Whipstock assembly for ultra-short radius lateral drilling

Abstract

The present application relates to a kind of ultra-short radius side tracking well build-in device, including flexible drill pipe, center flow passage is arranged in the inside of flexible drill pipe, the lower end of flexible drill pipe is connected with drill bit, and the end of drill bit is provided with mud overflow hole being communicated with center flow passage;Sealing cavity is fixed in the center flow passage close to drill bit, and well inclination data acquisition unit and pressure pulse generation unit are arranged in sealing cavity, wherein, well inclination data acquisition unit is used to obtain well inclination data in build-in process, to obtain control pulse according to well inclination data, pressure pulse generation unit is used to adjust mud flow through mud overflow hole according to control pulse, to generate corresponding mud pressure pulse, to decode build-in information after ground receives mud pressure pulse.The ultra-short radius side tracking well build-in device of the present application is by setting well inclination data acquisition unit and pressure pulse generation unit in limited space, the purpose of real-time acquisition build-in data is realized, and build-in situation is conveniently understood and mastered.

Description

Technical Field

[0001] This invention belongs to the field of ultra-short radius drilling technology, specifically relating to an ultra-short radius side-drilling directional drilling device. Background Technology

[0002] In old wells, horizontal wells can be drilled sideways to directly exploit remaining oil-rich areas or untapped reservoirs. This method has the advantages of low cost, high production efficiency, and can effectively improve the recovery rate.

[0003] However, while sidetracking utilizes the existing wellbore to reach the target area, it also causes some damage to the casing. Existing methods mostly employ coiled tubing sidetracking of horizontal wells, with build-up sections reaching tens or even hundreds of meters in length. This results in poor turning ability, large damage area to the casing, and difficult maintenance. To overcome these shortcomings, an ultra-short radius drilling method has been proposed.

[0004] Sidetracking operations include window opening, window repair, directional drilling, and horizontal drilling. Among these processes, the directional drilling process is closely related to the wellbore trajectory. It is necessary to transition the wellbore trajectory from a near-vertical state to a horizontal state based on window opening and window repair. Therefore, real-time understanding and control of the directional drilling situation is an essential technology. Summary of the Invention

[0005] To address all or some of the aforementioned problems, the present invention aims to provide an ultra-short radius side-drilling directional drilling device, which, through the configuration of a well inclination data acquisition unit and a pressure pulse generation unit, enables real-time monitoring of the directional drilling situation.

[0006] According to one aspect of the present invention, an ultra-short radius side drilling directional drilling device is provided, comprising a flexible drill pipe composed of a plurality of flexible short sections, wherein a central flow channel is provided inside the flexible drill pipe, a drill bit is connected to the lower end of the flexible drill pipe, and a mud flow hole communicating with the central flow channel is provided at the end of the drill bit;

[0007] A sealed cavity is fixed inside the central flow channel near the drill bit. The sealed cavity is equipped with a well inclination data acquisition unit and a pressure pulse generation unit. The well inclination data acquisition unit is used to acquire well inclination data during the well inclination process so as to obtain control pulses based on the well inclination data. The pressure pulse generation unit is used to adjust the mud flow rate through the mud flow hole according to the control pulses so as to generate corresponding mud pressure pulses so that the surface can receive the mud pressure pulses and decode the well inclination information.

[0008] Furthermore, the well deviation data acquisition unit is a triaxial acceleration sensor assembly installed in the sealed cavity, and the triaxial acceleration sensor assembly consists of three acceleration sensors.

[0009] Furthermore, the pressure pulse generating unit includes a battery pack, a drive motor, and a control circuit disposed within the sealed cavity. The battery pack supplies power to the control circuit, which in turn controls the drive motor. The lower end of the drive motor shaft extends out of the sealed cavity and is fixedly connected to a toothed disc. A throttling cylinder is fixedly connected inside the drill bit. Several mud holes are formed on the bottom of the throttling cylinder. The toothed disc is located inside the throttling cylinder and contacts the bottom of the cylinder. The rotation of the drive motor can cause the toothed disc to block the mud holes, or cause the toothed disc not to block the mud holes.

[0010] Furthermore, a plurality of the mud holes are evenly distributed on the throttling cylinder, the gear disc includes an annular block and a blocking block fixed on the outer circumference of the annular block, the blocking block can block the mud holes, the annular block is fixed on the motor shaft of the drive motor, the number of blocking blocks is equal to the number of mud holes, and the blocking blocks are evenly arranged.

[0011] Furthermore, the toothed disc has an arc-shaped groove, and a limiting pin is fixedly connected to the bottom of the throttling cylinder. The limiting pin is located in the arc-shaped groove and is used to limit the extreme rotation angle of the toothed disc from one extreme position to another. When the toothed disc rotates to one of the extreme positions, the area of ​​the toothed disc blocking the mud hole is the largest. When the toothed disc rotates to the other extreme position, the toothed disc does not block the mud hole.

[0012] Furthermore, the limit rotation angle of the gear disc is 45 degrees, and the maximum blocking area of ​​the gear disc covering the mud hole is 20% of the maximum flow area of ​​the mud hole; a reduction unit is provided in the sealed cavity, the drive motor is connected to the reduction unit, and the output shaft of the reduction unit is connected to the gear disc through a connecting pin; the number of mud flow holes is equal to the number of mud holes, and each mud hole is directly opposite a mud flow hole.

[0013] Furthermore, the control circuit includes a first transistor, a second transistor, a first relay, and a second relay, wherein the first transistor conducts to energize the coil of the first relay, and the second transistor conducts to energize the coil of the second relay.

[0014] The first relay has two contacts: first relay contact one and first relay contact two; the second relay has two contacts: second relay contact one and second relay contact two.

[0015] The fixed C terminal of the first relay contact is connected to the movable B terminal of the second relay contact and the movable A terminal of the second relay contact. The movable A terminal of the first relay contact is connected to the positive terminal of the battery pack, and the movable B terminal of the first relay contact is left unconnected.

[0016] The fixed C terminal of the first relay contact 2 is connected to the movable A terminal of the second relay contact 1 and the movable B terminal of the second relay contact 2. The movable A terminal of the first relay contact 2 is connected to the negative terminal of the battery pack, and the movable B terminal of the first relay contact 2 is left unconnected.

[0017] The C fixed terminal of the second relay contact one is connected to the + pin of the drive motor, and the C fixed terminal of the second relay contact two is connected to the - pin of the drive motor.

[0018] When the coil of the first relay is energized, the fixed C terminal of the first relay contact one is connected to the movable A terminal of the first relay contact one, and the fixed C terminal of the first relay contact two is connected to the movable A terminal of the first relay contact two.

[0019] When the coil of the second relay is energized, the fixed C terminal of the second relay contact one is connected to the movable A terminal of the second relay contact one, and the fixed C terminal of the second relay contact two is connected to the movable A terminal of the second relay contact two.

[0020] Furthermore, each of the flexible subsections includes a ball head, and the upper end of each ball head is connected to an outer sleeve via a torque pin. The uppermost outer sleeve is fixedly connected to an upper connector, and the lower end of the lowermost ball head is fixedly connected to a lower connector, which is fixedly connected to the drill bit. The lower end of each of the remaining ball heads is fixedly connected to a connecting sleeve, and each connecting sleeve is fixedly connected to the outer sleeve below it. A gap is provided between each torque pin and the ball head, between the lowermost outer sleeve and the lower connector, and between each of the remaining outer sleeves and the connecting sleeve below them to allow the flexible drill rod to bend.

[0021] Furthermore, the sealed cavity is disposed within the space formed by the lowest ball head, the lower connector, and the drill bit.

[0022] Furthermore, the sealed cavity includes a measurement and control housing, which is fixed in the central flow channel near the drill bit. The upper end of the measurement and control housing is sealed with a connecting structure. The connecting structure is a connecting nut, and a sealing ring is provided between the connecting nut and the measurement and control housing. A wrench hole is provided on the side of the connecting nut away from the measurement and control housing.

[0023] Furthermore, the outer side of the measurement and control housing is fitted with an upper stabilizing plate and a lower stabilizing plate, both of which are provided with through holes for mud to pass through; the lower stabilizing plate is limited between the lower connector and the drill bit, and the lower stabilizing plate is fixedly connected to the measurement and control housing.

[0024] Furthermore, the drill bit is provided with axial cutting teeth and lateral cutting teeth. The axial cutting teeth are evenly distributed at the lower end of the drill bit, and the lateral cutting teeth are used to generate lateral cutting force.

[0025] As can be seen from the above technical solution, the ultra-short radius side-drilling directional drilling device provided by the present invention has the following beneficial effects:

[0026] The ultra-short radius side-drilling directional drilling device of the present invention achieves the purpose of real-time acquisition of directional drilling data by setting up a well inclination data acquisition unit and a pressure pulse generation unit in a limited space, which facilitates real-time understanding and control of the directional drilling situation. Attached Figure Description

[0027] Figure 1 A schematic diagram illustrating the relationship between flexible short sections and curved pipes;

[0028] Figure 2 This is a cross-sectional view of the ultra-short radius side-drilling directional drilling device according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram showing the toothed disc not blocking the mud hole.

[0030] Figure 4 A schematic diagram showing the shielding of the mud hole by the gear disc;

[0031] Figure 5 This is a schematic diagram of the control circuit of an embodiment of the present invention (the drive motor is not rotating at this time);

[0032] Figure 6 This is a schematic diagram of the control circuit of an embodiment of the present invention (the drive motor rotates in one direction at this time);

[0033] Figure 7 This is a schematic diagram of the control circuit of an embodiment of the present invention (the drive motor is rotating in another direction at this time);

[0034] The attached figures are labeled as follows: 1. Drill bit; 2. Mud flow hole; 3. Lateral cutting tooth; 4. Throttle tube; 5. Mud hole; 6. Gear disc; 7. Lower centering plate; 8. Battery pack; 9. Measurement and control housing; 10. Reduction unit; 11. Anti-rotation pin; 12. Drive motor; 13. Triaxial accelerometer sensor assembly; 14. Control circuit; 15. Connecting nut; 16. Sealing ring; 17. Wrench hole; 18. Axial cutting tooth; 19. Connecting sleeve; 20. Ball head; 21. Lower connector; 22. Upper centering plate; 23. Upper connector; 24. Outer sleeve; 25. Spring retainer; 26. Torque pin; 27. Sealing ring; 28. Connecting pin; 29. ​​Limiting pin; 30. Arc groove. Detailed Implementation

[0035] To better understand the purpose, structure, and function of this invention, the following detailed description of an ultra-short radius side-drilling directional drilling device of this invention is provided in conjunction with the accompanying drawings.

[0036] The ultra-short radius in this invention refers to a build-up curvature radius of 1.25m-3.6m. In the prior art, sidetracking tools with this curvature radius are rare, and no related pressure pulse generators have been reported. Drilling tools suitable for this curvature radius require special flexible drill pipes. Taking a build-up section with a curvature radius R1 of 1.25m, an inner diameter d1 of 152.5mm, and a maximum diameter of 144mm for the flexible sub as an example, then... Figure 1 As shown, the midpoint gap Δ between the curved pipe and the single flexible drill rod section can be obtained:

[0037] Δ=d1-d2=152.5mm-144mm=8.5mm,

[0038] Therefore, the limit length L1 of the flexible short section that can pass through the curved pipe can be obtained:

[0039]

[0040] By substituting the values ​​into the calculation, L1 equals 300mm, meaning the limit length of the flexible short section that can pass through a curved pipe with a radius of curvature R1 of 1.25m and an inner diameter d1 of 152.5mm is 300mm. Within a length of 300mm, it is difficult to place the pulse generator and well inclination measurement components, thus making it impossible to obtain real-time inclination information during the well inclination process.

[0041] To overcome the shortcomings of existing technologies that cannot arrange pulse generators and wellbore deviation measurement components within a short limit length range, this invention proposes an ultra-short radius side-drilling directional drilling device, such as... Figure 2As shown, the directional drilling device includes a flexible drill pipe composed of several flexible short sections. A central flow channel is provided inside the flexible drill pipe. The lower end of the flexible drill pipe is connected to a drill bit 1. The end of the drill bit 1 is provided with a mud flow hole 2 communicating with the central flow channel. A sealed cavity is fixed in the central flow channel near the drill bit 1. The sealed cavity is equipped with a well inclination data acquisition unit and a pressure pulse generation unit. The well inclination data acquisition unit is used to acquire well inclination data during the directional drilling process so as to obtain control pulses based on the well inclination data. The pressure pulse generation unit is used to adjust the mud flow rate through the mud flow hole 2 according to the control pulses to generate corresponding mud pressure pulses so that the surface can receive the mud pressure pulses and decode the directional drilling information.

[0042] Specifically, in this embodiment of the invention, the non-bendable space at the lower end of the directional drilling device near the drill bit 1 is utilized. By setting up a well inclination data acquisition unit and a pressure pulse generation unit in this space, real-time directional drilling data during the directional drilling process can be acquired.

[0043] The well inclination data acquisition unit is used to acquire well inclination data during the well inclination process so as to obtain control pulses based on the well inclination data. The pressure pulse generation unit is used to adjust the mud flow rate through the mud flow hole 2 according to the control pulse to generate corresponding mud pressure pulses. After the ground receives the mud pressure pulses, it can decode the well inclination information, thereby realizing the purpose of inclination measurement at the drill bit 1 and timely guiding the leading edge trajectory during the well inclination process.

[0044] The settings of this invention enable real-time acquisition of orienteering data, facilitating real-time understanding and control of orienteering conditions.

[0045] In one specific embodiment, the well deviation data acquisition unit is a triaxial acceleration sensor assembly 13 disposed in a sealed cavity, which consists of three acceleration sensors.

[0046] This invention, designed for the characteristics of ultra-short radius directional drilling, omits components such as fluxgates and uses a triaxial accelerometer assembly 13 to measure well inclination, reducing the volume and achieving the goal of measuring well inclination at drill bit 1. This allows for timely guidance of the leading edge trajectory during the directional drilling process based on the measured well inclination.

[0047] Specifically, the accelerometer in this embodiment is a microgravity accelerometer, capable of detecting minute changes in gravity, with a resolution of μg. For example, an HQA-T 185S accelerometer is used. Since the azimuth of the sidetracking is determined before drilling and positioned using sidetracking tools, only the well inclination needs to be measured to understand the wellbore deviation. The well inclination angle DEV can be obtained from the gravitational accelerations gx, gy, and gz in the X, Y, and Z directions using a triaxial accelerometer.

[0048]

[0049] Furthermore, the signal output by the accelerometer can be either an analog signal or a digital signal. For analog signals, after digital-to-analog conversion, the pulse generation circuit processes them to generate a related pulse signal. For digital signals, the pulse generation circuit directly generates a related pulse signal, which is the control pulse.

[0050] Specifically, the method for obtaining control pulses based on the accelerometer signal is as follows: The accelerations measured by the sensor in the X, Y, and Z directions are converted into binary codes, such as the decimal number "185" being converted into binary "10111001". To achieve measurement accuracy, the resolution is expressed in μg. The measured data is pre-amplified by a certain factor, and the amplified data is still represented in binary form. For example, 185.4321 magnified 10000 times becomes 1854321, corresponding to the binary code "111000100101101110001". The accelerations in the X, Y, and Z directions are processed in the same way, generating 8-bit binary codes sequentially. In the binary code, "1" indicates the generation of a pressure pulse, and "0" indicates no pulse generation. Each bit is generated at a certain time interval. For example, each bit corresponds to a time of 0.1 seconds. For the binary code 1001, the first 0.1 seconds generates a pressure pulse, the second and third 0.1 seconds do not generate a pressure pulse, and the fourth 0.1 seconds generates a pressure pulse. This achieves the goal of obtaining control pulses based on well inclination data.

[0051] In one specific embodiment, the pressure pulse generating unit includes a battery pack 8, a drive motor 12, and a control circuit 14 disposed in a sealed cavity. The battery pack 8 is used to supply power to the control circuit 14, and the control circuit 14 is used to control the drive motor 12. The lower end of the motor shaft of the drive motor 12 extends out of the sealed cavity and is fixedly connected to the toothed disc 6. A throttling cylinder 4 is fixedly connected inside the drill bit 1. Several mud holes 5 are opened on the bottom of the throttling cylinder 4. The toothed disc 6 is located inside the throttling cylinder 4 and is in contact with the bottom of the throttling cylinder 4. The rotation of the drive motor 12 can drive the toothed disc 6 to block the mud holes 5, or drive the toothed disc 6 not to block the mud holes 5.

[0052] In this embodiment, the pressure pulse generating unit includes a battery pack 8, a drive motor 12, and a control circuit 14. The battery pack 8 supplies power to the control circuit 14 or other electrical equipment. The control circuit 14 controls the drive motor 12 according to the control pulses. The lower end of the motor shaft of the drive motor 12 extends out of the sealed cavity. The gear disk 6 is located below the sealed cavity. After the motor shaft of the drive motor 12 extends out of the sealed cavity, it is fixedly connected to the gear disk 6, thereby controlling the gear disk 6 through the drive motor 12.

[0053] Specifically, the drill bit 1 has a mounting hole at one end near the flexible drill rod, and the throttle cylinder 4 is installed inside the mounting hole. The throttle cylinder 4 and the drill bit 1 are connected by an anti-rotation pin 11, thereby preventing the rotation of the throttle cylinder 4. Several mud holes 5 are provided on the bottom wall of the throttle cylinder 4. The toothed disc 6 is located inside the throttle cylinder 4 and contacts the bottom wall of the throttle cylinder 4. As the drive motor 12 rotates, the toothed disc 6 rotates accordingly; when the toothed disc 6 rotates, the throttle cylinder 4 does not rotate, thus achieving the purpose of the toothed disc 6 either blocking or not blocking the mud holes 5. When the toothed disc 6 blocks the mud holes 5, the pressure of the mud flowing through the mud holes 5 increases, generating a corresponding mud pressure pulse; when the toothed disc 6 does not block the mud holes 5, the pressure of the mud flowing through the mud holes 5 remains unchanged, so no mud pressure pulse is generated.

[0054] In this embodiment of the invention, a geared disc 6 driven by a micro-drive motor 12 directly adjusts the mud flow rate through the mud flow hole 2 of the drill bit 1, making it suitable for generating mud pulses in ultra-short radius side-drilling situations. Thus, the combination of the drive motor 12, the geared disc 6, and the throttle cylinder 4 enables the generation or non-generation of mud pressure pulses.

[0055] In practice, the shielding area should be less than the maximum flow area of ​​the mud hole 5, that is, the toothed disc 6 should shield part of the flow area of ​​the mud hole 5 to ensure the safety of the drilling process. For example, the toothed disc 6 should shield a maximum of 20% of the flow area of ​​the mud hole.

[0056] Secondly, a reduction unit 10 can be installed inside the sealed cavity. The input shaft of the reduction unit 10 is connected to the motor shaft of the drive motor 12, and the output shaft of the reduction unit 10 is connected to the gear plate 6 through the connecting pin 28. This reduces the speed of the drive motor 12 and increases the torque through the reduction unit 10. That is, the battery pack 8, the triaxial acceleration sensor assembly 13, the control circuit 14, the drive motor 12, and the reduction unit 10 are arranged sequentially from left to right inside the sealed cavity.

[0057] Finally, in order for the pressurized mud passing through the mud hole 5 to flow directly out from the mud flow hole 2 on the drill bit 1, the number of mud flow holes 2 and the number of mud holes 5 should be equal, and each mud hole 5 should be directly opposite a mud flow hole 2.

[0058] In one specific embodiment, such as Figure 3-4 As shown, several mud holes 5 are evenly distributed on the throttle cylinder 4. The gear disk 6 includes an annular block and a blocking block fixed on the outer circumference of the annular block. The blocking block can block the mud holes 5. The annular block is fixed on the motor shaft of the drive motor 12. The number of blocking blocks is equal to the number of mud holes, and the blocking blocks are evenly arranged.

[0059] Specifically, with Figures 3-4As shown, several mud holes 5 are evenly distributed on the throttling cylinder 4. In a specific implementation, for example, the number of mud holes 5 is 4. The gear disk 6 includes an annular block and a blocking block. The annular block is fixedly connected to the motor shaft of the drive motor 12, and the blocking block is fixed on the outer circumference of the annular block. The blocking block and the annular block can be an integrally formed structure or a fixed structure that is fixedly connected together.

[0060] Secondly, the number of shielding blocks is equal to the number of mud holes 5, and the shielding blocks are evenly distributed, for example, as shown in the figure. Figure 3-4 As shown, there are 4 occlusion blocks, which are evenly distributed on the outer circumference of the ring block.

[0061] In one specific embodiment, such as Figure 3-4 As shown, an arc-shaped groove 30 is provided on the toothed disc 6, and a limiting pin 29 is fixedly connected to the bottom of the throttling cylinder 4. The limiting pin 29 is located in the arc-shaped groove 30. The limiting pin 29 is used to limit the extreme rotation angle of the toothed disc 6 from one extreme position to another extreme position. When the toothed disc 6 rotates to one extreme position, the area of ​​the toothed disc 6 blocking the mud hole 5 is the largest. When the toothed disc 6 rotates to the other extreme position, the toothed disc 6 does not block the mud hole 5.

[0062] In this embodiment, the rotation angle of the gear disk 6 is limited by the cooperation of the arc-shaped groove 30 and the limiting pin 29. Specifically, the arc-shaped groove 30 is formed on the gear disk 6, and the limiting pin 29 is fixedly connected to the bottom of the throttle cylinder 4, with the limiting pin 29 extending into the arc-shaped groove 30. As an alternative, the arc-shaped groove 30 can also be formed on the bottom of the throttle cylinder 4, and the limiting pin 29 can be fixedly connected to the gear disk 6, with the limiting pin 29 also extending into the arc-shaped groove 30.

[0063] In this embodiment, when the toothed disc 6 is in one of its extreme positions, the area of ​​the toothed disc 6 blocking the mud hole 5 is at its maximum, resulting in the maximum pressure of the passing mud and generating a mud pressure pulse. When the toothed disc 6 rotates to the other extreme position, it no longer blocks the mud hole 5, thus facilitating the adjustment of the toothed disc 6. Specifically, when a mud pressure pulse is needed, the drive motor 12 controls the toothed disc 6 to rotate to the extreme position blocking the mud hole 5; when a mud pressure pulse is not needed, the drive motor 12 controls the toothed disc 6 to rotate to the extreme position not blocking the mud hole 5.

[0064] Specifically, when the toothed disc 6 is in such a state Figure 3 At its extreme position, the toothed disc 6 does not block the mud hole 5. When the toothed disc 6 is at its extreme position... Figure 3 extreme positions towards Figure 4 During the extreme position rotation, the gear disk 6 begins to block the mud hole 5, and the blocking area of ​​the gear disk 6 blocking the mud hole 5 gradually increases until it reaches the designed maximum blocking area. When the maximum blocking area is reached, the gear disk 6 rotates to... Figure 4The extreme position. In specific implementation, for example, the extreme rotation angle of the toothed disc 6 is 45 degrees, and the maximum blocking area of ​​the toothed disc 6 blocking the mud hole 5 is 20% of the maximum flow area of ​​the mud hole 5.

[0065] In one specific embodiment, such as Figure 5 , Figure 6 , Figure 7 As shown, the control circuit 14 includes a first transistor T1, a second transistor T2, a first relay KA1, and a second relay KA2. The first transistor T1 is turned on to energize the coil of the first relay KA1, and the second transistor T2 is turned on to energize the coil of the second relay KA2.

[0066] The first relay KA1 has two contacts: first relay contact 1 KA1-1 and first relay contact 2 KA1-2; the second relay KA2 has two contacts: second relay contact 1 KA2-1 and second relay contact 2 KA2-2; the fixed C terminal of the first relay contact 1 KA1-1 is connected to the movable B terminal of the second relay contact 1 KA2-1 and the movable A terminal of the second relay contact 2 KA2-2; the movable A terminal of the first relay contact 1 KA1-1 is connected to the positive terminal of the battery pack; the first relay contact 1... The B movable terminal of KA1-1 is left floating; the C fixed terminal of the first relay contact KA1-2 is connected to the A movable terminal of the second relay contact KA2-1 and the B movable terminal of the second relay contact KA2-2; the A movable terminal of the first relay contact KA1-2 is connected to the negative terminal of the battery pack; the B movable terminal of the first relay contact KA1-2 is left floating; the C fixed terminal of the second relay contact KA2-1 is connected to the + pin of the drive motor; the C fixed terminal of the second relay contact KA2-2 is connected to the - pin of the drive motor.

[0067] When the coil of the first relay KA1 is energized, the fixed terminal C of the first relay contact KA1-1 is connected to the movable terminal A of the first relay contact KA1-1, and the fixed terminal C of the second relay contact KA1-2 is connected to the movable terminal A of the first relay contact KA1-2; when the coil of the second relay KA2 is energized, the fixed terminal C of the second relay contact KA2-1 is connected to the movable terminal A of the second relay contact KA2-1, and the fixed terminal C of the second relay contact KA2-2 is connected to the movable terminal A of the second relay contact KA2-2.

[0068] The control circuit 14 in this embodiment realizes the forward rotation of the drive motor 12, the reverse rotation of the drive motor 12, and the stopping of the drive motor 12.

[0069] For details, see Figure 5When the gear 6 reaches its limit position, the drive motor 12 stops rotating because both the first transistor T1 and the second transistor T2 are not conducting. At this time, the fixed C terminal of the first relay contact KA1-1 is connected to the floating terminal (i.e., the movable B terminal) of the first relay contact KA1-1, and the fixed C terminal of the first relay contact KA1-2 is connected to the floating terminal (i.e., the movable B terminal) of the first relay contact KA1-2. Therefore, neither the positive nor negative terminal of the battery pack is connected to the circuit, and electrical energy cannot be transmitted to the + and - pins of the drive motor 12. As a result, the drive motor 12 stops rotating, and the gear 6 does not rotate. This prevents the drive motor 12 from continuing to rotate and consuming the energy of the battery pack after the gear 6 reaches its limit position.

[0070] See Figure 6 After transistor T1 is turned on by the control circuit, the current on the collector C of transistor T1 flows through the coil of the first relay KA1. The coil works to connect the fixed C terminal of the first relay contact KA1-1 with the movable A terminal of the first relay contact KA1-1, and to connect the fixed C terminal of the first relay contact KA1-2 with the movable A terminal of the first relay contact KA1-2. At this time, both the positive and negative terminals of the battery pack are connected to the circuit. The positive terminal of the battery pack is connected to the + pin of the drive motor 12 after passing through the circuit, and the negative terminal of the battery pack is connected to the - pin of the drive motor 12 after passing through the circuit, thereby realizing the forward rotation of the drive motor 12, which drives the gear disk 6 to rotate in one direction.

[0071] See Figure 7 After both transistors T1 and T2 are turned on by the control circuit, the current in the collector (C) of transistor T1 flows through the coil of the first relay KA1. The coil's operation connects the fixed collector (C) of the first relay contact KA1-1 with its movable contact (A), and also connects the fixed collector (C) of the first relay contact KA1-2 with its movable contact (A). The current in the collector (C) of transistor T2 flows through the coil of the second relay KA2. The coil's operation then connects the... The fixed C terminal of the first relay contact KA2-1 is connected to the movable A terminal of the second relay contact KA2-1, so that the fixed C terminal of the second relay contact KA2-2 is connected to the movable A terminal of the second relay contact KA2-2. At this time, both the positive and negative terminals of the battery pack are connected to the circuit. The positive terminal of the battery pack is connected to the - pin of the drive motor 12 after passing through the circuit, and the negative terminal of the battery pack is connected to the + pin of the drive motor 12 after passing through the circuit, thereby realizing the reverse rotation of the drive motor 12, driving the gear disk 6 to rotate in the other direction.

[0072] In one specific embodiment, each flexible section includes a ball head 20. The upper end of each ball head 20 is connected to an outer sleeve 24 via a torque pin 26. The uppermost outer sleeve 24 is fixedly connected to an upper connector 23, and the lower end of the lowermost ball head 20 is fixedly connected to a lower connector 21. The lower connector 21 is fixedly connected to the drill bit 1. The lower end of each of the remaining ball heads 20 is fixedly connected to a connecting sleeve 19. Each connecting sleeve 19 is fixedly connected to the outer sleeve 24 below it. There are gaps between each torque pin 26 and the ball head 20, between the lowermost outer sleeve 24 and the lower connector 21, and between each of the remaining outer sleeves 24 and the connecting sleeve 19 below them, which allow the flexible drill rod to bend.

[0073] In this embodiment, each flexible section includes a ball head 20. The upper end of each ball head 20 is connected to the outer sleeve 24 via a torque pin 26, which is secured to the outer sleeve 24 by a spring retainer 25. Except for the lowermost ball head 20, the lower end of each of the other ball heads 20 is fixedly connected to a connecting sleeve 19. Each connecting sleeve 19 is fixedly connected to the outer sleeve 24 below it. The uppermost outer sleeve 24 is fixedly connected to the upper connector 23, and the lowermost ball head 20 is fixedly connected to the lower connector 21. This achieves the purpose of connecting the flexible drill rod to the drill bit 1 via the lower connector 21, and the purpose of connecting the flexible drill rod to other tubing via the upper connector 23. In practical implementation, the fixed connection in this embodiment can be achieved through a threaded connection.

[0074] Secondly, to achieve the goal of flexible drill pipe bending, in this embodiment, gaps are provided between each torque pin 26 and ball head 20, between the lowest outer sleeve 24 and lower connector 21, and between each of the remaining outer sleeves 24 and the connecting sleeve 19 below them to allow the flexible drill pipe to bend. Taking the first ball head 20 as an example, there is a gap between the torque pin 26 and the ball head 20, so the upper connector 23 and the outer sleeve 24 on the ball head 20 can bend relative to the ball head 20. The gap between the outer sleeve 24 and the connecting sleeve 19 provides room for the bending of the outer sleeve 24, making the bending of the outer sleeve 24 and the upper connector 23 possible. Similarly, the gap between the lowest outer sleeve 24 and the lower connector 21 also provides room for the bending of the lowest outer sleeve 24.

[0075] Finally, a sealing ring 27 is provided between each connecting sleeve 19 and the ball head 20 below it, and between the uppermost ball head 20 and the upper connector 23.

[0076] In one specific embodiment, the sealed cavity is disposed within the space formed by the lowermost ball head 20, the lower connector 21, and the drill bit 1.

[0077] Specifically, the ball head 20 at the bottom is fixedly connected to the lower connector 21, and the lower connector 21 is fixedly connected to the drill bit. Therefore, the space between the ball head 20 at the bottom, the lower connector 21 and the drill bit 1 is a space that cannot be bent. In this embodiment, the sealing cavity is set in this space.

[0078] In one specific embodiment, the sealed cavity includes a measurement and control housing 9, which is fixed in the central flow channel near the drill bit 1. The upper end of the measurement and control housing 9 is sealed with a connecting structure. The connecting structure is a connecting nut 15. A sealing ring 16 is provided between the connecting nut 15 and the measurement and control housing 9. A wrench hole 17 is provided on the side of the connecting nut 15 away from the measurement and control housing 9.

[0079] In this embodiment, the sealed cavity specifically includes a measurement and control housing 9 and a connecting nut 15. The measurement and control housing 9 facilitates the installation of a triaxial acceleration sensor assembly 13 inside the housing, thereby acquiring well inclination data during the well construction process using the triaxial acceleration sensor assembly 13. It also facilitates the installation of a battery pack 8, a drive motor 12, a measurement and control circuit, and a reduction unit 10 inside the housing. The connecting structure is designed to prevent mud from entering the measurement and control housing 9.

[0080] Secondly, in specific implementation, the connection structure is a connecting nut 15, a sealing ring 16 is provided between the connecting nut 15 and the measuring and control housing 9, and a wrench hole 17 is provided on the side of the connecting nut 15 away from the measuring and control housing 9.

[0081] In one specific embodiment, the outer side of the measurement and control housing 9 is fitted with an upper straightening plate 22 and a lower straightening plate 7, both of which are provided with through holes for mud to pass through; the lower straightening plate 7 is limited between the lower connector 21 and the drill bit 1, and the lower straightening plate 7 is fixedly connected to the measurement and control housing 9.

[0082] Specifically, the lower centering plate 7 is fixedly connected to the wall of the throttling cylinder 4 by screws. The throttling cylinder 4 is fixed to the drill bit 1 by the anti-rotation pin 11. The throttling cylinder 4 is fixedly connected to the lower centering plate 7, and the lower centering plate 7 is limited between the lower connector 21 and the throttling cylinder 4. The lower centering plate 7 is fitted onto the measuring and control housing 9, thereby achieving the purpose of centering the measuring and control housing 9 and preventing the measuring and control housing 9 from swinging. The lower centering plate 7 is fixedly connected to the measuring and control housing 9, thereby achieving axial limitation of the measuring and control housing 9. In addition, in order to allow the mud to enter the throttling cylinder 4 through the lower centering plate 7, the lower centering plate 7 in this embodiment is provided with a through hole for the mud to flow.

[0083] Secondly, the upper straightening plate 22 is positioned between the lower connector 21 and the lowest ball head 20, and the lower ball head 20 and the lower connector 21 limit the axial direction of the upper straightening plate 22. Furthermore, in order to allow the mud to enter the throttling cylinder 4 through the upper straightening plate 22, the upper straightening plate 22 in this embodiment is also provided with a through hole for the mud to flow through.

[0084] In one specific embodiment, the drill bit 1 is provided with axial cutting teeth 18 and lateral cutting teeth 3. The axial cutting teeth 18 are evenly distributed at the lower end of the drill bit 1, and the lateral cutting teeth 3 are used to generate lateral cutting force.

[0085] Specifically, the drill bit 1 in this embodiment is a directional drilling bit with axial cutting teeth 18 and lateral cutting teeth 3. The directional drilling bit in this embodiment is characterized by large lateral cutting force, small axial force, fewer and more evenly distributed total number of cutting teeth than horizontal drilling bits, slow feed rate in the directional section, and symmetrical distribution of mud flow holes 2 and cutting teeth at the end of the drill bit.

[0086] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0087] Furthermore, the terms "a," "two," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0088] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A short-radius side-drilling directional drilling device, characterized in that, The system includes a flexible drill rod composed of several flexible short sections, with a central flow channel inside the flexible drill rod. A drill bit is connected to the lower end of the flexible drill rod, and a mud flow hole communicating with the central flow channel is provided at the end of the drill bit. A sealed cavity is fixed inside the central flow channel near the drill bit. The sealed cavity is equipped with a well inclination data acquisition unit and a pressure pulse generation unit. The well inclination data acquisition unit is used to acquire well inclination data during the well inclination process so as to obtain a control pulse based on the well inclination data. The pressure pulse generation unit is used to adjust the mud flow rate through the mud flow hole according to the control pulse so as to generate a corresponding mud pressure pulse so that the surface can receive the mud pressure pulse and decode the well inclination information. The pressure pulse generating unit includes a battery pack, a drive motor, and a control circuit disposed within the sealed cavity. The battery pack supplies power to the control circuit, which in turn controls the drive motor. The lower end of the motor shaft of the drive motor extends out of the sealed cavity and is fixedly connected to a toothed disc. A throttle cylinder is fixedly connected inside the drill bit. Several mud holes are provided on the bottom of the throttle cylinder. The toothed disc is located inside the throttle cylinder and contacts the bottom of the throttle cylinder. The rotation of the drive motor can cause the toothed disc to block the mud holes, or cause the toothed disc to not block the mud holes. The toothed disc has an arc-shaped groove, and a limiting pin is fixedly connected to the bottom of the throttling cylinder. The limiting pin is located in the arc-shaped groove and is used to limit the extreme rotation angle of the toothed disc from one extreme position to another. When the toothed disc rotates to one of the extreme positions, the area of ​​the toothed disc blocking the mud hole is the largest. When the toothed disc rotates to the other extreme position, the toothed disc does not block the mud hole. The maximum rotation angle of the toothed disc is 45 degrees, and the maximum area of ​​the toothed disc blocking the mud hole is 20% of the maximum flow area of ​​the mud hole.

2. The ultra-short radius side-drilling directional drilling device according to claim 1, characterized in that, The well deviation data acquisition unit is a triaxial acceleration sensor assembly installed in the sealed cavity, which consists of three acceleration sensors.

3. The ultra-short radius side-drilling directional drilling device according to claim 1, characterized in that, A plurality of mud holes are evenly distributed on the throttling cylinder. The gear disc includes an annular block and a blocking block fixed on the outer circumference of the annular block. The blocking block can block the mud holes. The annular block is fixed on the motor shaft of the drive motor. The number of blocking blocks is equal to the number of mud holes, and the blocking blocks are evenly arranged.

4. The ultra-short radius side-drilling directional drilling device according to claim 1, characterized in that, A reduction unit is provided inside the sealed cavity. The drive motor is connected to the reduction unit. The output shaft of the reduction unit is connected to the gear plate through a connecting pin. The number of mud flow holes is equal to the number of mud holes, and each mud hole is directly opposite a mud flow hole.

5. The ultra-short radius side-drilling directional drilling device according to claim 1, characterized in that, The control circuit includes a first transistor, a second transistor, a first relay, and a second relay, wherein the first transistor conducts to energize the coil of the first relay, and the second transistor conducts to energize the coil of the second relay. The first relay has two contacts: first relay contact one and first relay contact two; the second relay has two contacts: second relay contact one and second relay contact two. The fixed C terminal of the first relay contact is connected to the movable B terminal of the second relay contact and the movable A terminal of the second relay contact. The movable A terminal of the first relay contact is connected to the positive terminal of the battery pack, and the movable B terminal of the first relay contact is left unconnected. The fixed C terminal of the first relay contact 2 is connected to the movable A terminal of the second relay contact 1 and the movable B terminal of the second relay contact 2. The movable A terminal of the first relay contact 2 is connected to the negative terminal of the battery pack, and the movable B terminal of the first relay contact 2 is left unconnected. The C fixed terminal of the second relay contact one is connected to the + pin of the drive motor, and the C fixed terminal of the second relay contact two is connected to the - pin of the drive motor. When the coil of the first relay is energized, the fixed C terminal of the first relay contact one is connected to the movable A terminal of the first relay contact one, and the fixed C terminal of the first relay contact two is connected to the movable A terminal of the first relay contact two. When the coil of the second relay is energized, the fixed C terminal of the second relay contact one is connected to the movable A terminal of the second relay contact one, and the fixed C terminal of the second relay contact two is connected to the movable A terminal of the second relay contact two.

6. The ultra-short radius side-drilling directional drilling device according to claim 1, characterized in that, Each of the flexible sections includes a ball head, and the upper end of each ball head is connected to an outer sleeve via a torque pin. The uppermost outer sleeve is fixedly connected to an upper connector, and the lower end of the lowermost ball head is fixedly connected to a lower connector, which is fixedly connected to the drill bit. The lower end of each of the remaining ball heads is fixedly connected to a connecting sleeve, and each connecting sleeve is fixedly connected to the outer sleeve below it. There are gaps between each torque pin and the ball head, between the lowermost outer sleeve and the lower connector, and between each of the remaining outer sleeves and the connecting sleeve below them, allowing the flexible drill rod to bend.

7. The ultra-short radius side-drilling directional drilling device according to claim 6, characterized in that, The sealed cavity is located within the space formed by the ball head, the lower connector, and the drill bit at the bottom.

8. The ultra-short radius side-drilling directional drilling device according to claim 6, characterized in that, The sealed cavity includes a measurement and control housing, which is fixed in the central flow channel near the drill bit. The upper end of the measurement and control housing is sealed with a connecting structure, which is a connecting nut. A sealing ring is provided between the connecting nut and the measurement and control housing. A wrench hole is provided on the side of the connecting nut away from the measurement and control housing.

9. The ultra-short radius side-drilling directional drilling device according to claim 8, characterized in that, The outer side of the measurement and control housing is fitted with an upper stabilizing plate and a lower stabilizing plate, both of which are provided with through holes for mud to pass through; the lower stabilizing plate is limited between the lower connector and the drill bit, and the lower stabilizing plate is fixedly connected to the measurement and control housing.

10. The ultra-short radius side-drilling directional drilling device according to claim 1, characterized in that, The drill bit is provided with axial cutting teeth and lateral cutting teeth. The axial cutting teeth are evenly distributed at the lower end of the drill bit, and the lateral cutting teeth are used to generate lateral cutting force.

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