Short-stem oil well pump

Abstract

The application discloses a short plunger oil well pump, which is characterized by the following technical scheme: an oil pipe is connected with a pump barrel through an oil pipe joint and a transition connecting sleeve; a suction inlet pump sleeve is connected with the lower end of the pump barrel; an oil pumping rod is connected with a plunger assembly through an oil pumping rod joint and a connecting mechanism; a drain hole is arranged on the transition connecting sleeve; a sliding sleeve matched with the drain hole is arranged in the transition connecting sleeve; the sliding sleeve is positioned through a steel ball positioning device; the connecting mechanism is composed of a catch spring, a guide rod and a variable-diameter connecting pipe which are connected with each other; a push sleeve installed on the catch spring connecting rod is matched with the sliding sleeve; a lock sleeve, a locking spring and a locking nut are installed on the guide rod with a guide connecting head at the upper end; and the catch claw of the catch spring is matched with the guide connecting head of the guide rod. The application has the advantages of reasonable structure, safe and reliable performance, short length of the plunger of the oil well pump, greatly reduced friction resistance between the plunger and the inner wall of the pump barrel, good energy-saving effect, elimination of the disadvantages of pump jamming, good sealing performance of the oil well pump and improved pump efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil production equipment, belongs to the improvement of the structure of the oil well pump for pumping underground oil reservoir, in particular to a short plunger oil well pump. BACKGROUND

[0002] At present, the oil production process generally uses the traditional long plunger tube type or rod type oil well pump. The traditional oil well pump has many problems in structural design and processing and manufacturing. The long plunger design of the traditional long plunger tube type or rod type oil well pump aims to improve the service life of the oil well pump and reduce leakage in rapid movement. However, due to the heterogeneity of the oil reservoir and the problems in structural design and processing and manufacturing, many failures are caused to the equipment during the operation of the oil well pump, resulting in very low working efficiency of the oil well pump.

[0003] In order to facilitate observation and analysis, taking a φ57 tube type pump as an example, during the processing of the inner diameter of the pump cylinder, many processing and manufacturing enterprises are difficult to ensure the straightness and concentricity of the processed inner diameter of the pump cylinder due to the low processing precision of the processing equipment, resulting in the phenomenon of pump jamming of the long plunger during movement, especially in thick oil production, the phenomenon of pump jamming by fine sand is more serious, accounting for 50-60% of the pump inspection workload. In light oil production, the main performance is wax jamming. In order to facilitate the installation of the long plunger, the long plunger is designed with a guide slope at both ends. Fluid is heterogeneous, and fine sand and paraffin inevitably accumulate and deposit between the guide slope and the inner diameter of the oil well pump cylinder, which easily causes pump jamming. The longer the plunger, the greater the frictional resistance, and the greater the loss of electric energy. If the viscosity of crude oil changes, the downhole speed of the plunger cannot be synchronized with the mechanical speed, which will cause stroke loss, deformation of the sucker rod in the oil pipe, and long-term rod breakage or pipe wear.

[0004] In addition, the pump efficiency problem of the oil well pump, due to the different properties of the oil reservoir, the gas and water in the oil reservoir, and the change of the viscosity of the crude oil with temperature, the fluid in the oil reservoir has great heterogeneity. Under the same conditions, the leakage of several fluids with different viscosities through the gap between the inner diameter of the oil well pump and the plunger is greatly different. The smaller the viscosity, the greater the leakage, the greater the negative pressure loss of the suction inlet of the oil well pump, and the lower the pump efficiency, resulting in the pump efficiency of the downhole oil well pump being only 20-30%, which is the current situation of oil production. SUMMARY

[0005] The purpose of the present application is to provide a short plunger oil well pump with reasonable structure, safe and reliable performance, short length of the plunger of the oil well pump, which can greatly reduce the frictional resistance between the plunger and the inner wall of the pump cylinder, good energy saving effect, eliminate the disadvantages of pump jamming, good sealing performance of the oil well pump, improve the pump efficiency, and meet the requirements of oil reservoirs of various properties for production operations.

[0006] The object of the present application is achieved by a short-piston oil pump, wherein a tubing is connected to a pump barrel by a tubing coupling and a transition coupling, a suction inlet pump sleeve is connected to a lower end of the pump barrel, a sucker rod is connected to a piston assembly in the pump barrel by a sucker rod coupling and a connecting mechanism, a drain hole is provided in the transition coupling, a sliding sleeve is provided in the transition coupling and cooperates with the drain hole, the sliding sleeve is positioned by a steel ball positioning device, the connecting mechanism is composed of a catch spring, a guide rod and a variable-diameter connecting pipe which are connected to each other, wherein a push sleeve installed on a connecting rod of the catch spring cooperates with the sliding sleeve, a lock sleeve, a lock spring and a lock nut are installed on the guide rod which has a guide connector at an upper end, a catch claw of the catch spring cooperates with the guide connector of the guide rod and locks the guide rod by the lock sleeve, a lower end of the guide rod is connected to the variable-diameter connecting pipe which has a drain hole by a threaded connection, a threaded pipe at a lower end of the variable-diameter connecting pipe is connected to the piston assembly by a threaded connection, a piston ring and a sealing ring are installed outside a piston of the piston assembly, a piston check valve device is installed on a fluid passage in the piston, a steel ball check valve device is installed on a lower port of the fluid passage, and a suction inlet check valve device is installed in the suction inlet pump sleeve.

[0007] The outer part of the present application is composed of tubing, tubing coupling, transition connecting sleeve, pump barrel and suction inlet pump sleeve through threaded connection. The sucker rod, sucker rod coupling and grab spring are connected through threaded connection, and the pull sleeve is connected in series on the grab spring connecting rod. The pull sleeve is made of soft wear-resistant and high-temperature-resistant material. The pull sleeve and the lock nut are connected through threaded connection. In order to prevent the sucker rod coupling and the grab spring from loosening and falling off, the lock nut is tightly connected with the sucker rod coupling, and the pull sleeve connected in series on the grab spring is used to block the oil drain hole on the transition connecting sleeve. In order to prevent the sliding sleeve from moving up and down during operation, a positioning steel ball, a positioning steel ball spring and a plug are assembled on the transition connecting sleeve to position the sliding sleeve. The grab spring is connected with the guide rod, and the plunger assembly is pushed into the suction inlet flow guide disc of the oil well pump. The lock sleeve is locked under the action of gravity, and the locking spring is compressed. When the guide rod enters the grab spring, the grab spring rapidly contracts by elasticity, and the locking spring pushes the lock sleeve to lock the grab spring and the guide rod. The guide rod and the variable diameter connecting pipe are connected through threaded connection. In order to prevent the guide rod and the variable diameter connecting pipe from loosening and falling off, the locking nut is installed on the guide rod and the variable diameter connecting pipe is tightly connected. The variable diameter connecting pipe and the plunger are connected through threaded connection. The outer diameter of the plunger is provided with a piston ring. In order to improve the service life of the piston ring, wear-resistant U-shaped sealing rings are installed on the upper and lower ends of the plunger in back-to-back manner. When the plunger moves up and down, it prevents oil sand and other foreign matters from entering and protecting the piston ring. The plunger check valve is installed on the fluid passage of the plunger. The plunger check valve adopts a conical design. The guide rod on the plunger check valve is provided with a check spring. The guide rod of the plunger check valve is guided and positioned by the flow guide disc. The plunger check valve and the plunger check valve seat are designed as linear sealing. The plunger check steel ball is installed on the lower part of the plunger. When the plunger assembly moves upward, the S surface of the plunger check valve is quickly closed under the gravity of the fluid in the tubing. The plunger check steel ball is designed to ensure the pump efficiency of the oil well pump. The plunger check steel ball and the plunger steel column check valve seat are designed as linear sealing. The locking sleeve and the plunger are connected through threaded connection, and the inner clamping spring clamps the plunger steel column check valve seat. The suction inlet of the oil well pump is designed to adopt a suction inlet check valve seat. The structure principle is the same as that of the plunger check valve, except that the flow area of the suction inlet is larger than that of the plunger check valve. When the plunger assembly is lowered, the fluid in the pump barrel overcomes the gravity of the plunger check steel ball and the plunger check valve, and the fluid generates internal pressure. The internal pressure presses the S surface of the suction inlet check valve and forms a resultant force with the check spring, so that the suction inlet check valve seat is quickly closed. The suction inlet check valve seat and the suction inlet check valve seat are designed as linear sealing. During well repair, the sucker rod is lifted, the pull sleeve and the lock sleeve on the plunger assembly are lifted to the upper limit of the sliding sleeve, the sliding sleeve limits the lock sleeve, the locking spring is compressed, the grab spring is separated from the guide rod, and the plunger assembly remains in the pump barrel. At this time, the sliding sleeve moves upward to open the oil drain hole, and the fluid in the tubing can remain in the wellbore through the oil drain hole. According to this working condition, if it is a heavy oil production huff and puff well, the short plunger oil well pump can be used for steam injection operation. The tubing, tubing coupling, transition connecting sleeve, pump barrel and suction inlet pump sleeve are connected through threaded connection.The sucker rod, sucker rod coupling, and the catch spring are connected by threads, and the catch spring connecting rod is connected with the pull sleeve. The pull sleeve is made of soft wear-resistant and high-temperature-resistant material, and the pull sleeve is connected with the locking nut. The pull sleeve connected with the catch spring pushes the sliding sleeve downward to seal the oil drain hole on the transition connecting sleeve. To prevent the sliding sleeve from moving up and down during work, a positioning steel ball, a positioning steel ball spring, and a plug are assembled on the transition connecting sleeve to position the sliding sleeve. The catch spring is connected with the plunger guide rod, and the catch spring compresses the locking spring under the action of gravity. When the guide rod enters the catch spring, the catch spring rapidly contracts by elasticity, and the locking spring pushes the lock sleeve to lock the catch spring and the guide rod. The guide rod is connected with the variable diameter connecting pipe by threads, and the locking nut is installed on the guide rod to prevent the guide rod and the variable diameter connecting pipe from loosening and falling off. The variable diameter connecting pipe is connected with the plunger by threads, and the plunger outer diameter is installed with a piston ring. To improve the service life of the piston ring, wear-resistant U-shaped sealing rings are installed on the upper and lower ends of the plunger. A plunger check valve is installed in the plunger, and the plunger check valve is designed in a conical shape. A check spring is installed on the plunger check valve guide rod, and the plunger check valve guide rod is guided and positioned by a flow guide disc. The plunger check valve and the plunger check valve seat are designed as linear sealing. A plunger check steel ball is installed on the lower part of the plunger, and the locking sleeve is connected with the plunger by threads. An inner snap spring clamps the plunger steel column check valve seat. The suction inlet is composed of a suction inlet check valve seat, a flow guide disc, a check spring, and a suction inlet check valve seat. The suction inlet check valve seat guide rod is guided and positioned by the flow guide disc, and the suction inlet check valve seat and the suction inlet check valve seat are designed as linear sealing.

[0008] The short plunger oil well pump is composed of a tubing coupling, an excess connection sleeve, a pump barrel, and a suction inlet pump sleeve. Inside the pump barrel is connected with a disengaging device claw spring through a sucker rod coupling, and the claw spring is connected with a guide rod. After the claw spring is connected with the guide rod, the lock sleeve is locked under the action of the locking spring, the claw spring and the guide rod are locked, the guide rod is connected with the plunger connector through a thread, the plunger connector is connected with the plunger through a thread, the plunger is externally installed with a piston ring, in order to improve the service life of the piston, a wear-resistant U-shaped ring is installed on the upper and lower ends of the plunger in a back-to-back manner, when the plunger moves up and down, the U-shaped ring can push away the oil sand or other foreign matters, prevent the oil sand or other foreign matters from entering the gap between the plunger and the pump barrel, cause the pump to be stuck and the plunger to be damaged, and thus protect the piston ring. A plunger check valve is installed in the plunger, the plunger check valve adopts a conical design, a check spring is installed on the guide rod of the plunger check valve, the guide rod of the plunger check valve is guided and positioned through a flow guide disc, the plunger check valve and the plunger check valve seat are designed as a linear seal. A plunger check steel ball is installed at the lower part of the plunger, when the plunger runs upward, the check valve and the plunger check steel ball are closed in time, leakage is reduced, the pump efficiency of the oil well pump is ensured, and the plunger check steel ball and the plunger check steel ball seat are designed as a linear seal. The suction inlet of the oil well pump is also provided with a suction inlet check valve, which has the same structure and principle as the plunger check valve, except that the flow area of the suction inlet is larger than that of the plunger check valve. When the plunger is lowered, the fluid in the pump barrel overcomes the gravity of the plunger check steel ball and the plunger check valve, the fluid generates internal pressure, the internal pressure exerts pressure on the S surface of the suction inlet check valve, and the suction inlet check valve is quickly closed under the combined force of the check spring and the internal pressure. The suction inlet check valve and the suction inlet check valve seat are designed as a linear seal.

[0009] The short plunger oil well pump is composed of a tubing coupling, an excess connection sleeve, a pump barrel, and a suction inlet pump sleeve. Inside the pump barrel is connected with a disengaging device claw spring through a sucker rod coupling, and the claw spring is connected with a guide rod. After the claw spring is connected with the guide rod, the lock sleeve is locked under the action of the locking spring, the claw spring and the guide rod are locked, the guide rod is connected with the plunger connector through a thread, the plunger connector is connected with the plunger through a thread, the plunger is externally installed with a piston ring, in order to improve the service life of the piston, a wear-resistant U-shaped ring is installed on the upper and lower ends of the plunger in a back-to-back manner, when the plunger moves up and down, the U-shaped ring can push away the oil sand or other foreign matters, prevent the oil sand or other foreign matters from entering the gap between the plunger and the pump barrel, cause the pump to be stuck and the plunger to be damaged, and thus protect the piston ring. A plunger check valve is installed in the plunger, the plunger check valve adopts a conical design, a check spring is installed on the guide rod of the plunger check valve, the guide rod of the plunger check valve is guided and positioned through a flow guide disc, the plunger check valve and the plunger check valve seat are designed as a linear seal. A plunger check steel ball is installed at the lower part of the plunger, when the plunger runs upward, the check valve and the plunger check steel ball are closed in time, leakage is reduced, the pump efficiency of the oil well pump is ensured, and the plunger check steel ball and the plunger check steel ball seat are designed as a linear seal. The suction inlet of the oil well pump is also provided with a suction inlet check valve, which has the same structure and principle as the plunger check valve, except that the flow area of the suction inlet is larger than that of the plunger check valve. When the plunger is lowered, the fluid in the pump barrel overcomes the gravity of the plunger check steel ball and the plunger check valve, the fluid generates internal pressure, the internal pressure exerts pressure on the S surface of the suction inlet check valve, and the suction inlet check valve is quickly closed under the combined force of the check spring and the internal pressure. The suction inlet check valve and the suction inlet check valve seat are designed as a linear seal.

[0010] The application has reliable performance, convenient operation, can meet the mining operation of oil reservoirs with various properties, has good energy-saving effect, and reduces the indirect cost of workover. In view of the production status of the pump barrel, the sealing length of the short-plunger oil well pump plunger is shortened by 6 times compared with the traditional oil well pump plunger, which greatly reduces the friction resistance between the plunger and the inner diameter of the pump barrel. Under the same conditions, 2-3kw•h of electricity is saved per day, the energy-saving effect is good, and the probability of pump jamming is very small. In order to control the leakage between the plunger and the inner diameter of the pump barrel, the plunger between the plunger and the inner diameter of the pump barrel is made of wear-resistant elastic material and piston ring, which eliminates the gap between the plunger and the inner diameter of the pump barrel. It is proved by the production site trial operation that the pump efficiency is more than 85%, and the performance is safe and reliable.

[0011] The application has reasonable structure, safe and reliable performance, short length of the oil well pump plunger, greatly reduced friction resistance between the plunger and the inner wall of the pump barrel, good energy-saving effect, eliminated disadvantages of pump jamming, good sealing performance of the oil well pump, improved pump efficiency, and can meet the mining operation of oil reservoirs with various properties. BRIEF DESCRIPTION OF DRAWINGS

[0012] The application will be further described below with reference to the drawings, Figure 1 is a schematic view of the main structure of the downhole installation of the application, Figure 2 is Figure 1 is a schematic view of the upper enlarged structure of the application, Figure 3 is Figure 1 is a schematic view of the middle enlarged structure of the application, Figure 4 is Figure 1 is a schematic view of the lower enlarged structure of the application. DETAILED DESCRIPTION

[0013] A short-plunger oil well pump, such as Figure 1As shown, the tubing 1 is threadedly connected to the pump barrel 16 through the tubing coupling 3 and the transition sleeve 5, the lower end of the pump barrel 16 is connected to the suction inlet pump sleeve 29, the sucker rod 2 is connected to the plunger assembly through the sucker rod coupling 4 and the connecting mechanism in the pump barrel 16, the transition sleeve 5 is provided with a bleed hole 8, and the transition sleeve 5 is provided with a sliding sleeve 9 matched with the bleed hole 8, the sliding sleeve 9 is positioned by a steel ball positioning device, the connecting mechanism is composed of a catch spring 12, a guide rod 13 and a variable diameter connecting pipe 17 connected with each other, wherein the push sleeve 11 installed on the catch spring connecting rod is matched with the sliding sleeve 9, the guide rod 13 with a guide connector at the upper end is installed with a lock sleeve 14, a locking spring 15 and a locking nut 10, the catch claws of the catch spring 12 are matched with the guide connector of the guide rod 13, and the guide rod 13 is locked through the lock sleeve 14, the lower end of the guide rod 13 is threadedly connected to the variable diameter connecting pipe 17 with an oil outlet hole 32, the threaded pipe at the lower end is threadedly connected to the plunger assembly, the piston ring 20 and the sealing ring 18 are installed outside the plunger 19 of the plunger assembly, the plunger check valve device is matched and installed on the fluid passage in the plunger 19, the steel ball check valve device is installed on the lower port of the fluid passage, and the suction inlet check valve device is matched and installed in the suction inlet pump sleeve 29. The structure of the catch spring 12 is that the catch claws are uniformly arranged at the lower end of the connecting rod, the lower end of the catch claw is provided with a clamping table matched with the taper table at the rear end of the guide connector of the guide rod, the locking nut 10 and the push sleeve 11 are matched and installed on the connecting rod, the locking nut 10 presses the sucker rod coupling 4, the steel ball positioning device is arranged on the transition sleeve 5, the steel ball 6 controlled by the spring 7 is matched with the positioning concave ring arranged on the outer wall of the sliding sleeve 9 to position the sliding sleeve 9, the push sleeve 11 is matched and installed in the sliding sleeve 9, and the push sleeve 11 frictionally drives the sliding sleeve 9. The push sleeve 11 is composed of flexible wear-resistant and high-temperature-resistant materials. The guide connector with a tapered tip is arranged at the upper end of the guide rod 13, a screw rod is arranged at the lower end of the guide rod 13, the lock sleeve 14, the locking spring 15, the locking nut and the variable diameter connecting pipe 17 are sequentially arranged and installed on the guide rod 13, the variable diameter connecting pipe 17 is locked through the locking nut, the locking spring 15 pushes the lock sleeve 14 upwards, and the clamping claws of the catch spring 12 are locked with the guide connector of the guide rod 13. The piston ring grooves are uniformly arranged on the outer diameter of the plunger 19, the piston ring 20 is matched and installed in the piston ring groove, and the sealing ring 18 is matched and installed at the upper and lower ends of the plunger 19. The sealing ring 18 is a U-shaped sealing ring installed back to back.In the lower end of the fluid passage of the plunger 19 is screwed the locking sleeve 27. In the inner wall of the locking sleeve 27 is installed the steel ball check valve seat 26 of the steel ball check valve device by the inner snap spring 28 set in the snap spring slot. The check steel ball 25 cooperates with the steel ball check valve seat 26. The locking sleeve sleeve pipe protruding from the upper part of the steel ball check valve seat 26 has its upper end cooperatively installed the plunger check valve seat 24 of the plunger check valve device. The valve core 23 is a combination of the upper conical platform and the lower conical tip. The conical tip surface of the valve core 23 linearly seals with the plunger check valve seat 24. The guide rod is set in the upper end of the conical platform of the valve core. The guide disc 21 is installed in the upper part of the fluid passage of the plunger through the variable diameter connecting pipe 17. The center guide hole of the guide disc 21 cooperates with the upper end of the guide rod with the check spring 22. The guide flow holes are uniformly set in the guide disc 21. The sealing ring 18 is cooperatively installed in the sealing ring groove formed by the upper end face of the plunger 19 and the stop platform of the variable diameter connecting pipe 17. The sealing ring 18 is cooperatively installed in the sealing ring groove formed by the lower end face of the plunger 19 and the stop platform of the locking sleeve 27. In the suction inlet sleeve 29 is installed the suction inlet check valve seat 31 of the suction inlet check valve device through the stop platform. The guide disc is installed in the upper part of the suction inlet check valve seat 31 through the set spacer sleeve 30. The conical tip surface of the valve core 23 linearly seals with the suction inlet check valve seat 31. The guide rod with the check spring is set in the upper end of the valve core 23. The upper end of the guide rod cooperates with the center guide hole of the guide disc. The sealing length of the plunger 19 is 200 mm.

Claims

1. A short-piston oil well pump, characterized by: Oil pipe 1) The pump barrel (16) is connected with the tubing coupling (3) and the transition connecting sleeve (5) by screw thread, the sucker rod (2) is connected with the plunger assembly in the pump barrel (16) through the sucker rod coupling (4) and the connecting mechanism, the oil drain hole (8) is arranged on the transition connecting sleeve (5), the sliding sleeve (9) matched with the oil drain hole (8) is arranged in the transition connecting sleeve (5), the sliding sleeve (9) is positioned by the steel ball positioning device, the connecting mechanism is composed of the catch spring (12), the guide rod (13) and the variable diameter connecting pipe (17) connected with each other, the catch sleeve (11) installed on the catch spring connecting rod is matched with the sliding sleeve (9), the guide connecting head with a taper tip is arranged on the upper end of the guide rod (13), the screw rod is arranged on the lower end of the guide rod (13), the lock sleeve (14), the locking spring (15), the locking nut one and the variable diameter connecting pipe (17) are installed on the guide rod (13) in sequence, the lower end of the guide rod (13) is connected with the variable diameter connecting pipe (17) with the oil outlet hole (32) by screw thread, the threaded pipe at the lower end of the variable diameter connecting pipe (17) is connected with the plunger assembly by screw thread, the piston ring (20) and the sealing ring (18) are installed on the outside of the plunger (19) of the plunger assembly, the plunger check valve device is installed on the fluid passage in the plunger (19) in matching mode, the steel ball check valve device is installed on the lower end of the fluid passage, the suction inlet check valve device is installed in the suction inlet pump sleeve (29) in matching mode; the structure of the catch spring (12) is that the evenly distributed catch claws are arranged on the lower end of the catch spring connecting rod, the clamping table matched with the taper table at the rear end of the guide connecting head of the guide rod is arranged on the lower end of the catch claw, the variable diameter connecting pipe (17) is locked by the locking nut one, the lock sleeve (14) is pushed up by the locking spring (15), the catch claws of the catch spring (12) are locked with the guide connecting head of the guide rod (13), the locking nut two (10) and the catch sleeve (11) are installed on the catch spring connecting rod in matching mode, the sucker rod coupling (4) is pressed by the locking nut two (10), the steel ball positioning device is arranged on the transition connecting sleeve (5), the steel ball (6) controlled by the spring (7) of the steel ball positioning device is matched with the positioning concave ring arranged on the outer wall of the sliding sleeve (9) to position the sliding sleeve (9), the catch sleeve (11) is installed in the sliding sleeve (9) in matching mode, the catch sleeve (11) frictionally drives the sliding sleeve (9);The piston ring groove is uniformly arranged on the outer diameter cylindrical surface of the plunger (19), and the piston ring (20) is fitted and installed in the piston ring groove. The sealing ring (18) is fitted and installed at the upper and lower ends of the plunger (19), respectively. The locking sleeve (27) is connected by screw thread at the lower end port of the fluid passage of the plunger (19). The steel ball check valve seat (26) of the steel ball check valve device is installed on the inner wall of the locking sleeve (27) through the inner snap spring (28) arranged in the snap spring groove. The check steel ball (25) cooperates with the steel ball check valve seat (26). The locking sleeve sleeve pipe protrudes above the upper part of the steel ball check valve seat (26), and the plunger check valve seat (24) of the plunger check valve device is fitted and installed at the upper end. The valve core (23) is composed of a combination of a conical platform at the upper part and a conical tip at the lower part. The conical tip surface of the valve core is linearly sealed with the plunger check valve seat (24). A guide rod is arranged at the upper end of the conical platform of the valve core. The flow guide disc (21) is installed at the upper part of the fluid passage of the plunger through the variable diameter connecting pipe (17). The central guide hole cooperates with the upper end of the guide rod provided with the check spring (22). The flow guide holes are uniformly arranged on the flow guide disc (21). The sealing ring (18) is fitted and installed in the sealing ring groove formed by the upper end face of the plunger (19) and the variable diameter connecting pipe (17). The sealing ring (18) is fitted and installed in the sealing ring groove formed by the lower end face of the plunger (19) and the locking sleeve (27). The suction inlet check valve seat (31) of the suction inlet check valve device is fitted and installed in the suction inlet pump sleeve (29) through the retaining platform. The flow guide disc is installed on the upper part of the suction inlet check valve seat (31) through the spacer sleeve (30). The conical tip surface of the valve core (23) is linearly sealed with the suction inlet check valve seat (31). The guide rod provided with the check spring is arranged at the upper end of the valve core (23). The upper end of the guide rod cooperates with the central guide hole of the flow guide disc.

2. The short-piston oil well pump according to claim 1, characterized in that: The sleeve (11) is made of flexible, wear-resistant, high-temperature-resistant material.

3. The short-piston oil well pump according to claim 1, characterized in that: The sealing ring (18) is a U-shaped sealing ring installed back to back.

4. The short-piston oil well pump according to claim 1, characterized in that: The sealing length of the plunger (19) is 200 mm.

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