A reinjection pump control system and automatic control method

Abstract

The present application relates to the technical field of oil drilling waste treatment, and particularly relates to a reinjection pump control system and an automatic control method, the reinjection pump control system comprising an engine electronic control module, a transmission case electronic control module, a field bus protocol converter, a programmable logic controller one, a man-machine interactive interface, a plunger pump signal unit and a system parameter comprehensive display instrument, wherein the actual reinjection discharge pressure is monitored, and the actual reinjection discharge pressure is adjusted by means of automatic gear reduction, automatic speed reduction or a combination of both, the actual reinjection discharge displacement is adjusted to the stage reinjection displacement R_d by adopting the idle gear back to the idling operation and the PID control method according to the difference AR between the actual reinjection discharge displacement and the stage reinjection displacement R_d, and the engine speed is automatically adjusted. Finally, the automatic control of the reinjection pressure and the reinjection displacement is realized, and the problems of low automation degree and low safety controllability of the existing equipment are solved.

Description

Technical Field

[0001] This invention relates to the field of oil drilling waste treatment technology, and in particular to a reinjection pump control system and automatic control method. Background Technology

[0002] In the field of oil drilling waste treatment, commonly used methods both domestically and internationally include backfilling, solidification, biological treatment, thermal desorption, and reinjection. Reinjection, as the treatment method closest to "zero emissions," involves reinjecting the waste generated during drilling back into the sealed formation. Its economic cost and environmental and social benefits are far superior to the other methods.

[0003] In this process, the reinjection pump skid is a mechanical device that pumps the ground rock cuttings into the sealed formation at a set pressure and flow rate. Reinjection pressure is a crucial safety parameter affecting the successful arrival of rock cuttings into the sealed formation, while reinjection flow rate is a critical parameter affecting the designed absorption of rock cuttings by the sealed formation. Therefore, the ability of the reinjection pump skid control system to achieve high-precision automatic control of reinjection pressure and flow rate directly impacts the safety and effectiveness of the operation.

[0004] Currently, reinjection technology is still in its early stages in China, with very few supporting devices and equipment. Existing equipment has low levels of automation and safety controllability. On the other hand, well sites and offshore platforms have extremely high electrical safety requirements. Positive pressure control systems can effectively isolate internal electrical components from external flammable gases, preventing on-site safety accidents caused by electrical component failures. Therefore, researching a reinjection pump control system and automatic control method has significant practical implications. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a reinjection pump control system and automatic control method to realize automatic control of reinjection pressure and reinjection discharge, thereby solving the problem that the existing equipment has low automation and safety controllability.

[0006] This invention provides the following technical solution: a reinjection pump control system, which includes an engine electronic control module, a transmission electronic control module, a fieldbus protocol converter, a programmable logic controller, a human-machine interface, a plunger pump signal unit, and a system parameter integrated display instrument;

[0007] The programmable logic controller (PLC) acquires engine coolant temperature, coolant level, lubricating oil temperature, and lubricating oil pressure data collected by the engine electronic control module via a fieldbus protocol converter. The engine electronic control module receives start / stop and speed adjustment control commands issued by the PLC via the fieldbus protocol converter.

[0008] The programmable logic controller (PLC) acquires data on transmission oil filter blockage, lubricating oil temperature, and lubricating oil pressure collected by the transmission electronic control module via a fieldbus protocol converter. The transmission electronic control module receives gear adjustment or unlocking commands issued by the PLC via the fieldbus protocol converter.

[0009] The plunger pump signal unit collects data on the plunger pump hydraulic end lubricating oil temperature, hydraulic end lubricating oil pressure, reinjection pressure, and reinjection displacement, and inputs them to the programmable logic controller as feedback values ​​for the reinjection pump control system.

[0010] The integrated display acquires component parameters via fieldbus and displays the required parameters for the current status through a user-selectable menu; the human-machine interface communicates with the programmable logic controller via industrial Ethernet protocol and displays component status, parameters, and curves in real time.

[0011] Preferably, it also includes a positive pressure control system, which includes a programmable logic controller (PLC) II and a gas injection and discharge control unit, wherein the PLC II is used to issue control commands to each execution unit;

[0012] The gas injection and discharge control unit includes an intake solenoid valve, an exhaust solenoid valve, a gas filter, a humidity sensor, a pressure sensor, and a status indicator light. It is used for the input, purification, replacement, and discharge of compressed air in the explosion-proof cabinet, and to keep the air pressure in the cabinet within a stable range.

[0013] Preferably, the positive pressure control system further includes a pressure measurement and control unit, which is used to monitor the air pressure value inside the explosion-proof cabinet in real time;

[0014] The pressure measurement and control unit includes a pressure sensor and a multi-color audible and visual alarm. The pressure measurement and control unit is set with four pressure settings: high pressure protection upper limit, positive pressure upper limit, positive pressure lower limit, and low pressure protection lower limit. When the real-time air pressure value exceeds the high pressure protection upper limit or falls below the low pressure protection lower limit, the programmable logic controller immediately executes an automatic power-off command, and the multi-color audible and visual alarm outputs a red alarm signal.

[0015] Preferably, the positive pressure control system further includes a combustible gas monitoring unit;

[0016] The combustible gas monitoring unit includes a combustible gas detector. The combustible gas monitoring unit has two upper limits: a warning upper limit and an automatic power-off limit. When the combustible gas concentration exceeds the warning upper limit, the multi-color audible and visual alarm outputs a yellow alarm signal, and at the same time, the positive pressure control system starts the compressed air replacement process. When the combustible gas concentration exceeds the automatic power-off limit, the programmable logic controller immediately executes the automatic power-off command, and the multi-color audible and visual alarm outputs a red alarm signal.

[0017] Preferably, the positive pressure control system further includes a pressure relief slope calculation unit, which is used to detect whether the sealing performance of the positive pressure control system is good under fully manual conditions;

[0018] The pressure relief slope calculation unit includes a pressure sensor and a controller slope calculation function block. After the positive pressure control system is started, the controller monitors the air pressure value inside the explosion-proof cabinet in real time, and detects and records the pressure drop value ΔP according to a fixed time period ΔT, and calculates the pressure relief time slope K = ΔP / ΔT. The closer the slope value is to 0, the better the sealing performance.

[0019] An automatic control method for a reinjection pump control system includes the following steps:

[0020] S1. The reinjection pump control system reads parameters during the reinjection operation via industrial Ethernet, including reinjection layer, number of stages, set stage reinjection discharge R_d, stage liquid name, stage liquid volume, total liquid volume, and stage operation pressure limit P_Max.

[0021] S2. Input the engine's rated power, maximum speed, reinjection pump plunger diameter, stroke, and transmission gear reduction ratio parameters. The system will automatically generate a reinjection pump displacement-pressure comparison table based on the mechanical calculation formula.

[0022] S3. Calculate the number of online systems to be adjusted and the maximum instantaneous displacement of a single vehicle based on the total reinjection volume, number of stages, and volume of liquid in each stage; calculate the friction of the fluid path and the maximum pressure overpressure value P_Ex of the corresponding stage path based on the reinjection layer, liquid name, construction pressure, and simulated rupture pressure value; P_Ex is greater than the upper limit of the stage operation pressure P_Max.

[0023] Based on the stage reinjection displacement R_d, the stage operating pressure limit P_Max, and the stage pressure overpressure value P_Ex of the fluid path, combined with the reinjection pump displacement pressure comparison table of the reinjection device itself, the initial gear G_0 and engine speed parameter R_0 of the device operation are generated.

[0024] S4. During the start-up phase, the engine automatically adjusts its speed to R_0, the transmission automatically adjusts its gear to G_0, and the pressure monitoring unit starts at the same time.

[0025] When the actual reinjection discharge pressure exceeds P_Max, the automatic control system of the reinjection pump will adjust the actual reinjection discharge pressure to below P_Max by automatically downshifting, automatically reducing the speed, or a combination of both, based on the difference ΔP_0 between the actual reinjection discharge pressure and P_Max.

[0026] When the actual reinjection discharge pressure exceeds P_Ex, the automatic control system immediately performs a neutral return operation.

[0027] When the actual reinjection discharge pressure is lower than P_Max, the reinjection pump automatic control system will use PID control method to automatically adjust the engine speed based on the difference ΔR between the actual reinjection discharge volume and the stage reinjection discharge volume R_d, and adjust the actual reinjection discharge volume to the stage reinjection discharge volume R_d.

[0028] S5. Construction in the current operation phase will continue under the control process of step S4. When the actual cumulative operation volume of the phase reaches the design volume of the current phase read in step S1, the current phase operation is completed; and the process enters the waiting mode for formation absorption and reinjection of fluid.

[0029] S6. The actual construction of each stage of the reinjection operation is carried out in a cycle according to steps S4 and S5. Using the stage liquid, stage liquid volume, and absorption waiting as preset reference values, after each cycle is completed, the system components are switched to standby mode. After five minutes, the operation is completed by shutting down the machine one by one without human intervention.

[0030] Preferably, before starting the operation, step S4 requires a pre-operation self-check of the automatic control system of the reinjection pump to check that the values ​​of each signal channel are within the range and the data is normal, and that the communication data flow of the power components is normal. If there is no initial value or the initial state of the components is abnormal, the self-check is completed and the start-up operation mode is indicated.

[0031] Preferably, during the operation of step S5, the system monitors the reinjection pressure value in real time and detects and records the pressure drop value ΔP_1 according to a fixed time period ΔT;

[0032] When the difference becomes negative, it indicates an anomaly in the formation absorption. The system will immediately sound an alarm, end the automatic process, and enter manual processing mode.

[0033] Conversely, the task design requires waiting for the absorption process to end before proceeding to the next stage of the task;

[0034] If other faults or alarm messages belonging to the red alarm level occur during the operation, the system will also immediately sound an alarm and enter manual handling mode, ending the automatic process.

[0035] This invention provides a reinjection pump control system and automatic control method. The system monitors the actual reinjection discharge pressure using a pressure detection unit. The automatic control system adjusts the actual reinjection discharge pressure based on the difference between the actual discharge pressure and P_Max (ΔP_0), employing automatic downshifting, automatic speed reduction, or a combination of both. It also automatically adjusts the engine speed using a neutral gear return operation and a PID control method based on the difference between the actual reinjection discharge volume and the stage reinjection volume (R_d), adjusting the stage reinjection volume (R_d) accordingly. When the actual cumulative working fluid volume for a stage reaches the designed volume for that stage, the current stage of operation is completed. Through the coordination of the engine electronic control module, transmission electronic control module, programmable logic controller, and plunger pump signal unit, automatic control of the reinjection pressure and volume is achieved, solving the problem of low automation and safety controllability in existing equipment. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the reinjection pump control system of the present invention;

[0037] Figure 2 This is a flowchart illustrating the operation of the positive pressure control system of the reinjection pump control system of the present invention.

[0038] Figure 3 This is a flowchart of the automatic control method for the reinjection pump control system of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] like Figure 1 As shown, the present invention provides a technical solution: a reinjection pump control system, which includes an engine electronic control module, a transmission electronic control module, a fieldbus protocol converter, a programmable logic controller, a human-machine interface, a plunger pump signal unit, and a system parameter integrated display instrument.

[0041] Among them, the programmable logic controller 1 obtains data such as engine coolant temperature, coolant level, lubricating oil temperature, and lubricating oil pressure collected by the engine electronic control module through the fieldbus protocol converter, and the engine electronic control module receives control commands such as start / stop and speed adjustment issued by the programmable logic controller 1 through the fieldbus protocol converter.

[0042] The programmable logic controller (PLC) acquires data such as the transmission oil filter blockage status, lubricating oil temperature, and lubricating oil pressure collected by the transmission electronic control module through a fieldbus protocol converter. The transmission electronic control module receives gear adjustment or unlocking commands issued by the PLC through the fieldbus protocol converter.

[0043] The plunger pump signal unit collects data such as the lubricating oil temperature and pressure at the hydraulic end of the plunger pump, as well as the reinjection pressure and reinjection displacement, and inputs them to the programmable logic controller as feedback values ​​for the reinjection pump control system.

[0044] The integrated display instrument acquires component parameters through the fieldbus and displays the parameters required for the current status through a user-selectable menu; the human-machine interface communicates with the programmable logic controller via the industrial Ethernet protocol, and can display component status, parameters, curves, etc. in real time.

[0045] like Figure 2 As shown, the reinjection pump control system also includes a positive pressure control system, which includes a programmable logic controller, a gas injection and discharge control unit, a pressure measurement and control unit, a combustible gas monitoring unit, and a pressure relief slope calculation unit.

[0046] The programmable logic controller 2 is used to issue control commands to each execution unit, so that each execution unit performs actions according to the control logic.

[0047] The gas injection and discharge control unit includes an intake solenoid valve, an exhaust solenoid valve, a gas filter, a humidity sensor, a pressure sensor, status indicator lights, and controller commands. It is used for the input, purification, replacement, and discharge of compressed air in the explosion-proof cabinet, and to keep the air pressure in the cabinet within a stable range.

[0048] After the positive pressure control system is activated, both the intake and exhaust solenoid valves open, introducing compressed air into the gas filter. The gas filter dehumidifies and desalinates the incoming air, reducing its humidity and salt content. Dehumidification prevents condensation inside the explosion-proof cabinet, which could cause circuit malfunctions, while desalination prevents corrosion of electrical components by airborne salts. The filtered compressed air enters the cabinet, replacing the existing gas. When the humidity sensor detects that the air humidity has reached the set requirement, the programmable logic controller (PLC) issues a command to close the exhaust solenoid valve and initiate unidirectional compressed air injection. Once the gas pressure inside the cabinet reaches the set positive pressure range, the intake solenoid valve closes, the status indicator light turns green, and the positive pressure control system activation is complete.

[0049] The pressure monitoring and control unit includes a pressure sensor, a multi-color audible and visual alarm, and a controller. The module's main function is to monitor the air pressure inside the explosion-proof cabinet in real time. The pressure monitoring and control unit has four pressure settings: a high-pressure protection upper limit, positive pressure upper and lower limits, and a low-pressure protection lower limit. When the real-time air pressure exceeds the high-pressure protection upper limit or falls below the low-pressure protection lower limit, the system considers the positive pressure control system to have failed, and the programmable logic controller immediately executes an automatic power-off command, triggering the multi-color audible and visual alarm to output a red alarm signal.

[0050] When the real-time air pressure value is higher than the upper limit of positive pressure but lower than the upper limit of high pressure protection, the programmable logic controller 2 executes the command to open the exhaust solenoid valve and close the intake solenoid valve; when the real-time air pressure value is lower than the lower limit of positive pressure but higher than the lower limit of power failure protection, the programmable logic controller 2 executes the command to open the intake solenoid valve and close the exhaust solenoid valve; in both cases, the multi-color audible and visual alarm will output a yellow alarm signal. When the real-time air pressure value reaches between the upper and lower limits of positive pressure, both the intake solenoid valve and the exhaust valve will automatically close, thereby realizing automatic pressure regulation of the positive pressure chamber of the positive pressure cabinet.

[0051] The flammable gas monitoring unit includes a flammable gas detector, an audible and visual alarm, and controller commands. Flammable gases are extremely dangerous and are a key focus of protection for all electrical cabinets. After the positive pressure control system is started, the flammable gas monitoring unit begins continuous operation. This monitoring unit has two upper limits: a warning upper limit and an automatic power-off limit. When the flammable gas concentration exceeds the warning upper limit, the multi-color audible and visual alarm outputs a yellow alarm signal, and the system simultaneously initiates the compressed air replacement process; when the flammable gas concentration exceeds the automatic power-off limit, the programmable logic controller immediately executes the automatic power-off command, and the multi-color audible and visual alarm outputs a red alarm signal.

[0052] The pressure relief slope calculation unit includes a pressure sensor and a controller slope calculation function block. It is used to detect the sealing performance of the positive pressure control system in fully manual mode. This function is only used during the sealing performance testing of the explosion-proof cabinet and provides a direct visual result of the sealing performance. After the positive pressure control system is started, the controller monitors the air pressure inside the explosion-proof cabinet in real time and detects and records the pressure drop value ΔP according to a fixed time period ΔT (adjustable). It then calculates the pressure relief slope K = ΔP / ΔT. The closer the slope value is to 0, the better the sealing performance.

[0053] In the above technical solution, when the positive pressure control system is running smoothly, if the system detects that the temperature inside the cabinet is higher than the first set value, it will start to execute the purging cycle. The constant pressure purging will stop when the second set temperature value is reached, so as to ensure that the electrical components in the confined space are not affected by the excessively high ambient temperature.

[0054] like Figure 3As shown, an automatic control method for a reinjection pump control system is based on the phased automatic control of two core parameters during reinjection operations: reinjection pressure and reinjection displacement. The method includes the following steps:

[0055] Step 1: The reinjection pump control system reads relevant parameters from the reinjection operation construction design software via industrial Ethernet, including reinjection layer, number of stages, set stage reinjection discharge R_d, stage liquid name, stage liquid volume, total liquid volume, and stage operation pressure limit P_Max.

[0056] Step 2: Input parameters such as engine rated power, maximum speed, reinjection pump plunger diameter, stroke, and transmission gear ratio. The system will automatically generate a reinjection pump displacement-pressure comparison table based on mechanical calculation formulas.

[0057]

[0058] Table 1 Comparison of Reinjection Pump Displacement and Pressure

[0059] Step 3: Calculate the number of online systems to be adjusted and the maximum instantaneous displacement of a single vehicle based on the total reinjection volume, number of stages, and stage liquid volume; derive the frictional resistance of the fluid path and the maximum overpressure value P_Ex of the corresponding stage path based on the reinjection layer, liquid name, construction pressure, and simulated rupture pressure value; P_Ex is greater than the stage operation pressure limit P_Max.

[0060] Based on the stage reinjection displacement R_d, the stage operating pressure limit P_Max, and the stage pressure overpressure value P_Ex along the fluid path, and in conjunction with the reinjection device's own reinjection pump displacement-pressure reference table, the initial operating gear G_0 and engine speed parameter R_0 are generated according to the following method:

[0061] If the stage reinjection displacement R_d belongs to (0, R_1_Max], then G_0 = 1, R_0 = R_1_Min;

[0062] If the stage reinjection displacement R_d belongs to (R_1_Max,R_2_Max], then G_0=2, R_0=R_2_Min;

[0063] If the stage reinjection displacement R_d belongs to (R_2_Max,R_3_Max], then G_0=3, R_0=R_3_Min;

[0064] If the stage reinjection displacement R_d belongs to (R_3_Max,R_4_Max], then G_0=4, R_0=R_4_Min;

[0065] If the stage reinjection displacement R_d belongs to (R_4_Max,R_5_Max], then G_0=5, R_0=R_5_Min;

[0066] In the above method, R_1_Min, R_2_Min, ...R_5_Min, R_1_Max, R_2_Max, ...R_5_Max correspond to the displacement values ​​of 1500RPM and 2100RPM in gears 1-5 of the displacement-pressure comparison table.

[0067] Step 4: Before the automatic control system of the reinjection pump starts running, it performs a self-check to check that the values ​​of each signal channel are within the range and the data is normal, and that the communication data flow of the power components is normal. If there is no initial value or the initial state of the components is abnormal, the self-check is completed and a prompt will indicate that the start-up phase operation mode is ready.

[0068] Step 5: During the startup phase, the engine automatically adjusts its speed to R_0, and the transmission automatically adjusts its gear to G_0. Simultaneously, the pressure monitoring unit activates. When the actual reinjection discharge pressure exceeds P_Max, the reinjection pump automatic control system will adjust the actual reinjection discharge pressure below P_Max by automatically downshifting, automatically reducing engine speed, or a combination of both, based on the difference between the actual reinjection discharge pressure and P_Max, ΔP_0. When the actual reinjection discharge pressure exceeds P_Ex, the automatic control system immediately engages neutral to idle. When the actual reinjection discharge pressure is lower than P_Max, the reinjection pump automatic control system will automatically adjust the engine speed using PID control based on the difference between the actual reinjection discharge volume and the stage reinjection volume R_d, ΔR, to adjust the actual reinjection discharge volume to the stage reinjection volume R_d. The engineering tuning methods for PID controller parameters mainly include the critical proportional method, the reaction curve method, and the decay method.

[0069] Step Six: Construction in the current operation phase will continue under the control process of Step Five. When the actual cumulative working fluid volume of the phase reaches the design fluid volume of the current phase read in Step One, the current phase of the operation is completed; and the process enters the waiting mode for formation absorption and reinjection of fluid.

[0070] During the process, the system monitors the reinjection pressure in real time and detects and records the pressure drop value ΔP_1 at a fixed time period ΔT (configurable). When the difference becomes negative, it indicates an anomaly in formation absorption. The system immediately alarms, terminates the automatic process, and enters manual handling mode; conversely, the operation design requires waiting for the absorption process to end before proceeding to the next stage. If other faults or alarm messages belonging to the red alarm level occur during the operation, the system will also immediately alarm, enter manual handling mode, and terminate the automatic process.

[0071] If other emergency alarms of the red level (user-defined, generally related to safety production such as power-end fire detection, construction pressure exceeding equipment limit pressure, etc.) occur during the operation, the system will directly jump to the end of the task.

[0072] Step Seven: The actual construction of each stage of the reinjection operation shall be carried out in a cycle according to Steps Five and Six. Using the stage liquid, stage liquid volume, and absorption waiting time as preset reference values, after each cycle is completed, the system components shall be switched to standby mode, and after five minutes, the operation shall be completed by shutting down the machine one by one without manual intervention.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An automatic control method for a reinjection pump control system, the reinjection pump control system comprising an engine electronic control module, a transmission electronic control module, a fieldbus protocol converter, a programmable logic controller, a human-machine interface, a plunger pump signal unit, and a system parameter integrated display instrument; The programmable logic controller (PLC) acquires engine coolant temperature, coolant level, lubricating oil temperature, and lubricating oil pressure data collected by the engine electronic control module via a fieldbus protocol converter. The engine electronic control module receives start / stop and speed adjustment control commands issued by the PLC via the fieldbus protocol converter. The programmable logic controller (PLC) acquires data on transmission oil filter blockage, lubricating oil temperature, and lubricating oil pressure collected by the transmission electronic control module via a fieldbus protocol converter. The transmission electronic control module receives gear adjustment or unlocking commands issued by the PLC via the fieldbus protocol converter. The plunger pump signal unit collects data on the plunger pump hydraulic end lubricating oil temperature, hydraulic end lubricating oil pressure, reinjection pressure, and reinjection displacement, and inputs them to the programmable logic controller as feedback values ​​for the reinjection pump control system. The integrated display acquires component parameters via fieldbus and displays the required parameters for the current status through a user-selectable menu; the human-machine interface communicates with the programmable logic controller via industrial Ethernet protocol and displays component status, parameters, and curves in real time. Its features include the following steps: S1, the reinjection pump control system reads the parameters during the reinjection operation through the industrial Ethernet, including the reinjection layer, number of stages, set stage reinjection discharge R_d, stage liquid name, stage liquid volume, total liquid volume, and stage operation pressure limit P_Max; S2. Input the engine's rated power, maximum speed, reinjection pump plunger diameter, stroke, and transmission gear reduction ratio parameters. The system will automatically generate a reinjection pump displacement-pressure comparison table based on the mechanical calculation formula. S3. Calculate the number of online systems to be adjusted and the maximum instantaneous displacement of a single vehicle based on the total reinjection volume, number of stages, and volume of liquid in each stage; calculate the friction of the fluid path and the maximum pressure overpressure value P_Ex of the corresponding stage path based on the reinjection layer, liquid name, construction pressure, and simulated rupture pressure value; P_Ex is greater than the upper limit of the stage operation pressure P_Max. Based on the stage reinjection displacement R_d, the stage operating pressure limit P_Max, and the stage pressure overpressure value P_Ex of the fluid path, combined with the reinjection pump displacement pressure comparison table of the reinjection device itself, the initial gear G_0 and engine speed parameter R_0 of the device operation are generated. S4. During the start-up phase, the engine automatically adjusts its speed to R_0, the transmission automatically adjusts its gear to G_0, and the pressure monitoring unit starts at the same time. When the actual reinjection discharge pressure exceeds P_Max, the automatic control system of the reinjection pump will adjust the actual reinjection discharge pressure to below P_Max by automatically downshifting, automatically reducing the speed, or a combination of both, based on the difference ΔP_0 between the actual reinjection discharge pressure and P_Max. When the actual reinjection discharge pressure exceeds P_Ex, the automatic control system immediately performs a neutral return operation. When the actual reinjection discharge pressure is lower than P_Max, the reinjection pump automatic control system will use PID control method to automatically adjust the engine speed based on the difference ΔR between the actual reinjection discharge volume and the stage reinjection discharge volume R_d, and adjust the actual reinjection discharge volume to the stage reinjection discharge volume R_d. S5. Construction in the current operation phase will continue under the control process of step S4. When the actual cumulative operation volume of the phase reaches the design volume of the current phase read in step S1, the current phase operation is completed; and the process enters the waiting mode for formation absorption and reinjection of fluid. S6. The actual construction of each stage of the reinjection operation is carried out in a cycle according to steps S4 and S5. Using the stage liquid, stage liquid volume, and absorption waiting as preset reference values, after each cycle is completed, the system components are switched to standby mode. After five minutes, the operation is completed by shutting down the machine one by one without human intervention.

2. The automatic control method for a reinjection pump control system according to claim 1, characterized in that: The reinjection pump control system also includes a positive pressure control system, which includes a programmable logic controller (PLC) II and a gas injection and discharge control unit. The PLC II is used to issue control commands to each execution unit. The gas injection and discharge control unit includes an intake solenoid valve, an exhaust solenoid valve, a gas filter, a humidity sensor, a pressure sensor, and a status indicator light. It is used for the input, purification, replacement, and discharge of compressed air in the explosion-proof cabinet, and to keep the air pressure in the cabinet within a stable range.

3. The automatic control method for a reinjection pump control system according to claim 2, characterized in that: The positive pressure control system also includes a pressure measurement and control unit, which is used to monitor the air pressure value inside the explosion-proof cabinet in real time. The pressure measurement and control unit includes a pressure sensor and a multi-color audible and visual alarm. The pressure measurement and control unit is set with four pressure settings: high pressure protection upper limit, positive pressure upper limit, positive pressure lower limit, and low pressure protection lower limit. When the real-time air pressure value exceeds the high pressure protection upper limit or falls below the low pressure protection lower limit, the programmable logic controller immediately executes an automatic power-off command, and the multi-color audible and visual alarm outputs a red alarm signal.

4. The automatic control method for a reinjection pump control system according to claim 3, characterized in that: The positive pressure control system also includes a combustible gas monitoring unit; The combustible gas monitoring unit includes a combustible gas detector. The combustible gas monitoring unit has two upper limits: a warning upper limit and an automatic power-off limit. When the combustible gas concentration exceeds the warning upper limit, the multi-color audible and visual alarm outputs a yellow alarm signal, and at the same time, the positive pressure control system starts the compressed air replacement process. When the combustible gas concentration exceeds the automatic power-off limit, the programmable logic controller immediately executes the automatic power-off command, and the multi-color audible and visual alarm outputs a red alarm signal.

5. The automatic control method for a reinjection pump control system according to claim 4, characterized in that: The positive pressure control system also includes a pressure relief slope calculation unit, which is used to detect whether the sealing performance of the positive pressure control system is good under fully manual conditions; The pressure relief slope calculation unit includes a pressure sensor and a controller slope calculation function block. After the positive pressure control system is started, the controller monitors the air pressure value inside the explosion-proof cabinet in real time, and detects and records the pressure drop value ΔP according to a fixed time period ΔT, and calculates the pressure relief time slope K=ΔP / ΔT. The closer the slope value is to 0, the better the sealing performance.

6. The automatic control method for a reinjection pump control system according to claim 1, characterized in that: Before starting the operation, step S4 requires a pre-operation self-check of the automatic control system of the reinjection pump. This check checks that the values ​​of each signal channel are within the range and the data is normal, and that the communication data flow of the power components is normal. If there is no initial value or the initial state of the components is abnormal, the self-check is completed and the start-up operation mode is indicated.

7. The automatic control method for a reinjection pump control system according to claim 1, characterized in that: During the operation of step S5, the system monitors the reinjection pressure value in real time and detects and records the pressure drop value ΔP_1 according to a fixed time period ΔT; When the difference becomes negative, it indicates an anomaly in the formation absorption. The system will immediately sound an alarm, end the automatic process, and enter manual processing mode. Conversely, the task design requires waiting for the absorption process to end before proceeding to the next stage of the task; When other faults or alarm messages belonging to the red alarm level occur during operation, such as alarms related to power end fire point monitoring, construction pressure exceeding equipment limit pressure, etc., the system will also immediately alarm and enter manual handling mode, ending the automatic process.

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