Power system and hydraulic oil pumping unit

Abstract

The application provides a power system and a hydraulic oil pumping machine. The power system is applied to the hydraulic oil pumping machine. The hydraulic oil pumping machine comprises a first oil cylinder and a second oil cylinder. The power system comprises: a first proportional directional valve connected between an oil tank and a rod cavity of at least one first oil cylinder; a second proportional directional valve connected between the oil tank and a rod cavity of at least one second oil cylinder; a first hydraulic pump having a first oil port and a second oil port, which are connected with a first oil inlet of the first proportional directional valve and a second oil inlet of the second proportional directional valve respectively; a control unit for controlling the first hydraulic pump to periodically reverse, so that a first piston rod of the at least one first oil cylinder and a second piston rod of the at least one second oil cylinder are synchronously reciprocated, and the movement direction of the first piston rod is opposite to that of the second piston rod; and the opening degree of the first proportional valve and the second proportional valve is adjusted to adjust the frequency of the synchronous reciprocation of the first piston rod and the second piston rod.

Description

Technical Field

[0001] This application relates to the field of oil extraction equipment technology, and particularly to a power system and a hydraulic pumping unit. Background Technology

[0002] An oil pumping unit, also known as an oil extraction unit, is a device that uses mechanical means to pump crude oil from the bottom of a well to the surface. Commonly used types include beam pumps, hydraulic pumps, and screw pumps. Among these, hydraulic pumping units are beamless oil extraction equipment that uses a hydraulic system to achieve reciprocating motion. They are primarily used to replace traditional beam pumping units to meet the needs of deep oil reservoir extraction. In a hydraulic pumping unit, the sucker rod is connected to the piston rod of the hydraulic cylinder. Driven by hydraulic oil, the piston rod drives the sucker rod to move linearly back and forth, thus extracting crude oil. Compared to traditional beam pumping units, hydraulic pumping units have advantages such as smaller footprint and lower cost.

[0003] In related technologies, when a hydraulic cylinder performs a downstroke under the gravity of the sucker rod, the discharged hydraulic oil usually flows directly back to the oil tank, failing to effectively convert the potential energy generated during the downstroke into usable power. This results in the hydraulic pump continuously consuming a large amount of electrical energy during the cylinder's upstroke, while the energy during the downstroke is wasted.

[0004] Meanwhile, when changes occur in the well's fluid level or production rate, requiring adjustments to the pumping unit's stroke rate to optimize production, existing adjustment methods are cumbersome and cannot achieve continuous, precise, stepless adjustment of the stroke rate. This limitation makes it difficult for the pumping unit to accurately match the well's operating conditions, resulting in low oil production efficiency. Utility Model Content

[0005] This application mainly provides a power system and a hydraulic pumping unit. The technical solution of this application is implemented as follows: In a first aspect, a power system is provided for use in a hydraulic pumping unit, the hydraulic pumping unit including at least one first cylinder and at least one second cylinder for connecting a sucker rod, the power system including: a first proportional directional valve connected between an oil tank and the rod chamber of the at least one first cylinder; a second proportional directional valve connected between the oil tank and the rod chamber of the at least one second cylinder; a first hydraulic pump having a first port and a second port, respectively connected to the first inlet of the first proportional directional valve and the second inlet of the second proportional directional valve; a control unit for controlling the first hydraulic pump to periodically rotate forward and reverse, so that the first piston rod of the at least one first cylinder and the second piston rod of the at least one second cylinder reciprocate synchronously, and the movement directions of the first piston rod and the second piston rod are opposite; and adjusting the opening degree of the first proportional directional valve and the second proportional directional valve to adjust the frequency of the synchronous reciprocating motion of the first piston rod and the second piston rod.

[0006] By using the above-mentioned technical means, two sets of oil cylinders are connected by a hydraulic pump and a proportional directional valve. By controlling the periodic forward and reverse rotation of the hydraulic pump and adjusting the opening of the proportional directional valve, the synchronous reciprocating motion and frequency regulation of the piston rod are realized. This effectively recovers the potential energy of the downstroke, improves the energy conversion efficiency, reduces the system energy consumption, and makes the stroke adjustment more flexible and convenient.

[0007] In some embodiments, the control unit is further configured to: when at least one first piston rod moves to a first preset top dead center, control the first hydraulic pump to reverse, so that the first piston rod moves downward, and the hydraulic oil in the at least one first cylinder flows into the second cylinder under the action of the gravity of the sucker rod connected to the first piston rod and the first driving force generated by the reverse rotation of the first hydraulic pump, so as to drive at least one second piston rod to move upward; when at least one second piston rod moves to a second preset top dead center, control the first hydraulic pump to rotate forward, so that the second piston rod moves downward, and the hydraulic oil in the at least one second cylinder flows into the first cylinder under the action of the gravity of the sucker rod connected to the second piston rod and the second driving force generated by the forward rotation of the first hydraulic pump, so as to drive at least one first piston rod to move upward.

[0008] Based on the aforementioned technical means, by controlling the forward and reverse rotation of the first hydraulic pump when the piston rod moves to the preset top dead center, the gravitational potential energy of the piston rod during its downward movement can be fully utilized. Combined with the driving force generated by the hydraulic pump, this achieves effective transmission of hydraulic oil between the cylinders. This allows the potential energy of the downward-moving cylinder to be efficiently converted into the power to drive the piston rod on the other side upward, significantly reducing dependence on external energy, improving the energy utilization efficiency of the entire power system, and solving the problem of insufficient energy recovery in traditional hydraulic systems.

[0009] In some embodiments, the power system further includes: a second hydraulic pump having a third port and a fourth port, respectively connected to a first outlet of the first proportional directional valve and a second outlet of the second proportional directional valve; at least one first solenoid valve, respectively disposed between the third port and the at least one first cylinder, for controlling the on / off state of at least one first oil passage between the at least one first cylinder and the third port; and at least one second solenoid valve, respectively disposed between the fourth port and the at least one second cylinder, for controlling the on / off state of at least one second oil passage between the at least one second cylinder and the fourth port.

[0010] Based on the aforementioned technical means, by introducing a second hydraulic pump and at least one solenoid valve, the system can achieve independent control or auxiliary operation of individual or partial cylinders, thereby effectively coping with complex downhole conditions, maintenance needs, and specific auxiliary functions, such as single-sided operation, single-cylinder operation, operation with different numbers of cylinders, or operation with different strokes. This removes limitations on the system when handling asynchronous or unbalanced conditions, enhancing its adaptability to diverse oil production scenarios.

[0011] In some embodiments, the control unit is further configured to: control the at least one first oil circuit to disconnect and the at least one second oil circuit to connect via the first solenoid valve and the second solenoid valve; control the second hydraulic pump to reverse so as to move at least one second piston rod upward; when the second piston rod moves to the middle position of the second stroke, control the at least one first oil circuit to connect and the at least one second oil circuit to disconnect via the first solenoid valve and the second solenoid valve; control the second hydraulic pump to rotate forward so as to move at least one first piston rod upward; when the first piston rod moves to the middle position of the first stroke, control the first oil circuit and the second oil circuit to disconnect via the first solenoid valve and the second solenoid valve; control the first hydraulic pump to rotate forward and reverse periodically so as to make the first piston rod and the second piston rod reciprocate synchronously.

[0012] By employing the aforementioned technical solution, and utilizing a second hydraulic pump and solenoid valve to precisely move the first and second piston rods to their preset stroke midpoints before the main synchronous reciprocating motion begins, the system is ensured to start synchronous reciprocating motion from a balanced and optimized starting point. This improves the system's startup efficiency, avoids shocks and instabilities that may result from initial position imbalances, and allows the system to immediately enter a stable synchronous operating state, thereby enhancing the overall reliability and performance.

[0013] In some embodiments, the control unit is further configured to: control a first number of first oil circuits in the at least one first oil circuit to be connected and the at least one second oil circuit to be disconnected via the first solenoid valve and the second solenoid valve; control the second hydraulic pump to rotate forward so that the first piston rods of the first number of first oil cylinders move upward; when the first number of first piston rods move to a first preset upper dead center, control the second hydraulic pump to stop so that the first number of first piston rods move downward, and the hydraulic oil in the first number of first oil cylinders flows into the oil tank through the first proportional directional valve under the gravity of the sucker rod; when the first number of first piston rods move to a first preset lower dead center, control the second hydraulic pump to rotate forward until the first number of first piston rods move upward to the first preset upper dead center; wherein, the first number is less than or equal to the number of first oil cylinders.

[0014] Based on the aforementioned technical means, by selectively connecting a portion of the first oil circuit and disconnecting the second oil circuit, the system can operate only the required number of first cylinders according to actual needs, such as partial well maintenance or intermittent oil pumping, thus avoiding unnecessary energy consumption. Simultaneously, during the piston rod's downward stroke, by controlling the second hydraulic pump to stop and utilizing the gravity of the sucker rod to return the hydraulic oil to the tank, gravitational potential energy is fully recovered, significantly reducing the system's energy consumption. This operating mode improves the oil extraction machine's operational flexibility and energy-saving effect, enabling the equipment to operate efficiently and economically under various working conditions.

[0015] In some embodiments, the control unit is further configured to: control the opening of the first proportional directional valve to adjust the descent speed of the first piston rods as the first number of first piston rods move from the first preset top dead center to the first preset bottom dead center.

[0016] Based on the aforementioned technical means, by actively controlling the opening of the first proportional directional valve during the movement of the first number of first piston rods from the first preset upper dead center to the first preset lower dead center, this application can achieve precise adjustment of the descent speed of the first piston rods. This allows the system to optimize the descent speed of the piston rods according to the actual working conditions of the oil well, such as downhole fluid level, crude oil viscosity, or formation pressure, thereby effectively avoiding "dry pumping" or unnecessary impacts. Furthermore, this precise descent speed control provides crucial technical support for achieving special operational functions such as "pump contact" and "unblocking."

[0017] In some embodiments, the control unit is further configured to: control a second number of first oil circuits to disconnect and a third number of second oil circuits to connect via the first solenoid valve and the second solenoid valve; control the second hydraulic pump to reverse so that the third number of second piston rods move upward; when the third number of second piston rods move to the middle position of the second stroke, control the second number of first oil circuits to connect and the third number of second oil circuits to disconnect via the first solenoid valve and the second solenoid valve; control the second hydraulic pump to rotate forward so that the second number of first piston rods move upward; control the second hydraulic pump to stop when the second number of first piston rods move to the middle position of the first stroke; control the first hydraulic pump to rotate forward and reverse periodically, and adjust the opening of the first proportional directional valve and the second proportional directional valve to a first opening and a second opening respectively, so that the second number of first piston rods and the third number of second piston rods reciprocate synchronously; wherein the first opening and the second opening are both related to the second number and the third number, and the second number and the third number are less than the number of first cylinders.

[0018] Based on the above technical means, when the number of hydraulic cylinders participating in the work on both sides is unequal, the opening degree of the first proportional directional valve and the second proportional directional valve are dynamically adjusted to be related to the actual number of hydraulic cylinders participating in the work. This allows for precise balance of hydraulic oil flow under asymmetrical load, thereby ensuring that the second number of first piston rods and the third number of second piston rods achieve smooth and efficient synchronous reciprocating motion.

[0019] In some embodiments, the control unit is further configured to: when the first stroke of the first cylinder and the second stroke of the second cylinder are different, during the periodic forward and reverse rotation of the first hydraulic pump, adjust the opening of the first proportional directional valve and the second proportional directional valve to a third opening and a fourth opening, respectively, so that the first piston rod and the second piston rod reciprocate synchronously; wherein, the first stroke is the distance difference between the first preset upper dead center and the first preset lower dead center of the first cylinder, the second stroke is the distance difference between the second preset upper dead center and the second preset lower dead center of the second cylinder, and the third opening and the fourth opening are both related to the first stroke and the second stroke.

[0020] Based on the aforementioned technical means, when the strokes of the first and second hydraulic cylinders differ, by adjusting the openings of the first and second proportional directional valves, the system can accurately compensate for the inconsistent hydraulic oil demand caused by the difference in cylinder strokes. This ensures that the first and second piston rods maintain stable synchronous reciprocating motion even under complex operating conditions with mismatched strokes. This effectively solves the problems of reduced piston rod motion efficiency, uncoordinated motion, or impact under traditional control methods, and improves the adaptability and operational stability of the power system to diverse oil well operating conditions.

[0021] In some embodiments, the first solenoid valve and the second solenoid valve are solenoid directional valves; the power system further includes a circulating unit, which is connected to the oil tank and is used to cool and filter the hydraulic oil in the oil tank.

[0022] In a second aspect, a hydraulic pumping unit is provided, comprising: at least one first cylinder and at least one second cylinder for connection to a sucker rod; and a power system as described in the first aspect. Attached Figure Description

[0023] Figure 1 A schematic diagram of a power system provided in an embodiment of this application; Figure 2 A schematic diagram of a power system provided for another embodiment of this application; Figure 3 A schematic diagram of the power system provided in the embodiments of this application in a unilateral working state; Figure 4 A schematic diagram of the power system provided in this application under asymmetric operating conditions on both sides; Figure 5 A schematic diagram illustrating the power system provided in this application under unequal operating conditions on both sides; Figure 6 This is a schematic structural diagram of the hydraulic pumping unit provided in the embodiments of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0026] In the following description, the terms "first, second, third" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0028] Oil pumping units, also known as oil extraction units, are devices that use mechanical means to pump crude oil from the bottom of a well to the surface. Commonly used types of equipment include beam pumps, hydraulic pumps, and screw pumps.

[0029] A walking beam pumping unit consists of a walking beam, a connecting rod, a crank mechanism, a gearbox, a power unit, and auxiliary equipment. During operation, the rotation of the electric motor is converted into the up-and-down movement of the walking beam via the gearbox and crank-connecting rod mechanism. The walking beam, through the polished rod and sucker rod, drives the plunger of the downhole pump to move up and down, continuously pumping crude oil from the wellbore. Therefore, it is also called a nodding donkey pump.

[0030] Beam pumping units are widely used due to their reliable performance, simple structure, and convenient operation and maintenance. However, some problems still exist with this type of equipment, which are explained in detail below: The average load rate of the motor in a beam pumping unit is less than 30%, resulting in low energy utilization. Furthermore, the inherent motion characteristics of the four-bar or double-bar linkage are mismatched with the variable downhole loads. Traditional balancing devices struggle to dynamically adapt to load changes, further exacerbating energy consumption. Simultaneously, the gearbox is prone to oil leaks, gear wear and shaft breakage, and the motor's rolling bearings are susceptible to wear and fatigue fracture. Connecting rods and crank pins also frequently fail due to uneven stress or installation errors. These component problems not only affect equipment operation but are also difficult to diagnose in their early stages due to their concealed nature. In addition, the fixed motion trajectory of the four-bar linkage prevents flexible adjustment of stroke and frequency, leading to "dry pumping" in low-production wells and further increasing equipment wear and energy consumption. Vibrations generated by the beam's oscillation are easily transmitted to the overall structure, potentially causing cracks in the support or base over time, and existing vibration damping devices have limited effectiveness. These types of equipment require frequent maintenance, which is labor-intensive and costly. They also have low levels of intelligence, rely on manual experience for traditional fault diagnosis, and have low adoption rates of intelligent diagnostic systems. Furthermore, the lifespan of components is significantly shortened under harsh conditions such as high temperature and high corrosion. Moreover, their integration with new energy systems such as photovoltaic energy storage is still in the exploratory stage and has not yet been widely applied.

[0031] A hydraulic pumping unit is a beamless oil extraction device that uses a hydraulic system to achieve reciprocating motion. It is primarily used to replace traditional beam pumping units to meet the needs of deep oil reservoir extraction. In a hydraulic pumping unit, the sucker rod is connected to the piston rod of the hydraulic cylinder. Driven by hydraulic oil, the piston rod drives the sucker rod to move linearly back and forth, thus extracting crude oil. Compared to traditional beam pumping units, hydraulic pumping units have advantages such as smaller footprint and lower cost.

[0032] Current hydraulic pumping units still face several pressing issues: For example, hydraulic oil is prone to contamination and deterioration due to oxidation, moisture, and impurities, leading to unstable system pressure and accelerated component wear. Oil pumps frequently experience abnormal noise, excessive noise, and insufficient flow due to air intake, filter blockage, or unsuitable oil viscosity. Key hydraulic components such as pump valve assemblies and cylinders are also susceptible to damage from prolonged high-pressure operation, corrosion, or aging seals, causing control failures, leaks, and affecting normal equipment operation. Furthermore, traditional hydraulic systems suffer from insufficient energy recovery, energy conversion losses still exist in secondary regulation technologies, and hydraulic parameters are not adequately matched to well conditions, leading to energy waste. Under extreme conditions, high temperatures cause hydraulic oil oxidation, low temperatures hinder oil suction, and dust or high humidity environments accelerate component corrosion, requiring some models to be equipped with cooling and heating devices. Poor sealing of the oil tank and pipelines can also allow moisture or particulate matter to intrude, causing malfunctions. In addition, pressure and displacement sensors have low reliability in harsh environments, and data distortion affects the control effect; the system maintenance is highly complex and requires professional technicians to operate, and whether faults can be repaired in a timely manner becomes an obstacle to promotion; most hydraulic systems adopt traditional control modes, which consume a lot of energy and have no obvious energy-saving effect, have few auxiliary functions, and are difficult to solve problems such as downhole wear and unsticking; the stroke and frequency adjustment steps are complex and have a limited range.

[0033] In summary, the main problems in the current application of hydraulic pumping units are insufficient energy recovery, high system energy consumption, and poor adjustability of stroke frequency.

[0034] For example, in a multi-well oilfield operation scenario, each hydraulic pumping unit is responsible for the oil production operation of one well. Under existing technology, when the hydraulic cylinder makes a downstroke under the gravity of the sucker rod, the discharged hydraulic oil usually flows directly back to the oil tank, failing to effectively convert the potential energy generated during the downstroke into usable power. This results in the hydraulic pump continuously consuming a large amount of electrical energy during the cylinder's upstroke, while the energy during the downstroke is wasted. Simultaneously, when the well's fluid level or production rate changes, requiring adjustments to the pumping unit's stroke rate to optimize production, the existing equipment's control system may only offer a limited selection of stroke rates, or the adjustment process may be cumbersome, unable to achieve continuous and precise stepless adjustment of the stroke rate. This limitation makes it difficult for the pumping unit to accurately match the dynamic operating conditions of the well, potentially leading to "dry pumping" or failure to maximize oil production efficiency.

[0035] If the above problems are not addressed, the operating efficiency of the hydraulic pumping unit will be affected. Continuous energy dissipation will lead to higher electricity consumption, directly increasing the operating costs of oil extraction. Simultaneously, the inability to flexibly adjust stroke and frequency to adapt to changing downhole conditions may result in low production efficiency, such as ineffective operation in low-producing wells, thereby accelerating equipment wear and increasing maintenance requirements. Ultimately, this will negatively impact the overall economic benefits and equipment reliability of the oilfield.

[0036] This application provides a power system and a hydraulic pumping unit to solve the above-mentioned problems. The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of a power system 100 provided in an embodiment of this application. The power system 100 is applied to a hydraulic pumping unit, which includes at least one first cylinder 210 and at least one second cylinder 220 for connecting a sucker rod.

[0038] It is understood that "at least one" in the embodiments of this application includes one or more, that is, the hydraulic pumping unit described above may include one or more first cylinders 210 and second cylinders 220. Furthermore, the number of first cylinders 210 and second cylinders 220 may be the same or different, and the embodiments of this application do not limit this.

[0039] Figure 1 This illustration shows a case where there are two of each of the first hydraulic cylinder 210 and the second hydraulic cylinder 220. It should be understood that... Figure 2 The two first cylinders 210 and two second cylinders 220 shown are merely examples.

[0040] Figure 1 The power system 100 includes: A first proportional directional valve 110 is connected between the oil tank and the rod chamber of at least one first cylinder 210.

[0041] The second proportional directional valve 120 is connected between the oil tank and the rod chamber of at least one second cylinder 220.

[0042] The rod chamber is the chamber through which the piston rod of the hydraulic cylinder passes, and the corresponding chamber is the rodless chamber. When pumping oil into the rod chamber, the piston rod moves toward the rodless chamber. In the technical solution of this application, this direction is defined as upward. When the piston rod moves upward, it drives the sucker rod to move, thereby extracting crude oil from the well.

[0043] A proportional directional valve is a valve that continuously adjusts the flow and direction of hydraulic oil according to a control signal. For example, a three-position four-way proportional directional valve may have a pressure port (P), a return port (T), an inlet port (A), and an outlet port (B). In the left position, PA and TB are open; in the neutral position, PT and AB are closed; and in the right position, PB and TA are open. In both the left and right positions, the proportional directional valve can control the opening of the valve spool by adjusting the magnitude of the current signal. By adjusting the valve spool opening, the flow rate of the hydraulic oil can be controlled.

[0044] The first hydraulic pump 130 has a first oil port 131 and a second oil port 132, which are respectively connected to the first oil inlet of the first proportional directional valve 110 and the second oil inlet of the second proportional directional valve 120.

[0045] The first hydraulic pump 130 is a power device that converts mechanical energy into hydraulic energy. It can be implemented by using a variable pump or a fixed pump in conjunction with a reversing device, such as a hydraulic motor driven by a servo motor. Its main purpose is to provide power to the hydraulic system and drive the oil cylinder to move.

[0046] The control unit 140 is used to control the first hydraulic pump 130 to periodically rotate forward and reverse so that the first piston rod of at least one first cylinder 210 and the second piston rod of at least one second cylinder 220 reciprocate synchronously, and the first piston rod and the second piston rod move in opposite directions; and to adjust the opening of the first proportional directional valve and the second proportional directional valve to adjust the frequency of the synchronous reciprocating motion of the first piston rod and the second piston rod.

[0047] In this embodiment, the control unit 140 is a device responsible for receiving sensor signals, processing data, and issuing control commands. It can be implemented using a programmable logic controller, an industrial computer, or a microcontroller.

[0048] The control unit 140 can control the first hydraulic pump 130 to cycle between forward and reverse working states according to a preset time or conditions, thereby realizing the synchronous reciprocating motion of the first cylinder 210 and the second cylinder 220 in opposite directions.

[0049] In this embodiment, synchronous reciprocating motion means that when the first piston rod of the first cylinder 210 moves downward, the second piston rod of the second cylinder 220 moves upward. When the first piston rod moves upward at a preset stop point, the second piston rod moves downward synchronously, so that the pistons of at least one cylinder can perform linear reciprocating motion in opposite directions at the same frequency.

[0050] Taking the downward movement of the first piston rod and the upward movement of the second piston rod as an example, during the downward movement of the first piston rod, the hydraulic oil in the rod chamber of the first piston rod is compressed by the gravity of the first piston rod itself and the sucker rod connected to the first piston rod, thereby forcing the hydraulic oil out of the rod chamber. The gravity of the first piston rod and the sucker rod will give this part of the hydraulic oil some kinetic energy. At the same time, the rotation of the first hydraulic pump 130 will give the hydraulic oil another part of kinetic energy, thereby pumping the hydraulic oil to the rod chamber of the second cylinder 220, which in turn pushes the second piston rod upward. After the second piston rod reaches the top dead center, the direction of the first hydraulic pump 130 is switched, so that the hydraulic oil flows from the second cylinder 220 to the first cylinder 210. By repeating the above steps, both the first cylinder 210 and the second cylinder 220 can perform linear reciprocating oil pumping actions.

[0051] In the technical solution provided in this application embodiment, the load weight of the hydraulic cylinder and the power provided by the first hydraulic pump are used to make the piston rods of the two hydraulic cylinders move synchronously in opposite directions, forming a "seesaw" type energy transfer. Compared with the beam pump and other hydraulic pumping units in related technologies, it has a significant energy-saving effect, and its energy-saving efficiency can reach 35%-45%.

[0052] Furthermore, the control unit 140 adjusts the opening degree of the first proportional directional valve 110 and the second proportional directional valve 120 according to preset parameters or real-time operating conditions. The opening degree of the proportional directional valve directly affects the flow rate of hydraulic oil, thereby controlling the movement speed of the piston rod. By adjusting the valve opening degree, the frequency of synchronous reciprocating motion of the piston rod can be adjusted, enabling the system to adapt to the stroke requirements of different oil wells. For example, when it is necessary to increase the stroke rate, the opening of the valve core of the proportional directional valve is increased to increase the hydraulic oil flow rate and accelerate the movement speed of the piston rod; conversely, the opening is decreased.

[0053] By controlling the hydraulic pump to periodically rotate forward and reverse and adjusting the opening of the proportional directional valve, the synchronous reciprocating motion and frequency regulation of the piston rod are achieved. This effectively recovers the potential energy of the downstroke, improves the energy conversion efficiency, reduces system energy consumption, and makes stroke adjustment more flexible and convenient.

[0054] In some embodiments, the control unit 140 is further configured to: control the first hydraulic pump 130 to reverse when at least one first piston rod moves to a first preset top dead center, so that the first piston rod moves downward, and the hydraulic oil in at least one first cylinder 210 flows into the second cylinder 220 under the action of the gravity of the sucker rod connected to the first piston rod and the first driving force generated by the reversal of the first hydraulic pump 130, so as to drive at least one second piston rod to move upward.

[0055] When at least one second piston rod moves to the second preset top dead center, the first hydraulic pump 130 is controlled to rotate forward so that the second piston rod moves downward. The hydraulic oil in at least one second cylinder 220 flows into the first cylinder 210 under the action of the gravity of the sucker rod connected to the second piston rod and the second driving force generated by the forward rotation of the first hydraulic pump 130, so as to drive at least one first piston rod to move upward.

[0056] The first preset top dead center refers to the highest position that the first piston rod can reach during its upward movement. This position can be determined based on the actual stroke requirements of the oil well, the physical stroke limit of the piston rod, or the safety boundary set by the system. For example, the position of the piston rod can be detected by a displacement sensor, limit switch, or encoder. When the preset point is reached, the corresponding control signal is triggered.

[0057] The second preset top dead center refers to the highest position that the second piston rod can reach during its upward movement. Its determination method is similar to that of the first preset top dead center, and it can be set according to the actual working conditions or system design.

[0058] The first driving force refers to the force generated by the reverse rotation of the first hydraulic pump 130 when the first piston rod moves downward, which pushes the hydraulic oil to flow. This force works together with the gravity of the sucker rod to ensure that the hydraulic oil can flow efficiently from the first cylinder 210 into the second cylinder 220.

[0059] Corresponding to the aforementioned first driving force, the second driving force refers to the force generated by the forward rotation of the first hydraulic pump 130 when the second piston rod moves downward, which pushes the hydraulic oil to flow. This force works together with the gravity of the sucker rod to ensure that the hydraulic oil can flow efficiently from the second cylinder 220 into the first cylinder 210.

[0060] More specifically, when at least one first piston rod moves upward and reaches a first preset top dead center, the control unit 140 issues a command to cause the first hydraulic pump 130 to reverse. This reversing action causes the first piston rod to begin moving downward, and at the same time, the first hydraulic pump 130, together with the gravity of the sucker rod connected to the first piston rod, generates a first driving force.

[0061] Under the combined effect of gravity and the aforementioned first driving force, the hydraulic oil in the first cylinder 210 can be effectively forced out and smoothly flow into the second cylinder 220, thereby driving at least one second piston rod to move upward. This design cleverly utilizes the gravitational potential energy of the first piston rod as it moves downward, and supplements it with the driving force generated by the reverse rotation of the hydraulic pump, converting this energy into the power to drive the piston rod on the other side upward, thus realizing energy recovery and reuse.

[0062] Similarly, when at least one second piston rod moves upward and reaches the second preset top dead center, the control unit 140 issues another command to cause the first hydraulic pump 130 to rotate forward. At this time, the second piston rod begins to move downward, and the gravity of its connected sucker rod, together with the second driving force generated by the forward rotation of the first hydraulic pump 130, effectively forces the hydraulic oil in the second cylinder 220 into the first cylinder 210. This allows the potential energy of the second piston rod moving downward to be fully utilized and converted into the power to drive at least one first piston rod to move upward.

[0063] Through the two symmetrical and precisely controlled cyclic processes described above, it is ensured that the potential energy of the downward cylinder can be efficiently transferred to the upward cylinder during the reciprocating motion of the piston rod. Compared to schemes that rely solely on periodic forward and reverse rotations, this scheme can make fuller use of the gravitational potential energy of the piston rod during its downward movement, reducing dependence on external energy and significantly improving the overall energy utilization efficiency of the hydraulic pumping unit. This solves the problem of insufficient energy recovery in traditional hydraulic systems and optimizes the operational balance and energy-saving effect of the entire power system.

[0064] Based on the aforementioned technical means, by controlling the forward and reverse rotation of the first hydraulic pump 130 when the piston rod moves to the preset top dead center, the gravitational potential energy of the piston rod during its downward movement can be fully utilized. Combined with the driving force generated by the hydraulic pump, this achieves effective transmission of hydraulic oil between cylinders. This allows the potential energy of the downward-moving cylinder to be efficiently converted into the power to drive the piston rod on the other side upward, thereby significantly reducing dependence on external energy, improving the energy utilization efficiency of the entire power system, and solving the problem of insufficient energy recovery in traditional hydraulic systems.

[0065] In some embodiments, see Figure 2 The power system 100 also includes: The second hydraulic pump 150 has a third oil port 151 and a fourth oil port 152, which are respectively connected to the first oil outlet of the first proportional directional valve 110 and the second oil outlet of the second proportional directional valve 120.

[0066] At least one first solenoid valve 160 is respectively disposed between the third oil port 151 and at least one first oil cylinder 210, for controlling the opening and closing of at least one first oil circuit between at least one first oil cylinder 210 and the second hydraulic pump 150.

[0067] At least one second solenoid valve 170 is respectively disposed between the fourth oil port 152 and at least one second oil cylinder 220, for controlling the opening and closing of at least one second oil circuit between at least one second oil cylinder 220 and the second hydraulic pump 150.

[0068] The second hydraulic pump 150 can be a variable displacement pump, a fixed displacement pump driven by an electric motor, or other pump types capable of providing controlled hydraulic flow. The second hydraulic pump 150 provides an auxiliary or independent hydraulic power source. The third port 151 and the fourth port 152 are the inlet and outlet ports of the second hydraulic pump 150, used to connect it to the hydraulic circuit. This connection allows the second hydraulic pump 150 to independently supply hydraulic oil to or recover hydraulic oil from the cylinder, without being entirely dependent on the main circulation of the first hydraulic pump 130.

[0069] For example, when the first hydraulic pump 130 is performing the main cycle, the second hydraulic pump 150 can serve as an auxiliary or supplementary power source to precisely control the cylinder, such as replenishing or releasing oil in different stroke modes, or providing independent driving force in single-side or single-cylinder modes.

[0070] The first solenoid valve 160 and the second solenoid valve 170 are electrically controlled switching elements capable of selectively controlling the on / off state of corresponding oil circuits. These solenoid valves can be, for example, two-position two-way valves, two-position three-way valves, or other configured solenoid valves. By using these solenoid valves, the hydraulic passages between the second hydraulic pump 150 and each cylinder can be selectively connected or disconnected. Therefore, the control unit 140 can precisely control the oil circuits of one or more cylinders as needed, achieving individual control or isolation of the cylinders.

[0071] The technical solution of this application constructs an auxiliary hydraulic circuit by introducing a second hydraulic pump 150 and at least one solenoid valve, which enhances the flexibility and versatility of the power system, enabling it to adapt to more complex oil production conditions and operational needs, and solves the problem that it is difficult to achieve independent control of a single or partial cylinder by relying solely on the main hydraulic pump.

[0072] Specifically, the second hydraulic pump 150 serves as an auxiliary power source, with its third port 151 and fourth port 152 connected to the first outlet of the first proportional directional valve 110 and the second outlet of the second proportional directional valve 120, respectively. This connection allows the second hydraulic pump 150 to independently supply hydraulic oil to or recover hydraulic oil from the cylinders, without relying entirely on the main circulation of the first hydraulic pump 130. At least one first solenoid valve 160 is located between the third port 151 and at least one first cylinder 210, while at least one second solenoid valve 170 is located between the fourth port 152 and at least one second cylinder 220. These solenoid valves, acting as independent switching elements, can selectively connect or disconnect the hydraulic passages between the second hydraulic pump 150 and each cylinder. Thus, the control unit 140 can precisely control the hydraulic circuits of one or a group of cylinders as needed, achieving individual control or isolation of the cylinders. For example, when the first hydraulic pump 130 is performing the main cycle, the second hydraulic pump 150 can serve as an auxiliary or supplementary power source to precisely control the cylinder, such as replenishing or releasing oil in different stroke modes, or providing independent driving force in single-side or single-cylinder modes.

[0073] In a preferred embodiment, the second hydraulic pump 150 can be a hydraulic motor driven by an auxiliary servo motor. Port A of this hydraulic motor can serve as the third oil port 151, and port B can serve as the fourth oil port 152. The third oil port 151 and the fourth oil port 152 can be connected to the first outlet of the first proportional directional valve 110 and the second outlet of the second proportional directional valve 120 via an integrated block. When independent control of a specific cylinder is required, the control unit 140 can send an electrical signal to the corresponding solenoid directional valve to energize it, thereby cutting off the oil circuit of that cylinder, or de-energize it, thereby opening the oil circuit. For example, in single-cylinder mode, if only one first cylinder 210 needs to be operated, the control unit 140 can control the solenoid directional valves corresponding to the other first cylinders 210 and all second cylinders 220 to cut off the oil circuit, keeping only the oil circuit of the required first cylinder 210 connected, and then drive it via the second hydraulic pump 150. This configuration allows the system to flexibly and selectively enable or disable specific cylinders, thereby enabling independent maintenance of some oil wells, intermittent pumping, or handling special downhole conditions, improving the system's operability and resource utilization.

[0074] Based on the aforementioned technical means, by introducing a second hydraulic pump 150 and at least one solenoid valve, the system can achieve independent control or auxiliary operation of individual or partial cylinders, thereby effectively coping with complex downhole conditions, maintenance needs, and specific auxiliary functions, such as single-sided operation, single-cylinder operation, operation with different numbers of cylinders, or operation with different strokes. This removes limitations on the system when handling asynchronous or unbalanced conditions, enhancing its adaptability to diverse oil production scenarios.

[0075] In some embodiments, the control unit 140 is further configured to: control at least one first oil circuit to disconnect and at least one second oil circuit to connect via a first solenoid valve 160 and a second solenoid valve 170; control the second hydraulic pump 150 to reverse so as to move at least one second piston rod upward; when the second piston rod moves to the middle position of the second stroke, control at least one first oil circuit to connect and at least one second oil circuit to disconnect via the first solenoid valve 160 and the second solenoid valve 170; control the second hydraulic pump 150 to rotate forward so as to move at least one first piston rod upward; when the first piston rod moves to the middle position of the first stroke, control both the first oil circuit and the second oil circuit to disconnect via the first solenoid valve 160 and the second solenoid valve 170; and control the first hydraulic pump 130 to periodically rotate forward and reverse so as to make the first piston rod and the second piston rod reciprocate synchronously.

[0076] The midpoints of the first and second strokes refer to the preset intermediate positions of the piston rod during their respective cylinder strokes. This can also be understood as the equilibrium point where the piston rod can move upwards and downwards throughout its entire working stroke, ensuring that at the start of synchronous reciprocating motion, the piston rod has sufficient upward and downward stroke space and is in a mechanically relatively balanced initial state.

[0077] Through the aforementioned control logic, the second hydraulic pump 150, the first solenoid valve 160, and the second solenoid valve 170 sequentially move the two sets of piston rods to their respective stroke midpoints. This ensures that when the main synchronous reciprocating motion (controlled by the first hydraulic pump 130) begins, the system can start from an optimal, balanced, and stable state, thereby improving startup efficiency and operational smoothness.

[0078] In one specific embodiment, the control unit 140 of the power system can be a programmable logic controller or an industrial computer, which runs a preset control algorithm. When the system needs to activate the dual-sided synchronous reciprocating motion mode, the control unit 140 first sends control signals to the first solenoid valve 160 and the second solenoid valve 170, for example, by changing the on / off state of their coils, so that the oil circuit connected to at least one first cylinder 210 is cut off, while the oil circuit connected to at least one second cylinder 220 is opened.

[0079] Control unit 140 controls the second hydraulic pump 150 to rotate in the reverse direction, thereby generating a reverse hydraulic flow that drives the piston rod of at least one second cylinder 220 to move upward. During this process, the position of the second piston rod can be monitored in real time using a displacement sensor. When the sensor signal indicates that the second piston rod has moved to the preset middle position of the second stroke, control unit 140 adjusts the state of the solenoid valve, for example, by changing its energizing combination, so that at least one first oil circuit is connected while at least one second oil circuit is disconnected. Subsequently, control unit 140 controls the second hydraulic pump 150 to rotate in the forward direction, generating a forward hydraulic flow that drives the piston rod of at least one first cylinder 210 to move upward. Similarly, by monitoring the displacement sensor signal of the first cylinder 210 piston rod, when the first piston rod moves to the preset middle position of the first stroke, control unit 140 readjusts the state of the solenoid valve, so that both the first and second oil circuits are disconnected, thereby isolating the second hydraulic pump 150 from the cylinder. After the piston rod is precisely pre-positioned, the control unit 140 will start the first hydraulic pump 130, causing it to rotate forward and reverse periodically, thereby driving the first piston rod and the second piston rod to perform synchronous reciprocating motion.

[0080] By employing the aforementioned technical solution, and utilizing the second hydraulic pump 150 and solenoid valve to precisely move the first and second piston rods to the preset stroke midpoint before the main synchronous reciprocating motion begins, the system is ensured to start synchronous reciprocating motion from a balanced and optimized starting point. This improves the system's startup efficiency, avoids shocks and instabilities that may result from initial position imbalance, and allows the system to immediately enter a stable synchronous operating state, thereby enhancing the overall reliability and performance.

[0081] The power systems described in the preceding technical solutions of this application are all applicable to scenarios where two sets of hydraulic cylinders can operate synchronously. In actual oil production operations, there are situations where some oil wells require maintenance or where the fluid level is low and intermittent pumping is necessary. In these scenarios, if the mode of synchronous reciprocating motion of all hydraulic cylinders is still adopted, it is impossible to meet the requirement of independent operation of some hydraulic cylinders, and it is also difficult to maximize the use of gravitational potential energy for energy saving, which will lead to unnecessary energy consumption or operational inconvenience.

[0082] To address the problems described above, this application provides the following technical solutions: In some embodiments, the control unit 140 is further configured to: control at least a first number of first oil circuits to be connected and at least a second oil circuit to be disconnected via a first solenoid valve 160 and a second solenoid valve 170; control the second hydraulic pump 150 to rotate forward so that the first piston rods of the first number of first cylinders 210 move upward; when the first number of first piston rods move to a first preset upper dead center, control the second hydraulic pump 150 to stop so that the first number of first piston rods move downward, and the hydraulic oil in the first number of first cylinders 210 flows into the oil tank through the first proportional directional valve 110 under the gravity of the sucker rod; when the first number of first piston rods move to a first preset lower dead center, control the second hydraulic pump 150 to rotate forward until the first number of first piston rods move upward to the first preset upper dead center; wherein, the first number is less than or equal to the number of at least one first cylinder 210.

[0083] The following example illustrates this point. Figure 1 and Figure 2 Taking a hydraulic pumping unit with four cylinders as an example, two are first cylinders 210 and two are second cylinders 220. When intermittent pumping is required for one of the first cylinders 210, the control unit 140 operates the first solenoid valve 160 and the second solenoid valve 170 to connect the first oil circuit corresponding to the target first cylinder 210, while ensuring that the second oil circuit and the other first oil circuits are disconnected.

[0084] For example, if the system has two first cylinders, A1 and A2, and two second cylinders, B1 and B2, when cylinder A1 is selected for independent operation, the control unit 140 will open the first solenoid valve 160 connected to cylinder A1, while opening the solenoid valves connected to cylinders A2, B1, and B2. The simplified schematic diagram of the power system at this time is as follows: Figure 3 As shown.

[0085] Then adjust the power system to the specified position via the solenoid valve. Figure 3 After the state shown, the control unit 140 controls the second hydraulic pump 150 to start rotating forward. The second hydraulic pump 150 delivers hydraulic oil to the rod chamber of cylinder A1, driving the first piston rod of cylinder A1 to move upward, completing the upstroke of oil extraction. When the first piston rod of cylinder A1 moves to the preset first top dead center, the control unit 140 controls the second hydraulic pump 150 to stop. At this time, since the first piston rod of cylinder A1 is connected to the sucker rod, the weight of the sucker rod will drive the piston rod to start moving downward, completing the downstroke. During this process, the hydraulic oil in cylinder A1 will flow back to the oil tank through the first proportional directional valve 110, thereby utilizing gravitational potential energy to achieve energy saving. When the first piston rod of cylinder A1 moves to the preset first bottom dead center, the control unit 140 again commands the second hydraulic pump 150 to rotate forward, driving the piston rod to move upward until it reaches the first preset top dead center again, completing a complete oil extraction cycle. In this way, even if only one cylinder needs to work, the system can operate efficiently and energy-savingly, greatly improving the adaptability and operating efficiency of the equipment.

[0086] Based on the aforementioned technical means, by selectively connecting part of the first oil circuit and disconnecting the second oil circuit, the system can operate only the required number of first cylinders according to actual needs, such as partial well maintenance or intermittent oil pumping, thus avoiding unnecessary energy consumption. Simultaneously, during the piston rod's downward stroke, by controlling the second hydraulic pump 150 to stop and utilizing the gravity of the sucker rod to return the hydraulic oil to the tank, gravitational potential energy is fully recovered, significantly reducing the system's energy consumption. This operating mode improves the oil extraction machine's operational flexibility and energy-saving effect, enabling the equipment to operate efficiently and economically under different working conditions.

[0087] The above embodiment proposes that in single-sided mode, after the first number of first piston rods move to the first preset top dead center, the second hydraulic pump 150 is stopped, causing the first number of first piston rods to move downwards under the gravity of the sucker rod. At this time, the hydraulic oil in the first number of first cylinders 210 flows into the oil tank through the first proportional directional valve 110. This allows the piston rods to descend due to their own weight, thereby achieving energy saving. However, in the above technical solution, the descent speed of the piston rods will be mainly determined by the load and the inherent flow resistance of the system, making it difficult to precisely adjust according to actual working conditions or specific operational requirements.

[0088] To address the need for precise control of the descent speed of the piston rod, in some embodiments, the control unit 140 is further configured to: control the opening of the first proportional directional valve 110 during the movement of a first number of first piston rods from a first preset top dead center to a first preset bottom dead center, thereby adjusting the descent speed of the first piston rods.

[0089] Specifically, when the piston rod moves downwards under gravity, the hydraulic oil in the cylinder is discharged and flows back to the oil tank through the first proportional directional valve 110. By precisely adjusting the opening of this valve through the control unit 140, the outflow rate of the hydraulic oil can be finely controlled, thereby achieving precise adjustment of the descent speed of the first piston rod. This control method means that the descent speed of the piston rod is no longer solely determined by the load and fixed flow resistance, but can be dynamically adjusted according to actual working conditions or operational requirements.

[0090] In one specific embodiment, the control unit 140 may be a programmable logic controller (PLC), which sends a 4-20mA current signal to the first proportional directional valve 110 via an analog output module to precisely control the valve opening. During the downward movement of the first number of first piston rods, the control unit 140 can monitor the position or speed of the piston rods in real time, and dynamically adjust the control signal sent to the first proportional directional valve 110 according to a preset descent speed curve or target speed.

[0091] Using the above technical solution, the "pump-bump" and "unblocking" functions of the pumping unit can also be realized. Specifically, when the "pump-bump" function is required, the control unit 140 can control the opening of the first proportional directional valve 110. When the sucker rod approaches the bottom of the well, the opening of the first proportional directional valve 110 is increased, causing the sucker rod to descend at a relatively fast speed. Precise speed control is performed before or at the moment of contact to achieve the desired impact effect. When the "unblocking" function is required, the control unit 140 can control the piston rod to move downward at a specific, usually faster speed, using the rapid flow of hydraulic oil and the impact force of the piston rod to clear downhole obstacles. In this way, the descent speed of the piston rod can be flexibly adjusted according to different operational needs, thereby optimizing the efficiency and safety of oil production operations.

[0092] Based on the aforementioned technical means, by actively controlling the opening of the first proportional directional valve 110 during the movement of the first number of first piston rods from the first preset upper dead center to the first preset lower dead center, this application can achieve precise adjustment of the descent speed of the first piston rods. This allows the system to optimize the descent speed of the piston rods according to the actual working conditions of the oil well, such as downhole fluid level, crude oil viscosity, or formation pressure, thereby effectively avoiding "dry pumping" or unnecessary impacts. Furthermore, this precise descent speed control provides crucial technical support for achieving special operational functions such as "pump contact" and "unblocking."

[0093] The technical solutions provided in the preceding embodiments can ensure smooth system drive and synchronous operation when the number of cylinders on both sides is the same, and can also control the hydraulic passage through solenoid valves, enabling the hydraulic pumping unit to operate on one side only. However, in practical applications, such as when some oil wells require maintenance or intermittent pumping, how to achieve synchronous operation when the number of cylinders is different becomes a further problem that needs to be solved.

[0094] To solve the above-mentioned technical problems, in some embodiments, the control unit 140 in the power system is further configured to: control a second number of first oil circuits to disconnect and a third number of second oil circuits to connect via a first solenoid valve 160 and a second solenoid valve 170; control the second hydraulic pump 150 to reverse so that a third number of second piston rods move upward; when the third number of second piston rods move to the middle position of the second stroke, control the second number of first oil circuits to connect and the third number of second oil circuits to disconnect via the first solenoid valve 160 and the second solenoid valve 170; control the second hydraulic pump 150 to rotate forward so that the second number of first piston rods move upward; when the second number of first piston rods move to the middle position of the first stroke, control both the first oil circuits and the second oil circuits to disconnect via the first solenoid valve 160 and the second solenoid valve 170; control the first hydraulic pump 130 to rotate forward and reverse periodically, and adjust the opening of the first proportional directional valve 110 and the second proportional directional valve 120 to the first opening and the second opening respectively, so that the second number of first piston rods and the third number of second piston rods reciprocate synchronously.

[0095] The second and third quantities refer to the number of piston rods of the first cylinder 210 and the second cylinder 220 that actually participate in the synchronous reciprocating motion under a specific working mode. These quantities can be determined according to the actual working conditions of the oil well, such as the need for partial well shutdown or intermittent oil pumping.

[0096] The first opening degree and the second opening degree refer to the valve core opening amount of the first proportional directional valve 110 and the second proportional directional valve 120. These opening degrees can be calculated and adjusted by the control unit 140 according to the actual number of the second number of first cylinders 210 and the third number of second cylinders 220 currently engaged in operation, so as to precisely control the flow of hydraulic oil to these cylinders, thereby achieving load balance and synchronous movement among different numbers of cylinders.

[0097] The following is a specific example to illustrate this, still using... Figure 1 and Figure 2 Taking a hydraulic pumping unit with four cylinders as an example, the system has two first cylinders, A1 and A2, and two second cylinders, B1 and B2. When cylinders A1, A2, and B1 are selected for operation, the control unit 140 can control the solenoid valve connected to cylinder B2 to always be in the open state. A simplified schematic diagram of the power system at this time is shown below. Figure 4 As shown.

[0098] Before the pumping unit starts, the first oil circuits corresponding to cylinders A1 and A2 are disconnected and the second oil circuit corresponding to cylinder B1 is connected via the first solenoid valve 160 and the second solenoid valve 170. The second hydraulic pump 150 is controlled to reverse, causing the second piston rod of cylinder B1 to move upward. When it reaches the corresponding stroke middle position, cylinders A1 and A2 are connected again by controlling the first solenoid valve 160 and the second solenoid valve 170, while cylinder B1 is disconnected. Then, the second hydraulic pump 150 is controlled to rotate forward, causing the piston rods of cylinders A1 and A2 to move upward. When they reach the corresponding stroke middle position, the second hydraulic pump 150 is controlled to stop, thus completing the initialization under this unbalanced working condition.

[0099] After the initialization is completed, the oil circuits corresponding to cylinders A1, A2, and B1 are all in the open state. The first hydraulic pump 130 is controlled to rotate periodically in both forward and reverse directions, and the openings of the first proportional directional valve 110 and the second proportional directional valve 120 are adjusted to the first opening and the second opening, respectively, so that the first piston rods of cylinders A1 and A2 reciprocate synchronously with the second piston rod of cylinder B1. The first and second openings are related to the number of first and second cylinders in the working state.

[0100] Based on the above technical means, when the number of hydraulic cylinders participating in the work on both sides is unequal, the opening degree of the first proportional directional valve 110 and the second proportional directional valve 120 is dynamically adjusted to be related to the actual number of hydraulic cylinders participating in the work. This allows for precise balance of hydraulic oil flow under asymmetrical load, thereby ensuring that the second number of first piston rods and the third number of second piston rods achieve smooth and efficient synchronous reciprocating motion.

[0101] In some of the solutions described above in this application, a control unit 140 is proposed to control the periodic forward and reverse rotation of the first hydraulic pump 130 and to adjust the opening of the first proportional directional valve 110 and the second proportional directional valve 120 so that the first piston rod and the second piston rod reciprocate synchronously. However, in actual oil production operations, the working conditions of oil wells may vary, resulting in different actual strokes of the connected first cylinder 210 and second cylinder 220. In this case, if the periodic forward and reverse rotation of the first hydraulic pump 130 is controlled in a conventional manner and the opening of the proportional directional valve is adjusted to control the frequency, it may not be able to effectively adapt to the situation where the strokes of the first cylinder 210 and the second cylinder 220 are inconsistent, resulting in reduced efficiency of synchronous reciprocating motion of the piston rod, or even uncoordinated motion or impact, thereby limiting the adaptability of the power system to complex oil well working conditions.

[0102] To address this issue, in some embodiments, the control unit 140 is further configured to: adjust the openings of the first proportional directional valve 110 and the second proportional directional valve 120 to a third and a fourth opening, respectively, during the periodic forward and reverse rotation of the first hydraulic pump 130 when the first stroke of the first cylinder 210 and the second stroke of the second cylinder 220 are different, so that the first piston rod and the second piston rod reciprocate synchronously; wherein, the first stroke is the distance difference between the first preset upper dead center and the first preset lower dead center of the first cylinder 210, the second stroke is the distance difference between the second preset upper dead center and the second preset lower dead center of the second cylinder 220, and the third and fourth openings are both related to the first and second strokes.

[0103] The first preset top dead center and the first preset bottom dead center are the highest and lowest points preset during the reciprocating motion of the piston rod of the first hydraulic cylinder 210. These two preset points together define the effective range of motion of the first hydraulic cylinder 210. Similarly, the second preset top dead center and the second preset bottom dead center define the effective range of motion of the second hydraulic cylinder 220.

[0104] When there is a difference between the first stroke of the first cylinder 210 and the second stroke of the second cylinder 220, the cylinder with the longer stroke requires more hydraulic oil to complete one stroke in the same amount of time, while the cylinder with the shorter stroke requires less hydraulic oil.

[0105] In the technical solution of this application embodiment, in the face of the above differences, the control unit 140 no longer simply adjusts the opening of the proportional directional valve uniformly, but adjusts the opening of the first proportional directional valve 110 and the second proportional directional valve 120 to the third opening and the fourth opening respectively. Based on the different valve openings, the difference in hydraulic oil demand is accurately compensated, ensuring that even if the stroke is mismatched, the two piston rods can maintain the expected synchronous reciprocating motion.

[0106] In a specific example, such as Figure 5 As shown, the first stroke of the first cylinder 210 is 1.8 meters, and the second stroke of the second cylinder 220 is 1.5 meters. During the process of controlling the first hydraulic pump 130 to periodically rotate forward and reverse to drive the piston rod to reciprocate, the control unit 140 will calculate and output control signals to the first proportional directional valve 110 and the second proportional directional valve 120 according to the preset control strategy. For the first cylinder 210 with a longer stroke, the third opening of its corresponding first proportional directional valve 110 may be set to be relatively large to allow more hydraulic oil to flow in or out, thereby ensuring that it completes a longer stroke in the same cycle; while for the second cylinder 220 with a shorter stroke, the fourth opening of its corresponding second proportional directional valve 120 may be relatively small.

[0107] Based on the aforementioned technical means, when the strokes of the first cylinder 210 and the second cylinder 220 are different, by adjusting the opening of the first proportional directional valve 110 and the second proportional directional valve 120, the system can accurately compensate for the inconsistent hydraulic oil demand caused by the difference in cylinder strokes. This ensures that the first piston rod and the second piston rod can maintain stable synchronous reciprocating motion even under complex working conditions with mismatched strokes. This effectively solves the problems of reduced piston rod motion efficiency, uncoordinated motion, or impact under traditional control methods, and improves the adaptability and operational stability of the power system to diverse oil well working conditions.

[0108] In some embodiments, the aforementioned first solenoid valve 160 and second solenoid valve 170 are solenoid directional valves. The power system also includes a circulation unit connected to the oil tank for filtering and cooling the hydraulic oil in the tank.

[0109] Figure 6 This is a schematic structural diagram of the hydraulic pumping unit provided in the embodiments of this application. Figure 6 The hydraulic pumping unit includes: at least one first cylinder 610, at least one second cylinder 620, and a power system 630.

[0110] The first hydraulic cylinder 610 and the second hydraulic cylinder 620 are used to connect to the sucker rod. The power system 630 is the power system 100 described in any of the preceding embodiments.

[0111] Compared to beam pumping units and hydraulic pumping units in related technologies, the technical solution provided in this application has the following advantages: Compared with beam pumping units and other hydraulic pumping units, the technical solution provided in this application embodiment can achieve stepless speed adjustment within a certain range of stroke count and stroke, and is simple, quick and easy to learn. Operators can learn it with only simple training. Moreover, the stroke count range is about 2 times higher than that of conventional beam pumping units and other hydraulic pumping units, which greatly improves oil production.

[0112] This dynamics system can use a variety of oil production modes (dual-sided mode, single-sided mode, single-sided single-cylinder mode, different stroke modes) to deal with various situations that may occur during production. In actual use, the mode can be selected at will according to the needs of the site, so as not to affect maintenance operations and at the same time ensure the oil production.

[0113] This technical solution also offers diversified solid control modes. Not only are multiple production modes available, but it also allows for real-time monitoring of each well's operating parameters via a cloud platform. Users can log in to their mobile phones to remotely start and stop equipment (enabling remote control of intermittent pumping), fine-tune parameters, remotely collect equipment operating status and parameters, receive dynamometer card feedback, and remotely collect equipment alarm information. With no hardware damage, it can essentially achieve an ideal state of unmanned operation and maintenance, significantly reducing maintenance costs. Simultaneously, it enhances the product's intelligence and integration, facilitating equipment management and optimizing areas currently lacking in beam and other hydraulic systems.

[0114] By combining hydraulic principles with control programs, the added pump-collision and unblocking functions better meet the needs of actual production. Compared with beam pumps and other hydraulic pumping units, the operation of the technical solution based on this application is more standardized and simpler, and it is a transformation result of the accumulated experience of many field operators.

[0115] The equipment has a high degree of integration. Compared with beam pumping units, the power system provided in this application has advantages such as smaller footprint, lower noise, and the ability to operate multiple wells with a single unit; it integrates many components such as servo motors, hydraulic motors, proportional directional valves, hydraulic oil tanks, circulating units, and high-pressure filters into a small area, making it fully functional and economical.

[0116] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0117] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0118] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or at least one embodiment or example. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0119] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A power system for use in a hydraulic pumping unit, the hydraulic pumping unit comprising at least one first cylinder and at least one second cylinder for connecting a sucker rod, characterized in that, The power system includes: A first proportional directional valve is connected between the oil tank and the rod chamber of the at least one first oil cylinder; A second proportional directional valve is connected between the oil tank and the rod chamber of the at least one second oil cylinder; The first hydraulic pump has a first oil port and a second oil port, which are respectively connected to the first oil inlet of the first proportional directional valve and the second oil inlet of the second proportional directional valve. The second hydraulic pump has a third oil port and a fourth oil port, which are respectively connected to the first oil outlet of the first proportional directional valve and the second oil outlet of the second proportional directional valve. At least one first solenoid valve is respectively disposed between the third oil port and the at least one first oil cylinder; At least one second solenoid valve is respectively disposed between the fourth oil port and the at least one second oil cylinder; A control unit is configured to control the first hydraulic pump to periodically rotate forward and reverse, so that the first piston rod of the at least one first cylinder and the second piston rod of the at least one second cylinder reciprocate synchronously, with the first piston rod and the second piston rod moving in opposite directions; and, Adjust the opening degree of the first proportional directional valve and the second proportional directional valve to adjust the frequency of the synchronous reciprocating motion of the first piston rod and the second piston rod; The control unit is further configured to: control the on / off state of at least one first oil passage between the at least one first oil cylinder and the third oil port via the at least one solenoid valve, and control the on / off state of at least one second oil passage between the at least one second oil cylinder and the fourth oil port via the at least one second solenoid valve.

2. The power system according to claim 1, characterized in that, The control unit is also used for: When at least one of the first piston rods moves to the first preset upper stop point, the first hydraulic pump is controlled to reverse so that the first piston rod moves downward. The hydraulic oil in the at least one first cylinder flows into the second cylinder under the action of the gravity of the sucker rod connected to the first piston rod and the first driving force generated by the reversal of the first hydraulic pump, so as to drive at least one of the second piston rods to move upward. When the at least one second piston rod moves to the second preset top dead center, the first hydraulic pump is controlled to rotate forward so that the second piston rod moves downward. The hydraulic oil in the at least one second cylinder flows into the first cylinder under the action of the gravity of the sucker rod connected to the second piston rod and the second driving force generated by the forward rotation of the first hydraulic pump, so as to drive the at least one first piston rod to move upward.

3. The power system according to claim 1, characterized in that, The control unit is also used for: The at least one first oil circuit is disconnected by controlling the first solenoid valve; The connection of at least one second oil circuit is controlled by the second solenoid valve; The second hydraulic pump is reversed to cause at least one of the second piston rods to move upward. When the second piston rod moves to the middle position of the second stroke, the at least one first oil circuit is connected and the at least one second oil circuit is disconnected by the control of the first solenoid valve and the second solenoid valve; Control the second hydraulic pump to rotate forward, so that at least one of the first piston rods moves upward; When the first piston rod moves to the middle position of the first stroke, the first oil circuit and the second oil circuit are both disconnected by the first solenoid valve and the second solenoid valve. The first hydraulic pump is controlled to rotate periodically in both forward and reverse directions so that the first piston rod and the second piston rod reciprocate synchronously.

4. The power system according to claim 1, characterized in that, The control unit is also used for: The first solenoid valve controls the connection of a first number of first oil circuits in at least one first oil circuit. At least one second oil circuit is disconnected by controlling the second solenoid valve; Control the second hydraulic pump to rotate forward, so that the first piston rod of the first number of first cylinders moves upward; When the first number of first piston rods move to the first preset upper stop point, the second hydraulic pump is controlled to stop, so that the first number of first piston rods move downward, and the hydraulic oil in the first number of first cylinders flows into the oil tank through the first proportional directional valve under the gravity of the sucker rod. When the first number of first piston rods move to the first preset lower dead center, control the second hydraulic pump to rotate forward until the first number of first piston rods move upward to the first preset upper dead center; Wherein, the first quantity is less than or equal to the number of the first hydraulic cylinders.

5. The power system according to claim 4, characterized in that, The control unit is also used for: During the movement of the first number of first piston rods from the first preset upper dead center to the first preset lower dead center, the opening of the first proportional directional valve is controlled to adjust the descent speed of the first piston rods.

6. The power system according to claim 1, characterized in that, The control unit is also used for: The first solenoid valve controls the disconnection of a second number of the first oil circuits; The second solenoid valve controls the connection of a third number of the second oil circuits; The second hydraulic pump is reversed to cause the third number of second piston rods to move upward. When the third number of second piston rods move to the middle position of the second stroke, the first solenoid valve controls the second number of first oil circuits to connect, and the second solenoid valve controls the third number of second oil circuits to disconnect. The second hydraulic pump is controlled to rotate forward, so that the second number of first piston rods move upward; When the second number of first piston rods move to the middle position of the first stroke, control the second hydraulic pump to stop; The first hydraulic pump is controlled to rotate periodically in the forward and reverse directions, and the openings of the first proportional directional valve and the second proportional directional valve are adjusted to the first opening and the second opening, respectively, so that the second number of first piston rods and the third number of second piston rods reciprocate synchronously. Wherein, the first opening degree and the second opening degree are both related to the second quantity and the third quantity, and the second quantity and the third quantity are less than the number of the first hydraulic cylinder.

7. The power system according to claim 1, characterized in that, The control unit is also used for: When the first stroke of the first cylinder and the second stroke of the second cylinder are different, during the process of controlling the first hydraulic pump to rotate periodically forward and reverse, the opening of the first proportional directional valve and the second proportional directional valve are adjusted to the third opening and the fourth opening, respectively, so that the first piston rod and the second piston rod reciprocate synchronously. Wherein, the first stroke is the distance difference between the first preset top dead center and the first preset bottom dead center of the first hydraulic cylinder, the second stroke is the distance difference between the second preset top dead center and the second preset bottom dead center of the second hydraulic cylinder, and the third opening degree and the fourth opening degree are both related to the first stroke and the second stroke.

8. The power system according to any one of claims 3-7, characterized in that, The first solenoid valve and the second solenoid valve are solenoid directional valves. The power system also includes a circulating unit, which is connected to the oil tank and is used to cool and filter the hydraulic oil in the oil tank.

9. A hydraulic pumping unit, characterized in that, include: At least one first hydraulic cylinder and at least one second hydraulic cylinder are used to connect to the sucker rod; as well as, The power system as described in any one of claims 1-8.

Images