An underground automatic reversing rodless pump

Abstract

The present invention discloses a downhole automatic reversing rodless pump, which comprises a pump barrel assembly and a piston assembly. The pump barrel assembly includes a plug, an inner tube, a short pump barrel, a long pump barrel, an outer tube, an upper limit short pump barrel and a production pump barrel, and the pump barrel assembly is fixed in a wellbore. The piston assembly includes a driving long piston rod, a driving piston, a nozzle, a connecting long piston rod and a production piston, and the piston assembly can reciprocate within the pump barrel assembly. A switch hole is provided on the connecting long piston rod, and a switch device is provided in cooperation with the switch hole. The switch device is linked with the up and down movements of the connecting long piston rod through a reversing trigger mechanism to realize the closing or opening of the switch hole. The present invention realizes downhole automatic reversing. Compared with the prior art solution of using surface equipment reversing to drive downhole pump units, it has a low failure rate and high efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole pump units, and particularly relates to a downhole automatic reversing rodless pump. Background Art

[0002] "Hydraulic piston production device and method for concentric pipes in coalbed methane wells" is an invention patent applied by the applicant on July 12, 2012, with the publication number CN102758602B. In this technical solution, ground equipment is used for commutation to drive the downhole pump unit, which has two disadvantages: 1. The commutation impact causes high failure rate of ground equipment; 2. When high and low pressures are switched in the wellbore, the tubing expands under pressure, resulting in an increase in the injection water volume and thus low efficiency.

[0003] To solve the above problems, the applicant has conducted research and improvement and proposed a downhole automatic reversing rodless pump. Summary of the Invention

[0004] The present invention provides a downhole automatic reversing rodless pump to solve the problems in the prior art.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A downhole automatic reversing rodless pump includes a pump barrel assembly and a piston assembly, wherein:

[0007] The pump barrel assembly includes a plug, an inner pipe, a short pump barrel, a long pump barrel, an outer pipe, an upper limit short pump barrel, and a production pump barrel. The pump barrel assembly is fixed in the wellbore;

[0008] The upper end of the plug is fixedly connected and sealed to the center pipe, and the lower end of the plug is fixedly connected and sealed to the upper end of the inner pipe; the inner pipe, the short pump barrel, the long pump barrel, the upper limit short pump barrel, and the production pump barrel are coaxially arranged from top to bottom and are fixedly connected and sealed to each other to form an inner pipe assembly; the inner pipe assembly is fixed in the outer pipe;

[0009] The piston assembly includes a driving long piston rod, a driving piston, a nozzle, a connecting long piston rod, and a production piston. The piston assembly can reciprocate in the pump barrel assembly;

[0010] The driving piston is installed in the long pump barrel and is slidably and sealedly connected thereto. The driving long piston rod slidably and sealedly passes through the short pump barrel and is fixedly connected to the driving piston; the nozzle is fixed to the lower side of the driving piston; the production piston is installed in the production pump barrel and is slidably and sealedly connected thereto. The connecting long piston rod slidably and sealedly passes through the upper limit short pump barrel, and the upper end of the connecting long piston rod is fixedly connected to the driving piston, and the lower end of the connecting long piston rod is fixedly connected to the production piston;

[0011] A central pipe channel A is formed in the plug, an annular channel B is directly formed between the tubing and the center pipe, an annular channel G is formed between the inner pipe assembly and the outer pipe, and the channel G is communicated with the channel B;

[0012] An axial first flow channel is provided on the driving long piston rod, and an axial second flow channel is provided on the driving piston. The second flow channel connects the first flow channel and the nozzle.

[0013] An axial third flow channel is provided on the connecting long piston rod. The upper end of the third flow channel is connected to the nozzle. At the same time, a radial fourth flow channel is provided on the connecting long piston rod. The long pump barrel forms a pump chamber D between the driving piston and the upper limit short pump barrel. The fourth flow channel connects the third flow channel and the pump chamber D.

[0014] The long pump barrel forms a pump chamber H between the short pump barrel and the driving piston. An external breathing hole connected to the wellbore is provided at the pump chamber H.

[0015] The production pump barrel forms a pump chamber K between the upper limit short pump barrel and the production piston. An internal drainage hole is provided on the production pump barrel. The internal drainage hole connects the pump chamber K and the channel G.

[0016] A switch hole is provided on the connecting long piston rod. The switch hole connects the third flow channel and the pump chamber K. At the same time, a switch device is provided in cooperation with the switch hole. The switch device is linked with the up and down movements of the connecting long piston rod through a commutation trigger mechanism to realize the closing or opening of the switch hole.

[0017] The production pump barrel forms a pump chamber J below the production piston. A drainage valve and a fixed valve are respectively provided at the position of the pump chamber J. The drainage valve connects the pump chamber J and the channel B, and the drainage valve is unidirectionally conductive from the pump chamber J to the channel B. The fixed valve connects the pump chamber J and the wellbore, and the fixed valve is unidirectionally conductive from the wellbore to the pump chamber J.

[0018] Further, the switch device is a switch sliding sleeve slidably sleeved on the connecting long piston rod.

[0019] The commutation trigger mechanism includes a commutation push rod provided on the production piston and a commutation stop block provided on the upper limit short pump barrel. The commutation push rod and the commutation stop block are in trigger cooperation with the switch sliding sleeve.

[0020] The commutation push rod axially penetrates through the production piston and is in sliding seal cooperation with it. The commutation push rod extends above and below the production piston. The commutation stop block is fixed on the lower side of the upper limit short pump barrel and protrudes downward.

[0021] Further, a commutation push plate is fixedly provided in the pump chamber J. The commutation push plate is in trigger cooperation with the commutation push rod.

[0022] Further, the inner pipe is threadedly connected to the short pump barrel, the short pump barrel is threadedly connected to the long pump barrel, the long pump barrel is threadedly connected to the upper limit short pump barrel, and the upper limit short pump barrel is threadedly connected to the production pump barrel.

[0023] Further, the upper end of the outer pipe is threadedly connected and sealed to the oil pipe, and the lower end of the outer pipe is fixedly connected and sealed to the production pump barrel.

[0024] Further, the driving long piston rod is in threaded connection with the driving piston.

[0025] Further, an installation groove is provided on the lower side of the driving piston. The nozzle is located in the installation groove. The upper end of the connecting long piston rod is in threaded connection with the driving piston to limit and fix the nozzle in the installation groove.

[0026] Further, the lower end of the connecting long piston rod is in threaded connection with the production piston.

[0027] Further, the nozzle is a Venturi nozzle.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. The present invention realizes automatic downhole commutation. Compared with the prior art solution of using surface equipment commutation to drive downhole pump sets, it has a low failure rate and high efficiency.

[0030] 2. The present invention forms a commutation trigger mechanism through a commutation stop block, a switch sliding sleeve, and a commutation push rod, which can be linked with the up and down movements of the connecting long piston rod to realize the closing or opening of the switch hole.

[0031] 3. The nozzle of the present invention adopts a Venturi structure to cooperate with the realization of automatic downhole commutation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of the present invention.

[0033] The drawings are only for illustrative purposes and should not be construed as a limitation to this patent; for better illustration of this embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

[0035] As Figure 1 shown, this embodiment discloses a downhole automatic commutation rodless pump, including a plug 1, an inner tube 2, a driving long piston rod 3, a short pump barrel 4, a long pump barrel 5, an outer tube 6, a driving piston 7, a Venturi nozzle 8, a connecting long piston rod 9, an upper limit short pump barrel 10, a switch sliding sleeve 11, a production pump barrel 12, a production piston 13, a commutation push rod 14, a drain valve 15, and a fixed valve 16. Among them:

[0036] The upper end of the plug 1 is fixedly connected to the central pipe by thread, and the lower end of the plug 1 is inserted into the upper joint of the inner pipe 2 and sealed by a sealing ring. In this embodiment, the plug 1 is selected in the form of internal insertion connection, and it can also be selected in the form of external insertion connection.

[0037] The inner pipe 2, the short pump barrel 4, the long pump barrel 5, the upper limit short pump barrel 10 and the production pump barrel 12 are coaxially arranged in sequence from top to bottom and are hermetically connected and fixed to form an inner pipe assembly; the inner pipe assembly is fixed in the outer pipe 6.

[0038] In this embodiment, the inner pipe 2 is threadedly connected to the short pump barrel 4, the short pump barrel 4 is threadedly connected to the long pump barrel 5, the long pump barrel 5 is threadedly connected to the upper limit short pump barrel 10, and the upper limit short pump barrel 10 is threadedly connected to the production pump barrel 12. After the above components are threadedly connected and sealed, they are installed and fixed in the outer pipe 6. The upper end of the outer pipe 6 is threadedly connected and sealed to the oil pipe, and the lower end of the outer pipe 6 is fixedly connected and sealed to the production pump barrel 12.

[0039] The above plug 1, inner pipe 2, short pump barrel 4, long pump barrel 5, upper limit short pump barrel 10, production pump barrel 12 and outer pipe 6 components that form the pump barrel assembly of the downhole pump set are fixed in the wellbore.

[0040] The driving piston 7 is installed in the long pump barrel 5 and is slidably and hermetically connected thereto. The driving long piston rod 3 slidably passes through the short pump barrel 4 in a sealed manner and is fixedly connected to the driving piston 7; the Venturi nozzle 8 is fixed on the lower side of the driving piston 7. The production piston 13 is installed in the production pump barrel 12 and is slidably and hermetically connected thereto. The connecting long piston rod 9 slidably passes through the upper limit short pump barrel 10 in a sealed manner, and the upper end of the connecting long piston rod 9 is fixedly connected to the driving piston 7, and the lower end of the connecting long piston rod 9 is fixedly connected to the production piston 13.

[0041] The above driving long piston rod 3, driving piston 7, nozzle 8, connecting long piston rod 9 and production piston part 13 components form the piston assembly of the downhole pump set and can reciprocate in the downhole pump set.

[0042] The matching clearances between the driving long piston rod 3 and the short pump barrel 4, the long pump barrel 5 and the driving piston 7, the connecting long piston rod 9 and the upper limit short pump barrel 10, and the production pump barrel 12 and the production piston 13 are very small to form a reciprocating operation seal and can reciprocate within the designed stroke.

[0043] In this embodiment, the driving long piston rod 3 is threadedly connected to the driving piston 7. An installation groove is provided on the lower side of the driving piston 4, and the Venturi nozzle 8 is located in the installation groove. The upper end of the connecting long piston rod 9 is threadedly connected to the driving piston 7 to limit and fix the Venturi nozzle 8 in the installation groove. The lower end of the connecting long piston rod 9 is threadedly connected to the production piston 13.

[0044] A central tube channel A is formed inside the plug 1. The oil pipe and the central tube directly form an annular channel B. An annular channel G is formed between the inner tube assembly and the outer tube 6, and the channel G communicates with the channel B.

[0045] An axial first flow channel is provided on the driving long piston rod 3, and an axial second flow channel is provided on the driving piston 7. The second flow channel connects the first flow channel and the Venturi nozzle 8.

[0046] An axial third flow channel is provided on the connecting long piston rod 9. The upper end of the third flow channel communicates with the Venturi nozzle 8. At the same time, a radial fourth flow channel is provided on the connecting long piston rod 9. The long pump barrel 5 forms a pump chamber D between the driving piston 7 and the upper limit short pump barrel 10, and the fourth flow channel connects the third flow channel and the pump chamber D.

[0047] The long pump barrel 5 forms a pump chamber H between the short pump barrel 4 and the driving piston 7. An external breathing hole C is provided at the pump chamber H and is connected to the wellbore outward.

[0048] The production pump barrel 12 forms a pump chamber K between the upper limit short pump barrel 10 and the production piston 13. An internal drainage hole E is provided on the production pump barrel 12, and the internal drainage hole E communicates the pump chamber K and the channel G.

[0049] A switch hole F is provided on the connecting long piston rod 9. The switch hole F communicates the third flow channel and the pump chamber K. At the same time, a switch device is provided in cooperation with the switch hole. The switch device is linked with the upward and downward movements of the connecting long piston rod 9 through a commutation trigger mechanism to realize the closing or opening of the switch hole.

[0050] In this embodiment, the switch device is a switch sliding sleeve 11 slidably sleeved on the connecting long piston rod 9. The connecting long piston rod 9 and the switch sliding sleeve 11 have a very small clearance for reciprocating operation sealing and can reciprocate within the designed stroke.

[0051] The commutation trigger mechanism includes a commutation push rod 14 provided on the production piston 13 and a commutation stop block 17 provided on the upper limit short pump barrel 10. The commutation push rod 14 and the commutation stop block 17 are in trigger cooperation with the switch sliding sleeve 11.

[0052] The commutation push rod 14 axially passes through the production piston 13 and is in sliding seal cooperation with it. The commutation push rod 14 extends above and below the production piston. The commutation push rod 14 can reciprocate with a small stroke relative to the production piston 13 and is sealed. The commutation stop block 17 is fixed on the lower side of the upper limit short pump barrel 10 and protrudes downward.

[0053] The production pump barrel 12 forms a pump chamber J below the production piston 13. A commutation push plate 18 is also fixedly provided in the pump chamber J, and the commutation push plate 18 is in trigger cooperation with the commutation push rod 14.

[0054] A drain valve 15 and a fixed valve 16 are respectively provided at the position of the pump chamber J. The drain valve 15 communicates the pump chamber J and the channel B, and the drain valve 15 is unidirectionally conductive from the pump chamber J to the channel B; the fixed valve 16 communicates the pump chamber J and the wellbore, and the fixed valve 16 is unidirectionally conductive from the wellbore to the pump chamber J.

[0055] The working principle of the present invention is as follows:

[0056] An external breathing hole C connected to the wellbore is provided at the pump chamber H, and the pressure in the pump chamber H is the same as that in the wellbore, which is a low-pressure chamber.

[0057] Downward movement: As Figure 1 shown, the switch sleeve 11 opens the switch hole F, and the rodless pumping surface equipment sends high-pressure water through the central pipe channel A. This high-pressure water acts on the driving long piston rod 3 to generate a downward force; when this high-pressure water passes through the Venturi nozzle 8, a jet flow is formed to generate negative pressure. The pump chamber D is a low-pressure chamber. The water flow passing through the Venturi nozzle 8 flows through the switch hole F and into the channel B formed by the tubing and the central pipe from the inner drain hole E, and then is discharged to the ground. A throttling pressure is generated when passing through the inner drain hole E, and this pressure is higher than the pressure below the pumping piston 13, thus generating a downward force. Under the action of the two forces, the piston is pushed downward. The fixed valve 16 closes, and the drain valve 15 opens, discharging the liquid below the pumping piston 13 into the channel B formed by the tubing and the central pipe. The drainage process is completed. When the reversing push rod 14 touches the upper surface of the fixed valve 16, the reversing push rod 14 pushes the switch sleeve 11 upward to close the switch hole F.

[0058] Upward movement: After the switch hole F is closed, the high-pressure water passing through the Venturi nozzle 8 enters the pump chamber D. The pump chamber D is a high-pressure chamber, and the upper part of the driving piston 7 is a low pressure. Under the action of this pressure, an upward force is generated. This force minus the downward force acting on the upper end face of the driving long piston rod 3 pushes the piston assembly upward. The fixed valve 16 opens, and the drain valve 15 closes, sucking the liquid in the wellbore, and the suction process is completed. After the switch sleeve 11 touches the upper limit short pump barrel 10, the switch hole F is opened.

[0059] The present invention realizes automatic downhole commutation. Compared with the existing technology that uses surface equipment commutation to drive downhole pump units, it has a low failure rate and high efficiency.

[0060] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be modified or equivalently replaced, and any modification or partial replacement without departing from the spirit and scope of the present invention should be covered by the scope of the claims of the present invention.

[0061] If terms such as "first" and "second" are used in this text to limit components, those skilled in the art should be aware that the use of "first" and "second" is merely for the convenience of describing the present invention and simplifying the description. Without additional statements, these terms have no special meaning.

[0062] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0063] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Claims

1. An underground automatic reversing rodless pump, characterized in that: It includes a pump barrel assembly and a piston assembly, wherein: The pump barrel assembly includes a plug, an inner tube, a short pump barrel, a long pump barrel, an outer tube, an upper limit short pump barrel and a production pumping barrel. The pump barrel assembly is fixed in the wellbore. The upper end of the plug is hermetically connected and fixed to the central tube, and the lower end of the plug is hermetically connected and fixed to the upper end of the inner tube; the inner tube, the short pump barrel, the long pump barrel, the upper limit short pump barrel and the production pumping barrel are coaxially arranged in sequence from top to bottom and are hermetically connected and fixed to each other to form an inner tube assembly; the inner tube assembly is fixed in the outer tube. The piston assembly includes a driving long piston rod, a driving piston, a nozzle, a connecting long piston rod and a production piston. The piston assembly can reciprocate in the pump barrel assembly. The driving piston is installed in the long pump barrel and is slidably and hermetically connected thereto. The driving long piston rod slidably passes through the short pump barrel in a sealed manner and is fixedly connected to the driving piston; the nozzle is fixed to the lower side of the driving piston; the production piston is installed in the production pumping barrel and is slidably and hermetically connected thereto. The connecting long piston rod slidably passes through the upper limit short pump barrel in a sealed manner, and the upper end of the connecting long piston rod is fixedly connected to the driving piston, and the lower end of the connecting long piston rod is fixedly connected to the production piston. A central tube passage A is formed in the plug, an annular passage B is directly formed between the tubing and the central tube, and an annular passage G is formed between the inner tube assembly and the outer tube. Passage G communicates with passage B. An axial first flow passage is provided on the driving long piston rod, and an axial second flow passage is provided on the driving piston. The second flow passage communicates the first flow passage and the nozzle. An axial third flow passage is provided on the connecting long piston rod. The upper end of the third flow passage communicates with the nozzle. At the same time, a radial fourth flow passage is provided on the connecting long piston rod; a pump chamber D is formed between the driving piston and the upper limit short pump barrel in the long pump barrel. The fourth flow passage communicates the third flow passage and the pump chamber D. A pump chamber H is formed between the short pump barrel and the driving piston in the long pump barrel. An external breathing hole connecting to the wellbore is provided at the pump chamber H. A pump chamber K is formed between the upper limit short pump barrel and the production piston in the production pumping barrel. An internal drainage hole is provided on the production pumping barrel. The internal drainage hole communicates the pump chamber K and the passage G. A switch hole is provided on the connecting long piston rod. The switch hole communicates the third flow passage and the pump chamber K. At the same time, a switch device is provided in cooperation with the switch hole. The switch device is linked with the upward and downward movements of the connecting long piston rod through a commutation trigger mechanism to realize the closing or opening of the switch hole. A pump chamber J is formed below the production piston in the production pumping barrel. A drainage valve and a fixed valve are respectively provided at the position of the pump chamber J. The drainage valve communicates the pump chamber J and the passage B, and the drainage valve is unidirectionally conductive from the pump chamber J to the passage B; the fixed valve communicates the pump chamber J and the wellbore, and the fixed valve is unidirectionally conductive from the wellbore to the pump chamber J.

2. The downhole automatic reversing rodless pump according to claim 1, characterized in that: The switch device is a switch sliding sleeve slidably sleeved on the connecting long piston rod. The commutation trigger mechanism includes a commutation push rod provided on the production piston and a commutation stop block provided on the upper limit short pump barrel; the commutation push rod and the commutation stop block are in trigger cooperation with the switch sliding sleeve. The commutation push rod axially passes through the production piston and is slidably and hermetically fitted therewith. The commutation push rod extends above and below the production piston; the commutation stop block is fixed to the lower side of the upper limit short pump barrel and protrudes downward.

3. The downhole automatic reversing rodless pump according to claim 2, wherein: A commutation push plate is fixedly provided in the pump chamber J. The commutation push plate is in trigger cooperation with the commutation push rod.

4. The downhole automatic reversing rodless pump according to claim 1, characterized in that: The inner tube is threadedly connected to the short pump barrel, the short pump barrel is threadedly connected to the long pump barrel, the long pump barrel is threadedly connected to the upper limit short pump barrel, and the upper limit short pump barrel is threadedly connected to the production pump barrel.

5. The downhole automatic reversing rodless pump according to claim 1, wherein: The upper end of the outer tube is threadedly connected and sealed to the tubing, and the lower end of the outer tube is fixedly connected and sealed to the production pump barrel.

6. The downhole automatic reversing rodless pump according to claim 1, characterized in that: The driving long piston rod is threadedly connected to the driving piston.

7. The downhole automatic reversing rodless pump according to claim 1, characterized in that: An installation groove is provided on the lower side of the driving piston. The nozzle is located in the installation groove. The upper end of the connecting long piston rod is threadedly connected to the driving piston to limit and fix the nozzle in the installation groove.

8. The downhole automatic reversing rodless pump according to claim 1, characterized in that: The lower end of the connecting long piston rod is threadedly connected to the production piston.

9. The downhole automatic reversing rodless pump according to any one of claims 1-8, characterized in that: The nozzle is a Venturi nozzle.

Images