A hydraulic control system for a hydraulic pumping unit

Abstract

The invention discloses a hydraulic control system for a hydraulic oil pump, comprising a main hydraulic system and a cooling system. A first variable pump motor and a second variable pump motor work alternately as a motor and a pump. When the first variable pump motor is driven by hydraulic oil, the first variable pump motor and the main motor jointly drive the second variable pump motor as a pump to supply oil to the outside. When the second variable pump motor is driven by hydraulic oil, the second variable pump motor and the main motor jointly drive the first variable pump motor as a pump to supply oil to the outside. The system has fewer hydraulic components and low energy consumption. The hydraulic oil passes through the oil tank and an independent cooling system in each cycle, which can more effectively realize the cooling of the hydraulic oil. The double variable plunger pump motor can realize the closed-loop control of the working mode and displacement, make full use of the downward energy of the hydraulic oil pump, and greatly reduce the power consumption of the oil pump.

Description

Technical Field

[0001] The invention relates to a hydraulic control system, in particular to a hydraulic control system for a hydraulic oil pumping unit. Background Art

[0002] At present, the main force in my country's oil field production operations is still the traditional beam pumping unit. With the continuous production of oil fields, the liquid supply capacity of the formation has become worse and worse, and the pump hanging has become deeper and deeper. The beam pumping unit has exposed the problems of high power consumption, difficulty in adjusting the stroke and frequency, and unsuitability for heavy oil production. In addition, traditional pumping units also have problems such as large footprint and weight.

[0003] Compared with the beam pumping unit, the hydraulic pumping unit has the following advantages: compact structure, light weight, low cost, stable operation, easy to achieve long stroke, convenient stroke adjustment, easy to achieve safety protection and obvious energy saving effect, etc. It is particularly suitable for oil production in mountainous areas, tidal flats and offshore platforms. Therefore, engineers and technicians from various countries have long been committed to the research and development of hydraulic pumping units, which has enabled hydraulic pumping units to be promoted and applied on a larger scale and achieve better economic benefits. Domestic research on hydraulic pumping units mainly focuses on the development of principle prototypes and test prototypes, and there are not many that are actually applied in actual production at oil production sites. The main reasons include: ① The hydraulic system uses ordinary switching valves and proportional valves to control the hydraulic cylinder or hydraulic motor. The hydraulic pump itself has a large throttling energy loss, and the energy recovery rate is not high, which is not recognized by users; ② The hydraulic system used for multiple wells requires all wells to stop operating when a problem occurs in one of the wells, affecting the oil field production capacity; ③ The hydraulic system used for multiple wells has similar strokes and loads for the hydraulic pumps of multiple wells, and has relatively high requirements. Even when the stroke lengths of multiple wells are quite different, energy cannot be collected, resulting in additional power consumption. Summary of the invention

[0004] The purpose of the present invention is to address the defects of the prior art and provide a hydraulic control system for a hydraulic pumping unit that can reduce the energy consumption of the hydraulic system of the hydraulic pumping unit itself, enhance the adaptability of the hydraulic system, and improve the energy-saving effect of the hydraulic pumping unit.

[0005] The technical solution of the present invention is: a hydraulic control system of a hydraulic pumping unit, comprising:

[0006] A main hydraulic system, the main hydraulic system includes a main motor, a double pump motor and an accumulator, the double pump motor includes a first variable pump motor and a second variable pump motor connected in series, the output shaft of the main motor is connected to the input end of the first variable pump motor and the second variable pump motor; one end of the first variable pump motor is connected to the oil tank, and the other end of the first variable pump motor is provided with a first fluid path and a second fluid path, the first fluid path is connected to the lower chamber of the first pumping unit cylinder, and the second fluid path is connected to the accumulator; one end of the second variable pump motor is connected to the oil tank, and the other end of the second variable pump motor is provided with a third fluid path and a fourth fluid path, the third fluid path is connected to the lower chamber of the second pumping unit cylinder, and the fourth fluid path is connected to the accumulator; the first fluid path, the second fluid path, the third fluid path and the fourth fluid path are respectively provided with a reversing valve;

[0007] A cooling system, the cooling system comprising a temperature sensor disposed in the oil tank and a cooling device disposed on a cooling circuit, wherein an inlet and an outlet of the cooling circuit are both connected to the oil tank;

[0008] When the first variable pump motor is driven by hydraulic oil, the first variable pump motor and the main motor jointly drive the second variable pump motor to supply oil to the outside in the form of a pump. When the second variable pump motor is driven by hydraulic oil, the second variable pump motor and the main motor jointly drive the first variable pump motor to supply oil to the outside in the form of a pump.

[0009] Preferably, the cooling device comprises a cooling pump, a cooler and an oil return filter which are sequentially arranged on a cooling circuit, a power input end of the cooling pump is connected to a cooling motor, and a liquid input end of the cooling pump is connected to an oil tank.

[0010] Preferably, a first high-pressure filter is installed between the reversing valve in the first fluid circuit and the lower chamber of the first pumping unit cylinder, and a second high-pressure filter is installed between the reversing valve in the third fluid circuit and the lower chamber of the second pumping unit cylinder.

[0011] Preferably, the main hydraulic system also includes a pressure sensor for measuring the hydraulic oil pressure in the lower chamber of the first pumping unit cylinder, the lower chamber of the second pumping unit cylinder and the accumulator; displacement sensors are respectively installed in the first pumping unit cylinder and the second pumping unit cylinder.

[0012] Preferably, the hydraulic control system further comprises a programmable controller, and the programmable controller is electrically connected to the pressure sensor, the displacement sensor, the temperature sensor, the first variable pump motor and the second variable pump motor respectively.

[0013] Preferably, the model of the programmable controller is SIMATIC S7-1200.

[0014] Preferably, the first variable pump motor and the second variable pump motor are both variable piston pump motors.

[0015] Preferably, the lower chamber of the first pumping unit hydraulic cylinder, the lower chamber of the second pumping unit hydraulic cylinder and the accumulator are all provided with a pressure relief valve for discharging hydraulic oil.

[0016] Preferably, pressure gauges for displaying the hydraulic oil pressure are installed on the lower chamber of the first pumping unit hydraulic cylinder, the lower chamber of the second pumping unit hydraulic cylinder and the accumulator.

[0017] Preferably, the first high-pressure filter and the second high-pressure filter are both bidirectional reversible filters; the reversing valve is a two-position two-way electromagnetic reversing valve; and the displacement sensor is a pull-rope displacement sensor.

[0018] Compared with the prior art, the present invention has the following advantages: ① The hydraulic oil passes through the oil tank in each circulation cycle, and the independent cooling system can more effectively realize the cooling of the hydraulic oil, thereby ensuring the operation effect of the hydraulic system and the oil cylinder of the oil pump; ② The double-type variable piston pump motor can realize the closed-loop control of the working mode and displacement, which can not only make full use of the downward energy of the hydraulic oil pump, but also greatly reduce the power consumption of the oil pump; and it no longer needs separate speed regulation, pressure regulation and frequent reversing hydraulic components, which will not cause system hydraulic shock, with fewer hydraulic components, less throttling loss and low energy consumption; ③ It is suitable for single-well and multi-well working modes, and double wells can be converted to single-well working online, and single-well maintenance will not affect the normal operation of other wells; ④ When double wells are working, there is no requirement for the stroke and oil volume of the two hydraulic oil pumps, and it has strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural flow chart of the present invention;

[0020] Figure 2 is a schematic diagram of the double well operation of the second embodiment of the present invention;

[0021] Figure 3 It is a schematic diagram of single well operation in embodiment 3 of the present invention.

[0022] In the figure: 1. main hydraulic system, 2. cooling system, 101. oil tank, 102. liquid level sensor, 103. air filter, 1041. first variable pump motor, 1042. second variable pump motor, 105. main motor, 1061. reversing valve A, 1062. reversing valve B, 1063. reversing valve C, 1064. reversing valve D, 1071. pressure gauge A, 1072. pressure gauge B, 1073. pressure gauge C, 1081. pressure sensor A, 1082. pressure sensor B, 1083. Pressure sensor C, 109. Accumulator, 1101. First high-pressure filter, 1102. Second high-pressure filter, 1111. Pressure relief valve A, 1112. Pressure relief valve B, 1113. Pressure relief valve C, 1121. First pumping unit hydraulic cylinder, 1122. Second pumping unit hydraulic cylinder, 1131. Displacement sensor A, 1132. Displacement sensor B, 201. Cooling pump, 202. Cooling motor, 203. Cooler, 204. Return oil filter, 205. Temperature sensor. DETAILED DESCRIPTION

[0023] The present invention is further described below with reference to the accompanying drawings and embodiments.

[0024] Embodiment 1

[0025] Reference Figure 1 As shown, a hydraulic control system of a hydraulic oil pump includes a main hydraulic system 1 and a cooling system 2.

[0026] The main hydraulic system includes a main motor 105, a dual pump motor and an accumulator 109. The dual pump motor includes a first variable pump motor 1041 and a second variable pump motor 1042 connected in series. The output shaft of the main motor 105 is connected to the input end of the first variable pump motor 1041 and the second variable pump motor 1042, that is, the first variable pump motor 1041 and the second variable pump motor 1042 are connected to the rotating main shaft of the main motor 105 through a common rotating main shaft. The first variable pump motor 1041 and the second variable pump motor 1042 are both variable piston pump motors, which can be used as pumps (i.e., driven by a motor or other power to discharge hydraulic oil) or motors (i.e., converting liquid pressure energy into torque and speed output to the outside).

[0027] One end oil port of the first variable pump motor 1041 is connected to the oil tank 101, and the other end oil port of the first variable pump motor 1041 is provided with a first liquid circuit and a second liquid circuit, the first liquid circuit is connected to the lower chamber of the first pumping unit cylinder 1121, and the second liquid circuit is connected to the accumulator 109; one end oil port of the second variable pump motor 1042 is connected to the oil tank 101, and the other end oil port of the second variable pump motor 1042 is provided with a third liquid circuit and a fourth liquid circuit, the third liquid circuit is connected to the lower chamber of the second pumping unit cylinder 1122, and the fourth liquid circuit is connected to the accumulator 109; the first liquid circuit, the second liquid circuit, the third liquid circuit and the fourth liquid circuit are respectively provided with a reversing valve A1061, a reversing valve B1062, a reversing valve C1063 and a reversing valve D1064. Specifically: the first fluid circuit is connected in sequence to the reversing valve B1062, the first high-pressure filter 1101 and the lower chamber of the first pumping unit cylinder 1121, the second fluid circuit is connected in sequence to the reversing valve A1061 and the accumulator 109; the third fluid circuit is connected in sequence to the reversing valve C1063, the second high-pressure filter 1102 and the lower chamber of the second pumping unit cylinder 1122, and the fourth fluid circuit is connected in sequence to the reversing valve D1064 and the accumulator 109.

[0028] The cooling system includes a temperature sensor 205 disposed in the oil tank 101 and a cooling device disposed on a cooling circuit. The inlet and the outlet of the cooling circuit are both connected to the oil tank 101 .

[0029] When the first variable pump motor 1041 is driven by hydraulic oil, the first variable pump motor 1041 and the main motor 105 jointly drive the second variable pump motor 1042 to supply oil to the outside in the form of a pump. When the second variable pump motor 1042 is driven by hydraulic oil, the second variable pump motor 1042 and the main motor 105 jointly drive the first variable pump motor 1041 to supply oil to the outside in the form of a pump.

[0030] The cooling device includes a cooling pump 201, a cooler 203 and an oil return filter 204 which are sequentially arranged on the cooling circuit. The power input end of the cooling pump 201 is connected to a cooling motor 202, and the liquid input end of the cooling pump 201 is connected to the oil tank 101. The cooling pump 201 sucks hydraulic oil from the oil tank 101, passes through the cooler 203 and the oil return filter 204 in sequence after pressurization, and then returns to the oil tank 101. The cooling system uses forced air cooling to cool the hydraulic oil.

[0031] In addition, the reversing valves A1061, B1062, C1063 and D1064 are two-position two-way electromagnetic reversing valves. When the electromagnetic reversing valve is not energized, the electromagnetic reversing valve is in a state of disconnection of the liquid circuit, and when it is energized, the electromagnetic reversing valve is in a state of connection of the liquid circuit. The main hydraulic system 1 is equipped with pressure gauges A1071, B1072 and C1073, which are respectively used to display the hydraulic oil pressure in the lower chamber of the first pumping unit cylinder 1121, the lower chamber of the second pumping unit cylinder 1122 and the accumulator 109; and pressure relief valves A1111, B1112 and C1113 are respectively installed to release the hydraulic oil in the lower chamber of the first pumping unit cylinder 1121, the lower chamber of the second pumping unit cylinder 1122 and the accumulator 109. The high-pressure filter is a two-way reversible filter. An air filter 103 is installed at the upper end of the oil tank 101 .

[0032] Pressure sensor A1081, pressure sensor B1082 and pressure sensor C1083 are used to measure the hydraulic oil pressure of the lower chamber of the first pumping unit cylinder 1121, the lower chamber of the second pumping unit cylinder 1122 and the accumulator 109 respectively; the first pumping unit cylinder 1121 and the second pumping unit cylinder 1122 are respectively installed with displacement sensor A1131 and displacement sensor B1132, which are used to measure the displacement of the cylinder piston, and the displacement sensor is a pull rope displacement sensor; the temperature sensor 205 and the liquid level sensor 102 are installed in the oil tank 101 to measure the temperature and liquid level of the hydraulic oil;

[0033] The hydraulic control system further includes a programmable controller, which may be a PLC programmable controller, which is electrically connected to the pressure sensor, the displacement sensor, the temperature sensor 205, the first variable pump motor 1041 and the second variable pump motor 1042. The model of the programmable controller is SIMATIC S7-1200. It can monitor the oil pressure, temperature, liquid level, cylinder piston displacement and electrical parameters of the variable pump motor in real time, and control the start and stop of the main hydraulic system 1 and the cooling system 2, the working state of the electromagnetic reversing valve, the working mode and displacement of the first variable pump motor 1041 and the second variable pump motor 1042.

[0034] Embodiment 2

[0035] This embodiment is an embodiment of a hydraulic control system for a hydraulic pumping unit operating in two wells, as shown in the attached Figure 2 Double-well operation means that a set of hydraulic pumping unit hydraulic control system provides hydraulic source for the hydraulic pumping units of two wells at the same time. At this time, the second and fourth fluid circuits of the hydraulic control system do not participate in the work, and the reversing valve A1061 and the reversing valve D1064 are placed in the fluid circuit disconnection state, and the reversing valve B1062 and the reversing valve C1063 are placed in the fluid circuit connection state.

[0036] When the sucker rod of the first oil well descends, the piston rod of the first pumping unit cylinder 1121 is driven to fall. After the hydraulic oil in the lower chamber of the first pumping unit cylinder 1121 passes through the first high-pressure filter 1101 and the reversing valve B1062, it drives the first variable pump motor 1041 to rotate and drives the second variable pump motor 1042 to supply oil to the outside in the form of a pump together with the main motor 105. After the hydraulic oil of the first variable pump motor 1041 does work, it returns to the oil tank 101. The hydraulic oil sucked and pumped out by the second variable pump motor 1042 from the oil tank 101 passes through the reversing valve C1063 and the second high-pressure filter 1102 in turn to reach the lower chamber of the second pumping unit cylinder 1122, pushing the piston rod of the second pumping unit cylinder 1122 to drive the sucker rod of the second oil well upward, completing the first oil lifting of the second oil well.

[0037] When the second oil well sucker rod descends, the piston rod of the second pumping unit cylinder 1122 is driven to fall, and the hydraulic oil in the lower chamber of the second pumping unit cylinder 1122 drives the second variable pump motor 1042 to rotate through the second high-pressure filter 1102 and the reversing valve C1063, and drives the first variable pump motor 1041 to supply oil to the outside in the form of a pump together with the main motor 105. The hydraulic oil of the second variable pump motor 1042 returns to the oil tank 101 after doing work, and the hydraulic oil sucked from the oil tank 101 by the first variable pump motor 1041 and then pumped out passes through the reversing valve B1062 and the first high-pressure filter 1101 in turn to reach the lower chamber of the first pumping unit cylinder 1121, pushing the piston rod of the first pumping unit cylinder 1121 to drive the sucker rod of the first oil well upward, completing a first oil lift of the first oil well.

[0038] The automatic control device, i.e., a programmable controller, can monitor the oil pressure, temperature, liquid level, displacement of the cylinder piston, and the electrical parameters of the variable pump motor in real time, and control the start and stop of the cooling system 2, the working state of the electromagnetic reversing valve, the working mode and displacement of the variable pump motor. The automatic control device automatically starts and stops the cooling system 2 according to the set range of the hydraulic oil temperature, and controls the hydraulic oil temperature in the oil tank 101 within the target temperature range. The automatic control device automatically matches the displacement of the variable pump motor and the motor speed according to the hydraulic oil pressure in the lower chamber of the first pumping unit cylinder 1121 and the lower chamber of the second pumping unit cylinder 1122, and the displacement of the piston of the first pumping unit cylinder 1121 and the piston of the second pumping unit cylinder 1122, so that the downward gravity of the sucker rod can be utilized to the maximum extent, thereby achieving the purpose of energy saving.

[0039] Embodiment 3

[0040] This embodiment is an embodiment of a hydraulic control system for a hydraulic pumping unit operating in a single well. Figure 3. During the operation of the dual wells, when one well needs maintenance, one well needs to be stopped for operation, while the other well needs to maintain normal oil production; compared with the second embodiment, the third embodiment stops the second pumping unit and continues to operate the first pumping unit. At this time, it is only necessary to put the reversing valve A1061 and the reversing valve C1063 in the liquid circuit disconnection state, and put the reversing valve B1062 and the reversing valve D1064 in the liquid circuit connection state, then the first liquid circuit and the fourth liquid circuit participate in the work, and the second liquid circuit and the third liquid circuit do not participate in the work.

[0041] When the first oil well sucker rod descends, it drives the piston rod of the first pumping unit cylinder 1121 to fall, and the hydraulic oil in the lower chamber of the first pumping unit cylinder 1121 drives the first variable pump motor 1041 to rotate through the first high-pressure filter 1101 and the reversing valve B1062, and drives the second variable pump motor 1042 to supply oil to the outside in the form of a pump together with the main motor 105. The hydraulic oil of the first variable pump motor 1041 returns to the oil tank 101 after doing work, and the hydraulic oil sucked and pumped out by the second variable pump motor 1042 from the oil tank 101 reaches the accumulator 109 through the reversing valve D1064. After the piston rod of the first pumping unit cylinder 1121 falls to the lowest point, the hydraulic oil in the accumulator 109 drives the second variable pump motor 1042 to rotate after passing through the reversing valve D1064, and drives the first variable pump motor 1041 to supply oil to the outside in the form of a pump together with the main motor 105. The hydraulic oil of the second variable pump motor 1042 returns to the oil tank 101 after doing work. The hydraulic oil sucked in and pumped out by the first variable pump motor 1041 from the oil tank 101 passes through the reversing valve B1062 and the first high-pressure filter 1101 in turn to reach the lower chamber of the first pumping unit cylinder 1121, pushing the piston rod of the first pumping unit cylinder 1121 to drive the sucker rod of the first oil well upward, completing an oil lift of the first oil well.

[0042] The automatic control device monitors the oil pressure, temperature, liquid level, cylinder piston displacement and electrical parameters of the variable pump motor in real time, and controls the start and stop of the main hydraulic system 1 and the cooling system 2, the working state of the reversing valve, the working mode and displacement of the variable pump motor. The automatic control device automatically starts and stops the cooling system 2 according to the set range of the hydraulic oil temperature, and controls the hydraulic oil temperature in the oil tank 101 within the target temperature range. The automatic control device automatically matches the displacement of the variable pump motor and the motor speed according to the hydraulic oil pressure in the lower chamber of the first pumping unit cylinder 1121 and the accumulator 109, and the displacement of the piston of the first pumping unit cylinder 1121, so that the downward gravity of the sucker rod can be utilized to the greatest extent, achieving the purpose of energy saving.

[0043] In the embodiment, during normal operation, the reversing valve is in a connected or disconnected state, there is no frequent reversal, and no system hydraulic shock will be caused.

[0044] This system has fewer hydraulic components and lower energy consumption; the hydraulic oil passes through the oil tank in each cycle and the independent cooling system can more effectively cool the hydraulic oil; the double-type variable piston pump motor can achieve closed-loop control of the working mode and displacement, fully utilizing the downward energy of the hydraulic pump and greatly reducing the power consumption of the pump.

[0045] The present invention is not limited to the above-mentioned embodiments. Various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention. The changed contents still fall within the protection scope of the present invention.

Claims

1. A hydraulic control system for a hydraulic pumping unit, characterized in that: include: A main hydraulic system, the main hydraulic system includes a main motor, a double pump motor and an accumulator, the double pump motor includes a first variable pump motor and a second variable pump motor connected in series, the output shaft of the main motor is connected to the input end of the first variable pump motor and the second variable pump motor; one end of the first variable pump motor is connected to the oil tank, and the other end of the first variable pump motor is provided with a first fluid path and a second fluid path, the first fluid path is connected to the lower chamber of the first pumping unit cylinder, and the second fluid path is connected to the accumulator; one end of the second variable pump motor is connected to the oil tank, and the other end of the second variable pump motor is provided with a third fluid path and a fourth fluid path, the third fluid path is connected to the lower chamber of the second pumping unit cylinder, and the fourth fluid path is connected to the accumulator; the first fluid path, the second fluid path, the third fluid path and the fourth fluid path are respectively provided with a reversing valve; A cooling system, the cooling system comprising a temperature sensor disposed in the oil tank and a cooling device disposed on a cooling circuit, wherein an inlet and an outlet of the cooling circuit are both connected to the oil tank; When the first variable pump motor is driven by hydraulic oil, the first variable pump motor and the main motor jointly drive the second variable pump motor to supply oil to the outside in the form of a pump. When the second variable pump motor is driven by hydraulic oil, the second variable pump motor and the main motor jointly drive the first variable pump motor to supply oil to the outside in the form of a pump.

2. A hydraulic control system for a hydraulic pumping unit according to claim 1, characterized in that: The cooling device comprises a cooling pump, a cooler and an oil return filter which are sequentially arranged on a cooling circuit. The power input end of the cooling pump is connected to a cooling motor, and the liquid input end of the cooling pump is connected to an oil tank.

3. A hydraulic control system for a hydraulic pumping unit according to claim 2, characterized in that: A first high-pressure filter is installed between the reversing valve in the first fluid circuit and the lower chamber of the first pumping unit cylinder, and a second high-pressure filter is installed between the reversing valve in the third fluid circuit and the lower chamber of the second pumping unit cylinder.

4. A hydraulic control system for a hydraulic pumping unit according to claim 3, characterized in that: The main hydraulic system also includes a pressure sensor for measuring the hydraulic oil pressure in the lower chamber of the first pumping unit cylinder, the lower chamber of the second pumping unit cylinder and the accumulator; displacement sensors are respectively installed in the first pumping unit cylinder and the second pumping unit cylinder.

5. A hydraulic control system for a hydraulic pumping unit according to claim 4, characterized in that: The hydraulic control system further comprises a programmable controller, which is electrically connected to the pressure sensor, the displacement sensor, the temperature sensor, the first variable pump motor and the second variable pump motor respectively.

6. A hydraulic control system for a hydraulic pumping unit according to claim 5, characterized in that: The model of the programmable controller is SIMATIC S7-1200.

7. The hydraulic control system of a hydraulic pumping unit according to claim 1, characterized in that: The first variable displacement pump motor and the second variable displacement pump motor are both variable displacement plunger pump motors.

8. The hydraulic control system of a hydraulic pumping unit according to claim 1, characterized in that: The lower chamber of the first pumping unit hydraulic cylinder, the lower chamber of the second pumping unit hydraulic cylinder and the accumulator are all provided with a pressure relief valve for discharging hydraulic oil.

9. The hydraulic control system of a hydraulic pumping unit according to claim 1, characterized in that: The lower chamber of the first pumping unit hydraulic cylinder, the lower chamber of the second pumping unit hydraulic cylinder and the accumulator are all equipped with pressure gauges for displaying the hydraulic oil pressure.

10. The hydraulic control system of a hydraulic pumping unit according to claim 4, characterized in that: The first high-pressure filter and the second high-pressure filter are both bidirectional reversible filters; the reversing valve is a two-position two-way electromagnetic reversing valve; and the displacement sensor is a pull-rope displacement sensor.

Images