots 21, each slot 21 housing a telescopic grinding head 6. Preferably, the main body 2 has three slots 21, each slot 21 containing a mounting hole 22, and a pin 5 installed in each mounting hole 22. The telescopic grinding head 6 is detachably connected to the main body 2 via the pin 5. Multiple water channels 25 are evenly distributed on the right end of the main body 2, and these channels communicate with through holes within the main body 2. A bottom wear-resistant area (24) is provided on the right end face of the main body 2, and this area is covered with YD alloy or wear-resistant material. A wear-resistant area 63 is provided on the outer side of the telescopic grinding head 6, and this area is also covered with YD alloy or wear-resistant material. By covering the area with YD alloy or wear-resistant material, the milling efficiency is effectively improved, thus achieving a better treatment effect on fallen fish. Milling the tubular column is existing technology. In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", 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 utility model 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 utility model.

[0029] The upper connector 1 is provided with an O-ring groove at the end where it connects to the body 2. An O-ring is installed in the O-ring groove for sealing. The upper connector 1 is provided with a first through hole 11 inside as a flow channel.

[0030] The body 2 has an inner hole step 23. When the piston 3 moves to the right under the action of hydraulic force, the inner hole step 23 can abut against the limiting step 31 of the piston 3, so as to limit the piston 3 by the body 2.

[0031] The left end face of piston 3 contacts the right end face of upper connector 1. An annular groove 33 is provided on the right end. A limiting step 31 is provided at the middle position of the outer side of piston 3. A second through hole 32 is provided inside. The diameter of the second through hole 32 is smaller than the diameter of the first through hole 11. That is, the upper connector 1 has a larger through hole and the piston 3 has a smaller through hole. When the liquid flows through, the inner diameter of the through hole suddenly changes from a large through hole to a small through hole, thus generating a pressure difference, which provides power for the movement of piston 3. Since there is a limiting step 31 in the middle of piston 3, when the hydraulic force increases, the limiting step 31 will press against the inner hole step 23 of body 2, thereby determining the maximum opening diameter of telescopic grinding head 6.

[0032] The telescopic grinding head 6 is elongated and has a ramp 62 on its inner side. The ramp 62 contacts the right end of the piston 3. The left end of the telescopic grinding head 6 has a protruding structure 61, which is placed in the annular groove 33 of the piston 3. When the piston 3 moves to the right under the action of hydraulic force, its right end can push the ramp 62 of the telescopic grinding head 6, causing each telescopic grinding head 6 to rotate outward and open along the pin 5. When the hydraulic force disappears, the spring 4 pushes the piston 3 to move to the left. During the leftward movement of the piston 3, the right step of the annular groove 33 on the piston 3 can drive the protruding structure 61 of the telescopic grinding head 6, forcibly rotating and retracting the telescopic grinding head 6 into the groove 21 inside the body 2.

[0033] This invention allows the material to smoothly pass through the reduced diameter section at the upper end of the sand-proof tubing, reaching the lower end where milling is required. When the hydraulic variable-diameter milling shoe reaches the top of the fish, the pump is activated and the milling tubing is rotated. During milling, the pump provides fluid flow, which sequentially passes through the first through-hole 11, the second through-hole 32, and the through-hole within the body 2, finally flowing out through the water tank 25 at the end of the body 2. When the fluid flows from the first through-hole 11 through the second through-hole 32, a pressure difference is generated, providing power (hydraulic force) for the movement of the piston 3. Under the action of hydraulic force, the spring 4 is compressed, and the piston 3 moves downward, pushing the telescopic milling head 6 outward, thereby achieving the purpose of milling fish with large diameters or larger outer diameters. By controlling the flow rate of the liquid entering the inner cavity of the body 2, the opening angle of the telescopic milling head 6 can be adjusted, thus controlling the milling diameter, making it suitable for fish of different sizes. After the operation is completed, the pump is stopped, the hydraulic pressure disappears, and spring 4 gradually returns to its initial state. During this return process, spring 4 provides a spring force to piston 3. Under the action of the spring force, piston 3 moves upward, forcibly retracting the telescopic grinding head 6 into the body 2, thereby ensuring the safety of the workover string. The tubing string, pump, and fish dropper are all existing technologies.

[0034] The specific operating method is as follows:

[0035] 1. Before going down into the well, check whether the drill pipe threads are intact and whether the water holes are unobstructed. The YD alloy or wear-resistant material must not exceed 2 mm of the body diameter.

[0036] 2. Connect the hydraulic variable diameter grinding shoe described in this utility model to the lowest end of the milling string and lower it into the well.

[0037] 3. When the hydraulic variable-diameter grinding shoe of this utility model is lowered to 2m-3m above the top of the fish, the pump is started to flush the top of the fish. After the well-washing fluid flow from the wellhead is stable, the rotary table is started to slowly lower the milling string. The hydraulic variable-diameter grinding shoe mechanism of this utility model is installed at the lower part of the milling string. The rotary table rotates to mill the string, thereby driving the hydraulic variable-diameter grinding shoe mechanism to rotate, and thus the hydraulic variable-diameter grinding shoe contacts the fish for grinding. Existing technology for drill pipe and rotary table.

[0038] Precautions:

[0039] 1. The drilling speed should not be too fast.

[0040] 2. The pump must not be stopped during operation.

[0041] 3. If there is no progress at a single point for a long period of time, the cause should be analyzed and measures should be taken.

[0042] 4. The abrasive shoe should not be used on moving fish, as it may cause the fish to be pulled to the bottom of the well or damaged.

[0043] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A hydraulic variable diameter shoe grinding mechanism, characterized in that: The body includes an upper connector (1), a main body (2), a piston (3), a spring (4), and a telescopic grinding head (6). The left end of the main body (2) is threaded to the upper connector (1), and the right end is milled with multiple evenly distributed slots (21). Each slot (21) contains a telescopic grinding head (6). The piston (3) is installed inside the main body (2). A space is formed between the outer wall of the piston (3) and the inner wall of the main body (2). A spring (4) is installed in this space. The spring (4) is sleeved on the outside of the piston (3). At the same time, the spring (4) is pre-compressed between the main body (2) and the piston (3) and provides a pre-tightening force. Multiple water grooves (25) are evenly distributed on the right end of the main body (2). At the same time, the water grooves (25) are connected to the through holes inside the main body (2).

2. The hydraulic variable diameter shoe grinding mechanism according to claim 1, characterized in that: The upper connector (1) is provided with a threaded oil drill pipe for connecting to the milling pipe string at one end away from the main body (2). The upper connector (1) is provided with an O-ring groove at the end connected to the main body (2). An O-ring is installed in the O-ring groove. The upper connector (1) is provided with a first through hole (11).

3. The hydraulic variable diameter shoe grinding mechanism according to claim 2, characterized in that: The left end face of the piston (3) contacts the right end face of the upper connector (1). An annular groove (33) is provided on the right end. A limiting step (31) is provided at the middle position of the piston (3). A second through hole (32) is provided inside. At the same time, the diameter of the second through hole (32) is smaller than the diameter of the first through hole (11).

4. The hydraulic variable diameter shoe grinding mechanism according to claim 3, characterized in that: The main body (2) has three slots (21), each slot (21) has a mounting hole (22), and a pin (5) is installed in each mounting hole (22). The telescopic grinding head (6) is detachably connected to the main body (2) through the pin (5). The right end face of the main body (2) has a bottom wear-resistant area (24), and the bottom wear-resistant area (24) is covered with YD alloy or wear-resistant material.

5. A hydraulic variable diameter shoe grinding mechanism according to claim 4, characterized in that: The body (2) has an inner hole step (23) inside. When the piston (3) moves to the right under the action of hydraulic force, the inner hole step (23) can abut against the limiting step (31) of the piston (3) to realize the limiting of the body (2) on the piston (3).

6. A hydraulic variable diameter shoe grinding mechanism according to claim 3, characterized in that: The telescopic grinding head (6) is long and narrow. The outer side of the telescopic grinding head (6) is provided with a wear-resistant area (63), and the wear-resistant area (63) is covered with YD alloy or wear-resistant material.

7. A hydraulic variable diameter shoe grinding mechanism according to claim 6, characterized in that: The inner side of the telescopic grinding head (6) is provided with a ramp (62), which is in contact with the right end of the piston (3). The left end of the telescopic grinding head (6) is provided with a protruding structure (61), which is placed in the annular groove (33) of the piston (3). When the piston (3) moves to the right under the action of hydraulic force, its right end can push the ramp (62) of the telescopic grinding head (6), so that each telescopic grinding head (6) rotates outward along the pin (5). When the hydraulic force disappears, the spring (4) pushes the piston (3) to move to the left. During the movement of the piston (3) to the left, the right step of the annular groove (33) on the piston (3) can drive the protruding structure (61) of the telescopic grinding head (6), forcibly rotating the telescopic grinding head (6) back into the groove (21) inside the body (2).

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