A drill and mill through fishing workover tool

Abstract

The application discloses a drilling and milling sand fishing workover tool, which is characterized in that a plurality of sand fishing grooves are arranged on the tool body, so that the sand carrying capacity of the tool is greatly improved, the fast-sinking sand can be fished, the past-sinking sand can also be brought back to the ground, the well bottom sand can be more thoroughly removed, the operation efficiency and the workover stimulation effect are greatly improved, the workover cycle is prolonged, the workover cost is reduced, and the up-returning capacity of the sand is increased through the additionally arranged reverse circulation hole. In addition, the sand fishing grooves are provided with a plurality of levels from top to bottom, which is equivalent to setting a plurality of levels for the sinking sand, so that the fishing rate is more than 70%, and the complex downhole accidents caused by the sinking sand, such as the pipe sticking and the burying of the drilling tool, can be effectively avoided, and the safety risk of the downhole operation is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil tools, in particular to a drilling and milling fishing workover tool. BACKGROUND

[0002] In the middle and later stages of oil and gas production wells, the sand at the bottom of the well is serious, which fills the bottom of the well and leads to reduced production or no production. Therefore, it is necessary to flush and sand fishing operation for oil and gas production wells.

[0003] However, when using the existing workover tool for flushing and sand fishing operation, the sand settling speed is very fast, and the bottom flow field cannot be changed, resulting in insufficient sand returning speed and sand carrying capacity, which cannot effectively bring the sand back to the ground, and it is difficult to completely remove the sand at the bottom of the well. Not only is the single operation time long, but the production increase effect is poor, and the oil and gas production well needs to be flushed and sand fishing again in a short time, so repeated, resulting in high workover cost.

[0004] In addition, the existing workover tool has an unreasonable structure, so that during the sand fishing operation, complex accidents such as sticking and sand sinking, filling the drilling tool, and the like often occur, resulting in a large safety risk in the well.

[0005] It is urgent to solve the above problems. SUMMARY

[0006] In order to solve the technical problems that the existing workover tool is difficult to completely remove the sand at the bottom of the well and prone to safety accidents in the well, the present application provides a drilling and milling fishing workover tool.

[0007] The technical scheme is as follows:

[0008] A drilling and milling fishing workover tool, comprising a tool body in a round rod structure, the lower end of the tool body has a drilling and milling head, the outer circumferential surface of the tool body is provided with sand fishing grooves arranged side by side from bottom to top, the outer diameters of the sand fishing grooves are the same, and the grooves of the sand fishing grooves are all directed to the upper end of the tool body, the drilling and milling head protrudes from the tool body in the circumferential direction, a plurality of anti-circulation holes are arranged on the drilling and milling head in the circumferential direction, and each anti-circulation hole penetrates the upper and lower end faces of the drilling and milling head.

[0009] Compared with the prior art, the present application has the following advantages:

[0010] The drill and mill through fishing workover tool adopts the above technical scheme, by arranging multiple sand fishing grooves on the tool body, not only the sand carrying capacity of the tool is greatly improved, but also the fast sinking sand can be fished, the past sinking sand can also be brought back to the ground, so that the well bottom sand can be more thoroughly removed, the operation efficiency and the workover stimulation effect are greatly improved, the workover cycle is prolonged, the workover cost is reduced, and by additionally arranging the back circulation hole, the sand returning capacity is increased, and since the sand fishing grooves are arranged in multiple from top to bottom, the sinking sand is equivalent to being arranged in multiple from barriers, the fishing rate is more than 70%, so that the sinking sand caused downhole complex accidents such as sticking and burying of the drilling tool can be effectively avoided, and the safety risk of downhole operation is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a structural schematic view of the present application;

[0012] Figure 2 It is a sectional view of the present application when no ball is thrown;

[0013] Figure 3 It is a sectional view of the present application after the ball is thrown;

[0014] Figure 4 It is a structural schematic view of the lower end face of the drill and mill head. DETAILED DESCRIPTION

[0015] The present application is further described below in combination with the embodiments and the drawings.

[0016] As shown in Figure 1 and Figure 2 , a drill and mill through fishing workover tool mainly includes a tool body 1 in a round rod structure, the lower end of the tool body 1 is provided with a drill and mill head 2, by arranging the drill and mill head 2, the drill and mill through fishing workover tool has two functions of drilling and milling, in the embodiment, the tool body 1 and the drill and mill head 2 are integrally formed, the structural strength is high, and it is durable.

[0017] The outer circumferential surface of the tool body 1 is provided with sand fishing grooves 3 arranged side by side from bottom to top, the outer diameters of the sand fishing grooves 3 are the same, and the slots of the sand fishing grooves 3 are all directed to the upper end of the tool body 1, by arranging multiple sand fishing grooves 3 on the tool body 1, not only the sand carrying capacity of the tool is greatly improved, but also the fast sinking sand can be fished, the past sinking sand can also be brought back to the ground, so that the well bottom sand can be more thoroughly removed, the operation efficiency and the workover stimulation effect are greatly improved, the workover cycle is prolonged, the workover cost is reduced, and since the sand fishing grooves 3 are arranged in multiple from top to bottom, the sinking sand is equivalent to being arranged in multiple from barriers, the fishing rate is more than 70%, so that the sinking sand caused downhole complex accidents such as sticking and burying of the drilling tool can be effectively avoided, and the safety risk of downhole operation is greatly reduced.

[0018] Further, each of the sand troughs 3 comprises a sand trough wall 3a in a circular ring structure and a sand trough bottom 3b in a conical surface structure, the sand trough bottom 3b extending inwardly and obliquely from a lower edge of the corresponding sand trough wall 3a to the outer wall of the tool body 1. By designing the sand trough bottom 3b in a conical surface structure, the influence on the flow field of the drilling fluid can be effectively reduced, and the sand storage capacity of the sand trough 3 can be increased. Further, the oblique angle a of the sand trough bottom 3b is less than 45°, thereby further reducing the influence on the flow field of the drilling fluid and increasing the sand storage capacity of the sand trough 3.

[0019] In the embodiment, the drill milling head 2 is integrally formed with each of the sand troughs 3, and has high structural strength and is durable.

[0020] Please refer to Figures 1-3 , the drill milling head 2 protrudes from the tool body 1 in the circumferential direction, and a plurality of reverse circulation holes 4 are formed in the drill milling head 2 and distributed in the circumferential direction, each of the reverse circulation holes 4 penetrating the upper and lower end faces of the drill milling head 2. Moreover, by additionally providing the reverse circulation holes 4 on the drill milling head 2, the upward returning capacity of the sand can be increased, and the sand capture amount can be improved. In the embodiment, the reverse circulation holes 4 are arranged obliquely inward along the radial direction of the drill milling head 2 from top to bottom, thereby being able to cooperate with the sand trough bottom 3b in a conical surface structure to guide the drilling fluid carrying sand to return upward more smoothly.

[0021] Please refer to Figures 2-4 , the lower end face of the drill milling head 2 is uniformly distributed with downward protruding inserts 7. By providing the inserts 7, the drilling and milling capacity of the tool can be effectively improved. In the embodiment, the inserts 7 are preferably made of diamond, which has high hardness and can not only drill and mill relatively hard sand layers, but also easily explore the sand face wellbore, thereby being able to accurately check the sand face wellbore.

[0022] The inserts 7 are nine in total, and every three inserts 7 arranged in a ring shape form an insert group, and the three insert groups are arranged in the radial direction of the drill milling head 2 from inside to outside, thereby greatly improving the drilling and milling capacity of the tool. Among them, the included angle between the adjacent inserts 7 in each insert group is 120°. Further, the three inserts 7 of the outermost insert group protrude from the outer circumferential surface of the drill milling head 2, thereby being able to improve the drilling and milling capacity and avoid the problem of sticking.

[0023] Please refer to Figure 2 and Figure 3The tool body 1 has a central water hole 5 extending vertically along its central axis. The lower end of the central water hole 5 extends downwardly through the lower end surface of the drilling and milling head 2. The tool body 1 is divided into an upper section and a middle and lower section from top to bottom. Sand chutes 3 are axially distributed on the outer peripheral surface of the middle and lower section. The upper portion of the central water hole 5 is enlarged to form a ball-dropping section 5a. The lower end of the ball-dropping section 5a forms a conical ball-dropping seat seal 5b. Several bypass water holes 6 are circumferentially formed around the ball-dropping section 5a. The inner end of each bypass water hole 6 is connected to the ball-dropping section 5a, and the outer end of each bypass water hole 6 extends through the outer wall of the upper section of the tool. When the sealing ball 8 is not dropped, the drilling fluid mainly flows from the central water hole 5 into the wellbore at the lower end (only a small amount overflows from the bypass water hole 6), enhancing bottomhole jetting, drilling through, and water horsepower to achieve better sand flushing footage. This is particularly suitable for situations with severe bottomhole sand settling. When sealing ball 8 is dropped to block ball-dropping seat seal 5b, drilling fluid in central borehole 5 emerges from bypass boreholes 6 and flows downward, scouring the surrounding wellbore walls and forming a mixed flow with the return drilling fluid from the overall drilling fluid system. This significantly alters the bottomhole flow distribution, increases the return velocity, and improves sand-carrying capacity. Furthermore, the absence of sand bailing troughs 3 around bypass boreholes 6 prevents obstruction to the flow of drilling fluid. Therefore, this drilling, milling, and bailing workover tool performs multiple functions: drilling, milling, bailing, and bailing.

[0024] In this embodiment, the diameter of the main portion of the central water hole 5 is preferably 12 mm to 18 mm, meeting the requirements of the bottom hole flow field engineering for positive drilling and milling. A bypass valve can also be provided at the outer end of the bypass water hole 6 to prevent drilling fluid from overflowing from the bypass water hole 6 when the ball is not being dropped.

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0026] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0027] In the present application, unless otherwise explicitly specified and limited, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "over" of a first feature to a second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. "Under", "below" and "underneath" of a first feature to a second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0028] Finally, it should be noted that the above description is only for the preferred embodiments of the present application, and those of ordinary skill in the art can make various similar modifications under the inspiration of the present application without departing from the purpose and scope of the present application, and such modifications fall within the protection scope of the present application.

Claims

1. A drill and mill under-reaming workover tool comprising a tool body (1) in the form of a round bar, the lower end of the tool body (1) having a drill and mill head (2), characterised in that: The outer circumferential surface of the tool body (1) is provided with sand recovery grooves (3) arranged side by side from bottom to top, the outer diameters of the sand recovery grooves (3) are the same, and the openings of the sand recovery grooves (3) all face the upper end of the tool body (1), the drill milling head (2) protrudes from the tool body (1) in the circumferential direction, and a plurality of reverse circulation holes (4) are arranged on the drill milling head (2) in the circumferential direction, and each reverse circulation hole (4) penetrates the upper and lower end surfaces of the drill milling head (2); Each sand recovery groove (3) comprises a sand recovery groove wall (3a) in a circular ring structure and a sand recovery groove bottom (3b) in a conical surface structure, and the sand recovery groove bottom (3b) extends inwardly and obliquely from the lower edge of the corresponding sand recovery groove wall (3a) to the outer wall of the tool body (1); The oblique angle (α) of the sand recovery groove bottom (3b) is less than 45°; The reverse circulation holes (4) are arranged obliquely inwardly from top to bottom along the radial direction of the drill milling head (2); The tool body (1) is provided with a central water eye (5) penetrating the tool body (1) from top to bottom along the central axis of the tool body (1), the lower end of the central water eye (5) penetrates the lower end surface of the drill milling head (2), the tool body (1) is sequentially divided into an upper tool segment and a middle and lower tool segment from top to bottom, each sand recovery groove (3) is arranged on the outer circumferential surface of the middle and lower tool segment in the axial direction, the upper part of the central water eye (5) is expanded to form a ball launching segment (5a), the lower end of the ball launching segment (5a) forms a ball launching seat seal (5b) in a conical surface structure, and the circumferential direction of the ball launching segment (5a) is provided with a plurality of bypass water eyes (6), the inner ends of the bypass water eyes (6) are in communication with the ball launching segment (5a), and the outer ends of the bypass water eyes (6) penetrate the outer wall of the upper tool segment.

2. The drill and mill under-reaming fishing workover tool of claim 1, wherein: The lower end surface of the drill milling head (2) is uniformly provided with downward protruding inserts (7).

3. The drill and mill under-reaming fishing and workover tool of claim 2, wherein: There are nine inserts (7) in total, every three inserts (7) arranged in a ring shape form an insert group, and the three insert groups are arranged from inside to outside along the radial direction of the drill milling head (2).

4. The drill and mill under-reaming fishing and workover tool of claim 3, wherein: The three inserts (7) of the outermost insert group protrude from the outer circumferential surface of the drill milling head (2).

5. The drill and mill under-reaming fishing and workover tool of claim 1, wherein: The tool body (1) and the drill milling head (2) are integrally formed.

6. The drill and mill under-reaming and fishing workover tool of claims 1 or 5, wherein: The drill milling head (2) and the sand recovery grooves (3) are integrally formed.

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