All-metal screw drill motor and underground power drill

Abstract

The utility model provides an all-metal screw drill motor and an underground power drill, and relates to the technical field of petroleum drilling equipment, the all-metal screw drill motor comprises a motor stator and a motor rotor which are made of metal materials, and outer spiral protrusions on the motor rotor and inner spiral grooves formed in the motor stator form a conjugate meshing pair. The spiral sealing cavity is formed between the motor stator and the motor rotor, the motor stator and the motor rotor are made of metal materials, a rubber part of a drilling tool motor in the prior art is omitted, higher loads can be borne, the high-temperature screw drilling tool is more suitable for being used in high-temperature special slurry for a long time, and the problems that in the prior art, a traditional high-temperature screw drilling tool is poor in high-temperature-resistant performance and poor in sealing performance are solved. And the method is not suitable for ultra-deep oil-gas exploration and development in a high-temperature (greater than 180 DEG C) environment at the bottom of the well.

Description

Technical Field

[0001] The utility model relates to the technical field of oil drilling equipment, in particular to a full metal screw drill motor and a downhole power drill. Background Art

[0002] Screw drill tools are a type of volumetric downhole power drill tools, which are currently widely used in oil and gas drilling projects. They are mainly used for directional wells, directional deflection, directional drilling or twisting operations in horizontal wells, and can also be used in vertical well composite drilling processes to increase the mechanical drilling speed. Conventional screw drill tools mainly include four parts: a bypass valve assembly, a motor assembly, a universal shaft assembly and a drive shaft assembly. The motor assembly consists of two components: a motor stator and a motor rotor. The motor stator is a layer of vulcanized nitrile rubber bonded to the inner wall of a steel pipe through a mold injection molding process, and the motor rotor is a wear-resistant and corrosion-resistant steel screw with a hard chrome-plated surface. The main problems with the existing technology are:

[0003] First, nitrile rubber has weak physical properties and low temperature resistance (≤180°C), and is prone to swelling in special mud systems (such as white oil). These factors will cause the motor to lose power during operation, and in severe cases, the rubber will fall off prematurely and fail, reducing drilling efficiency. The existing technology can only make up for the shortcomings of insufficient rubber performance by improving the rubber formula or the structure of the rubber layer, such as using equal wall thickness technology to extend the service life of the motor stator, but it still cannot break through the technical bottleneck of rubber heat resistance. In particular, the development of drilling technology to ultra-deep formations has put forward the requirement of screw temperature resistance above 180°C, and the existing technology is even more unable to meet the needs of production.

[0004] Second, due to the low pressure holding capacity of conventional motor nitrile rubber (the pressure holding capacity of ordinary rubber motor is 0.8MPa per stage, and the pressure holding capacity of hard rubber motor is 1.55MPa per stage), in order to ensure the sealing performance of the motor, the meshing line type mostly adopts the ordinary inner cycloid outer equidistant line type, which inevitably has the phenomenon of "buckle" at local sharp corners, resulting in meshing error, which needs to be compensated by rubber deformation; in order to improve the contact condition of the stator motor rotor and reduce wear, it is necessary to increase the equidistance to increase the curvature radius, and the equidistance radius coefficient is usually around 2.0. This increases the friction of the stator motor rotor and reduces the mechanical efficiency. As the well temperature increases, the motor stator rubber expands due to heat, which aggravates the mutual interference between the stator motor rotor, increases the internal heat of the rubber, and further reduces the working efficiency.

[0005] CN115162973 A discloses an oil-resistant high temperature resistant screw drill, including a motor assembly, an anti-drop assembly, a bypass valve assembly and other structures. The screw reinforces the internal structure of the rubber bushing by supporting the ball seat; the wear resistance of the rubber bushing is improved by using the rubber wear-resistant layer; the oil resistance of the rubber bushing is improved under the action of the oil-resistant base layer, thereby increasing the service life of the rubber bushing. However, the screw drill cannot solve the problem of high temperature resistance of 180°C, and is not suitable for oil and gas exploration and development in ultra-deep layers with a bottom hole circulation temperature exceeding 180°C. Utility Model Content

[0006] The utility model aims to provide an all-metal screw drill motor and a downhole power drill to alleviate the technical problem that the traditional high-temperature screw drill in the prior art has poor high-temperature resistance and is not suitable for ultra-deep oil and gas exploration and development in a high-temperature (>180°C) environment at the bottom of the well.

[0007] In order to solve the above technical problems, the technical solution provided by the utility model is:

[0008] The all-metal screw drill motor provided by the utility model comprises: a motor stator and a motor rotor;

[0009] The motor stator is formed with an inner spiral groove;

[0010] The outer surface of the motor rotor is formed with an outer spiral protrusion;

[0011] The motor rotor extends into the inner spiral groove, and the outer spiral protrusion abuts against the inner spiral groove to form a conjugate meshing pair, so that a spiral sealing cavity is formed between the outer spiral protrusion and the inner spiral groove;

[0012] The motor stator and the motor rotor are both configured to be made of metal material.

[0013] In an alternative embodiment,

[0014] The motor stator is configured as a steel pipe, and an inner spiral surface is integrally formed inside the motor stator, and the inner spiral surface is surrounded to form the inner spiral groove.

[0015] In an alternative embodiment,

[0016] The motor rotor is configured as a steel screw.

[0017] In an alternative embodiment,

[0018] The groove wall of the inner spiral groove is provided with a strengthening layer, and the strengthening layer is used to improve the wear resistance and corrosion resistance of the surface of the inner spiral groove.

[0019] In an alternative embodiment,

[0020] The surface of the outer spiral protrusion is provided with a strengthening layer, and the strengthening layer is used to improve the wear resistance and corrosion resistance of the surface of the outer spiral protrusion.

[0021] In an alternative embodiment,

[0022] The groove wall line shape of the inner spiral groove is an outer equidistant line of a short-amplitude hypocycloid, with a short-amplitude coefficient of 0.90 to 0.99 and an equidistant radius coefficient of 0.70 to 0.85.

[0023] In an alternative embodiment,

[0024] The outer contour line shape of the outer spiral protrusion is a conjugate curve of the groove wall line shape of the inner spiral groove.

[0025] In an alternative embodiment,

[0026] The spiral directions of the motor stator and the motor rotor are both left-handed and have the same pitch.

[0027] In a second aspect, the downhole power drilling tool provided by the utility model includes the all-metal screw drilling tool motor.

[0028] Based on the above technical solutions, the technical effects that can be achieved by the utility model are:

[0029] The utility model provides a full-metal screw drill motor, comprising a motor stator and a motor rotor made of metal material. The outer spiral protrusion on the motor rotor and the inner spiral groove formed in the motor stator form a conjugate meshing pair, so that a spiral sealing cavity is formed between the motor stator and the motor rotor. The motor stator and the motor rotor are both made of metal materials, and the rubber part of the drill motor in the prior art is eliminated. The motor can withstand higher loads and is more suitable for long-term use in high-temperature special mud. The technical problem that the traditional high-temperature screw drill in the prior art has poor high-temperature resistance and is not suitable for ultra-deep oil and gas exploration and development in a high-temperature (>180°C) environment at the bottom of the well is alleviated. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A sectional view of the overall structure of the all-metal screw drill motor provided by an embodiment of the utility model;

[0032] Figure 2 for Figure 1A cross-sectional view of the structure from a side view.

[0033] Icon: 1-motor stator; 2-motor rotor; 3-inner spiral groove; 4-outer spiral protrusion. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0037] like Figure 1 , Figure 2 As shown, the all-metal screw drill motor provided in this embodiment includes: a motor stator 1 and a motor rotor 2; the motor stator 1 is formed with an inner spiral groove 3; the outer surface of the motor rotor 2 is formed with an outer spiral protrusion 4; the motor rotor 2 extends into the inner spiral groove 3, and the outer spiral protrusion 4 abuts against the inner spiral groove 3 to form a conjugate meshing pair, so that a spiral sealing cavity is formed between the outer spiral protrusion 4 and the inner spiral groove 3; the motor stator 1 and the motor rotor 2 are both set to metal materials.

[0038] Specifically, the motor stator 1 is configured as a steel tube, and an inner spiral surface is integrally formed inside the motor stator 1 , and the inner spiral surface is surrounded to form an inner spiral groove 3 , that is, the motor stator 1 is a steel tube having an integrally formed inner spiral surface inside.

[0039] The motor stator 1 is made of metal material with small thermal deformation and resistance to acid, alkali and special additives in mud. It overcomes the problems of low temperature resistance and weak ability to adapt to special mud in the existing technology. The metal-to-metal contact improves the motor's pressure holding capacity and output torque. After a large number of tests, it is found that the pressure holding capacity is 2-3 times the maximum pressure holding capacity of existing nitrile rubber.

[0040] Secondly, after the rubber layer inside the motor stator 1 is removed, the major diameter of the linear profile of the motor stator 1 increases by more than ten millimeters, thereby increasing the flow area and displacement, which is beneficial to improving the cleaning quality of the wellbore.

[0041] The motor rotor 2 is a steel screw with a surface coated with wear-resistant and corrosion-resistant material.

[0042] The metal motor stator 1 has an integrally formed inner spiral groove 3 inside, which forms a special conjugate meshing pair with the outer spiral protrusion 4 formed on the outer surface of the motor rotor 2, thereby forming a spiral sealing cavity between the motor stator 1 and the motor rotor 2.

[0043] It should be noted that the conjugate meshing pair is specifically that the outer spiral protrusion 4 can rotate eccentrically in the inner spiral groove 3, and when rotating, the outer spiral protrusion 4 always abuts against the groove wall of the inner spiral groove 3 to prevent the outer spiral protrusion 4 from rotating. Figure 1 For example, Figure 1 In the embodiment, the outer spiral protrusion 4 at the bottom is embedded in the inner spiral groove 3, and the outer spiral protrusion 4 at the top is abutted against the groove wall of the inner spiral groove 3, so that a spiral sealing cavity is formed at the top. Figure 2 For example, the outer spiral protrusion 4 on the right side is embedded in the inner spiral groove 3, and the outer spiral protrusion 4 on the left side abuts against the groove wall of the inner spiral groove 3, forming a spiral sealing cavity on the left side.

[0044] The all-metal screw drill motor provided in this embodiment includes a motor stator 1 and a motor rotor 2 made of metal materials. The outer spiral protrusion 4 on the motor rotor 2 forms a conjugate meshing pair with the inner spiral groove 3 formed in the motor stator 1, so that a spiral sealing cavity is formed between the motor stator 1 and the motor rotor 2. The motor stator 1 and the motor rotor 2 are both made of metal materials, and the rubber part of the drill motor in the prior art is eliminated. It can withstand higher loads and is more suitable for long-term use in high-temperature special muds, which alleviates the technical problem that traditional high-temperature screw drills in the prior art have poor high-temperature resistance and are not suitable for ultra-deep oil and gas exploration and development in a high-temperature (>180°C) environment at the bottom of the well.

[0045] In an optional embodiment, the groove wall of the inner spiral groove 3 is provided with a strengthening layer, which can be set as a hard coating. The strengthening layer effectively improves the wear resistance and corrosion resistance of the surface of the inner spiral groove 3. The strengthening layer can also be set as other materials as long as it can improve the wear resistance and corrosion resistance.

[0046] In an optional embodiment, a strengthening layer is provided on the surface of the outer spiral protrusion 4. The strengthening layer can be set as a hard coating. The strengthening layer effectively improves the wear resistance and corrosion resistance of the surface of the outer spiral protrusion 4. The strengthening layer can also be set as other materials as long as it can improve the wear resistance and corrosion resistance.

[0047] Providing a strengthening layer on the motor rotor 2 and the motor stator 1 can better overcome the scouring effect of mud.

[0048] In an optional embodiment, the groove wall line type of the inner spiral groove 3 is the outer equidistant line of the short-amplitude hypocycloid, with a short-amplitude coefficient of 0.90-0.99 and an equidistant radius coefficient of 0.70-0.85; the outer contour line type of the outer spiral protrusion 4 is the conjugate curve of the groove wall line type of the inner spiral groove 3. The adoption of this line type parameter can eliminate the problem of "knocking" of the line type sharp corners, does not produce meshing errors, is conducive to pure rolling, and can also obtain a larger flow area, reduce sensitivity to hard particles in the mud, and reduce the maximum sliding speed and centrifugal inertia force. The short-amplitude hypocycloid design with small equidistant can obtain a curve with smooth and continuous curvature, thereby reducing the friction loss and impact vibration under the condition of metal-to-metal hard contact between the motor stator and rotor.

[0049] Specifically, the motor stator 1 line shape is designed as a short-amplitude inner cycloid and an equidistant line, with a short-amplitude coefficient of 0.90 to 0.99 and an equidistant radius coefficient of 0.70 to 0.85. The motor rotor 2 line shape is a conjugate curve of the motor stator 1 line shape. When the screw drill stator is in an environment where the bottom hole circulation temperature is greater than 180°C (or in a special mud system), the high-pressure mud drives the motor rotor 2 to rotate in the motor stator 1, converting the liquid energy into mechanical energy. The torque and speed output by the motor are transmitted to the drill bit through the internal transmission system of the screw drill to achieve rock breaking drilling.

[0050] In an optional embodiment, the spiral directions of the motor stator 1 and the motor rotor 2 are both left-handed, and the pitches are the same.

[0051] Specifically, the spiral directions of the motor stator 1 and the motor rotor 2 are both left-handed, with the same pitch, and the number of threads of the motor stator 1 is one more than the number of threads of the motor rotor 2 .

[0052] The all-metal screw drill motor provided in this embodiment can realize the reliable operation of the metal motor. Its unique all-metal structure enables it to have the advantages of resistance to high temperatures above 180°C, resistance to special mud, high pressure holding capacity, large output torque and long service life.

[0053] The motor meshing line shape designed by the utility model is more suitable for metal-to-metal hard contact, which can increase the flow area, reduce the maximum sliding speed and the centrifugal inertia force of the rotor, reduce wear, and extend the life of the motor; plus the surface has a strengthening layer, which effectively overcomes the scouring of the parts by mud.

[0054] The downhole power drilling tool provided in this embodiment includes an all-metal screw drilling tool motor.

[0055] Since the technical effect of the downhole power drill provided in this embodiment is the same as the technical effect of the all-metal screw drill motor provided in the above embodiment, it will not be repeated here.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. An all-metal screw drill motor, characterized in that: include: A motor stator (1) and a motor rotor (2); The motor stator (1) is formed with an inner spiral groove (3); The outer surface of the motor rotor (2) is formed with an outer spiral protrusion (4); The motor rotor (2) extends into the inner spiral groove (3), and the outer spiral protrusion (4) abuts against the inner spiral groove (3) to form a conjugate meshing pair, so that a spiral sealing cavity is formed between the outer spiral protrusion (4) and the inner spiral groove (3); The motor stator (1) and the motor rotor (2) are both made of metal materials; The groove wall line shape of the inner spiral groove (3) is an outer equidistant line of a short-amplitude hypocycloid, with a short-amplitude coefficient of 0.90 to 0.99 and an equidistant radius coefficient of 0.70 to 0.85; The outer contour line shape of the outer spiral protrusion (4) is a conjugate curve of the groove wall line shape of the inner spiral groove (3).

2. The all-metal screw drill motor according to claim 1, characterized in that: The motor stator (1) is configured as a steel pipe, and an inner spiral surface is integrally formed inside the motor stator (1), and the inner spiral surface is surrounded to form the inner spiral groove (3).

3. The all-metal screw drill motor according to claim 1, characterized in that: The motor rotor (2) is configured as a steel screw.

4. The all-metal screw drill motor according to claim 1, characterized in that: The groove wall of the inner spiral groove (3) is provided with a strengthening layer, and the strengthening layer is used to improve the wear resistance and corrosion resistance of the surface of the inner spiral groove (3).

5. The all-metal screw drill motor according to claim 1, characterized in that: The surface of the external spiral protrusion (4) is provided with a strengthening layer, and the strengthening layer is used to improve the wear resistance and corrosion resistance of the surface of the external spiral protrusion (4).

6. The all-metal screw drill motor according to claim 1, characterized in that: The motor stator (1) and the motor rotor (2) are both left-handed in spiral direction and have the same pitch.

7. A downhole power drilling tool, characterized in that: It comprises a full metal screw drill motor as described in any one of claims 1-6.

Images