Well repair drill bit

Abstract

The utility model relates to the field of rotary tunneling type drill bits characterized by wear-resistant parts, in particular to a workover drill bit. The well repair drill bit comprises a drill bit body, a drilling edge is arranged at the front end of the body, a breaking jet hole is formed in the front end face of the body, a liquid flow cavity is formed in the drill bit body, a power-assisted jet hole is further formed in the cavity wall of the liquid flow cavity, the power-assisted jet hole extends from the inner circumferential wall of the body to the outer circumferential wall of the body, and the extending path is linear. The extending direction is opposite to the drilling direction; or a power-assisted spray head is embedded in the cavity wall of the liquid flow cavity, and the spraying direction of the power-assisted spray head is opposite to the drilling direction. When water flow passes through the power-assisted jet hole, the jet direction of the water flow is opposite to the drilling direction of the drill bit to form reverse thrust, and as the position of the power-assisted jet hole is close to the drilling position of the drill bit, the loss is small in the torque transmission process, so that the drill bit is pushed to accelerate the rotation speed of the drill bit, and the plug drilling efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the field of rotary drilling bits characterized by wear-resistant components, in particular to a well repair drill bit. Background Art

[0002] As oilfield development enters the later stage, well conditions are severely damaged, and casing leaks often occur. During the repair of such wells, it is often necessary to squeeze the drill plug in the leaking section. However, due to the long drill pipe, the torque of the scraper drill bit or the sleeve milling drill bit will be lost during the transmission process. The structure of the scraper drill bit or the sleeve milling drill bit means that the scraper drill bit or the sleeve milling drill bit can only rely on the friction between the blade or the high-strength alloy material laid on the bottom and the ash plug to break the ash plug during drilling. As a result, the drill bit speed is not high when drilling the ash plug, and the efficiency of breaking the ash plug is not high. In addition, the scraper drill bit or the sleeve milling drill bit cannot be changed in diameter. When the drilled hole cannot meet the demand, the drill bit can only be replaced back and forth during construction. To achieve the goal, at least two drilling plug constructions are required, and the construction times are high and the cycle is long.

[0003] Currently, there is a drill bit, such as that disclosed in Chinese invention patent publication number CN102337840A, which features a slit nozzle at the center of the front end of the drill bit to increase the force required to break the drilled object. Furthermore, an expansion drill bit is positioned behind the slit nozzle to expand the hole diameter, thus addressing the issue of frequent drilling operations. However, the drill bit still has a flat head, and the addition of the slit nozzle to break the drilled object does not significantly improve the efficiency of a single drilling pass.

[0004] Another existing drill bit, such as that disclosed in Chinese Utility Model Patent No. CN205000899U, features a tapered cutting edge, which to some extent addresses the slow drilling speed issue associated with flat-head drill bits. However, this still results in low drill speed and drilling efficiency due to torque transmission loss. Utility Model Content

[0005] The utility model aims to provide a workover drill bit to solve the problem of low drilling efficiency during well workover caused by a long drill pipe, loss of torque during torque transmission, low drill bit rotation speed and weak crushing ability.

[0006] To achieve the above objectives, the well repair drill bit of the present invention adopts the following technical solutions:

[0007] A well repair drill bit includes a drill bit body, a drilling edge is provided at the front end of the body, a crushing jet hole is provided on the front end surface of the body, a liquid flow cavity is provided in the drill bit body, and a power-boosting injection hole is provided on the cavity wall of the liquid flow cavity. The power-boosting injection hole extends from the inner circumferential wall to the outer circumferential wall of the body, the extension path is linear, and the extension direction is back to the drilling direction; or a power-boosting nozzle is buried in the cavity wall of the liquid flow cavity, and the injection direction of the power-boosting nozzle is back to the drilling direction.

[0008] Furthermore, there are multiple crushing jet holes and they are evenly arranged on the front end surface of the main body, and there are multiple power-boosting injection holes and they are evenly arranged along the circumference of the main body.

[0009] Furthermore, the plurality of boosting injection holes are all located in the same axial section.

[0010] Furthermore, a plurality of diameter-expanding blades are provided at intervals on the outer peripheral surface of the rear end of the body, and flow channels are formed between adjacent diameter-expanding blades.

[0011] Furthermore, the power-boosting injection hole is located between the diameter-expanding blade and the drilling edge.

[0012] Furthermore, the diameter-expanding blade is an arc-shaped blade.

[0013] Furthermore, a cemented carbide drilling blade is connected to the front end surface of the body, and the cutting edge of the drilling blade constitutes the drilling edge.

[0014] Furthermore, the drilling blade is welded to the front end surface of the body.

[0015] Furthermore, a mounting groove is provided on the front end surface of the body, and the drilling blade is installed in the mounting groove.

[0016] Further, the drilling edges are arranged obliquely so that each drilling edge forms an inverted cone shape.

[0017] Beneficial effects: The utility model is an improved invention for a well repair drill bit. Specifically, the utility model crushes and drills the ash plug under the assisting action of the drilling blade and the power-assisted injection hole or the power-assisted nozzle. When the water flows through the power-assisted injection hole, the water injection direction is opposite to the drilling direction of the drill bit, forming a reverse thrust. Since the position of the power-assisted injection hole is relatively close to the drilling position of the drill bit, the loss in the process of transmitting torque is not large, thereby pushing the drill bit to accelerate the rotation speed of the drill bit and improve the drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the present utility model.

[0019] In the figure: 1, upper joint, 2, expansion blade, 3, main body, 4, drilling edge, 5, jet hole, 6, power jet hole, 7, small drill body, 8, liquid flow cavity. DETAILED DESCRIPTION

[0020] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0021] The utility model aims to solve the problem that the existing well repair drill bit has a long drill rod, which causes torque loss during torque transmission and weak crushing ability, resulting in low drill bit rotation speed and limited drilling efficiency when drilling ash plugs. The utility model specifically proposes a well repair drill bit with a power-assisted injection hole or a power-assisted nozzle. Water flows through the power-assisted injection hole or the power-assisted nozzle to form a crushing force and reverse thrust, thereby pushing the drill bit to accelerate the drill bit rotation speed and improve the drilling efficiency.

[0022] Based on the above problems and inventive concepts, the utility model mainly provides power-assisted spray holes or power-assisted nozzles on the circumference and end face of the drill bit body, and sets the spray direction to assist the rotation of the drill bit and the breaking of ash plugs, thereby increasing the rotation speed and improving the drilling efficiency.

[0023] like Figure 1 As shown, in a basic embodiment, the front end of the well repair drill bit is provided with a tapered drilling blade 4. During operation, the tip of the drilling blade 4 is used to drill into the ash plug, increasing the pressure on the ash plug and thus improving drilling efficiency. At the same time, to further increase the drilling speed and improve the efficiency of a single drilling, a liquid flow cavity 8 is provided in the drill bit body. The liquid flow cavity 8 is connected to the jet hole 5. The direction of the jet hole 5 corresponds to the front side of the front end of the drilling blade 4 to form a jet. This can pre-impact the drilled object in front of the front end of the drilling blade 4 during drilling, helping to break up the ash plug and improving the efficiency of a single drilling during well repair.

[0024] During the drilling process of the drill bit, the friction between the drill bit tip and the ash plug will generate a large amount of heat. If the tip is not protected by cooling and lubricating, the life of the drill bit will be greatly shortened. The jet hole 5 forms a jet at the front side of the front end of the drilling blade 4 to ensure that the water flow ejected by the jet hole 5 can impact the drill bit tip, cool and lubricate the drill bit tip, and improve the life of the drill bit. At the same time, when the water flows through the power-assisted jet hole 6, the direction of the water flow is opposite to the drilling direction of the drill bit, forming a reverse thrust, which drives the drill bit to rotate faster, thereby increasing the drill bit speed and improving the drilling efficiency. The high-pressure water flow ejected by the jet hole 5 can also flush the mud on the drilling blade 4, preventing the ash plug mud from wrapping around the drilling blade 4 and affecting the drilling efficiency.

[0025] In a preferred embodiment, a power-boosting nozzle is buried in the wall of the liquid flow cavity. The spraying direction of the power-boosting nozzle is opposite to the drilling direction. When the water flows through the power-boosting nozzle, the water spraying direction is opposite to the drilling direction of the drill bit to form a reverse thrust, which drives the drill bit to rotate faster, thereby increasing the drill bit speed and improving the drilling efficiency.

[0026] In a preferred embodiment, the utility model has multiple power-boosting injection holes 6 that are evenly and circumferentially arranged, which can ensure that the thrust provided to the drill bit by the power-boosting injection holes 6 is even and balanced, and can avoid the danger caused by the drilling direction of the well repair drill bit being affected; in other embodiments, the well repair drill bit can be provided with only one power-boosting injection hole 6. Compared with multiple power-boosting injection holes 6, the water pressure ejected by a single power-boosting injection hole 6 will be stronger, it will be easier to break the ash plug, and it can provide greater thrust for the drill bit rotation.

[0027] Furthermore, in a preferred embodiment, the multiple power-boosting injection holes 6 are all located in the same axial cross-section to ensure uniform force on the drill bit in different directions. In other embodiments, the multiple power-boosting injection holes 6 may not be located in the same cross-section. In this case, multiple power-boosting injection holes 6 are arranged along the axial direction of the workover drill bit body, allowing the water flow to spray onto a larger area of ash plugs, thereby improving the efficiency of ash plug removal.

[0028] In a preferred embodiment, in order to achieve the required hole diameter in a single drilling, a plurality of expansion blades 2 are provided at intervals on the outer peripheral surface of the rear end of the drill body, and a flow channel is formed between adjacent expansion blades 2 so that the water flow ejected from the jet hole 5 and the booster injection hole 6 can flow back with the crushed ash plug.

[0029] In a preferred embodiment, the boosting jet hole 6 is located between the expanding blade 2 and the drilling edge 4. Since the high-pressure water flow ejected from the boosting jet hole 6 can produce the same effect of breaking up ash plugs as the high-pressure water flow ejected from the jet hole 5, it can facilitate the construction of the expanding blade 2 and improve the efficiency of eye expansion.

[0030] In a preferred embodiment, the drilling edge 4 is formed by the blade of a cemented carbide drilling blade connected to the front end. Compared to the material of the drill body, cemented carbide has higher hardness, better wear resistance, and higher temperature resistance, thereby ensuring the sharpness of the drilling edge and drilling performance, increasing the tool life and drilling efficiency.

[0031] The connection method between the drilling blade and the front end face of the drill bit should preferably be welding, which has good adaptability and strong shock resistance. Of course, in other embodiments, bolt connection can be used. In this case, if the drilling edge 4 of the well repair drill bit is damaged during actual operation, it will be more convenient to replace or repair the damaged drilling edge.

[0032] In a preferred embodiment, a mounting groove is provided on the front end face, and the drilling blade is installed in the mounting groove, which can increase the contact and connection area between the drilling blade and the drill bit body, and the fixation of the two is more reliable; in other embodiments, the drilling blade is directly connected to the front end face of the drill bit, which can reduce the processing and manufacturing costs of the well repair drill bit.

[0033] During specific implementation, the thread of the upper joint is connected to the oil pipe, the assembly is lowered to the gray surface position, and the pump circulation is started. When the pump pressure reaches a certain value, water flows through the jet hole and aligns with the tip of the drilling blade to form a jet to help break the ash plug. At the same time, the tip of the drilling blade drills the ash plug. After the drilling blade drills the channel, the expanding blade continues to expand the hole through the channel. The power-assisted jet hole sprays high-pressure water to help break the ash plug and provide reverse thrust for the drill bit to increase the drill bit speed. The water sprayed from the jet hole and the power-assisted jet hole flows back to the top of the well repair drill bit through the flow channel, thereby realizing the efficient drilling of the lost section during well repair by the utility model.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. The scope of patent protection of the present invention shall be based on the claims. Any equivalent structural changes made using the description and drawings of the present invention shall also be included in the scope of protection of the present invention.

Claims

1. A well repair drill bit, comprising a body, a drilling edge provided at the front end of the body, a crushing jet hole provided at the front end surface of the body, and a liquid flow cavity provided in the body, characterized in that: A power-boosting spray hole is also provided on the wall of the liquid flow cavity, and the power-boosting spray hole extends from the inner wall to the outer wall of the main body, the extension path is linear, and the extension direction is back to the drilling direction; or a power-boosting nozzle is buried in the wall of the liquid flow cavity, and the injection direction of the power-boosting nozzle is back to the drilling direction.

2. The well repair drill bit according to claim 1, characterized in that: There are multiple crushing jet holes and they are evenly arranged on the front end surface of the body, and there are multiple boosting injection holes and they are evenly arranged along the circumference of the body.

3. The well repair drill bit according to claim 2, characterized in that: The plurality of boosting injection holes are all located in the same axial section.

4. The well repair drill bit according to any one of claims 1 to 3, characterized in that: A plurality of diameter-expanding blades are arranged at intervals on the outer peripheral surface of the rear end of the body, and flow channels are formed between adjacent diameter-expanding blades.

5. The well repair drill bit according to claim 4, characterized in that: The power-boosting injection hole is located between the diameter-expanding blade and the drilling edge.

6. The well repair drill bit according to claim 4, characterized in that: The diameter-expanding blade is an arc-shaped blade.

7. The well repair drill bit according to claim 1, characterized in that: The front end surface of the body is connected with a cemented carbide drilling blade, and the cutting edge of the drilling blade constitutes the drilling edge.

8. The well repair drill bit according to claim 7, characterized in that: The drilling blade is welded to the front end surface of the body.

9. The well repair drill bit according to claim 8, characterized in that: A mounting groove is provided on the front end surface of the body, and the drilling blade is installed in the mounting groove.

10. The well repair drill bit according to claim 1, wherein: The drilling edges are arranged obliquely so that each drilling edge forms an inverted cone shape.

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