Hydraulic oscillator and drill string

Abstract

This application provides a hydraulic oscillator and drill string. The hydraulic oscillator includes an inner cylinder with an upper connector, an outer cylinder with a lower connector, a rotating mandrel vertically positioned within the outer cylinder and rotatably connected to it, and a vortex shroud fitted onto the rotating mandrel and fixedly connected to the outer cylinder. The upper inner side of the outer cylinder is connected to the outer side of the inner cylinder near the upper connector via a spline joint. A piston and an elastic element are disposed between the outer surface of the inner cylinder and the inner surface of the outer cylinder. The vortex shroud is provided with vortex holes, and the outer surface of the rotating mandrel is provided with multiple circumferentially distributed flow grooves. Drilling fluid flows into the flow grooves through the vortex holes, driving the rotating mandrel to rotate. The flow area between the flow grooves and the vortex holes changes periodically with the rotation of the rotating mandrel. The hydraulic oscillator provided in this application achieves pressure pulse function in a novel way, eliminating the need for a throttle valve plate mechanism susceptible to erosion, which improves the performance of the hydraulic oscillator and extends its service life.

Description

Technical Field

[0001] This application relates to the field of drilling engineering technology, and in particular to a hydraulic oscillator and drill string. Background Technology

[0002] At present, unconventional oil and gas resources such as shale gas and shale oil have become the key areas of exploration and development both domestically and internationally. Increasing the length of the horizontal section in shale reservoirs can not only significantly increase the controlled reserves of a single shale oil and gas well, but also increase the seepage area, which is conducive to improving the productivity and final production of a single well. At the same time, it also reduces the number of platforms deployed, saves investment, and reduces the cost per thousand cubic meters of gas.

[0003] However, as the length of the horizontal section increases, the frictional torque during drilling increases and becomes highly unstable, leading to difficulties in pressure transmission and low drilling efficiency. To address this, researchers have developed friction-reducing tools for long horizontal well sections, with hydraulic oscillators being a typical example. Traditional hydraulic oscillators generally use a throttle valve mechanism to achieve pressure pulse functionality, which has weaknesses such as limited temperature resistance, severe erosion of the throttle valve mechanism, rapid wear rate of the oscillation propulsion mechanism, and low efficiency. Summary of the Invention

[0004] In view of this, this application provides a hydraulic oscillator and drill string. The hydraulic oscillator achieves pressure pulse function in a new way, eliminating the need for a throttle valve plate mechanism that is susceptible to erosion, which helps to improve the performance of the hydraulic oscillator and extend its service life.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A hydraulic oscillator, comprising:

[0007] Inner cylinder, with an upper connector;

[0008] The outer cylinder has a lower connector;

[0009] The rotating spindle is vertically positioned inside the cavity of the outer cylinder and rotatably connected to the outer cylinder.

[0010] A swirl shield is fitted onto the rotating spindle and fixedly connected to the outer cylinder.

[0011] The upper inner side of the outer cylinder is connected to the outer side of the inner cylinder near the upper connector via a spline joint. The rotating mandrel is located below the inner cylinder. A piston and an elastic element are disposed between the outer surface of the inner cylinder and the inner surface of the outer cylinder, with the elastic element located on the side of the piston away from the rotating mandrel. The vortex shroud is provided with vortex holes, and the outer surface of the rotating mandrel is provided with multiple circumferentially distributed flow grooves. Drilling fluid flows into the flow grooves through the vortex holes, driving the rotating mandrel to rotate. The flow area between the flow grooves and the vortex holes changes periodically with the rotation of the rotating mandrel to generate periodic pressure pulse waves.

[0012] Preferably, in the above-mentioned hydraulic oscillator, the piston includes a stationary piston fixed to the lower part of the inner cylinder and a balance piston slidably sleeved in the middle part of the inner cylinder. The inner surface of the outer cylinder has an annular rib that fits against the outer surface of the inner cylinder. The space between the lower surface of the annular rib and the upper surface of the stationary piston is the upper cavity of the stationary piston, and the space between the upper surface of the annular rib and the lower surface of the balance piston is the lower cavity of the balance piston. The outer cylinder has a vent hole communicating with the upper cavity of the stationary piston, and the inner cylinder has a connecting hole communicating with the lower cavity of the balance piston. The swirling hole communicates with the lower cavity of the stationary piston below the stationary piston.

[0013] Preferably, in the above-mentioned hydraulic oscillator, the upper surface of the balance piston and the spline pair are separated by an oil-sealed cavity filled with oil, and the spline pair and the elastic element are immersed in the oil.

[0014] Preferably, in the above-mentioned hydraulic oscillator, the bottom of the lower cavity of the stationary piston is formed by the upper surface of the first obstructing fluid fixedly disposed in the outer cylinder. The first obstructing fluid has a first guide hole for connecting the lower cavity of the stationary piston and the vortex hole. The upper end of the rotating spindle is rotatably connected to the lower end of the first obstructing fluid. The lower end of the rotating spindle is rotatably connected to the upper end of the second obstructing fluid fixedly disposed in the outer cylinder. The second obstructing fluid has a second guide hole for connecting the flow channel and the inner cavity of the lower connector.

[0015] Preferably, in the above-mentioned hydraulic oscillator, the first obstructing fluid, the rotating mandrel, and the second obstructing fluid all have a central channel, and the central channels of the three are connected to form a central diversion hole that connects the lower cavity of the stationary piston and the inner cavity of the lower connector.

[0016] Preferably, in the above-mentioned hydraulic oscillator, the upper surface of the first fluid-blocking component is a raised cone shape.

[0017] Preferably, in the above-mentioned hydraulic oscillator, there are multiple first guide holes and / or second guide holes, which are evenly distributed around the rotation axis of the rotating spindle.

[0018] Preferably, in the above-mentioned hydraulic oscillator, the first guide hole is a round hole or an arc-shaped oval hole, and / or, the second guide hole is a round hole or an arc-shaped oval hole.

[0019] Preferably, in the above-mentioned hydraulic oscillator, the flow channel is a straight channel extending axially along the rotating spindle, or the flow channel is an inclined channel extending along a spiral line.

[0020] A drill string comprising a hydraulic oscillator as disclosed in any of the foregoing.

[0021] As can be seen from the above technical solution, in the hydraulic oscillator provided in this application, a rotating spindle is rotatably installed inside the outer cylinder cavity, and a vortex shroud is fixedly installed. The vortex shroud is provided with vortex holes, and multiple circumferentially distributed flow grooves are provided on the outer surface of the rotating spindle. The vortex shroud is fitted onto the rotating spindle, and the drilling fluid flowing into the flow grooves through the vortex holes can drive the rotating spindle to rotate. Moreover, the flow area between the flow grooves and the vortex holes changes periodically with the rotation of the rotating spindle, thus generating periodic pressure pulse waves. Therefore, the entire tool does not require a throttle valve plate mechanism to achieve the pressure pulse function. Instead, it relies on the rotation of the rotating spindle with flow grooves to effectively integrate the power function and the pressure pulse function, which is beneficial to improving the performance of the hydraulic oscillator and extending its service life. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a cross-sectional view of the hydraulic oscillator provided in Embodiment 1 of this application;

[0024] Figure 2 yes Figure 1 Schematic diagram of section AA in the diagram;

[0025] Figure 3 yes Figure 1 Schematic diagram of the BB section in the diagram;

[0026] Figure 4 yes Figure 1 Schematic diagram of the CC section in the diagram;

[0027] Figure 5 yes Figure 1 Schematic diagram of the DD section in the diagram;

[0028] Figure 6yes Figure 1 A three-dimensional schematic diagram of the rotating spindle 14 in the middle;

[0029] Figure 7 yes Figure 1 A schematic diagram of the minimum flow area of ​​the CC section in the middle;

[0030] Figure 8 yes Figure 1 A schematic diagram of the CC section under the condition of maximum flow area;

[0031] Figure 9 This is a cross-sectional view of the hydraulic oscillator provided in Embodiment 2 of this application;

[0032] Figure 10 This is a three-dimensional schematic diagram of the rotating spindle 14 of the hydraulic oscillator provided in Embodiment 3 of this application.

[0033] The diagram is marked as follows:

[0034] 1. Drive shaft; 2. Spline sleeve; 3. Upper oil plug; 4. Disc spring assembly; 5. Disc spring sleeve; 6. Lower oil plug; 7. Balance piston; 8. Connecting shaft; 9. Energy-enhancing sleeve; 10. Stationary piston; 11. Adapter joint; 12. Upper thrust bearing; 13. Swirl cover; 14. Rotating spindle; 15. Rotary cylinder housing; 16. Lower thrust bearing; 17. Lower joint; 18. Oil seal cavity; 19. Lower cavity of balance piston; 20. Connecting hole; 21. Upper cavity of stationary piston; 22. Breathing hole; 23. Lower cavity of stationary piston; 24. Upper guide hole; 25. Annular guide cavity; 26. Swirl hole; 27. Small flow groove; 28. Large flow groove; 29. ​​Lower guide hole; 30. Central branch hole. Detailed Implementation

[0035] This application provides a hydraulic oscillator and drill string. The hydraulic oscillator achieves pressure pulse function in a new way, eliminating the need for a throttle valve plate mechanism that is susceptible to erosion. This improves the performance of the hydraulic oscillator and extends its service life.

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] like Figures 1-6As shown, this application provides a hydraulic oscillator, including an inner cylinder with an upper connector, an outer cylinder with a lower connector, a rotating spindle 14 vertically positioned within the outer cylinder and rotatably connected to it, and a vortex shroud 13 fitted onto the rotating spindle 14 and fixedly connected to the outer cylinder. The vortex shroud 13 is provided with vortex holes 26, and the outer surface of the rotating spindle 14 is provided with a plurality of circumferentially distributed flow grooves. Drilling fluid flows into the flow grooves through the vortex holes 26, driving the rotating spindle 14 to rotate. The flow area between the flow grooves and the vortex holes 26 changes periodically with the rotation of the rotating spindle 14 to generate periodic pressure pulse waves. The components of the hydraulic oscillator are described below:

[0038] In this embodiment, the inner cylinder mainly includes a drive shaft 1 and a connecting shaft 8. The lower end of the drive shaft 1 is threadedly connected to the connecting shaft 8. The upper part of the drive shaft 1 has an upper connector, which can be connected and assembled into the drill string to obtain torque. The outer cylinder mainly includes a spline sleeve 2, a disc spring sleeve 5, an energy-enhancing sleeve 9, a conversion connector 11, a rotary drum housing 15, and a lower connector 17. The lower end of the spline sleeve 2 is threadedly connected to the disc spring sleeve 5. The lower end of the disc spring sleeve 5 is threadedly connected to the energy-enhancing sleeve 9. The lower end of the energy-enhancing sleeve 9 is threadedly connected to the conversion connector 11. The lower end of the conversion connector 11 is threadedly connected to the rotary drum housing 15. The lower end of the rotary drum housing 15 is threadedly connected to the lower connector 17.

[0039] The outer side of the middle part of the drive shaft 1 is engaged with the spline sleeve 2 for transmission and can move up and down within the spline sleeve 2. A piston and an elastic element are arranged between the outer surface of the inner cylinder and the inner surface of the outer cylinder. The elastic element is located on the side of the piston away from the rotating spindle 14. Specifically, in this embodiment, the elastic element is a disc spring assembly 4, and the piston includes a stationary piston 10 fixed to the lower part of the inner cylinder and a balance piston 7 slidably sleeved in the middle part of the inner cylinder. The disc spring sleeve 5 contains the disc spring assembly 4, the connecting shaft 8, and the balance piston 7. The drive shaft 1 passes through the spline sleeve 2 and the disc spring assembly 4 in sequence. The lower end of the connecting shaft 8 passes through the inner hole of the energy-enhancing sleeve 9 and is threadedly connected to the stationary piston 10. The inner wall of the energy-enhancing sleeve 9 is in contact with the outer circular surface of the stationary piston 10 and can make the stationary piston 10 move up and down. The inner bore of the balance piston 7 is fitted onto the outside of the connecting shaft 8. The outer surface of the balance piston 7 is in contact with the inner bore of the disc spring sleeve 5, allowing the balance piston 7 to move up and down relative to the connecting shaft 8 and the disc spring sleeve 5. A closed oil-sealed cavity 18 is formed between the upper end face of the balance piston 7 and the drive shaft 1, spline sleeve 2, disc spring sleeve 5, and connecting shaft 8. A lower balance piston cavity 19 is formed between the lower end face of the balance piston 7 and the disc spring sleeve 5 and the energy-enhancing sleeve 9. An upper stationary piston cavity 21 is formed between the inner wall of the energy-enhancing sleeve 9 and the upper end face of the stationary piston 10, and a lower stationary piston cavity 23 is formed between the inner wall of the energy-enhancing sleeve 9 and the lower end face of the stationary piston 10. In other words, the inner bore surface at the upper end of the energy-enhancing sleeve 9 forms an annular rib that fits against the outer surface of the inner cylinder. The lower surface of this annular rib forms the upper stationary piston cavity 21 with the upper surface of the stationary piston 10, and the upper surface of this annular rib forms the lower balance piston cavity 19 with the lower surface of the balance piston 7. Figure 1 As shown, the energy-boosting sleeve 9 has a breather hole 22 in the middle, and the upper chamber 21 of the stationary piston is connected to the breather hole 22 to ensure that the pressure in the upper chamber 21 of the stationary piston is consistent with the outside. The connecting shaft 8 has a connecting hole 20 in the middle, and the lower chamber 23 of the stationary piston and the lower chamber 19 of the balance piston are connected through the connecting hole 20.

[0040] The rotating cylinder housing 15 houses a swirl shield 13 and a rotating spindle 14. The inner upper end of the rotating cylinder housing 15 is threadedly connected to the outer lower end of the swirl shield 13. The bottom of the lower chamber 23 of the stationary piston is formed by the upper surface of the conversion joint 11 (i.e., the first flow barrier). The inner lower end of the conversion joint 11 is in contact with the swirl shield 13, forming an annular guide cavity 25 between the swirl shield 13 and the rotating cylinder housing 15. The inner circumference of the conversion joint 11 is evenly distributed with upper guide holes 24 (i.e., the first guide holes), the circumference of the swirl shield 13 is evenly distributed with swirl holes 26, and the outer surface of the rotating spindle 14 is evenly distributed with spiral-shaped small flow grooves 27 and large flow grooves 28. The upper end of the rotating spindle 14 is radially engaged with the conversion joint 11 through an upper thrust bearing 12, and the lower end of the rotating spindle 14 is radially engaged with a portion of the rotating cylinder housing 15 (i.e., the second flow barrier) through a lower thrust bearing 16. The lower end of the rotating cylinder shell 15 has uniformly distributed lower guide holes 29 (i.e., second guide holes) on its inner circumference.

[0041] like Figure 1 As shown, a lower oil plug 6 is installed on the middle circumference of the disc spring sleeve 5, and an upper oil plug 3 is installed on the middle circumference of the spline sleeve 2. During assembly, the upper oil plug 3 and the lower oil plug 6 are disconnected, one end is connected to the oil injection pipeline, and the other end is connected to the discharge pipeline to inject a certain volume of hydraulic oil into the oil sealing cavity 18, so that the transmission spline that mates with the spline sleeve 2 and the disc spring assembly 4 in the oil sealing cavity 18 are completely immersed in the oil medium environment, thereby reducing the wear rate and improving the oscillation propulsion efficiency. After the oil injection is completed, the upper oil plug 3 and the lower oil plug 6 are tightened and fixed respectively.

[0042] like Figures 1 to 8 As shown, when the hydraulic oscillator is working, the drilling fluid flows downwards through the central holes of the drive shaft 1 and connecting shaft 8 into the lower chamber 19 of the balance piston and the lower chamber 23 of the stationary piston, and then continues downwards sequentially through the upper guide hole 24, the annular guide cavity 25, and the vortex hole 26. When the vortex hole 26 is connected to the small flow channel 27, the flow area is minimized (e.g., Figure 7 As shown), the drilling fluid pressure increases; when the vortex orifice 26 is connected to the large flow channel 28, the flow area is at its maximum (as shown). Figure 8 As shown, the drilling fluid pressure decreases. Simultaneously, because the vortex orifices 26 are distributed with a radial inclination (e.g., clockwise), the drilling fluid flowing out of the vortex orifices 26 drives the rotating mandrel 14 to rotate, causing the drilling fluid to alternately flow into the small flow channel 27 and the large flow channel 28 and finally flow out through the lower guide hole 29, thus generating periodic pressure pulse waves. The pressure pulse waves are transmitted upwards to the lower chamber 23 of the stationary piston and the lower chamber 19 of the balance piston, jointly causing the stationary piston 10 and the balance piston 7 to drive the transmission shaft 1 and the connecting shaft 8 to compress the disc spring assembly 4, forming a reciprocating extension and retraction, producing an axial oscillation effect. Therefore, the entire tool does not require a throttle valve plate mechanism to achieve the pressure pulse function. Instead, it relies on the rotation of the rotating mandrel 14 with flow channels to effectively integrate the power function and the pressure pulse function. That is, the rotating mandrel 14 itself can rotate by the drive of the drilling fluid, and at the same time, the drilling fluid generates periodic pressure pulse waves. This effectively improves the temperature resistance of the hydraulic oscillator and helps to extend its service life.

[0043] like Figure 9 As shown in another embodiment of this application, the conversion joint 11, the rotating mandrel 14, and the rotating cylinder housing 15 are all provided with a through central diversion hole 30, which is used to divert the drilling fluid flowing into the lower chamber 23 of the stationary piston, thereby reducing the total amount of drilling fluid flowing into the small flow channel 27 or the large flow channel 28 after diversion, thereby reducing the rotational speed, pressure drop, and oscillation frequency of the pressure pulse generated by the rotating mandrel 14, and meeting the performance requirements of low pressure drop and low oscillation frequency of the tool under special drilling conditions.

[0044] like Figure 10As shown, in another specific structural embodiment of the rotating mandrel 14, the outer surface of the rotating mandrel 14 is uniformly distributed with straight-edged small flow channels 27 and large flow channels 28. This increases the driving force of the drilling fluid flowing into the small flow channels 27 and large flow channels 28, thereby effectively improving the rotational speed of the rotating mandrel 14 and the oscillation frequency of the generated pressure pulses, meeting the performance requirements of high oscillation frequency for tools under special drilling conditions. That is, the flow channels can be either inclined channels extending along a spiral or straight channels extending along the axial direction of the rotating mandrel 14. It should be noted that the accompanying drawings of this application only exemplarily show the case where the flow channels include small flow channels 27 and large flow channels 28. It should be understood that the flow channels can be configured to include, for example, three or more different sizes of flow channels, or each flow channel can be configured to be the same size, as long as the flow area between the flow channel and the vortex hole 26 can change periodically with the rotation of the rotating mandrel 14.

[0045] During manufacturing, the hydraulic oscillation drag reduction tool is preferably made entirely of metal internally, without any rubber materials, to achieve good high-temperature and corrosion resistance. Besides disc spring assembly 4, other types of elastic components, such as coil springs, can also be used. Figure 1 As shown, to optimize the flow state of the drilling fluid, this embodiment preferably designs the upper surface of the middle part (i.e., the first flow barrier) of the adapter 11 as a raised cone shape, which allows the drilling fluid to flow better into the upper guide hole 24. The upper guide hole 24 and the lower guide hole 29 are typically multiple and evenly distributed around the rotation axis of the rotating spindle 14. Besides being designed as an arc-shaped oval hole, the upper guide hole 24 and the lower guide hole 29 can also be designed as other shapes such as round holes.

[0046] This application also provides a drill string that includes the hydraulic oscillator disclosed in the above embodiments. Since the hydraulic oscillator disclosed in the above embodiments has the aforementioned technical effects, the drill string having this hydraulic oscillator also has the aforementioned technical effects, and will not be described again here.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hydraulic oscillator, characterized in that, include: Inner cylinder, with an upper connector; The outer cylinder has a lower connector; The rotating spindle is vertically positioned inside the cavity of the outer cylinder and rotatably connected to the outer cylinder. A swirl shield is fitted onto the rotating spindle and fixedly connected to the outer cylinder. The upper inner side of the outer cylinder is connected to the outer side of the inner cylinder near the upper connector via a spline joint. The rotating mandrel is located below the inner cylinder. A piston and an elastic element are disposed between the outer surface of the inner cylinder and the inner surface of the outer cylinder. The elastic element is located on the side of the piston away from the rotating mandrel. Swirl holes are evenly distributed on the circumference of the swirl cover. Small flow channels and large flow channels are evenly distributed on the outer circular surface of the rotating mandrel. The swirl holes are inclined relative to the radial direction. The drilling fluid flowing out of the swirl holes will drive the rotating mandrel to rotate, so that the drilling fluid alternately flows into the small flow channels and the large flow channels and finally flows out through the lower guide hole, thereby generating periodic pressure pulse waves. The piston includes a stationary piston fixed to the lower part of the inner cylinder and a balance piston slidably sleeved in the middle part of the inner cylinder. The inner surface of the outer cylinder has an annular rib that fits against the outer surface of the inner cylinder. The space between the lower surface of the annular rib and the upper surface of the stationary piston is the upper cavity of the stationary piston, and the space between the upper surface of the annular rib and the lower surface of the balance piston is the lower cavity of the balance piston. The outer cylinder has a vent hole communicating with the upper cavity of the stationary piston, and the inner cylinder has a connecting hole communicating with the lower cavity of the balance piston. The swirling hole communicates with the lower cavity of the stationary piston below the stationary piston.

2. The hydraulic oscillator according to claim 1, characterized in that, The upper surface of the balance piston and the spline pair form an oil-sealed cavity filled with oil, and the spline pair and the elastic element are immersed in the oil.

3. The hydraulic oscillator according to claim 1, characterized in that, The bottom of the lower cavity of the stationary piston is formed by the upper surface of the first obstructing fluid fixedly disposed in the outer cylinder. The first obstructing fluid has a first guide hole for connecting the lower cavity of the stationary piston and the swirling hole. The upper end of the rotating spindle is rotatably connected to the lower end of the first obstructing fluid. The lower end of the rotating spindle is rotatably connected to the upper end of the second obstructing fluid fixedly disposed in the outer cylinder. The second obstructing fluid has a second guide hole for connecting the flow groove and the inner cavity of the lower connector.

4. The hydraulic oscillator according to claim 3, characterized in that, The first flow barrier, the rotating mandrel, and the second flow barrier all have a central channel, and the central channels of the three are connected to form a central flow divider hole that connects the lower cavity of the stationary piston and the inner cavity of the lower connector.

5. The hydraulic oscillator according to claim 3, characterized in that, The upper surface of the first fluid barrier is a raised cone shape.

6. The hydraulic oscillator according to claim 3, characterized in that, There are multiple first and / or second guide holes, which are evenly distributed around the rotation axis of the rotating mandrel.

7. The hydraulic oscillator according to claim 3, characterized in that, The first guide hole is a round hole or an arc-shaped oval hole, and / or the second guide hole is a round hole or an arc-shaped oval hole.

8. The hydraulic oscillator according to any one of claims 1 to 7, characterized in that, The flow channel is a straight channel extending axially along the rotating spindle, or the flow channel is an inclined channel extending along a spiral line.

9. A drill string, characterized in that, Includes the hydraulic oscillator as described in any one of claims 1 to 8.

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