A flexible sucker rod hydraulic pumping aid device and method and downhole pull-assisting cylinder

Abstract

The present invention discloses a flexible sucker rod hydraulic pumping assist device and method and a downhole pull-assist cylinder. The flexible sucker rod hydraulic pumping assist device comprises a flexible sucker rod, a rigid sucker rod and a pump, wherein the lower end of the rigid sucker rod is connected to the plunger of the pump; further comprises a downhole pull-assist cylinder and a ground hydraulic control device; the upper end of the downhole pull-assist cylinder is connected to the lower end of the flexible sucker rod, and the lower end of the downhole pull-assist cylinder is connected to the upper end of the rigid sucker rod; the ground hydraulic control device is connected to the hydraulic hole of the downhole pull-assist cylinder through a hydraulic pipe. The present invention has simple process, high reliability and easy modification and installation; it assists the sucker rod to go downward, avoiding the instability of the pressure rod and the wear of the pipe rod; the hydraulic fluid stroke is closed and circulated, which is green and energy-saving.

Description

Technical Field

[0001] The invention relates to the field of oil production technology, in particular to a flexible sucker rod hydraulic pumping aid device and method and a downhole pull-assisting cylinder. Background Art

[0002] In machine-extracted wells, the liquid column load on the pumping unit and the sucker rod is large. On the one hand, the pumping unit has high energy consumption, high electricity consumption, low mechanical efficiency, and poor economic benefits; on the other hand, the working stress of the sucker rod is large and it is easy to be pulled apart. In addition, the force state of the sucker rod when it is downward is compressive stress, and when it is upward, it is tensile stress. The amplitude of the alternating stress of the sucker rod is large, and the sucker rod is prone to fatigue damage. The service life of the sucker rod is short, the production cycle of the oil well is short, and the development efficiency of the oil field is poor. At present, with the application of carbon fiber sucker rods, the problem of insufficient working stress of the sucker rod has been solved to a certain extent, but the incoordination between the downstroke of the pumping unit and the downstroke of the oil pump leads to the instability of the compression rod of the carbon fiber sucker rod. The main reason is the characteristics of light weight and high flexibility of flexible sucker rods such as carbon fiber. Some researchers design a weighted rod at the end of the sucker rod, but this also increases the load of the sucker rod, resulting in an increase in the power consumption of the pumping unit, and cannot effectively achieve the purpose of deep pumping with flexible rods for conventional pumping units.

[0003] Publication (announcement) number: CN101550808B, Publication (announcement) date: 2011-06-08. It relates to a self-unblocking process for a flexible sucker rod column. It mainly solves the problem that the flexible sucker rod of a double-range flexible pumping unit cannot be unblocked. When the speed of the downhole pump plunger slows down due to soft sticking, the pumping unit works normally during the upstroke. During the downstroke, the vibrator sleeve and the secondary weighting rod continue to move downward, while the vibrator mandrel, the primary weighting rod and the plunger do not move. Then, the upper sleeve and the secondary weighting rod produce a hammering effect on the mandrel and the primary weighting rod, and at the same time, the weight of the secondary weighting rod participates in it, producing a boosting effect. This force overcomes the friction between the plunger and the pump barrel, allowing it to unblock. The invention has the characteristics of rapid unblocking and reliable action.

[0004] Publication (announcement) number: CN201288517Y, Publication (announcement) date: 2009-08-12 It relates to a sucker rod auxiliary pumping stabilizer, including a center rod, joints are arranged at both ends of the center rod, a first centralizing body and a second centralizing body are arranged on the center rod, the first centralizing body includes three first centralizing claws, and the second centralizing body includes three second centralizing claws. When the sucker rod moves downward, the first centralizing body moves upward under the action of friction, the first centralizing body and the second centralizing body are separated, and crude oil flows upward through the gap between the first centralizing claws and the second centralizing claws. When the sucker rod moves upward, the first centralizing body moves downward under the action of friction, and the first centralizing body slides into the gap of the second centralizing body to form a plunger. When the sucker rod moves upward and downward, the first centralizing body and the second centralizing body can both play a centralizing role, thereby preventing friction between the sucker rod and the pumping pipe. When the sucker rod moves upward, it can also play a role in reducing the pressure difference between the upper and lower parts of the plunger, thereby improving the pumping efficiency.

[0005] Publication (announcement) number: CN201100121Y, Publication (announcement) date: 2008-08-13 A pumping pump straightening and pumping aid device used in the petroleum industry is disclosed, which is suitable for oil wells that use a rod pump to produce oil. The device includes an elastic straightening part and a pumping aid part, the pumping aid part is provided with a liquid flow channel, the elastic straightening part is sleeved on the pumping aid part, and the device is connected to the pumping rod column. The leakage of the pumping pump can be reduced, a higher negative pressure is formed in the pump barrel, the oil intake is increased, the filling coefficient of the pumping pump is improved, and the probability of "liquid hammer" of the pumping pump is reduced. When the pumping pump is pumping oil in the up and down strokes, under the action of staged oil lifting, the elastic elongation of the pumping rod during the up stroke is reduced, that is, the stroke loss is reduced. By lifting the well fluid step by step through the device, the leakage at the oil pipe connection can be reduced, so as to achieve the purpose of improving pump efficiency and increasing the crude oil production of a single well.

[0006] Publication (announcement) number: CN105971528B, Publication (announcement) date: 2018-06-01. It relates to a pump rod anti-wear and pumping aid straightening device, belonging to the technical field of oilfield equipment. It includes a steel body, which is a hollow structure, and an anti-wear and pumping aid structure is mounted on the steel body. The two ends of the anti-wear and pumping aid structure are annular structures, and the middle is an ellipsoid structure. The ellipsoid structure is provided with a pumping aid hole. The pump rod can be straightened in the center of the oil pipe to prevent the pump rod from wearing eccentrically, so that the friction area between the pump rod and the oil pipe is small, the friction resistance is reduced, and the pumping efficiency is improved.

[0007] In summary, the technical solutions of the above-disclosed technologies, the technical problems to be solved, and the beneficial effects produced are all different from the present invention. Regarding more technical features, technical problems to be solved, and beneficial effects of the present invention, the above-disclosed technical documents do not provide any technical inspiration. Summary of the invention

[0008] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a flexible sucker rod hydraulic pumping-assisting device and method and a downhole pulling-assisting cylinder, which have simple process, high reliability and easy modification and installation; they assist the sucker rod to go downward to avoid instability of the pump rod and wear of the pipe rod; the hydraulic fluid stroke is closed and circulated, which is green and energy-saving.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A flexible sucker rod hydraulic pumping aid device comprises a flexible sucker rod, a rigid sucker rod and a pump, wherein the lower end of the rigid sucker rod is connected to a plunger of the pump;

[0011] It also includes downhole auxiliary pulling cylinder and ground hydraulic control device;

[0012] The upper end of the downhole auxiliary pull cylinder is connected to the lower end of the flexible sucker rod, and the lower end of the downhole auxiliary pull cylinder is connected to the upper end of the rigid sucker rod;

[0013] The ground hydraulic control device is communicated with the hydraulic hole of the underground pulling-assisting cylinder through a hydraulic pipe.

[0014] Furthermore, it also includes a dynamometer, which is electrically connected to the ground hydraulic control device via a data line.

[0015] Furthermore, the downhole pulling-assisting cylinder comprises a piston tube and a piston cylinder;

[0016] The center of the piston tube is an axial through hole, and the outer wall of the piston tube has an integrally formed outward-facing ring plate;

[0017] The piston tube coaxially passes through the piston cylinder, and the circumferential surface of the outward-expanded ring plate forms a sliding seal with the inner wall of the piston cylinder, that is, the outward-expanded ring plate is used as a piston in the piston cylinder.

[0018] Further, the piston cylinder includes a sealing cylinder, an upper joint, and a lower joint;

[0019] The upper joint is connected to the upper port of the sealing cylinder, and a central hole for passing the piston tube is provided at the center of the upper joint. The inner wall of the central hole of the upper joint and the outer wall of the piston tube form a sliding sealing pair, and the upper joint is provided with a hydraulic hole leading to the sealing cylinder;

[0020] The lower joint is connected to the lower port of the sealing tube. A lower joint center hole is provided in the center of the lower joint for passing the piston tube. The inner wall of the lower joint center hole and the outer wall of the piston tube form a sliding sealing pair. The lower joint is provided with a balancing hole that can be connected to the sealing tube.

[0021] Furthermore, the upper joint is also provided with a pressure relief hole which can be communicated with the sealing cylinder, and a pressure relief valve is installed on the pressure relief hole. The upper end of the upper joint is connected to the oil pipe in the casing, and the lower end of the lower joint is connected to the upper end of the pump barrel of the oil pump through a short section of the oil pipe.

[0022] Furthermore, the downhole auxiliary pulling cylinder also includes an upper rod connector and a lower rod connector;

[0023] The upper rod connector is installed at the upper end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube, and the upper rod connector is connected and fixed to the upper flexible sucker rod;

[0024] The lower rod connector is installed at the lower end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube. The lower rod connector is fixedly connected to the rigid sucker rod below.

[0025] Furthermore, the ground hydraulic control device includes a control cabinet, a fluid storage tank, and a solenoid valve;

[0026] The solenoid valve has three ports, namely, an inlet, an outlet and a return port. The outlet of the solenoid valve is connected to the hydraulic hole of the downhole auxiliary pulling cylinder through a hydraulic pipe, the inlet of the solenoid valve is connected to the outlet of the liquid storage tank through a control cabinet and a liquid inlet pipe, and the return port of the solenoid valve is connected to the recovery port of the liquid storage tank through a return liquid pipe.

[0027] Furthermore, the control cabinet includes a control circuit and a booster pump. The control circuit is electrically connected to the booster pump, the control circuit is electrically connected to the dynamometer, the control circuit is electrically connected to the solenoid valve, and the control circuit is electrically connected to the liquid level sensor of the liquid level gauge in the liquid storage tank.

[0028] In order to achieve the above object, the present invention adopts the following technical solutions:

[0029] A method for using a flexible sucker rod hydraulic pumping aid device comprises the following steps:

[0030] The dynamometer collects the stroke data of the flexible sucker rod and transmits it to the control cabinet. The control cabinet controls the opening and closing of the solenoid valve and pumps the liquid in the liquid storage tank into the hydraulic pipe according to the collected stroke data and the liquid level data of the liquid storage tank.

[0031] When the flexible sucker rod is in the downward stroke, the control cabinet sends a signal to open the downward injection channel of the solenoid valve, the pump in the control cabinet starts, the liquid in the liquid storage tank is injected into the downhole auxiliary pull cylinder through the hydraulic control pipe, the piston tube moves downward under the hydraulic pressure, and pulls the flexible sucker rod downward, and the well fluid under the piston tube is discharged through the balance hole;

[0032] When the flexible sucker rod is in the upward stroke, the control cabinet controls the solenoid valve channel to change direction, and the liquid above the piston tube in the downhole auxiliary pull tube flows back to the liquid storage tank through the hydraulic pipe, and the pressure in the hydraulic pipe is released. Under the pulling force of the flexible sucker rod in the upward stroke, the piston tube moves upward, and the pressure above the piston tube in the sealing tube is also safely released through the pressure relief hole and the pressure relief valve;

[0033] After the downstroke and upstroke are completed, the downhole auxiliary puller completes its hydraulic auxiliary pumping function. At the same time, the sucker rod is always in a tensile stress state to avoid the instability of the pressure rod, resulting in pipe wear and other adverse conditions that damage the life of the pipe string.

[0034] In order to achieve the above object, the present invention adopts the following technical solutions:

[0035] A downhole pulling cylinder for pumping oil with a flexible sucker rod, comprising a piston tube and a piston cylinder;

[0036] The center of the piston tube is an axial through hole, and the outer wall of the piston tube has an integrally formed outward-facing ring plate;

[0037] The piston tube coaxially passes through the piston cylinder, and the circumferential surface of the outward-expanded ring plate forms a sliding seal with the inner wall of the piston cylinder, that is, the outward-expanded ring plate is used as a piston in the piston cylinder.

[0038] Further, the piston cylinder includes a sealing cylinder, an upper joint, and a lower joint;

[0039] The upper joint is connected to the upper port of the sealing cylinder, and a central hole for passing the piston tube is provided at the center of the upper joint. The inner wall of the central hole of the upper joint and the outer wall of the piston tube form a sliding sealing pair, and the upper joint is provided with a hydraulic hole leading to the sealing cylinder;

[0040] The lower joint is connected to the lower port of the sealing tube. A lower joint center hole is provided in the center of the lower joint for passing the piston tube. The inner wall of the lower joint center hole and the outer wall of the piston tube form a sliding sealing pair. The lower joint is provided with a balancing hole that can be connected to the sealing tube.

[0041] Furthermore, the upper joint is also provided with a pressure relief hole which can be communicated with the sealing cylinder, and a pressure relief valve is installed on the pressure relief hole. The upper end of the upper joint is connected to the oil pipe in the casing, and the lower end of the lower joint is connected to the upper end of the pump barrel of the oil pump through a short section of the oil pipe.

[0042] Furthermore, the downhole auxiliary pulling cylinder also includes an upper rod connector and a lower rod connector;

[0043] The upper rod connector is installed at the upper end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube, and the upper rod connector is connected and fixed to the upper flexible sucker rod;

[0044] The lower rod connector is installed at the lower end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube. The lower rod connector is fixedly connected to the rigid sucker rod below.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention controls the ground hydraulic control system through the data of the wellhead dynamometer. When the sucker rod is in the downward stroke, the ground pumps hydraulic pressure to make the piston in the downhole auxiliary pull cylinder move downward, pulling the end of the sucker rod downward, so that the sucker rod is always in a tensile stress state, avoiding the occurrence of adverse conditions such as instability of the compression rod and pipe rod wear that damages the life of the pipe column.

[0047] The invention is suitable for flexible sucker rod oil production, conventional rod deep pumping, heavy oil well machine production and other oil production process pipe strings. It has important significance in reducing the instability of the pressure rod, avoiding pipe rod wear, improving the efficiency of the pumping unit system, and extending the service life of the oil production pipe string, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a structural schematic diagram of a flexible sucker rod hydraulic pumping assist device of the present invention;

[0049] Figure 2 It is a schematic structural diagram of the underground pulling-assisting cylinder of the present invention.

[0050] In the figure: flexible sucker rod 1, wellhead dynamometer 2, casing spool 3, oil pipe 4, casing 5, downhole pulling cylinder 6, rigid sucker rod 7, oil pump 8, hydraulic pipe 9, control cabinet 10, liquid storage tank 11 and solenoid valve 12, upper rod connector 601, piston tube 602, upper joint 603, pressure relief valve 604, sealing cylinder 605, lower joint 606, lower rod connector 607. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Embodiment 1:

[0053] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0054] A flexible sucker rod hydraulic pumping aid device, comprising a flexible sucker rod 1, a rigid sucker rod 7, and a pump 8, wherein the lower end of the rigid sucker rod is connected to a plunger of the pump;

[0055] It also includes an underground pulling cylinder 6 and a ground hydraulic control device;

[0056] The upper end of the downhole auxiliary pull cylinder is connected to the lower end of the flexible sucker rod, and the lower end of the downhole auxiliary pull cylinder is connected to the upper end of the rigid sucker rod;

[0057] The ground hydraulic control device is communicated with the hydraulic hole of the underground pulling-assisting cylinder through a hydraulic pipe.

[0058] Furthermore, it also includes a dynamometer 2, which is electrically connected to the ground hydraulic control device via a data line.

[0059] Further, the downhole pulling cylinder includes a piston tube 602 and a piston cylinder;

[0060] The center of the piston tube is an axial through hole, and the outer wall of the piston tube has an integrally formed outward-facing ring plate;

[0061] The piston tube coaxially passes through the piston cylinder, and the circumferential surface of the outward-expanded ring plate forms a sliding seal with the inner wall of the piston cylinder, that is, the outward-expanded ring plate is used as a piston in the piston cylinder.

[0062] Further, the piston cylinder includes a sealing cylinder 605, an upper joint 603, and a lower joint 606;

[0063] The upper joint is connected to the upper port of the sealing cylinder. The center of the upper joint is provided with an upper joint center hole for passing the piston tube. The inner wall of the upper joint center hole and the outer wall of the piston tube form a sliding sealing pair. The upper joint is provided with a hydraulic hole 6032 that can lead to the sealing cylinder.

[0064] The lower joint is connected to the lower port of the sealing tube. A lower joint center hole is provided in the center of the lower joint for passing the piston tube. The inner wall of the lower joint center hole and the outer wall of the piston tube form a sliding sealing pair. The lower joint is provided with a balancing hole that can be connected to the sealing tube.

[0065] Furthermore, the upper joint also has a pressure relief hole 6031 that can be connected to the sealing cylinder, and a pressure relief valve 604 is installed on the pressure relief hole. The upper end of the upper joint is connected to the oil pipe 4 in the casing 5, and the lower end of the lower joint is connected to the upper end of the pump barrel of the oil pump through a short section of the oil pipe.

[0066] Furthermore, the downhole auxiliary pulling cylinder further includes an upper rod connector 601 and a lower rod connector 607;

[0067] The upper rod connector is installed at the upper end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube, and the upper rod connector is connected and fixed to the upper flexible sucker rod;

[0068] The lower rod connector is installed at the lower end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube. The lower rod connector is fixedly connected to the rigid sucker rod below.

[0069] Furthermore, the ground hydraulic control device includes a control cabinet 10, a fluid storage tank 11, and a solenoid valve 12;

[0070] The solenoid valve has three ports, namely, an inlet, an outlet and a return port. The outlet of the solenoid valve is connected to the hydraulic hole of the downhole auxiliary pulling cylinder through a hydraulic pipe, the inlet of the solenoid valve is connected to the outlet of the liquid storage tank through a control cabinet and a liquid inlet pipe, and the return port of the solenoid valve is connected to the recovery port of the liquid storage tank through a return liquid pipe.

[0071] Furthermore, the control cabinet includes a control circuit and a booster pump. The control circuit is electrically connected to the booster pump, the control circuit is electrically connected to the dynamometer, the control circuit is electrically connected to the solenoid valve, and the control circuit is electrically connected to the liquid level sensor of the liquid level gauge in the liquid storage tank.

[0072] refer to Figure 1 The wellhead dynamometer 2 is installed on the top of the oil well Christmas tree. The lower end of the flexible sucker rod 1 is connected to the upper end of the downhole auxiliary pull tube 6. The lower end of the downhole auxiliary pull tube 6 is connected to the rigid sucker rod 7. The rigid sucker rod 7 is connected to the oil pump 8. At the same time, the downhole auxiliary pull tube 6 is connected to the oil pipe 4 and lowered into the casing 5. The rigid sucker rod 7 is covered with an oil pipe. The oil pipe is connected to the downhole auxiliary pull tube 6 at the top and the oil pump 8 at the bottom. The lower end of the hydraulic pipe 9 is connected to the hydraulic hole of the downhole auxiliary pull tube 6 through a sealing pressure nail 901, and the upper end passes through the casing spool 3 (through a multi-tube The solenoid valve 12 is connected to the liquid storage tank 11 through a sealing plug 902, and the solenoid valve 12 is connected to the liquid storage tank 11 through a return pipe 1202. The solenoid valve 12 and the control cabinet 10 also have a liquid supply pipe. A liquid inlet pipe 1102 is connected between the control cabinet 10 and the liquid storage tank 11. Data signals are transmitted between the wellhead dynamometer 2 and the control cabinet 10, as well as between the solenoid valve 12 and the control cabinet 10, and between the liquid level sensor of the liquid storage tank 11 and the control cabinet 10 through cables 201, 1201, and 1101 respectively.

[0073] The middle part of the upper rod connector 601 in the downhole auxiliary pulling tube 6 is connected to the lower end of the flexible sucker rod 1, and the outer cylindrical surface is threadedly connected to the upper end of the piston tube 602. The piston tube 602 is inserted into the sealing tube 605. The upper and lower ends of the sealing tube 605 are respectively threadedly connected to the upper joint 603 and the lower joint 606. A pressure relief hole 6031 is provided on one side of the upper joint 603, and a pressure relief valve 604 is installed on the pressure relief hole 6031. A hydraulic hole 6032 is provided on the other side of the upper joint 603, and the lower joint 606 has circumferentially evenly distributed balance holes 6061. The middle part of the lower rod connector 607 can be connected to the rigid sucker rod 7 below, and the outer cylindrical surface is threadedly connected to the lower end of the piston tube 602.

[0074] When applied on site, after the device described in the invention is put into the well with the supporting pipe, a flexible sucker rod hydraulic pumping method described in the invention is implemented, and the travel data of the flexible sucker rod 1 is collected through the wellhead dynamometer 2 and transmitted to the control cabinet 10. The control cabinet 10 controls the opening and closing of the solenoid valve 12 and pumps the liquid of the liquid storage tank 11 into the hydraulic pipe 9 according to the collected travel data and the liquid level data of the liquid storage tank 11. When the flexible sucker rod 1 is in the downward stroke, the control cabinet 10 sends a signal to open the downward injection channel of the solenoid valve 12, the pump in the control cabinet 10 is started, and the liquid in the liquid storage tank 11 is injected into the downhole auxiliary pull cylinder 6 through the hydraulic control pipe 9. The piston tube 602 moves downward under the hydraulic pressure and pulls the flexible sucker rod 1 downward. The well fluid below the piston tube 602 is discharged through the balance hole 6061. When the flexible sucker rod 1 is on its upward stroke, the control cabinet 10 controls the solenoid valve 12 to reverse the fluid flow channel, and the liquid above the piston tube 602 of the downhole auxiliary pulling cylinder 6 flows back to the liquid storage tank 11 through the hydraulic pipe 9. The pressure in the hydraulic pipe 9 is released, and under the action of the pulling force of the flexible sucker rod 1 during the upward stroke, the piston tube 602 moves upward, and the excess pressure formed above the piston tube 602 in the sealing cylinder 605 can be safely released through the pressure relief hole 6031 and the pressure relief valve 604.

[0075] The ground hydraulic control system is controlled by the data from the wellhead dynamometer. The technology of controlling the hydraulic system with the dynamometer and the related technology itself are widely used in this field and are existing technologies. They can be directly applied for control and the specific control process will not be repeated. Those skilled in the art will understand it.

[0076] The present invention controls the ground hydraulic control system through the data of the wellhead dynamometer. When the sucker rod is in the downward stroke, the ground pumps hydraulic pressure to make the piston in the downhole auxiliary pull cylinder move downward, pulling the end of the sucker rod downward, so that the sucker rod is always in a tensile stress state, avoiding the occurrence of adverse conditions such as instability of the compression rod and pipe rod wear that damages the life of the pipe column.

[0077] The invention is suitable for flexible sucker rod oil production, conventional rod deep pumping, heavy oil well machine production and other oil production process pipe strings. It has important significance in reducing the instability of the pressure rod, avoiding pipe rod wear, improving the efficiency of the pumping unit system, and extending the service life of the oil production pipe string, and has broad application prospects.

[0078] Embodiment 2:

[0079] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0080] A flexible sucker rod hydraulic pumping aid device, comprising a flexible sucker rod 1, a rigid sucker rod 7, and a pump 8, wherein the lower end of the rigid sucker rod is connected to a plunger of the pump;

[0081] It also includes an underground pulling cylinder 6 and a ground hydraulic control device;

[0082] The upper end of the downhole auxiliary pull cylinder is connected to the lower end of the flexible sucker rod, and the lower end of the downhole auxiliary pull cylinder is connected to the upper end of the rigid sucker rod;

[0083] The ground hydraulic control device is communicated with the hydraulic hole of the underground pulling-assisting cylinder through a hydraulic pipe.

[0084] Further, the downhole pulling cylinder includes a piston tube 602 and a piston cylinder;

[0085] The center of the piston tube is an axial through hole, and the outer wall of the piston tube has an integrally formed outward-facing ring plate;

[0086] The piston tube coaxially passes through the piston cylinder, and the circumferential surface of the outward-expanded ring plate forms a sliding seal with the inner wall of the piston cylinder, that is, the outward-expanded ring plate is used as a piston in the piston cylinder.

[0087] Further, the piston cylinder includes a sealing cylinder 605, an upper joint 603, and a lower joint 606;

[0088] The upper joint is connected to the upper port of the sealing cylinder. The center of the upper joint is provided with an upper joint center hole for passing the piston tube. The inner wall of the upper joint center hole and the outer wall of the piston tube form a sliding sealing pair. The upper joint is provided with a hydraulic hole 6032 that can lead to the sealing cylinder.

[0089] The lower joint is connected to the lower port of the sealing tube. A lower joint center hole is provided in the center of the lower joint for passing the piston tube. The inner wall of the lower joint center hole and the outer wall of the piston tube form a sliding sealing pair. The lower joint is provided with a balancing hole that can be connected to the sealing tube.

[0090] Furthermore, the upper joint also has a pressure relief hole 6031 that can be connected to the sealing cylinder, and a pressure relief valve 604 is installed on the pressure relief hole. The upper end of the upper joint is connected to the oil pipe 4 in the casing 5, and the lower end of the lower joint is connected to the upper end of the pump barrel of the oil pump through a short section of the oil pipe.

[0091] Furthermore, the downhole auxiliary pulling cylinder further includes an upper rod connector 601 and a lower rod connector 607;

[0092] The upper rod connector is installed at the upper end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube, and the upper rod connector is connected and fixed to the upper flexible sucker rod;

[0093] The lower rod connector is installed at the lower end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube. The lower rod connector is fixedly connected to the rigid sucker rod below.

[0094] Embodiment 3:

[0095] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0096] A downhole pulling-assisting cylinder, the downhole pulling-assisting cylinder comprising a piston tube 602 and a piston cylinder;

[0097] The center of the piston tube is an axial through hole, and the outer wall of the piston tube has an integrally formed outward-facing ring plate;

[0098] The piston tube coaxially passes through the piston cylinder, and the circumferential surface of the outward-expanded ring plate forms a sliding seal with the inner wall of the piston cylinder, that is, the outward-expanded ring plate is used as a piston in the piston cylinder.

[0099] Further, the piston cylinder includes a sealing cylinder 605, an upper joint 603, and a lower joint 606;

[0100] The upper joint is connected to the upper port of the sealing cylinder. The center of the upper joint is provided with an upper joint center hole for passing the piston tube. The inner wall of the upper joint center hole and the outer wall of the piston tube form a sliding sealing pair. The upper joint is provided with a hydraulic hole 6032 that can lead to the sealing cylinder.

[0101] The lower joint is connected to the lower port of the sealing tube. A lower joint center hole is provided in the center of the lower joint for passing the piston tube. The inner wall of the lower joint center hole and the outer wall of the piston tube form a sliding sealing pair. The lower joint is provided with a balancing hole that can be connected to the sealing tube.

[0102] Furthermore, the upper joint also has a pressure relief hole 6031 that can be connected to the sealing cylinder, and a pressure relief valve 604 is installed on the pressure relief hole. The upper end of the upper joint is connected to the oil pipe 4 in the casing 5, and the lower end of the lower joint is connected to the upper end of the pump barrel of the oil pump through a short section of the oil pipe.

[0103] Furthermore, the downhole auxiliary pulling cylinder further includes an upper rod connector 601 and a lower rod connector 607;

[0104] The upper rod connector is installed at the upper end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube, and the upper rod connector is connected and fixed to the upper flexible sucker rod;

[0105] The lower rod connector is installed at the lower end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube. The lower rod connector is fixedly connected to the rigid sucker rod below.

[0106] Although all the above embodiments use Figure 1 to Figure 2 However, as a person skilled in the art can clearly know, there is no need to provide a separate drawing to represent, as long as the missing parts or structural features in the embodiment are removed from the drawing. This is clear to those skilled in the art. Of course, the embodiment with more parts or structural features is only the optimal embodiment, and the embodiment with fewer parts is the basic embodiment, but it can also achieve the basic purpose of the present invention, so all these variant embodiments are within the protection scope of the present invention.

[0107] All parts and components not discussed in detail in this application and the connection methods of the parts and components in this application belong to the well-known technology in this technical field and will not be described in detail, such as welding, threaded connection, etc.

[0108] In the present invention, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0109] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0110] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A flexible sucker rod hydraulic pumping device, comprising a flexible sucker rod, a rigid sucker rod, and a pump, wherein the lower end of the rigid sucker rod is connected to a plunger of the pump; It is characterized in that It also includes downhole auxiliary pulling cylinder and ground hydraulic control device; The upper end of the downhole auxiliary pull cylinder is connected to the lower end of the flexible sucker rod, and the lower end of the downhole auxiliary pull cylinder is connected to the upper end of the rigid sucker rod; The ground hydraulic control device is connected to the hydraulic hole of the underground pulling cylinder through a hydraulic pipe; It also includes a dynamometer, which is electrically connected to the ground hydraulic control device via a data line; The downhole pulling cylinder comprises a piston tube and a piston cylinder; The center of the piston tube is an axial through hole, and the outer wall of the piston tube has an integrally formed outward-facing ring plate; The piston tube coaxially passes through the piston cylinder, and the circumferential surface of the outward-expanded ring plate forms a sliding seal with the inner wall of the piston cylinder, that is, the outward-expanded ring plate is used as a piston in the piston cylinder; The piston cylinder comprises a sealing cylinder, an upper joint and a lower joint; The upper joint is connected to the upper port of the sealing cylinder, and a central hole for passing the piston tube is provided at the center of the upper joint. The inner wall of the central hole of the upper joint and the outer wall of the piston tube form a sliding sealing pair, and the upper joint is provided with a hydraulic hole leading to the sealing cylinder; The lower joint is connected to the lower port of the sealing tube. A lower joint center hole is provided in the center of the lower joint for passing the piston tube. The inner wall of the lower joint center hole and the outer wall of the piston tube form a sliding sealing pair. The lower joint is provided with a balancing hole that can be connected to the sealing tube.

2. A flexible sucker rod hydraulic pumping aid device according to claim 1, characterized in that: The upper joint also has a pressure relief hole that can be connected to the sealing cylinder, and a pressure relief valve is installed on the pressure relief hole. The upper end of the upper joint is connected to the oil pipe in the casing, and the lower end of the lower joint is connected to the upper end of the pump barrel of the oil pump through a short oil pipe joint.

3. A flexible sucker rod hydraulic pumping aid device according to claim 1 or 2, characterized in that: The downhole auxiliary pulling cylinder also includes an upper rod connector and a lower rod connector; The upper rod connector is installed at the upper end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube, and the upper rod connector is connected and fixed to the upper flexible sucker rod; The lower rod connector is installed at the lower end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube. The lower rod connector is fixedly connected to the rigid sucker rod below.

4. A flexible sucker rod hydraulic pumping aid device according to claim 1 or 2, characterized in that: The ground hydraulic control device includes a control cabinet, a fluid storage tank, and a solenoid valve; The solenoid valve has three ports, namely, an inlet, an outlet and a return port. The outlet of the solenoid valve is connected to the hydraulic hole of the downhole auxiliary pulling cylinder through a hydraulic pipe, the inlet of the solenoid valve is connected to the outlet of the liquid storage tank through a control cabinet and a liquid inlet pipe, and the return port of the solenoid valve is connected to the recovery port of the liquid storage tank through a return liquid pipe.

5. A flexible sucker rod hydraulic pumping aid device according to claim 4, characterized in that: The control cabinet includes a control circuit and a booster pump. The control circuit is electrically connected to the booster pump, the control circuit is electrically connected to the dynamometer, the control circuit is electrically connected to the solenoid valve, and the control circuit is electrically connected to the liquid level sensor of the liquid level gauge in the liquid storage tank.

6. A method for using the flexible sucker rod hydraulic pumping aid device as claimed in claim 1, characterized in that: The following steps are involved: The dynamometer collects the stroke data of the flexible sucker rod and transmits it to the control cabinet. The control cabinet controls the opening and closing of the solenoid valve and pumps the liquid in the liquid storage tank into the hydraulic pipe according to the collected stroke data and the liquid level data of the liquid storage tank. When the flexible sucker rod is in the downward stroke, the control cabinet sends a signal to open the downward injection channel of the solenoid valve, the pump in the control cabinet starts, the liquid in the liquid storage tank is injected into the downhole auxiliary pull cylinder through the hydraulic control pipe, the piston tube moves downward under the hydraulic pressure, and pulls the flexible sucker rod downward, and the well fluid under the piston tube is discharged through the balance hole; When the flexible sucker rod is in the upward stroke, the control cabinet controls the solenoid valve channel to change direction, and the liquid above the piston tube in the downhole auxiliary pull tube flows back to the liquid storage tank through the hydraulic pipe, and the pressure in the hydraulic pipe is released. Under the pulling force of the flexible sucker rod in the upward stroke, the piston tube moves upward, and the pressure above the piston tube in the sealing tube is also safely released through the pressure relief hole and the pressure relief valve; After the downstroke and upstroke are completed, the downhole auxiliary puller completes its hydraulic auxiliary pumping function. At the same time, the sucker rod is always in a tensile stress state to avoid the instability of the pressure rod, resulting in pipe wear and other adverse conditions that damage the life of the pipe string.

7. A downhole pulling cylinder for the flexible sucker rod hydraulic pumping device as claimed in claim 1, characterized in that: Including piston tube and piston cylinder; The center of the piston tube is an axial through hole, and the outer wall of the piston tube has an integrally formed outward-facing ring plate; The piston tube coaxially passes through the piston cylinder, and the circumferential surface of the outward-expanded ring plate forms a sliding seal with the inner wall of the piston cylinder, that is, the outward-expanded ring plate is used as a piston in the piston cylinder.

8. The downhole pulling-assisting cylinder for a flexible sucker rod hydraulic pumping-assisting device according to claim 7, characterized in that: The piston cylinder comprises a sealing cylinder, an upper joint and a lower joint; The upper joint is connected to the upper port of the sealing cylinder, and a central hole for passing the piston tube is provided at the center of the upper joint. The inner wall of the central hole of the upper joint and the outer wall of the piston tube form a sliding sealing pair, and the upper joint is provided with a hydraulic hole leading to the sealing cylinder; The lower joint is connected to the lower port of the sealing tube. A lower joint center hole is provided in the center of the lower joint for passing the piston tube. The inner wall of the lower joint center hole and the outer wall of the piston tube form a sliding sealing pair. The lower joint is provided with a balancing hole that can be connected to the sealing tube.

9. The downhole pulling-assisting cylinder for a flexible sucker rod hydraulic pumping-assisting device according to claim 7, characterized in that: The upper joint also has a pressure relief hole that can be connected to the sealing cylinder, and a pressure relief valve is installed on the pressure relief hole. The upper end of the upper joint is connected to the oil pipe in the casing, and the lower end of the lower joint is connected to the upper end of the pump barrel of the oil pump through a short oil pipe joint.

10. A downhole pulling-assisting cylinder for a flexible sucker rod hydraulic pumping-assisting device according to claim 8 or 9, characterized in that: The downhole auxiliary pulling cylinder also includes an upper rod connector and a lower rod connector; The upper rod connector is installed at the upper end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube, and the upper rod connector is connected and fixed to the upper flexible sucker rod; The lower rod connector is installed at the lower end of the piston tube, and is provided with an axial through hole that can communicate with the piston tube. The lower rod connector is fixedly connected to the rigid sucker rod below.

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