Hydraulic drive rodless oil pumping device commutation method and structure

Abstract

The present application relates to the technical field of oil extraction, and provides a hydraulic driving rodless oil extraction device reversing method and structure, the reversing structure adopts coaxial multi-layer nested layout, the outer shell is alternately integrated with six fluid channels and six bolt connection holes in a ring shape; from outside to inside, the inside is sequentially provided with a reversing valve core, a reversing top rod and a plunger connecting rod, cooperated with upper and lower lock caps and a plunger assembly, and adopts a reversing mode combining mechanical triggering and hydraulic driving; the reversing method drives the reversing top rod to switch the control oil way through plunger movement, pushes the reversing valve core to move axially, realizes automatic switching of liquid inlet and outlet of the upper and lower liquid cylinders, and completes unified lifting of the spent liquid in cooperation with a multi-stage sealing leakage recovery structure. The present application has high reversing reliability, high structure integration degree and long service life, can realize continuous oil extraction in the whole stroke, and improves the oil extraction efficiency.

Description

Technical Field

[0001] This invention relates to the field of oilfield production technology, and more specifically, to a reversing method and structure for a hydraulically driven rodless oil production device. Background Technology

[0002] As domestic oilfield development gradually enters the medium-to-high water-cut stage and deep well development phase, traditional rod-based oil production systems suffer from problems such as severe rod and tubing wear, low system efficiency, and poor adaptability to deviated wells, making it difficult to meet the oil production needs of complex well conditions. Hydraulic-driven rodless oil production technology uses a surface high-pressure pump as a power source, driving the plunger to reciprocate and lift the produced fluid through downhole fluid channels and a reversing structure. It eliminates the need for a sucker rod string, offering advantages such as compact structure, applicability to deviated and deep wells, and low operation and maintenance costs, making it an important technological direction in the field of rodless oil production.

[0003] Existing hydraulically driven rodless oil production units mainly fall into two categories regarding downhole reversing structures: pure hydraulic reversing and pure mechanical reversing. Pure hydraulic reversing structures rely on hydraulic pressure differences to switch valve cores, which are prone to reversing jamming and response lag under high-temperature, high-sand-content downhole conditions, resulting in insufficient operational reliability. Pure mechanical reversing structures rely on mechanical collisions to trigger reversing, leading to high reversing impact loads, rapid wear of key components, and short service life. Furthermore, the fluid channel layout of existing reversing structures is dispersed, with low integration of working fluid, spent fluid, and produced fluid channels, resulting in an overall large radial dimension of the unit, making it unsuitable for small-bore oil production operations. Additionally, the complex sealing structures between different flow channels are prone to fluid cross-contamination, impacting oil production efficiency. Summary of the Invention

[0004] To overcome the shortcomings mentioned above, this invention aims to provide a reversing method and structure for a hydraulically driven rodless oil production device, which can solve the aforementioned problems.

[0005] A reversing structure for a hydraulically driven rodless oil production device includes a coaxially arranged outer housing and a reversing actuator assembled inside the outer housing.

[0006] The outer shell has an axially through central hole at its center. Six independent axially extending fluid channels and six bolt connection holes are evenly distributed along the circumference of the annular wall of the outer shell. The six fluid channels are, in sequence, a working fluid injection channel, an upper and lower cylinder discharge channel, a working fluid depletion return channel one, a working fluid depletion return channel two, a bottom-hole produced fluid lifting channel one, and a bottom-hole produced fluid lifting channel two. The bolt connection holes are axially through holes used to fix and connect the pump casing body at both ends of the oil production device.

[0007] The reversing actuator includes a reversing valve core, a reversing push rod, an upper reversing valve locking cap, a lower reversing valve locking cap, a plunger connecting rod, an upper plunger assembly, and a lower plunger assembly. The reversing valve core is a hollow cylindrical structure and is axially slidably and coaxially assembled within the central hole. The reversing push rod is a hollow sleeve structure and is axially slidably and coaxially inserted through the central through hole of the reversing valve core. The plunger connecting rod is coaxially inserted through the central hole of the reversing push rod, with its upper end fixedly connected to the upper plunger assembly and its lower end fixedly connected to the lower plunger assembly. The upper reversing valve locking cap is fixedly installed at the upper end port of the central hole, located above the reversing valve core. The lower reversing valve locking cap is fixedly installed at the lower end port of the central hole, located below the reversing valve core.

[0008] Furthermore, the wall of the directional valve upper locking cap is provided with a directional valve upper locking cap drain channel and a directional valve upper locking cap drain channel in the radial direction;

[0009] The outer end of the drain channel of the locking cap on the reversing valve is connected to the working fluid injection channel, and the inner end faces the outer wall of the reversing push rod; the inner end of the drain channel of the locking cap on the reversing valve faces the outer wall of the reversing push rod, and the outer end is connected to the liquid collection chamber on the reversing valve core inside the reversing valve core.

[0010] The upper part of the outer wall of the reversing push rod is provided with an annular channel on the reversing push rod. When the reversing push rod is at the upper dead point, the annular channel on the reversing push rod simultaneously connects the upper lock cap drain channel of the reversing valve with the inner end of the upper lock cap drain channel of the reversing valve.

[0011] Furthermore, the wall of the lower locking cap of the reversing valve is provided with a drain channel and a drain port along the radial direction;

[0012] The outer end of the drain channel of the lower lock cap of the reversing valve is connected to the working fluid injection channel, and the inner end faces the outer wall of the reversing push rod; the inner end of the drain port of the lower lock cap of the reversing valve faces the outer wall of the reversing push rod, and the outer end is connected to the lower liquid collection chamber of the reversing valve core inside the reversing valve core.

[0013] The lower part of the outer wall of the reversing push rod is provided with a lower annular channel. When the reversing push rod is at the lower stop point, the lower annular channel of the reversing push rod is simultaneously connected to the inner end of the lower lock cap drain channel of the reversing valve and the lower lock cap drain port of the reversing valve.

[0014] Furthermore, the upper part of the outer wall of the reversing valve core is provided with an upper annular channel, and the lower part of the outer wall is provided with a lower annular channel.

[0015] The reversing valve core has a working fluid inlet radially opened on its side wall. The outer end of the working fluid inlet can slide axially with the reversing valve core and is connected to the working fluid injection channel. The inner end of the working fluid inlet is connected to the upper annular channel and the lower annular channel of the reversing valve core, respectively.

[0016] The side wall of the reversing valve core is also provided with an inlet for the upper liquid cylinder discharge channel and a outlet for the lower liquid cylinder discharge channel; the outer end of the inlet for the upper liquid cylinder discharge channel is connected to the upper section of the upper and lower liquid cylinder discharge channels, and the inner end is connected to the upper annular channel of the reversing valve core; the outer end of the outlet for the lower liquid cylinder discharge channel is connected to the lower section of the upper and lower liquid cylinder discharge channels, and the inner end is connected to the lower annular channel of the reversing valve core.

[0017] Furthermore, the upper plunger assembly includes an upper plunger, an upper pump cylinder, and an upper reversing protective inner sleeve; the upper pump cylinder is coaxially fixed to the upper end of the outer shell, the upper plunger is slidably fitted inside the upper pump cylinder, the upper reversing protective inner sleeve is fixedly connected to the lower end face of the upper plunger, and the lower end of the upper reversing protective inner sleeve abuts against the upper end of the reversing push rod.

[0018] The lower plunger assembly includes a lower plunger, a lower pump barrel, and a lower reversing protective inner sleeve; the lower pump barrel is coaxially fixed to the lower end of the outer shell, the lower plunger is slidably fitted inside the lower pump barrel, and the lower reversing protective inner sleeve is fixedly connected to the upper end face of the lower plunger, with the upper end of the lower reversing protective inner sleeve abutting against the lower end of the reversing push rod.

[0019] The upper end of the plunger connecting rod is fixedly connected to the upper plunger, and the lower end is fixedly connected to the lower plunger, so as to realize the synchronous axial movement of the upper and lower plungers.

[0020] Furthermore, an upper reversing protection outer sleeve is coaxially sleeved on the outer side of the upper reversing protection inner sleeve. The upper end of the upper reversing protection outer sleeve is sealed to the upper pump cylinder, and the lower end is sealed to the upper end face of the upper locking cap of the reversing valve. The annular space between the upper reversing protection outer sleeve and the upper reversing protection inner sleeve forms an upper reversing protection manifold. The upper reversing protection manifold is connected to the working fluid depletion return channel through the upper reversing protection sleeve drainage channel.

[0021] The lower reversing protection inner sleeve is coaxially fitted with a lower reversing protection outer sleeve. The lower end of the lower reversing protection outer sleeve is sealed to the lower pump cylinder, and the upper end is sealed to the lower end face of the reversing valve lower lock cap. The annular space between the lower reversing protection outer sleeve and the lower reversing protection inner sleeve forms a lower reversing protection liquid collection chamber. The lower reversing protection liquid collection chamber is connected to the working fluid depletion return channel through the lower reversing protection sleeve drainage channel.

[0022] The present invention also provides a reversing method for a hydraulically driven rodless oil production device, which is based on the above-mentioned reversing structure and includes a lower stroke reversing operation process and an upper stroke reversing operation process.

[0023] The downward stroke reversing operation process is as follows: the high-pressure working fluid flows downward along the working fluid injection channel, passes through the drain channel of the upper lock cap of the reversing valve, the annular channel on the reversing rod, and enters the upper liquid collection chamber of the reversing valve core, pushing the reversing valve core to slide downward to the lower stop point; the working fluid injection channel is connected to the annular channel on the reversing valve core through the working fluid inlet, and the high-pressure working fluid flows into the upper section of the upper and lower liquid cylinder drain channels through the inlet of the upper liquid cylinder drain channel, enters the upper liquid cylinder, and pushes the upper plunger, plunger connecting rod, and lower plunger downward synchronously; the working fluid in the lower liquid cylinder enters the lower annular channel of the reversing valve core through the lower section of the upper and lower liquid cylinder drain channels and the drain port of the lower liquid cylinder drain channel, and finally flows into the working fluid return channel and rises to the ground.

[0024] The upper stroke reversing operation process is as follows: When the upper plunger descends to the reversing position, it pushes the reversing push rod down to the lower dead center through the upper reversing protection inner sleeve, cutting off the control flow channel on the upper locking cap side and simultaneously connecting the control flow channel on the lower locking cap side; the high-pressure working fluid descends along the working fluid injection channel, passes through the lower locking cap drain channel of the reversing valve, the lower annular channel of the reversing push rod, and the lower locking cap drain port of the reversing valve, and enters the lower liquid collection chamber of the reversing valve core, pushing the reversing valve core to slide upward to the upper dead center; the working fluid injection channel is connected to the lower annular channel of the reversing valve core through the working fluid inlet, and the high-pressure working fluid flows into the lower section of the upper and lower liquid cylinder drain channels through the lower liquid cylinder drain channel outlet, enters the lower liquid cylinder, and pushes the lower plunger, plunger connecting rod, and upper plunger to move upward synchronously; the working fluid in the upper liquid cylinder enters the upper annular channel of the reversing valve core through the upper section of the upper and lower liquid cylinder drain channels and the upper liquid cylinder drain channel inlet, and finally merges into the working fluid return channel and rises to the ground.

[0025] Furthermore, during the downward stroke reversing operation, the low-pressure liquid in the lower manifold of the reversing valve core is discharged into the working fluid depletion return channel one through the lower manifold drain port and the lower lock cap drain channel of the reversing valve; the sealing leakage liquid in the upper reversing protection manifold and the lower reversing protection manifold respectively flows into the working fluid depletion return channel one through the upper reversing protection sleeve drain channel and the lower reversing protection sleeve drain channel, and is lifted to the ground along with the working fluid depletion.

[0026] Furthermore, during the upper stroke reversing operation, the low-pressure liquid in the upper liquid collection chamber of the reversing valve core is discharged into the working fluid depletion return channel one through the upper liquid collection chamber drain port and the upper lock cap drain channel of the reversing valve; the sealing leakage liquid in the upper reversing protection liquid collection chamber and the lower reversing protection liquid collection chamber is respectively discharged into the working fluid depletion return channel one through the corresponding drain channels, and is lifted to the ground together with the working depletion liquid.

[0027] Furthermore, during the reciprocating motion of the upper and lower plungers, the produced fluid at the bottom of the well is continuously lifted upward through the first and second bottom-hole produced fluid lifting channels, respectively, to achieve continuous oil production operations throughout the entire stroke.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] ① In this invention, a reversing mode combining mechanical triggering and hydraulic drive is adopted. The reversing rod is driven by the movement of the plunger to switch the control oil circuit, and then the hydraulic pressure pushes the reversing valve core to complete the reversing. This not only avoids the impact and wear problem of pure mechanical reversing, but also solves the defects of pure hydraulic reversing such as lag and jamming, thus improving the reliability and stability of reversing.

[0030] ② In this invention, a multi-channel integrated outer shell structure with alternating circumferential distribution is adopted, which integrates all flow channels such as working fluid injection, depleted fluid return, and produced fluid lifting with bolt connection holes into the outer shell wall. The structure is uniformly stressed and compact, which improves the structural integration.

[0031] ③ In this invention, a multi-layered structure of coaxially nested valve core, push rod, and connecting rod is set up, which, together with the control flow channel of the upper and lower locking caps, realizes the layered layout of the control oil circuit and the power oil circuit. The flow channel logic is clear, the sealing level is well defined, and the risk of fluid leakage failure is reduced.

[0032] ④ In this invention, a multi-stage sealing and leakage fluid recovery chamber is set up to collect the leaked working fluid at the protective sleeve into the exhausted fluid return channel for lifting, thereby avoiding cross-contamination between the working fluid and the produced fluid, reducing the risk of seal failure, and improving the service life of the device and the oil production efficiency.

[0033] ⑤ In this invention, the working fluid inlet and outlet and the waste fluid recovery are completed simultaneously during the reversal process. The produced fluid can be continuously lifted through the dual lifting channels, achieving continuous fluid inlet and continuous lifting for oil production, and further improving the efficiency of oil production operations. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0035] Figure 1 This is a radial sectional view of the reversing valve housing;

[0036] Figure 2 This is a schematic diagram of the reversing valve housing;

[0037] Figure 3 It is a cross-sectional schematic diagram of the working fluid injection channel to the bottom-of-well produced fluid lifting channel and the upper and lower liquid cylinder discharge channels (working fluid inlet state during the lower stroke);

[0038] Figure 4 It is a cross-sectional schematic diagram of the working fluid depletion return channel to the bottom-of-well produced fluid lifting channel and the upper / lower liquid cylinder discharge channel (lower stroke depletion return state);

[0039] Figure 5 It is a cross-sectional schematic diagram of the working fluid injection channel to the bottom-of-well produced fluid lifting channel and the upper / lower liquid cylinder discharge channel (working fluid inlet state during the upper stroke);

[0040] Figure 6 This is a cross-sectional diagram of the working fluid injection channel to the bottom-of-well produced fluid lifting channel and the upper / lower liquid cylinder discharge channel (upper stroke, exhausted fluid return state).

[0041] In the diagram: 1. Working fluid injection channel; 2. Outer shell; 3. Upper reversing protection outer sleeve sealing ring; 4. Upper reversing protection inner sleeve sealing ring; 5. Upper reversing protection outer sleeve; 6. Reversing valve upper locking cap; 7. Reversing valve upper locking cap drain channel; 8. Reversing push rod upper annular channel; 9. Reversing push rod; 10. Reversing valve core; 11. Upper liquid cylinder drain channel inlet; 12. Reversing valve core upper annular channel; 13. Working fluid inlet; 14. Lower liquid cylinder drain channel drain outlet; 15. Plunger connector 16. Lower annular channel of the reversing valve core; 17. Lower annular channel of the reversing push rod; 18. Drainage channel of the lower lock cap of the reversing valve; 19. Lower reversing protection outer sleeve; 20. Lower reversing protection inner sleeve rubber ring; 21. Lower reversing protection inner sleeve; 22. Lower retaining ring; 23. Lower pump cylinder; 24. Lower plunger; 25. Sealing rubber ring of the lower reversing protection outer sleeve; 26. Lower lock cap of the reversing valve; 27. Drainage port of the lower lock cap of the reversing valve; 28. Lower manifold of the reversing valve core; 29. ​​Upper manifold of the reversing valve core; 30. 31. Upper reversing protection inner sleeve; 32. Upper plunger; 33. Upper retaining ring; 34. Upper pump cylinder; 35. Upper reversing protection sleeve drain channel; 36. Upper drain port of working fluid depletion lifting channel; 37. Intermediate partition of upper and lower liquid cylinder drain channels; 38. Lower drain port of working fluid depletion lifting channel; 39. Lower reversing valve lower lock cap drain channel; 40. Lower reversing protection sleeve drain channel; 41. Lower reversing protection manifold; 42. Lower manifold drain port; 43. Upper reversing valve lower lock cap drain channel; 44. Upper reversing protection inner sleeve drain channel; 45. Upper reversing protection inner sleeve drain channel; 46. Upper reversing protection inner sleeve drain channel; 47. Upper reversing protection inner sleeve drain channel; 48. Upper reversing protection inner sleeve drain channel; 49. Upper reversing protection inner sleeve drain channel; 40. Upper reversing protection inner sleeve drain channel; 41. Upper reversing protection inner sleeve drain channel; 42. Upper reversing protection inner sleeve drain channel; 43. Upper reversing protection inner sleeve ... 44. Protective manifold; 45. Reversing rod isolation inner sleeve; 46. Working fluid lower inlet channel; 47. Lower cylinder inlet channel; 48. Reversing valve lower lock cap inlet; 49. Upper and lower cylinder discharge channels; 40. Upper cylinder discharge channel; 41. Lower cylinder discharge channel; 42. Working fluid depletion return channel one; 53. Working fluid depletion return channel two; 54. Bottom-hole produced fluid lifting channel one; 55. Bottom-hole produced fluid lifting channel two; 56. Center hole; 57. Bolt connection hole. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation

[0043] like Figures 1-6 As shown in the figure, the reversing structure of the hydraulically driven rodless oil production device in this embodiment is a coaxial multi-layer nested cylindrical structure, mainly composed of an outer shell 2 and an internal reversing actuator, used for reversing the downhole dynamic fluid of the hydraulically driven rodless oil production device to realize the reciprocating motion of the plunger and the continuous lifting of the produced fluid.

[0044] like Figures 1-6 As shown, the outer shell 2 is an integral cylindrical structure, serving as the supporting base for the entire reversing device. It has a central hole 53 that runs through the entire axial length, used to install the internal reversing actuator.

[0045] like Figures 1-2 As shown, within the annular wall of the outer shell 2, six independent circular fluid channels extending axially and evenly distributed along the circumference are connected to six circular bolt holes 54. That is, a bolt hole 54 is arranged between every two fluid channels to ensure uniform circumferential force on the outer shell. The six fluid channels are, in sequence: working fluid injection channel 1, upper and lower liquid cylinder discharge channel 48, working fluid depletion return channel one 49, working fluid depletion return channel two 50, bottom hole produced fluid lifting channel one 51, and bottom hole produced fluid lifting channel two 52.

[0046] Bolt connection hole 54 is an axial through hole used to pass through connecting bolts, fixing the pump barrel outer sleeve body of the oil production device at both ends of the reversing structure to the outer shell 2, forming an integral pump barrel structure. The pump barrel outer sleeve body is correspondingly machined with axial deep hole channels, which are connected and sealed with each axial channel on the outer shell 2 to form a closed fluid circulation channel, providing a power transmission and fluid lifting path for the downhole oil production device.

[0047] like Figures 1-6As shown, the functions of each fluid channel are as follows: the working fluid injection channel 1 is used to transport the high-pressure working fluid injected by the three-plunger pump on the ground; the upper and lower cylinder discharge channel 48 is provided with an internal partition 37, which divides the channel into the upper cylinder discharge channel 481 and the lower cylinder discharge channel 482, which are connected to the upper and lower cylinders respectively, and are used to input power fluid into the cylinder or discharge waste fluid; the working fluid waste return channel 1 49 and the working fluid waste return channel 2 50 are used to lift the working waste fluid after work back to the ground; the bottom well produced fluid lifting channel 1 51 and the bottom well produced fluid lifting channel 2 52 are used to lift the crude oil produced at the bottom of the well to the ground.

[0048] like Figures 1-6 As shown, the internal reversing actuator is coaxially assembled in the center hole 53 of the housing 2. It adopts a four-layer coaxial nested structure consisting of the housing, reversing valve core, reversing push rod, and plunger connecting rod. From the outside to the inside, the components are housing 2, reversing valve core 10, reversing push rod 9, and plunger connecting rod 15. With the cooperation of upper and lower locking caps, plunger assembly, and sealing protection structure, automatic reversing is achieved through mechanical triggering and hydraulic drive.

[0049] like Figures 1-6 As shown, the upper locking cap 6 and the lower locking cap 26 of the directional control valve are fixedly installed on the upper and lower ports of the central hole 53 by threads or interference fit, respectively, and play a role in axial limiting, sealing and flow channel transfer for the internal directional control valve core 10. The upper locking cap 6 is located directly above the directional control valve core 10, and the lower locking cap 26 is located directly below the directional control valve core 10.

[0050] The directional valve core 10 is a hollow cylindrical structure that can be slidably mounted in the middle of the central hole 53 along the axial direction. Its outer wall is clearance-fitted with the inner wall of the central hole 53 and is provided with a dynamic sealing structure. The upper end of the directional valve core 10 is provided with an independent upper hydraulic chamber 29, and the lower end is provided with an independent lower hydraulic chamber 28. The two chambers are not connected to each other and serve as the upper and lower hydraulic chambers for directional driving, respectively.

[0051] An annular groove is machined on the upper part of the outer wall of the reversing valve core 10 to form an upper annular channel 12 of the reversing valve core; an annular groove is machined on the lower part of the outer wall to form a lower annular channel 16 of the reversing valve core. The two annular channels are independent of each other and correspond to different flow channel connection states.

[0052] The working fluid inlet 13 is radially machined on the side wall of the reversing valve core 10. The outer end of the working fluid inlet 13 faces the inner wall of the outer casing 2 and can move axially with the reversing valve core 10. It is connected to the working fluid injection channel 1 on the outer casing respectively. The inner end of the working fluid inlet 13 is connected to the upper annular channel 12 and the lower annular channel 16 of the reversing valve core respectively.

[0053] The side wall of the reversing valve core 10 is also machined with an upper liquid cylinder drain channel inlet 11 and a lower liquid cylinder drain channel outlet 14. The upper liquid cylinder drain channel inlet 11 is opened radially, with its outer end corresponding to the upper section (upper liquid cylinder drain channel 481) of the upper and lower liquid cylinder drain channels 48, and its inner end corresponding to the upper annular channel 12 of the reversing valve core; the lower liquid cylinder drain channel outlet 14 is opened radially, with its outer end corresponding to the lower section (lower liquid cylinder drain channel 482) of the upper and lower liquid cylinder drain channels 48, and its inner end corresponding to the lower annular channel 16 of the reversing valve core.

[0054] like Figures 1-6 As shown, the reversing push rod 9 is a hollow sleeve structure, coaxially inserted into the central through hole of the reversing valve core 10, and can slide independently axially relative to the reversing valve core 10. An annular groove is machined on the upper part of the outer wall of the reversing push rod 9, forming an upper annular channel 8; an annular groove is machined on the lower part of the outer wall, forming a lower annular channel 17. The upper end of the reversing push rod abuts against the upper plunger assembly, and the lower end abuts against the lower plunger assembly, moving axially synchronously with the reciprocating motion of the plunger to achieve the switching of the control oil circuit.

[0055] Two independent channels are radially formed on the wall of the directional valve upper locking cap 6: the directional valve upper locking cap drain channel 7 and the directional valve upper locking cap drain channel 30. The outer end of the directional valve upper locking cap drain channel 7 is connected to the working fluid injection channel 1, and the inner end opening faces the outer wall of the directional valve push rod 9; the inner end opening of the directional valve upper locking cap drain channel 30 faces the outer wall of the directional valve push rod 9, and the outer end is connected to the liquid collection chamber 29 on the directional valve core.

[0056] When the reversing push rod 9 is at the top dead center position, the annular channel 8 on the reversing push rod is aligned with the inner openings of the drain channel 7 and the drain channel 30 of the upper lock cap of the reversing valve, so that the two are connected and the high-pressure working fluid can enter the upper fluid chamber to push the valve core downward; when the reversing push rod 9 moves downward, the inner ends of the annular channel 8 on the reversing push rod are offset from the inner ends of the two channels, and the control oil circuit is cut off.

[0057] Two independent channels are radially formed on the wall of the lower locking cap 26 of the directional valve: the lower locking cap drain channel 18 and the lower locking cap drain port 27. The outer end of the lower locking cap drain channel 18 is connected to the working fluid injection channel 1, and the inner end opening faces the outer wall of the directional push rod 9; the inner end opening of the lower locking cap drain port 27 faces the outer wall of the directional push rod 9, and the outer end is connected to the lower fluid collection chamber 28 of the directional valve core.

[0058] When the reversing push rod 9 is at the bottom dead center position, the lower annular channel 17 of the reversing push rod is simultaneously aligned with the inner end opening of the lower lock cap drain channel 18 and the lower lock cap drain port 27 of the reversing valve, so that the two are connected and the high pressure working fluid can enter the lower manifold to push the valve core upward; when the reversing push rod 9 moves upward, the inner ends of the lower annular channel 17 of the reversing push rod are offset from the inner ends of the two channels, and the control oil circuit is cut off.

[0059] like Figures 1-6 As shown, the plunger connecting rod 15 is a solid rod shape, coaxially passing through the central inner hole of the reversing push rod 9. Its upper end is fixedly connected to the center of the lower end face of the upper plunger 32, and its lower end is fixedly connected to the center of the upper end face of the lower plunger 24, so that the upper plunger 32, the plunger connecting rod 15, and the lower plunger 24 form a rigid synchronous moving body.

[0060] The upper plunger assembly includes an upper plunger 32, an upper pump barrel 34, an upper reversing protective inner sleeve 31, and an upper reversing protective outer sleeve 5. The upper pump barrel 34 is coaxially fixedly connected to the upper end of the outer casing 2, maintaining coaxiality with the outer casing 2. The upper plunger 32 is slidably installed in the inner cavity of the upper pump barrel 34 through a seal. The lower end face of the upper plunger 32 is fixedly connected to the upper reversing protective inner sleeve 31, which extends downwards, and its lower end face abuts against the upper end face of the reversing push rod 9.

[0061] The upper reversing protection outer sleeve 5 is coaxially fitted onto the outside of the upper reversing protection inner sleeve 31. Its upper end is sealed to the lower end of the upper pump cylinder 34, and its lower end is sealed to the upper end face of the reversing valve upper locking cap 6. The annular space between the upper reversing protection outer sleeve 5 and the upper reversing protection inner sleeve 31 forms the upper reversing protection manifold 43, which is used to collect the working fluid leaking from the seal. The upper reversing protection manifold 43 is connected to the working fluid depletion return channel 49 through the upper reversing protection sleeve drainage channel 35, which can discharge the leaked fluid into the depletion channel for lifting.

[0062] An upper reversing protective sleeve sealing ring 3 is provided between the mating surface of the upper reversing protective sleeve 5 and the outer shell 2, and an upper reversing protective inner sleeve sealing ring 4 is provided between the upper reversing protective inner sleeve 31 and the mating surface, realizing multi-stage static and dynamic sealing. An upper retaining ring 33 is also provided at the upper end of the upper pump cylinder 34 to limit the upper dead center position of the upper plunger 32.

[0063] The lower plunger assembly includes a lower plunger 24, a lower pump barrel 23, a lower reversing protective inner sleeve 21, and a lower reversing protective outer sleeve 19. The lower pump barrel 23 is coaxially and fixedly connected to the lower end of the outer casing 2, maintaining coaxiality with the outer casing 2. The lower plunger 24 is slidably installed in the inner cavity of the lower pump barrel 23 through a seal. The lower reversing protective inner sleeve 21 is fixedly connected to the upper end face of the lower plunger 24. The lower reversing protective inner sleeve 21 extends upward, and its upper end face abuts against the lower end face of the reversing push rod 9.

[0064] The lower reversing protection outer sleeve 19 is coaxially sleeved on the outside of the lower reversing protection inner sleeve 21. Its lower end is sealed to the upper end of the lower pump cylinder 23, and its upper end is sealed to the lower end face of the reversing valve lower lock cap 26. The annular space between the lower reversing protection outer sleeve 19 and the lower reversing protection inner sleeve 21 forms the lower reversing protection manifold 41, which is used to collect the working fluid leaking from the seal. The lower reversing protection manifold 41 is connected to the working fluid depletion return channel 49 through the lower reversing protection sleeve drainage channel 40, which can discharge the leaked fluid into the depletion channel for lifting.

[0065] A lower reversing protective outer sleeve 19 is provided with a lower reversing protective outer sleeve sealing ring 25 between its mating surface and the outer shell 2, and a lower reversing protective inner sleeve sealing ring 20 is provided between its mating surface and the lower reversing protective inner sleeve 21, achieving multi-stage static and dynamic sealing. A lower retaining ring 22 is also provided at the lower end of the lower pump cylinder 23 to limit the lower stop position of the lower plunger 24.

[0066] The reversing method of the hydraulically driven rodless oil production device in this embodiment is based on the above-mentioned reversing structure. It adopts a combined principle of mechanical reversing triggering and hydraulic driving reversing, and is divided into two cyclic processes: the lower stroke reversing operation and the upper stroke reversing operation, as detailed below:

[0067] like Figures 4-5 As shown, in the initial state, the reversing push rod 9 is at the top dead center position, and the annular channel 8 on the reversing push rod is connected to the drain channel 7 of the upper lock cap of the reversing valve and the drain channel 30 of the upper lock cap of the reversing valve.

[0068] The high-pressure working fluid output from the surface three-plunger pump is injected downhole through the tubing string. It flows downwards along the circumferential working fluid injection channel 1 of the outer casing 2, first entering the directional valve upper lock cap drainage channel 7 of the directional valve upper lock cap 6, then flowing into the directional valve upper lock cap drainage channel 30 through the annular channel 8 on the directional push rod, and finally entering the upper fluid collection chamber 29 of the directional valve core. As the high-pressure working fluid continues to be injected, the pressure in the upper fluid collection chamber 29 of the directional valve core increases, pushing the directional valve core 10 downwards along the central hole 53 until it reaches the lower dead center position.

[0069] When the directional valve core 10 reaches its lower dead center, the working fluid inlet 13 on the side wall of the directional valve core aligns and connects with the working fluid injection channel 1, and simultaneously connects with the annular channel 12 on the upper part of the directional valve core. High-pressure working fluid enters the annular channel 12 on the upper part of the directional valve core through the working fluid inlet 13, then flows through the upper cylinder discharge channel inlet 11 into the upper cylinder discharge channel 481 of the upper and lower cylinder discharge channels 48, and finally enters the upper cylinder cavity above the upper plunger 32. The high-pressure working fluid pushes the upper plunger 32 downwards, and the upper plunger 32 drives the lower plunger 24 to move downwards synchronously via the plunger connecting rod 15.

[0070] During the downward movement of the lower plunger 24, the working fluid in the lower cylinder chamber below the lower plunger 24 is squeezed and flows upward through the lower cylinder discharge channel 482. It enters the lower annular channel 16 of the reversing valve core through the discharge port 14 of the lower cylinder discharge channel, and then flows into the working fluid return channel 49 through the lower discharge port 38 of the working fluid lifting channel, and is lifted upward along the channel to the ground.

[0071] Meanwhile, the low-pressure liquid in the lower manifold 28 of the reversing valve core is discharged into the working fluid depletion return channel 49 through the lower manifold drain port 42 and the lower lock cap drain channel 39 of the reversing valve; the sealing leakage liquid collected in the upper reversing protection manifold 43 and the lower reversing protection manifold 41 is discharged into the working fluid depletion return channel 49 through the upper reversing protection sleeve drain channel 35 and the lower reversing protection sleeve drain channel 40 respectively, and is lifted to the ground along with the working depletion liquid to prevent the leakage liquid from entering the produced fluid channel.

[0072] During the downward movement of the upper and lower plungers, the produced fluid at the bottom of the well enters the lifting channel through the pump valve, and is continuously lifted upward through the bottom produced fluid lifting channel 1 51 and the bottom produced fluid lifting channel 2 52, respectively, to achieve continuous oil production during the downward movement.

[0073] like Figures 5-6 As shown, when the upper plunger 32 moves downward to the set reversing position, the upper reversing protection inner sleeve 31 at the lower end of the upper plunger contacts the upper end of the reversing push rod 9, pushing the reversing push rod 9 to move downward synchronously. When the reversing push rod 9 moves to the lower stop position, the annular channel 8 on the reversing push rod is offset downward, cutting off the connection between the upper lock cap drain channel 7 and the upper lock cap drain channel 30 of the reversing valve; at the same time, the lower annular channel 17 on the reversing push rod moves downward to the corresponding position, connecting the lower lock cap drain channel 18 and the lower lock cap drain port 27 of the reversing valve.

[0074] At this time, the high-pressure working fluid continues to flow downward along the working fluid injection channel 1, flowing into the lower lock cap drain channel 18 of the lower lock cap 26 of the reversing valve, and then into the lower lock cap drain port 27 of the reversing valve through the annular channel 17 under the reversing push rod, finally entering the lower manifold chamber 28 of the reversing valve core. As the high-pressure working fluid continues to be injected, the pressure in the lower manifold chamber 28 of the reversing valve core increases, pushing the reversing valve core 10 to move upward along the central hole 53 until it reaches the top dead center position.

[0075] When the reversing valve core 10 reaches its top dead center, the working fluid inlet 13 on the side wall of the reversing valve core aligns and connects with the working fluid injection channel 1, and simultaneously connects with the lower annular channel 16 of the reversing valve core. High-pressure working fluid enters the lower annular channel 16 of the reversing valve core through the working fluid inlet 13, then flows through the lower cylinder discharge port 14 into the lower cylinder discharge channel 482 of the upper and lower cylinder discharge channels 48, and finally enters the lower cylinder cavity below the lower plunger 24. The high-pressure working fluid pushes the lower plunger 24 upwards, and the lower plunger 24 drives the upper plunger 32 to move upwards synchronously via the plunger connecting rod 15.

[0076] During the upward movement of the upper plunger 32, the working fluid in the upper liquid cylinder cavity above the upper plunger 32 is squeezed and flows downward through the upper liquid cylinder discharge channel 481. It enters the annular channel 12 on the reversing valve core through the upper liquid cylinder discharge channel inlet 11, and then flows into the working fluid return channel 49 through the upper working fluid lifting channel discharge port 36, and is lifted upward along the channel to the ground.

[0077] At the same time, the low-pressure liquid in the upper liquid collection chamber 29 of the reversing valve core is discharged into the working fluid depletion return channel 49 through the upper liquid collection chamber drain port and the upper lock cap drain channel 30 of the reversing valve; the sealing leakage liquid collected in the upper reversing protection liquid collection chamber 43 and the lower reversing protection liquid collection chamber 41 is discharged into the working fluid depletion return channel 49 through the corresponding drain channels, and is lifted to the ground along with the working depletion liquid.

[0078] During the upward movement of the upper and lower plungers, the produced fluid at the bottom of the well is continuously lifted upward through the bottom produced fluid lifting channel 1 51 and the bottom produced fluid lifting channel 2 52, thereby achieving continuous oil production during the upward movement.

[0079] When the upper plunger 32 moves upward to the upper dead center position, the lower reversing protection inner sleeve 21 drives the reversing push rod 9 to reset upward, reconnecting the control oil circuit on the upper lock cap side, and the reversing valve core switches to the lower stroke state again. This cycle repeats to achieve continuous reciprocating motion of the plunger and continuous lifting of the produced fluid.

[0080] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A reversing structure for a hydraulically driven rodless oil extraction device, characterized in that, It includes a coaxially arranged outer housing (2) and a reversing actuator assembled inside the outer housing (2); The outer shell (2) has an axially through central hole (53) at its center. The annular wall of the outer shell (2) has six axially extending independent fluid channels and six bolt connection holes (54) evenly distributed along the circumference. The six fluid channels are, in order, the working fluid injection channel (1), the upper and lower liquid cylinder discharge channel (48), the working fluid depletion return channel one (49), the working fluid depletion return channel two (50), the bottom well produced fluid lifting channel one (51), and the bottom well produced fluid lifting channel two (52). The bolt connection hole (54) is an axial through hole used to fix and connect the pump cylinder outer shell body at the upper and lower ends of the oil production device. The reversing actuator includes a reversing valve core (10), a reversing push rod (9), a reversing valve upper locking cap (6), a reversing valve lower locking cap (26), a plunger connecting rod (15), an upper plunger assembly, and a lower plunger assembly; the reversing valve core (10) is a hollow cylindrical structure and is axially slidably coaxially assembled in the central hole (53); the reversing push rod (9) is a hollow sleeve structure and is axially slidably coaxially inserted in the central through hole of the reversing valve core (10); The plunger connecting rod (15) is coaxially inserted into the center hole of the reversing push rod (9), with its upper end fixedly connected to the upper plunger assembly and its lower end fixedly connected to the lower plunger assembly; the upper locking cap (6) of the reversing valve is fixedly installed at the upper end port of the center hole (53), located above the reversing valve core (10); the lower locking cap (26) of the reversing valve is fixedly installed at the lower end port of the center hole (53), located below the reversing valve core (10).

2. The reversing structure of a hydraulically driven rodless oil production device according to claim 1, characterized in that, The wall of the directional valve upper lock cap (6) is provided with a directional valve upper lock cap drain channel (7) and a directional valve upper lock cap drain channel (30) in the radial direction. The outer end of the drain channel (7) on the directional valve lock cap is connected to the working fluid injection channel (1), and the inner end faces the outer wall of the directional valve push rod (9); the inner end of the drain channel (30) on the directional valve lock cap faces the outer wall of the directional valve push rod (9), and the outer end is connected to the liquid collection chamber (29) on the directional valve core inside the directional valve core (10); The upper part of the outer wall of the reversing push rod (9) is provided with an annular channel (8) on the reversing push rod. When the reversing push rod (9) is at the upper stop point, the annular channel (8) on the reversing push rod is simultaneously connected to the inner end of the upper lock cap drain channel (7) of the reversing valve and the upper lock cap drain channel (30) of the reversing valve.

3. The reversing structure of a hydraulically driven rodless oil production device according to claim 1, characterized in that, The wall of the reversing valve lower lock cap (26) is provided with a reversing valve lower lock cap drain channel (18) and a reversing valve lower lock cap drain port (27) in the radial direction. The outer end of the drain channel (18) of the lower lock cap of the reversing valve is connected to the working fluid injection channel (1), and the inner end faces the outer wall of the reversing push rod (9); the inner end of the drain port (27) of the lower lock cap of the reversing valve faces the outer wall of the reversing push rod (9), and the outer end is connected to the lower liquid collection chamber (28) of the reversing valve core (10) inside the reversing valve core; The lower part of the outer wall of the reversing push rod (9) is provided with a reversing push rod lower annular channel (17). When the reversing push rod (9) is at the lower stop point, the reversing push rod lower annular channel (17) is simultaneously connected to the inner end of the reversing valve lower lock cap drain channel (18) and the reversing valve lower lock cap drain port (27).

4. The reversing structure of a hydraulically driven rodless oil production device according to claim 1, characterized in that, The upper part of the outer wall of the reversing valve core (10) is provided with an upper annular channel (12) and the lower part of the outer wall is provided with a lower annular channel (16). The reversing valve core (10) has a working fluid inlet (13) radially opened on its side wall. The outer end of the working fluid inlet (13) can slide axially with the reversing valve core (10) and is connected to the working fluid injection channel (1). The inner end of the working fluid inlet (13) is connected to the upper annular channel (12) of the reversing valve core and the lower annular channel (16) of the reversing valve core, respectively. The side wall of the reversing valve core (10) is also provided with an upper liquid cylinder drain channel inlet (11) and a lower liquid cylinder drain channel outlet (14); the outer end of the upper liquid cylinder drain channel inlet (11) is connected to the upper section of the upper and lower liquid cylinder drain channels (48), and the inner end is connected to the upper annular channel (12) of the reversing valve core; the outer end of the lower liquid cylinder drain channel outlet (14) is connected to the lower section of the upper and lower liquid cylinder drain channels (48), and the inner end is connected to the lower annular channel (16) of the reversing valve core.

5. The reversing structure of a hydraulically driven rodless oil extraction device according to claim 1, characterized in that, The upper plunger assembly includes an upper plunger (32), an upper pump cylinder (34), and an upper reversing protective inner sleeve (31); the upper pump cylinder (34) is coaxially fixed to the upper end of the outer shell (2), the upper plunger (32) is sealed and slidably assembled inside the upper pump cylinder (34), the upper reversing protective inner sleeve (31) is fixedly connected to the lower end face of the upper plunger (32), and the lower end of the upper reversing protective inner sleeve (31) abuts against the upper end of the reversing push rod (9); The lower plunger assembly includes a lower plunger (24), a lower pump barrel (23), and a lower reversing protective inner sleeve (21); the lower pump barrel (23) is coaxially fixed to the lower end of the outer shell (2), the lower plunger (24) is sealed and slidably assembled inside the lower pump barrel (23), the lower reversing protective inner sleeve (21) is fixedly connected to the upper end face of the lower plunger (24), and the upper end of the lower reversing protective inner sleeve (21) abuts against the lower end of the reversing push rod (9); The upper end of the plunger connecting rod (15) is fixedly connected to the upper plunger (32), and the lower end is fixedly connected to the lower plunger (24), so as to realize the synchronous axial movement of the upper and lower plungers.

6. The reversing structure of a hydraulically driven rodless oil production device according to claim 5, characterized in that, The upper reversing protection inner sleeve (31) is coaxially fitted with an upper reversing protection outer sleeve (5). The upper end of the upper reversing protection outer sleeve (5) is sealed to the upper pump cylinder (34), and the lower end is sealed to the upper end face of the reversing valve upper lock cap (6). The annular space between the upper reversing protection outer sleeve (5) and the upper reversing protection inner sleeve (31) forms an upper reversing protection liquid collection chamber (43). The upper reversing protection liquid collection chamber (43) is connected to the working fluid depletion return channel (49) through the upper reversing protection sleeve drainage channel (35). The lower reversing protection inner sleeve (21) is coaxially fitted with a lower reversing protection outer sleeve (19). The lower end of the lower reversing protection outer sleeve (19) is sealed to the lower pump cylinder (23), and the upper end is sealed to the lower end face of the reversing valve lower lock cap (26). The annular space between the lower reversing protection outer sleeve (19) and the lower reversing protection inner sleeve (21) forms a lower reversing protection liquid collection chamber (41). The lower reversing protection liquid collection chamber (41) is connected to the working fluid depletion return channel (49) through the lower reversing protection sleeve drainage channel (40).

7. A reversing method for a hydraulically driven rodless oil production device, implemented based on the reversing structure described in any one of claims 1-6, characterized in that, This includes the lower stroke reversing operation process and the upper stroke reversing operation process; The downward stroke reversing operation process is as follows: the high-pressure working fluid flows downward along the working fluid injection channel (1), passes through the drain channel (7) on the upper lock cap of the reversing valve, the annular channel (8) on the reversing rod, and the drain channel (30) on the upper lock cap of the reversing valve, and enters the liquid collection chamber (29) on the upper lock cap of the reversing valve core, pushing the reversing valve core (10) to slide downward to the lower stop point; the working fluid injection channel (1) is connected to the annular channel (12) on the upper lock cap of the reversing valve core through the working fluid inlet (13), and the high-pressure working fluid... The working fluid flows into the upper section of the upper and lower cylinder drainage channels (48) through the inlet (11) of the upper cylinder drainage channel, enters the upper cylinder and pushes the upper plunger (32), plunger connecting rod (15) and lower plunger (24) to move down synchronously; the working fluid in the lower cylinder enters the lower annular channel (16) of the reversing valve core through the lower section of the upper and lower cylinder drainage channels (48) and the drain outlet (14) of the lower cylinder drainage channel, and finally flows into the working fluid return channel (49) and is lifted to the ground; The upper stroke reversing operation process is as follows: when the upper plunger (32) moves down to the reversing position, it pushes the reversing rod (9) down to the lower dead point through the upper reversing protection inner sleeve (31), cutting off the control flow channel on the upper locking cap side and simultaneously connecting the control flow channel on the lower locking cap side; the high-pressure working fluid moves down along the working fluid injection channel (1), passes through the lower locking cap drain channel (18) of the reversing valve, the lower annular channel (17) of the reversing rod, and the lower locking cap drain port (27) of the reversing valve, and enters the lower liquid collection chamber (28) of the reversing valve core, pushing the reversing valve core (10) to slide upward to the upper dead point; the working fluid injection channel Channel (1) is connected to the lower annular channel (16) of the reversing valve core through the working fluid inlet (13). The high-pressure working fluid flows into the lower section of the upper and lower cylinder drain channel (48) through the drain port (14) of the lower cylinder drain channel, enters the lower cylinder and pushes the lower plunger (24), plunger connecting rod (15) and upper plunger (32) to move upward synchronously. The working fluid in the upper cylinder enters the upper annular channel (12) of the reversing valve core through the upper section of the upper and lower cylinder drain channel (48) and the upper cylinder drain channel inlet (11), and finally flows into the working fluid return channel (49) and is lifted to the ground.

8. The reversing method of a hydraulically driven rodless oil production device according to claim 7, characterized in that, During the downward stroke reversing operation, the low-pressure liquid in the lower manifold (28) of the reversing valve core is discharged into the working fluid depletion return channel (49) through the lower manifold drain port (42) and the lower lock cap drain channel (39) of the reversing valve; the sealing leakage liquid in the upper reversing protection manifold (43) and the lower reversing protection manifold (41) is discharged into the working fluid depletion return channel (49) through the upper reversing protection sleeve drain channel (35) and the lower reversing protection sleeve drain channel (40) respectively, and is lifted to the ground along with the working fluid depletion.

9. A reversing method for a hydraulically driven rodless oil production device according to claim 7, characterized in that, During the upper stroke reversing operation, the low-pressure liquid in the upper liquid collection chamber (29) of the reversing valve core is discharged into the working fluid depletion return channel one (49) through the upper liquid collection chamber drain port and the upper lock cap drain channel (30) of the reversing valve; the sealing leakage liquid in the upper reversing protection liquid collection chamber (43) and the lower reversing protection liquid collection chamber (41) is discharged into the working fluid depletion return channel one (49) through the corresponding drain channels, and is lifted to the ground along with the working depletion liquid.

10. A reversing method for a hydraulically driven rodless oil production device according to claim 7, characterized in that, During the reciprocating motion of the upper and lower plungers, the produced fluid at the bottom of the well is continuously lifted upward through the first (51) and the second (52) bottom produced fluid lifting channels, respectively, to achieve continuous oil production operation throughout the entire stroke.

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