A method for forming the internal curved flow channel of a PDC drill bit.

Abstract

This invention discloses a method for forming an internal curved flow channel in a PDC (Polymer Diode Cartridge) drill bit. First, a specially shaped bend is designed and fabricated, with dimensions identical to the curved flow channel. Second, the specially shaped bend is assembled into the drill bit mold and temporarily sealed. Then, material is loaded into the drill bit mold and sintered. Finally, the mold is opened to remove the temporary seal, forming the curved flow channel. The specially shaped bend is formed using 3D printing or hot bending. The 3D printing material is nickel-based tungsten carbide, nickel-based high-temperature alloy, or steel, while the hot bending material is low-carbon steel or low-carbon alloy seamless steel pipe. Before assembly with the drill bit mold, the bend is filled with resin sand and cured at 200-300℃. The process of loading, sintering, and mold cleaning produces a precision-controlled internal curved flow channel. This invention provides a new solution for installing high-pressure or ultra-high-pressure nozzles on the cutter wings of a PDC drill bit, significantly improving downhole rock-breaking efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil drilling bits. More particularly, the present application relates to a method for forming an internal curved flow channel of a matrix PDC bit. BACKGROUND

[0002] PDC bits are widely used in oil drilling and have the characteristics of long footage and high drilling speed with the rapid development of polycrystalline diamond compact technology. Matrix PDC bits have the advantages of erosion resistance and wear resistance and have good application effects in some hard formations. With the increasing drilling activities of global oil and gas deep wells, horizontal wells and special process wells, the demand for special bits is also increasing.

[0003] Drilling engineering practices at home and abroad show that the combined rock breaking mode of high-pressure jetting drilling fluid hydraulic rock breaking and bit cutting tooth mechanical rock breaking by using downhole supercharging devices can greatly improve the drilling efficiency of deep formations. This requires the drilling fluid to be divided into two branches, one of which is used as normal pressure drilling fluid and transmitted to the bottom of the well through the bit slurry hole and the conventional nozzle, and the other is used to output high-pressure or super-high pressure drilling fluid through the downhole supercharging device, high-pressure pipe and the internal special curved flow channel of the bit, so as to realize mechanical and hydraulic combined rock breaking and greatly improve the rock breaking efficiency.

[0004] In order to achieve the best hydraulic rock breaking effect, the outlet of the high-pressure or super-high pressure drilling fluid flow channel is usually designed at the nose or shoulder position of the PDC bit, and the azimuth relationship with the compact and the jet angle of the flow channel are precisely required, so the size and angle of the internal curved flow channel of the bit are highly required, especially how to form a precise curved flow channel in the internal matrix PDC bit is one of the key problems in the implementation of the technology.

[0005] Chinese utility model patent CN2410409Y mentions a matrix PDC comprehensive drilling curved flow channel bit, which is characterized in that the flow channel between the steel core hollow core and the nozzle is designed as a curved flow channel, thereby increasing the jet angle. The curved flow channel described in the patent is only made into a curved shape from the conventional flow channel, which cannot be applied to high-pressure or super-high pressure jet flow channels, and the specific forming method of the curved flow channel is not mentioned. SUMMARY

[0006] An object of the present application is to provide a method for forming an internal curved flow channel of a matrix PDC bit, which provides a new scheme for installing high-pressure or super-high pressure nozzles on the bit wing of a matrix bit, and is beneficial to greatly improving the downhole rock breaking efficiency.

[0007] To achieve these objectives and other advantages according to the present invention, a method for forming a curved flow channel inside a PDC drill bit is provided. First, a specially shaped bend is designed and prepared, which is exactly the same as the shape and size of the curved flow channel. Second, the specially shaped bend is assembled into the drill bit mold and temporarily sealed. Then, material is loaded into the drill bit mold and sintered. Finally, the mold is opened to remove the temporary seal of the specially shaped bend, forming the curved flow channel.

[0008] Preferably, a three-dimensional model of the curved flow channel is designed according to its shape and size, and then a specially shaped curved pipe is prepared by 3D printing or hot bending based on the three-dimensional model.

[0009] Preferably, the 3D printing material is a nickel-based high-temperature alloy, a nickel-based tungsten carbide, or steel, and the hot bending material is steel.

[0010] Preferably, before assembling the special-shaped bend with the drill bit mold, resin sand is filled into the special-shaped bend and cured at a temperature of 200-300℃.

[0011] Preferably, after the specially shaped bend is assembled, one end is connected to the center of the drill bit slurry hole, and the other end is sealed and fixed inside the drill bit mold by a special graphite substitute rod.

[0012] Preferably, the special graphite substitute rod is stepped, with one end fitting perfectly into a specially shaped bend, and the other end connected to the drill bit mold, and its diameter is consistent with the diameter of the high-pressure or ultra-high-pressure nozzle.

[0013] Preferably, a conventional graphite substitute rod is also installed inside the drill bit mold to form a conventional nozzle flow channel, and the distance between the specially shaped bend and the inner wall of the drill bit mold and the conventional graphite substitute rod is not less than 10mm.

[0014] Preferably, the filling of the drill bit mold is carried out in the cavity formed by the drill bit mold, the steel core, and the prepared special-shaped bent tube. Specifically, tungsten carbide powder, crystalline tungsten powder, and copper alloy bonding metal are filled in sequence. During the filling of tungsten carbide powder and crystalline tungsten powder, multiple vibrations are performed to ensure compaction. The vibration intensity is gradually increased from small to large, the vibration frequency is 50-100Hz, and the amplitude is 1.0-2.5mm. The sintering process is carried out in a sintering furnace with a temperature of 1175℃-1195℃, a pressureless impregnation process for 1-3 hours, and directional cooling of the bottom of the mold after exiting the furnace.

[0015] Preferably, the mold opening and cleaning process involves opening the drill bit mold, removing the special graphite substitute rod and the conventional graphite substitute rod using a hand drill, sandblasting the drill bit body and the curved flow channel, and blowing the curved flow channel with compressed air to remove loose resin sand, thus forming an internal curved flow channel that penetrates the drill bit slurry hole and the drill bit blades.

[0016] Preferably, the outer surface of the specially shaped bend is sandblasted before assembly to remove oxide scale and contaminants.

[0017] The present invention has at least the following beneficial effects:

[0018] 1. The method for forming curved flow channels inside the PDC drill bit described in this invention can form curved flow channels with precise size and shape inside the PDC drill bit, making it possible to install high-pressure or ultra-high-pressure nozzles with special injection angle requirements on the drill bit blades. This is conducive to the promotion and application of downhole pressurization devices and can significantly improve downhole rock breaking efficiency.

[0019] 2. The 3D printing of nickel-based tungsten carbide tubes or nickel-based high-temperature alloy tubes and hot bending of seamless steel tubes in this invention can ensure the accuracy of the dimensions and angles of the bent flow channels after sintering, creating conditions for the subsequent connection of high-pressure or ultra-high-pressure tubes.

[0020] 3. The curved flow channel forming method of the present invention does not affect the external structure and conventional function of the matrix PDC drill bit, nor does it affect the performance of the drill bit. It provides a convenient forming method for the complex-shaped curved flow channels inside the matrix PDC drill bit.

[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the curved flow channel of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0024] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 invention 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 invention.

[0025] like Figure 1 As shown, the present invention provides a method for forming the internal curved flow channel of a PDC drill bit, comprising the following steps:

[0026] Design a 3D model of a curved flow channel - fabricate a specially shaped bent pipe - assemble the drill bit mold with the specially shaped bent pipe - load and sintering - mold opening and cleaning.

[0027] The specially shaped bend is designed based on the three-dimensional curvature of the drill bit's internal flow channel. One end connects to the center of the bottom of the drill bit's slurry hole, and the other end connects to the nose or shoulder of the drill bit's cutter wing. It is formed by 3D printing or hot bending, and its dimensions and angles meet the requirements of the three-dimensional model. The 3D printing material is selected from nickel-based tungsten carbide, nickel-based high-temperature alloys, or steel, while the hot bending material is selected from steel, such as low-carbon steel or low-carbon alloy steel seamless steel pipe.

[0028] Before being assembled with the drill bit mold, the specially shaped bend is filled with resin sand and cured at 200-300℃ to prevent molten metal from seeping into the bend and clogging the hole during the sintering process. After sintering, loose sand particles are formed to facilitate mold opening and cleaning.

[0029] Before assembly, the outer surface of the specially shaped bend is sandblasted to remove oxide scale and contaminants, ensuring a good metallurgical bond between the outer surface of the specially shaped bend 3 and the matrix. One end of the specially shaped bend is connected to the center of the drill bit slurry hole 4, and the other end is connected to one end of the drill bit blade. During assembly, it is fixed to the bottom of the drill bit mold by connecting it with a special graphite substitute rod 1. The special graphite substitute rod is stepped; the thinner part passes through the specially shaped bend, is sintered, and then drilled through by the drill bit. The thicker part connects to the drill bit mold, and its diameter is consistent with the diameter of the high-pressure or ultra-high-pressure nozzle. It is subsequently drilled to form a hole for fixing the high-pressure or ultra-high-pressure nozzle. A conventional graphite substitute rod 2 is installed at the bottom of the drill bit mold 5 to form a conventional nozzle flow channel. The drill bit mold is assembled with the specially shaped bend. The drill bit mold is made of graphite and ensures that the distance between the specially shaped bend 3 and the inner wall of the drill bit mold 5, as well as the conventional graphite substitute rod 2, is not less than 10mm to prevent erosion and leakage of the high-pressure curved flow channel during subsequent use.

[0030] After the special-shaped bent tube 3 and drill bit mold 5 are assembled, the material loading process is carried out. Material loading involves sequentially filling the cavity formed by the drill bit mold, the steel core (sintered inside the drill bit mold, with a joint for easy subsequent processing and connection), and the prepared special-shaped bent tube with tungsten carbide powder, crystalline tungsten powder, and copper alloy bonding metal. During the filling of tungsten carbide and crystalline tungsten powder, multiple vibrations are required to compact the powder. The vibration intensity should be gradually increased from low to high, with a vibration frequency of 50-100Hz and an amplitude of 1.0-2.5mm, to avoid displacement or damage to the assembled special-shaped bent tube 3. Sintering involves heating at 1175℃-1195℃ in a sintering furnace after material loading, holding at that temperature for 1-3 hours for pressureless impregnation, and then directional cooling of the bottom of the mold after exiting the furnace.

[0031] Mold opening and cleaning involves opening the drill bit mold, using a suitable-sized electric drill to remove special graphite substitute rod 1 and conventional graphite substitute rod 2, sandblasting the drill bit body and curved flow channels, and using compressed air to blow away the curved flow channels to remove loose resin sand, forming an internal curved flow channel that penetrates the drill bit slurry hole and drill bit blades.

[0032] In the process of forming the curved flow channel of the present invention, a special-shaped curved tube is prepared by 3D printing of nickel-based tungsten carbide or nickel-based high-temperature alloy or by hot bending of seamless steel pipes of carbon steel or low-carbon alloy steel. Before assembly, resin sand is filled into the curved tube for curing. During the sintering process, the curved tube is pre-embedded in fillers such as tungsten carbide powder for sintering. After sintering, the outer circle of the special-shaped curved tube forms a good bond with the matrix, and the resin sand inside the special-shaped curved tube is loosened to form a curved flow channel inside the matrix with precise size and shape.

[0033] Example 1: A method for forming the internal curved flow channel of a PDC drill bit, comprising the following steps: designing a three-dimensional model of the curved flow channel - preparing a specially shaped bent tube - assembling the drill bit mold with the specially shaped bent tube - loading and sintering - mold opening and cleaning.

[0034] First, the special-shaped bend 3 is 3D printed using nickel-based tungsten carbide or nickel-based high-temperature alloy, and its size and angle meet the requirements of the three-dimensional model.

[0035] Secondly, one end of the special-shaped bend 3 is connected to the center of the drill bit slurry hole 4, and the other end of the special-shaped bend 3 is fixed to the bottom of the drill bit mold 5 after being connected to a special graphite substitute rod 1. Before assembling the special-shaped bend 3 with the drill bit mold 5, resin sand is filled into the special-shaped bend 3 and cured at a temperature of 200-300℃ to prevent molten metal from seeping into the special-shaped bend during the sintering process and clogging the hole. After sintering, loose sand particles are formed to facilitate mold opening and cleaning.

[0036] Then, after the special-shaped bend 3 is assembled with the drill bit mold 5, tungsten carbide powder is filled into the drill bit mold 5 and vibrated multiple times to ensure compaction. The vibration intensity should be increased slowly from small to large, with a vibration frequency of 50-100Hz and an amplitude of 1.0-2.5mm, to avoid displacement or damage to the assembled special-shaped bend 3. Then, crystalline tungsten powder and copper alloy bonding metal are sequentially filled into the drill bit mold 5. The mold is then heated at 1175℃-1195℃ in a sintering furnace, held at the temperature for 1-3 hours for pressureless impregnation, and then directionally cooled at the bottom of the mold after exiting the furnace.

[0037] Finally, open the drill bit mold 5, use a suitable electric drill to remove the special graphite substitute rod 1 and the conventional graphite substitute rod 2, sandblast the drill bit body and curved flow channel, and use compressed air to blow away the curved flow channel to remove loose resin sand, forming an internal curved flow channel that penetrates the drill bit slurry hole and drill bit blades.

[0038] Example 2: A method for forming the internal curved flow channel of a PDC drill bit, comprising the following steps: designing a three-dimensional model of the curved flow channel - preparing a special-shaped curved tube - assembling the drill bit mold with the special-shaped curved tube - loading and sintering - mold opening and cleaning.

[0039] The difference from Example 1 is that the special-shaped bend 3 is made of seamless steel pipe of low carbon steel or low carbon alloy steel by hot bending, and its size and angle meet the requirements of the three-dimensional model. The remaining steps are the same as in Example 1.

[0040] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method of forming an internal curved flow channel of a matrix PDC bit, the curved flow channel for transporting high or ultra-high pressure drilling fluid, characterized by, Firstly, a three-dimensional model of the curved flow channel is designed according to the shape and size of the curved flow channel, and then the special-shaped elbow pipe which is completely the same as the shape and size of the curved flow channel is prepared by 3D printing or hot bending forming based on the three-dimensional model; Secondly, the special-shaped elbow pipe is assembled into the drill bit mold and temporarily sealed; before the special-shaped elbow pipe is assembled, resin sand is filled in the special-shaped elbow pipe and cured at a temperature of 200-300 DEG C; after the special-shaped elbow pipe is assembled, one end is connected to the center of the drill bit hole, and the other end is fixed in the drill bit mold by sealing connection through a special graphite substitute rod; the special graphite substitute rod is a stepped type, one end of which is matched in the special-shaped elbow pipe, and the other end is connected to the drill bit mold, and the diameter is consistent with that of the high-pressure or super-high-pressure nozzle, and the subsequent drilling forms a hole for fixing the high-pressure or super-high-pressure nozzle; Then, the drill bit mold is filled with materials and sintered; wherein, a conventional graphite substitute rod is also installed in the drill bit mold to form a conventional nozzle flow channel; Finally, the mold is opened and cleaned, the drill bit mold is opened, the special graphite substitute rod and the conventional graphite substitute rod are removed by using a hand drill, the drill bit body and the curved flow channel are sandblasted and cleaned, and the curved flow channel is blown by compressed air to clean out the loose resin sand, forming an internal curved flow channel through the drill bit hole and the drill bit wing.

2. The method of claim 1, wherein the inner curved flow channel of the matrix PDC bit is formed by the steps of: The 3D printing material is selected from nickel-based high-temperature alloy, nickel-based tungsten carbide or steel material, and the hot bending material is steel material.

3. The method of claim 1, wherein the inner curved flow channel of the matrix PDC bit is formed by the steps of: The distance between the special-shaped elbow pipe and the inner wall of the drill bit mold and the conventional graphite substitute rod is not less than 10 mm.

4. The method of claim 1, wherein the inner curved flow channel of the matrix PDC bit is formed by the steps of: The material filling in the drill bit mold is carried out in the cavity formed by the drill bit mold, steel core and prepared special-shaped elbow pipe, specifically: tungsten carbide powder, crystalline tungsten powder and copper alloy binder metal are filled in turn, the tungsten carbide powder and crystalline tungsten powder are vibrated multiple times to ensure compaction, the vibration intensity is slowly increased from small to large, the vibration frequency is 50-100 Hz, and the amplitude is 1.0-2.5 mm; the sintering forming is specifically: the pressureless impregnation process of heating at a temperature of 1175 DEG C-1195 DEG C and 1-3 hours of holding is carried out in the sintering furnace, and the mold bottom is directionally cooled after the furnace is discharged.

5. The method of claim 1, wherein the inner curved flow channel of the matrix PDC bit is formed by the steps of: The outer surface of the special-shaped elbow pipe is sandblasted and cleaned before assembly to remove oxidation scale and contaminants.

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