A pumping unit electric parameter acquisition and suspension point dynamometer inversion device and method

Abstract

The application discloses a pumping unit electric parameter acquisition and polished rod dynamometer inversion device and method, and relates to the technical field of oilfield mechanical oil production equipment monitoring. The device comprises a three-phase voltage sampling module, a three-phase current sampling module, an electric energy metering module, a main control module, a communication module; the main control module is internally provided with a timing acquisition unit, a power curve processing unit, a polished rod movement calculation unit, a polished rod load inversion unit, a wellbore and pumping unit basic parameter calculation unit, a matching parameter storage module, a local debugging module, a power conversion and partition power supply module. The application does not need to add a polished rod load and displacement sensor on site, and can reduce installation and maintenance difficulty; partition isolation power supply, isolation RS485 and CRC16 check can improve operation stability in an oilfield strong electromagnetic interference environment, and the device has high integration and can remotely complete pumping unit well condition diagnosis, energy consumption and balance state analysis.

Description

Technical Field

[0001] This invention relates to the field of oilfield mechanical oil production equipment monitoring technology, and more specifically to a device and method for collecting electrical parameters of oil pumping units and inverting suspension point dynamometer diagrams. Background Technology

[0002] Beam pumping units are widely used surface drive equipment in rod pump oil production systems. During operation, electrical parameters such as three-phase voltage, three-phase current, active power, power factor, and energy consumption on the motor input side reflect load changes and operating status. Continuous acquisition and analysis of these electrical parameters provide a basis for energy consumption analysis, balance status assessment, well condition diagnosis, and operational optimization.

[0003] Currently, oilfield operations typically utilize methods such as manual inspections, clamp meters, ordinary electricity meters, remote monitoring terminals, or dynamometers to acquire pumping unit operating data. Manual inspections and ordinary electricity meters are primarily used to obtain basic electrical parameters such as voltage, current, power, and energy. Remote monitoring terminals are mainly used for uploading pumping unit operating status, start / stop control, and parameter display. Dynamometers typically collect suspension point load and displacement data using load and displacement sensors to obtain the pumping unit's dynamometer diagram. While these existing technologies can achieve pumping unit operating data acquisition and status monitoring to a certain extent, they still have the following shortcomings.

[0004] First, traditional manual inspections and ordinary electrical parameter measurements can only obtain basic data such as voltage, current, and power at a certain moment or within a short period of time, making it difficult to continuously obtain power change curves over one or more complete operating cycles of the pumping unit. Therefore, these methods are insufficient to reflect the periodic load change characteristics of the pumping unit during the upstroke and downstroke processes.

[0005] Second, existing ordinary electrical parameter acquisition devices mostly focus on displaying or uploading data such as three-phase voltage, three-phase current, active power, power factor and electrical energy. They lack the functions of continuous acquisition, periodic interception, interpolation standardization, smoothing processing and feature point recognition of power curves, making it difficult to further invert the suspension point load and suspension point dynamometer diagram of the pumping unit based on the power curve on the motor input side.

[0006] Third, existing dynamometer card testing methods typically require the installation of load sensors at the pumping unit suspension rope or polished rod location, along with displacement or angular displacement sensors to acquire suspension point displacement data. While this method can directly obtain the dynamometer card, on-site installation and maintenance are relatively complex. The sensors are exposed to the oilfield environment for extended periods, making them susceptible to factors such as vibration, temperature, humidity, installation location, and mechanical shock, which limits the stability of the test and its long-term online application capability.

[0007] Fourth, the electromagnetic interference at the oilfield site is strong. The start-up and shutdown of pumping unit motors, the operation of frequency converters, long-distance communication lines, and the potential difference at the site can all affect the acquisition and communication circuits. If the electrical parameter acquisition device lacks communication isolation, power isolation, and analog-to-digital partitioning design, problems such as sampling data fluctuations, communication anomalies, data loss, and even main control circuit reset due to interference can easily occur.

[0008] Fifth, although some existing pumping unit monitoring systems can achieve remote data upload or operating parameter adjustment, the electrical parameter acquisition, parameter storage, communication isolation, power curve processing, suspension point dynamometer diagram inversion, and wellbore and pump basic parameter calculation are often independent of each other, resulting in low system integration. It is difficult to directly use the motor-side electrical parameters to complete the generation of the pumping unit suspension point dynamometer diagram, dynamic fluid level calculation, effective stroke calculation, and filling degree judgment.

[0009] Therefore, existing technologies still require a device and method for acquiring electrical parameters of pumping units and inverting suspension point dynamometer diagrams suitable for oilfield environments. Based on the acquisition of electrical parameters such as three-phase voltage, three-phase current, and active power, the device should continuously obtain the operating power curve of the pumping unit. Then, based on the single-cycle power curve, the parameters of the four-bar linkage mechanism of the pumping unit, and the crank balance parameters, the device should calculate the suspension point displacement, torque factor, and suspension point load to generate a suspension point dynamometer diagram. This would reduce the dependence on suspension point load sensors and displacement sensors, and provide a data foundation for pumping unit operation monitoring, energy consumption analysis, and well condition analysis. Summary of the Invention

[0010] In view of this, the present invention provides a device and method for acquiring electrical parameters and inverting the suspension point dynamometer diagram of a pumping unit. This device continuously acquires the three-phase voltage, three-phase current, and active power at the input side of the pumping unit motor to form the original power curve during pumping unit operation. Based on a preset or externally input number of single-cycle sampling points, the original power curve is periodically truncated, interpolated, smoothed, and the curve starting point is rearranged. The suspension point displacement and torque factor are calculated based on the geometric parameters of the pumping unit's four-bar linkage. The suspension point load is inverted based on the active power, pumping unit stroke rate, crank balance torque, torque factor, and load correction parameters. Finally, a suspension point dynamometer diagram is generated based on the suspension point displacement and suspension point load.

[0011] To achieve the above objectives, the present invention provides the following technical solution: A device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point includes: a three-phase voltage sampling module, a three-phase current sampling module, an energy metering module, a main control module, and a communication module; The three-phase voltage sampling module is connected to the three-phase power supply line of the pumping unit motor to collect three-phase voltage signals, and inputs the voltage sampling signals after proportional conversion, filtering and protection processing into the power metering module. The three-phase current sampling module is connected to the current sampling circuit set on the three-phase power supply line of the pumping unit motor. It is used to collect three-phase current signals and input the current sampling signals after sampling, filtering and protection processing into the power metering module. The power metering module is connected to the three-phase voltage sampling module, the three-phase current sampling module and the main control module respectively. It is used to obtain real-time electrical parameter data including at least active power based on the voltage sampling signal and the current sampling signal, and transmit the real-time electrical parameter data to the main control module. The main control module is the core of the device's data processing and control, including a timing acquisition unit, a power curve processing unit, a suspension point motion calculation unit, a suspension point load inversion unit, and a wellbore and oil pump basic parameter calculation unit; The timing acquisition unit is used to continuously read the active power output by the power metering module according to the preset sampling interval, and store multiple active power sampling points in the order of sampling time to form the original power curve; The power curve processing unit is used to extract one pumping unit operating cycle from the original power curve according to the preset or externally input single-cycle sampling point number, and to perform interpolation, smoothing and curve start-point rearrangement on the extracted power curve to obtain a standard single-cycle power curve with a uniform number of points. The suspension point motion calculation unit is used to calculate the suspension point displacement and torque factor based on the geometric parameters of the four-bar linkage of the pumping unit, the crank rotation direction, and the crank angle corresponding to each sampling point. The suspension point load inversion unit is used to convert the active power of each sampling point into crankshaft torque based on the standard single-cycle power curve and pumping unit stroke, and to calculate the suspension point load corresponding to each sampling point by combining the crank balance torque, torque factor and load correction parameters. The wellbore and pump foundation parameter calculation unit is used to generate a dynamometer diagram of the pumping unit suspension point with the suspension point displacement as the abscissa and the suspension point load as the ordinate. The communication module is connected to the main control module and the external terminal respectively, and is used to upload real-time electrical parameter data, power curve and suspension point dynamometer diagram data, and to receive operating parameters sent by the external terminal.

[0012] Optionally, the timing acquisition unit generates active power sampling cycles through a timer and stops the current acquisition after the number of active power sampling points reaches a preset number; the timer generates a timing signal every 2ms, and after accumulating 35 timing signals, a 70ms active power sampling interval is formed, and 500 active power sampling points are continuously acquired to form the original power curve.

[0013] Optionally, the power curve processing unit extracts one pumping unit operating cycle from the original power curve based on the number of sampling points per cycle, and uses linear interpolation to convert the extracted power curve into a standard single-cycle power curve including 150 power points and performs multi-point smoothing; the power curve processing unit is also used to calculate the power change rate between adjacent power points, and rearrange the starting point of the standard single-cycle power curve according to the power change rate and the power change characteristics of the pumping unit's upstroke and downstroke, to determine the upstroke interval and downstroke interval.

[0014] Optionally, the geometric parameters of the four-bar linkage of the pumping unit include at least one of the following: walking beam front arm length, walking beam rear arm length, connecting rod length, crank radius, horizontal dimension of the base rod, vertical dimension of the base rod, and crank offset angle; the suspension point motion calculation unit is used to establish the motion relationship of the four-bar linkage of the pumping unit based on the geometric parameters, and to calculate the walking beam swing angle, suspension point displacement, and torque factor corresponding to each sampling point within one cycle of crank rotation.

[0015] Optionally, the suspension point load inversion unit determines the crank angular velocity based on the pumping unit stroke, calculates the crankshaft torque based on the active power and crank angular velocity at each sampling point, calculates the crank balance torque varying with the crank angle based on the crank balance parameters, crank angle, and crank offset angle, and calculates the suspension point load based on the crankshaft torque, crank balance torque, torque factor, and load correction parameters. For the upstroke and downstroke, corresponding load correction parameters are used respectively. When the absolute value of the torque factor is less than a preset threshold or the change between adjacent suspension point loads exceeds a preset limit, at least one of linear interpolation, curve fitting, amplitude limiting, and smoothing processing is performed on the suspension point load in the corresponding sampling interval based on the adjacent effective suspension point load points and power change characteristics.

[0016] Optionally, the main control module also includes a well condition parameter calculation unit; the well condition parameter calculation unit is used to calculate at least one of the following based on the upper stroke load, lower stroke load and suspension point displacement characteristics in the suspension point indicator diagram, and in combination with pump diameter, oil pressure, casing pressure, water cut and friction load correction parameters: dynamic fluid level, effective stroke and filling degree.

[0017] Optionally, it also includes a parameter storage module, a local debugging module, and a power conversion and zoned power supply module connected to the main control module; the parameter storage module is used to store the geometric structure parameters, crank balance parameters, wellbore and pump basic parameters, communication parameters, sampling parameters, and power metering calibration parameters of the four-bar linkage of the pumping unit; the local debugging module is used to set parameters, read data, and debug the device through at least one of Bluetooth communication, serial communication, button or display module; the communication module adopts RS485 communication structure, and the communication data frame adopts CRC16 check method; the power conversion and zoned power supply module is used to provide working power to the three-phase voltage sampling module, three-phase current sampling module, power metering module, main control module, communication module, parameter storage module and local debugging module.

[0018] A method for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point includes the following steps: S1. Collect the three-phase voltage signal and three-phase current signal in the power supply line of the oil pumping unit motor, and obtain real-time electrical parameter data including at least active power based on the three-phase voltage signal and three-phase current signal. S2. Continuously read the active power according to the preset sampling interval, and store multiple active power sampling points in the order of sampling time to form the original power curve; S3. Based on the preset or externally input single-cycle sampling point number, extract one pumping unit operating cycle from the original power curve, and perform interpolation, smoothing, power change rate calculation and curve start-point rearrangement on the extracted power curve in sequence to obtain a standard single-cycle power curve with a uniform number of points, and determine the upstroke interval and downstroke interval. S4. Based on the geometric parameters of the four-bar linkage of the pumping unit, the crank rotation direction, and the crank angle corresponding to each sampling point, calculate the suspension point displacement and torque factor corresponding to each sampling point. S5. Determine the crank angular velocity based on the pumping unit stroke, convert the active power at each sampling point in the standard single-cycle power curve into crank shaft torque, calculate the crank balance torque based on the crank balance parameters, crank angle and crank offset angle, and calculate the suspension load corresponding to each sampling point by combining the crank shaft torque, crank balance torque, torque factor and load correction parameters. S6. When the absolute value of the torque factor is less than the preset threshold or the change between adjacent suspension point loads exceeds the preset limit, at least one of the following processes is performed on the suspension point load in the corresponding sampling interval: interpolation, fitting, amplitude limiting, and smoothing, based on the characteristics of adjacent effective suspension point loads and power changes. S7. Generate the dynamometer diagram of the pumping unit suspension point with the suspension point displacement as the abscissa and the suspension point load as the ordinate.

[0019] Optionally, in step S2, 500 active power sampling points are continuously collected at a sampling interval of 70 ms; in step S3, the truncated single-cycle power curve is converted into a standard single-cycle power curve including 150 power points by linear interpolation; the acquisition start command and operating parameters issued by the external terminal are received through RS485 communication with CRC16 verification, and at least one of the following is uploaded to the external terminal: real-time electrical parameter data, original power curve, standard single-cycle power curve, suspension point displacement, suspension point load, and suspension point dynamometer diagram data.

[0020] Optionally, after generating the suspension point indicator diagram, based on the upper stroke load, lower stroke load, and suspension point displacement characteristics in the suspension point indicator diagram, and combined with pump diameter, oil pressure, casing pressure, water content, and friction load correction parameters, at least one of the following can be calculated: dynamic fluid level, effective stroke, and degree of filling.

[0021] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a device and method for collecting electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point, which has the following beneficial effects: (1) The present invention can simultaneously collect electrical parameters such as three-phase voltage, three-phase current, active power, power factor, frequency and energy on the motor side of the beam pumping unit. Compared with manual inspection, single-point measurement by ordinary ammeter or ordinary energy meter, it can obtain more continuous and complete pumping unit operation electrical parameter data, providing a data basis for pumping unit operation status monitoring.

[0022] (2) This invention can not only collect real-time electrical parameters, but also continuously collect active power data during the operation of the pumping unit according to a set sampling period, forming a power curve within one or more operating cycles of the pumping unit. In this way, the periodic load change characteristics during the upstroke and downstroke of the pumping unit can be reflected, providing a basis for subsequent suspension point dynamometer inversion and well condition diagnosis.

[0023] (3) According to the preset or externally input single-cycle sampling point number, the present invention extracts one pumping unit operation cycle from the continuous power data, and converts the power curves of different cycle lengths into standard single-cycle power curves with a uniform number of points through interpolation, smoothing, power change rate calculation and curve start point rearrangement, thereby improving the data consistency of subsequent mechanism calculation and suspension load inversion.

[0024] (4) The present invention calculates the suspension point displacement and torque factor based on the geometric structural parameters of the four-bar linkage of the pumping unit, and inverses the suspension point load based on the active power on the input side of the motor, the pumping unit stroke, the crank balance torque, the torque factor and the load correction parameters, thereby generating a suspension point dynamometer diagram, which can reduce the dependence on suspension point load sensor and displacement sensor.

[0025] (5) The present invention can calculate at least one of the dynamic fluid level, effective stroke and fullness based on the upper stroke load, lower stroke load and suspension point displacement characteristics in the suspension point dynamometer diagram, and combined with pump diameter, oil pressure, casing pressure, water cut and friction load correction parameters, so as to provide a reference for the analysis of pumping unit operation status and well condition.

[0026] (6) The present invention adopts an isolated RS485 communication structure and performs CRC16 verification on the communication data frame, which can reduce the impact of electromagnetic interference, surge impact and ground potential difference on communication stability in the oil field and improve the reliability of long-distance data transmission.

[0027] (7) The present invention is equipped with a parameter storage module, which can save the device address, communication parameters, pumping unit structural parameters, wellbore and pump basic parameters, sampling parameters and calibration parameters. The key parameters are not lost after the device is powered off, which is beneficial for long-term operation and maintenance on site.

[0028] (8) The present invention adopts a partitioned power supply and isolation design for the analog sampling part, digital control part and communication part, which can reduce the interference of digital circuit and communication circuit on analog sampling signal, improve the stability of electrical parameter acquisition and the safety of device operation.

[0029] (9) This invention integrates electrical parameter acquisition, power curve acquisition, parameter storage, isolated communication, curve processing, suspension point dynamometer diagram inversion and wellbore and pump basic parameter calculation into the same device, which improves the system integration and facilitates installation, commissioning and application at the oilfield pumping unit site.

[0030] (10) The present invention can read real-time electrical parameters, power curves, suspension point dynamometer data and well condition calculation results through configuration screen, host computer or remote monitoring terminal, providing data support for digital management, remote monitoring and intelligent diagnosis of pumping unit. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is a block diagram of the overall structure of the pumping unit electrical parameter acquisition and suspension point dynamometer diagram inversion device provided by the present invention; Figure 2 This is a schematic diagram showing the connection between the three-phase voltage sampling module, the three-phase current sampling module, and the power metering module provided by the present invention. Figure 3This is a schematic diagram of the communication connection between the power metering module and the main control module provided by the present invention. Figure 4 This is a connection diagram of the main control module, parameter storage module, local debugging module and isolation communication module provided by the present invention. Figure 5 This is a schematic diagram of the power isolation module structure provided by the present invention; Figure 6 Flowchart of the method for electrical parameter acquisition and suspension point dynamometer diagram inversion provided by the present invention; Figure 7 A flowchart for single-cycle power curve truncation, interpolation, smoothing, and curve start point rearrangement provided by the present invention; Figure 8 The flowchart for suspension point motion calculation, suspension point load inversion, suspension point dynamometer diagram generation, and well condition analysis provided by this invention; Figure 9 This is a schematic diagram of the PCB board layout provided by the present invention; Figure 10 This is a schematic diagram of the physical structure of the device provided by the present invention. Detailed Implementation

[0033] 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.

[0034] Based on the analysis of the current situation, the research objectives of this technical solution are as follows: (1) Provides a device and method for acquiring electrical parameters of a pumping unit and inverting the dynamometer diagram of the suspension point, in order to solve the problem that existing pumping unit electrical parameter acquisition devices can usually only acquire basic electrical parameters such as voltage, current and power, and it is difficult to continuously obtain the power curve within the complete operating cycle of the pumping unit, and it is impossible to further invert the suspension point load, generate the suspension point dynamometer diagram and calculate the basic parameters of the wellbore and the pumping pump based on the electrical parameter data.

[0035] (2) By collecting electrical parameters such as three-phase voltage, three-phase current and active power on the motor side of the pumping unit, the operating power curve of the pumping unit is formed. Combined with the structural parameters of the pumping unit and the basic parameters of the wellbore and the pumping pump, the power curve is processed, the suspension point displacement is calculated, the suspension point load is inverted, the suspension point dynamometer diagram is generated, and the dynamic liquid level, effective stroke and fullness are calculated. This solves the problems of traditional pumping unit dynamometer diagram testing relying on load sensors and displacement sensors, complex on-site installation and maintenance, and long-term operation stability being greatly affected by the environment.

[0036] (3) By setting up isolated communication, parameter storage and partitioned power supply structure, the device’s acquisition stability, communication reliability and long-term operation adaptability in oilfield environment are improved, so as to solve the problem of insufficient stability of electrical parameter acquisition and data upload under the conditions of strong electromagnetic interference, long communication distance and obvious ground potential difference in oilfield.

[0037] Therefore, this invention discloses a device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point, such as... Figure 1 As shown, it includes: a three-phase voltage sampling module, a three-phase current sampling module, an energy metering module, a main control module, and a communication module.

[0038] like Figure 2 As shown, the three-phase voltage sampling module is connected to the three-phase power supply line of the pumping unit motor. It is used to collect three-phase voltage signals and input the voltage sampling signals, after proportional conversion, filtering, and protection processing, into the energy metering module. The three-phase voltage sampling module includes a voltage transformer, a current-limiting resistor, a filter capacitor, and a protection circuit. The three-phase voltage signal undergoes electrical isolation and proportional conversion through the voltage transformer, and then passes through the current-limiting circuit, filter circuit, and protection circuit to output the voltage sampling signal to the voltage sampling terminal of the energy metering module. The function of this module is to convert the high-voltage AC voltage of the pumping unit motor into a low-voltage sampling signal that the energy metering module can recognize, while simultaneously achieving isolation between the high-voltage side and the low-voltage acquisition side.

[0039] The three-phase current sampling module is connected to the current sampling circuit installed on the three-phase power supply line of the pumping unit motor. It is used to collect three-phase current signals and input the sampled, filtered, and protected current signals into the energy metering module. The three-phase current signals are introduced through a current transformer or current sampling interface, and after processing by sampling resistors, filtering circuits, and protection circuits, the current sampling signals are output to the current sampling terminal of the energy metering module. The function of this module is to obtain the three-phase operating current of the pumping unit motor, providing basic data for the calculation of active power, power factor, energy, and power curves.

[0040] like Figure 3 As shown, the energy metering module is connected to the three-phase voltage sampling module, the three-phase current sampling module, and the main control module, respectively. It is used to obtain real-time electrical parameter data such as active power, reactive power, apparent power, RMS voltage, RMS current, power factor, frequency, and energy based on the voltage and current sampling signals, and then transmits the real-time electrical parameter data to the main control module. In one embodiment, the energy metering module is implemented using a three-phase energy metering chip. The main control module is connected to the energy metering module via serial communication signal lines such as SCLK, DIN, DOUT, and CS, and reads the real-time electrical parameter data and active power data from the energy metering module according to a set timing sequence.

[0041] like Figure 4As shown, the main control module is the core of data processing and control in this device. It integrates a timing acquisition unit, a power curve processing unit, a suspension point motion calculation unit, a suspension point load inversion unit, and a wellbore and pump basic parameter calculation unit. It is used to complete system initialization, communication protocol parsing, data verification, parameter reading and saving, real-time electrical parameter reading, power curve acquisition, power curve processing, suspension point displacement calculation, suspension point load inversion, suspension point dynamometer diagram generation, and wellbore and pump basic parameter calculation. In one embodiment, the main control module is implemented using an STM32 series microcontroller.

[0042] The communication module is connected to the main control module and external terminals (such as external configuration screen, host computer, remote monitoring terminal or pumping unit controller) respectively. It adopts an electrical isolation architecture and is used to upload real-time electrical parameter data, power curve and suspension point dynamometer diagram data, and receive operating parameters sent by external terminals.

[0043] Furthermore, the timed acquisition unit, upon receiving a power curve acquisition start command from an external terminal, continuously reads the active power output by the power metering module according to a preset sampling interval, and stores multiple active power points in the order of sampling time to form the original power curve during the operation of the pumping unit. In one embodiment, the timed acquisition unit generates an active power sampling cycle through a timer, and stops the current acquisition after the number of active power sampling points reaches a preset number; the timer generates a timing signal every 2ms, and after accumulating 35 timing signals, a 70ms active power sampling interval is formed. After continuously acquiring 500 active power sampling points, the original power curve is formed. The above sampling interval, number of sampling points, and acquisition duration can also be set according to the pumping unit stroke, stroke, and field application requirements.

[0044] Furthermore, the power curve processing unit is used to extract one pumping unit operating cycle from the continuously acquired original power curve according to a preset or externally input single-cycle sampling point number, and to interpolate, smooth, and rearrange the starting points of the extracted power curve to obtain a standard single-cycle power curve with a uniform number of points. Specifically, the length and position of the data to be extracted are determined according to the single-cycle sampling point number, and the extracted single-cycle power data is converted into a standard single-cycle power curve with a uniform number of points using an interpolation method; the interpolated power curve is smoothed at multiple points to reduce sampling noise; the power change rate between adjacent power points is calculated, and the starting points of the standard single-cycle power curve are rearranged according to the power change rate, peaks, troughs, and power change characteristics of the pumping unit's upstroke and downstroke to determine the upstroke and downstroke intervals. In one embodiment, the original power curve includes 500 active power sampling points, and the extracted single-cycle power curve is converted into a 150-point standard single-cycle power curve through linear interpolation.

[0045] Furthermore, the suspension point motion calculation unit is used to calculate the suspension point displacement and torque factor based on the geometric parameters of the four-bar linkage of the pumping unit, the crank rotation direction, and the crank angle corresponding to each sampling point. The geometric parameters include the length of the walking beam front arm, the length of the walking beam rear arm, the connecting rod length, the crank radius, the horizontal dimension of the base rod, the vertical dimension of the base rod, and the crank offset angle. The suspension point motion calculation unit establishes the motion relationship of the four-bar linkage of the pumping unit based on the geometric parameters, calculates the walking beam swing angle and suspension point position corresponding to each sampling point within one crank rotation cycle, and obtains the suspension point displacement based on the difference between the suspension point position and the reference position; simultaneously, it calculates the torque factor corresponding to each crank angle position based on the geometric relationship of the four-bar linkage. The suspension point displacement serves as the abscissa of the suspension point dynamometer diagram, and the torque factor is used to convert the crankshaft torque into a suspension point load.

[0046] Furthermore, the suspension point load inversion unit is used to convert the active power of each sampling point into crankshaft torque based on the standard single-cycle power curve and the pumping unit stroke count. It then calculates the suspension point load corresponding to each sampling point by combining the crank balance torque, torque factor, and load correction parameters. The suspension point load inversion unit determines the crank angular velocity based on the pumping unit stroke count and calculates the corresponding crankshaft torque based on the active power and crank angular velocity at each sampling point. It calculates the crank balance torque that varies periodically with the crank angle based on the crank balance parameters, crank angle, suspension point dead point phase, and crank offset angle. It corrects the crankshaft torque using load correction parameters corresponding to the upstroke and downstroke strokes, respectively. Finally, it calculates the suspension point load corresponding to each sampling point based on the corrected crankshaft torque, crank balance torque, and torque factor.

[0047] When the absolute value of the torque factor is less than the preset threshold or the change between adjacent suspension point loads exceeds the preset limit, the torque conversion result of the corresponding sampling point is not directly used. Instead, based on the adjacent effective suspension point load points and power change characteristics, at least one of the following is performed on the suspension point load in the corresponding sampling interval: linear interpolation, curve fitting, amplitude limiting, and smoothing, in order to reduce the abnormal load caused by the small torque factor near the upper dead point and lower dead point.

[0048] The wellbore and pump foundation parameter calculation unit is used to generate a dynamometer diagram of the pumping unit suspension point with the suspension point displacement as the abscissa and the suspension point load as the ordinate.

[0049] The main control module also includes a well condition parameter calculation unit. This unit calculates at least one of the following based on the upstroke load, downstroke load, and suspension point displacement characteristics in the suspension point indicator diagram, combined with pump diameter, oil pressure, casing pressure, water cut, and friction load correction parameters: dynamic fluid level, effective stroke, and degree of filling. The well condition parameter calculation unit averages and corrects for the upstroke and downstroke loads and friction loads, calculates the plunger area based on the pump diameter, calculates the well fluid mixing density based on the water cut, and calculates the dynamic fluid level based on oil pressure and casing pressure. It also calculates the effective stroke based on the suspension point displacement difference between characteristic points in the suspension point indicator diagram and calculates the degree of filling based on the ratio between effective displacements in different directions.

[0050] Furthermore, the device also includes a parameter storage module connected to the main control module, used to store the geometric parameters of the four-bar linkage of the pumping unit, the crank balance parameters, the basic parameters of the wellbore and the pump, the communication parameters, the sampling parameters, and the power metering calibration parameters.

[0051] The geometric parameters include the length of the walking beam front arm, the length of the walking beam rear arm, the connecting rod length, the crank radius, the horizontal dimension of the base rod, the vertical dimension of the base rod, the crank offset angle, and the crank rotation direction; the crank balance parameters include the crank balance torque parameters; the wellbore and pump foundation parameters include the pump diameter, pipe diameter, casing diameter, oil pressure, casing pressure, water cut, pump depth, and friction load correction parameters; the communication parameters include the device address, baud rate, and data address; the sampling parameters include the pumping unit strokes, the number of sampling points per cycle, the power sampling interval, and the number of power sampling points; and the power metering calibration parameters include at least one of voltage gain, voltage bias, current gain, current bias, phase compensation, and power bias. The parameter storage module is used to save the above parameters after the device is powered off. In one embodiment, the parameter storage module uses an EEPROM memory and interacts with the main control module via an I²C bus.

[0052] Furthermore, this device also includes a local debugging module connected to the main control module, which allows field personnel to perform parameter setting, data reading, and program debugging operations via short-range communication methods (such as Bluetooth communication module, serial port debugging interface, buttons, or display module). Through the local debugging module, field personnel can read real-time electrical parameters, modify communication parameters, view acquisition status, or perform equipment debugging.

[0053] like Figure 5As shown, this device also includes a power conversion and zoned power supply module. This module includes at least one of an input protection circuit, a filtering circuit, a step-down circuit, an isolation power supply, and a multi-channel voltage regulator circuit, used to provide operating power to the three-phase voltage sampling module, the three-phase current sampling module, the energy metering module, the main control module, the communication module, the parameter storage module, and the local debugging module, respectively. The analog sampling section, the digital control section, and the communication section are arranged in zones and powered separately to reduce the impact of digital switching noise and communication interference on the voltage and current sampling signals.

[0054] Furthermore, the communication module adopts an RS485 communication structure. The main control module connects to the communication module via a serial communication interface, and the communication module connects to an external configuration panel, host computer, or remote monitoring terminal via RS485-A and RS485-B signal lines. The communication data frames use CRC16 checksum verification. The main control module verifies the device address, function code, data address, and checksum in the received data frame. After successful verification, it performs real-time data reading, parameter saving, power curve acquisition, or result uploading operations.

[0055] Furthermore, this embodiment also provides a method for acquiring electrical parameters of an oil pumping unit and inverting the dynamometer card at the suspension point. The complete overall process of electrical parameter acquisition and dynamometer card inversion is as follows: Figure 6 As shown, the power curve processing sub-process is as follows: Figure 7 As shown, the sub-process of suspension point motion-load inversion-well condition analysis is as follows: Figure 8 As shown. The specific steps are as follows: S1. Complete the power-on of the device and system initialization. Read the pre-stored parameters in the parameter storage module, including the geometric parameters of the pumping unit, the basic parameters of the wellbore and the pump, the communication parameters, the sampling parameters, the metering calibration parameters and the alarm thresholds. The system initialization includes: initialization of the main control chip, initialization of the power metering module, initialization of the parameter storage module, initialization of the isolation communication module and initialization of the timer.

[0056] The control module for the three-phase voltage sampling collects the voltage signals of phases A, B, and C of the three-phase power supply line of the pumping unit. After processing by electrical isolation, proportional conversion, current limiting circuit, filtering circuit, and protection circuit, the voltage sampling signal is output to the energy metering module. Simultaneously, the control module for the three-phase current sampling collects the current signals of phases A, B, and C of the pumping unit motor. After processing by sampling resistor, filtering circuit, and protection circuit, the current sampling signal is output to the energy metering module. The energy metering module completes sampling and metering of the two sampling signals and outputs real-time electrical parameter data such as active power, effective voltage value, effective current value, power factor, frequency, and energy to the main control module. The main control module reads the above data through a serial communication interface.

[0057] S2. The external terminal sends a power curve acquisition start command through the communication module. The communication module, which uses an isolated RS485 communication structure, performs CRC16 verification on the command communication data frame, sequentially verifying the device address, function code, register address, and check code. If the verification fails, the data frame is discarded. After successful verification, the main control module calls the internally integrated timing acquisition unit, clears the power curve array and resets the timing variable, and continuously reads the active power output by the power metering module according to the set sampling interval, storing all power points in the power curve array in chronological order. When the number of power points in the power curve array reaches the set value, the main control module stops the current power curve acquisition and sets the acquisition completion flag, obtaining the original power curve during the operation of the pumping unit.

[0058] S3. The main control module calls the power curve processing unit to extract one pumping unit operating cycle from the original power curve based on the preset or externally input single-cycle sampling point number. Subsequently, the main control module uses interpolation to convert the extracted single-cycle power curve into a standard single-cycle power curve with a uniform number of points, and performs multi-point smoothing on the interpolated power curve. It calculates the power change rate between adjacent power points, and based on the power change rate, peaks, troughs, and the power change characteristics of the pumping unit's upstroke and downstroke, rearranges the starting points of the standard single-cycle power curve to determine the upstroke and downstroke intervals. In one embodiment, the original power curve includes 500 active power sampling points, and the standard single-cycle power curve includes 150 power points.

[0059] S4. The main control module calls the suspension point motion calculation unit. The suspension point motion calculation unit establishes the motion relationship of the four-bar linkage of the pumping unit based on the length of the walking beam front arm, the length of the walking beam rear arm, the length of the connecting rod, the crank radius, the horizontal dimension of the base rod, the vertical dimension of the base rod, the crank offset angle, and the crank rotation direction. It calculates the walking beam swing angle, suspension point position, and torque factor based on the crank angle corresponding to each standard power point, and obtains the suspension point displacement based on the difference between the suspension point position and the reference position.

[0060] S5. The main control module calls the suspension point load inversion unit. The suspension point load inversion unit determines the crank angular velocity based on the pumping unit stroke, calculates the crankshaft torque based on the active power and crank angular velocity at each sampling point in the standard single-cycle power curve, calculates the crank balance torque based on the crank balance parameters, crank angle, suspension point dead point phase and crank offset angle, and calculates the suspension point load based on the crankshaft torque, crank balance torque and torque factor, respectively, using the load correction parameters corresponding to the upstroke and downstroke.

[0061] S6. When the absolute value of the torque factor is less than the preset threshold or the change between adjacent suspension point loads exceeds the preset limit, the main control module performs at least one of the following on the corresponding sampling interval based on the adjacent effective suspension point load points and power change characteristics: linear interpolation, curve fitting, amplitude limiting, and smoothing.

[0062] S7, the wellbore and pump foundation parameter calculation unit, uses the suspension point displacement as the abscissa and the suspension point load as the ordinate to generate the pumping unit suspension point dynamometer diagram.

[0063] The well condition parameter calculation unit calculates at least one of the following based on the upper stroke load, lower stroke load, and suspension point displacement characteristics in the suspension point indicator diagram, combined with pump diameter, oil pressure, casing pressure, water cut, and friction load correction parameters: dynamic fluid level, effective stroke, and degree of filling.

[0064] The main control module uploads at least one of the following to the external terminal via the communication module: real-time electrical parameter data, raw power curve, standard single-cycle power curve, suspension point displacement, suspension point load, suspension point dynamometer diagram, and well condition analysis results. After the external terminal issues a parameter modification command, the main control module performs device address, function code, data address, and CRC16 verification on the received data frame. After successful verification, it writes the updated geometric parameters of the pumping unit's four-bar linkage, crank balance parameters, load correction parameters, wellbore and pump foundation parameters, communication parameters, sampling parameters, or power metering calibration parameters into the parameter storage module.

[0065] like Figure 9 As shown, in one PCB implementation, a three-phase voltage sampling module, a three-phase current sampling module, an energy metering module, a main control module, a parameter storage module, an isolation communication module, a power isolation module, terminal blocks, and a communication interface are arranged on the same PCB board. The terminal blocks are located at the edge of the PCB board for easy connection to the three-phase voltage, current, and external lines; the communication interface is located on the side of the PCB board closer to the external communication connection for easy access to RS485 or a debugging interface; the power isolation module and the step-down module are located near the power input to reduce power supply noise and provide stable power to each functional module; the main control module, the energy metering module, and the sampling module maintain a relatively reasonable distance to reduce interference between strong and weak electrical signals.

[0066] like Figure 10 As shown, in a practical embodiment, the device of the present invention can be integrated into a pumping unit electrical parameter acquisition board or installed in a control box. In field use, the current sampling signals from the three-phase power supply line and the pumping unit motor are connected to the terminal block, and the configuration panel or host computer is connected to the isolated communication module via a communication interface. After power-on, the device can complete the acquisition of pumping unit electrical parameters, power curve acquisition, suspension point dynamometer diagram inversion, and uploading of basic parameters of the wellbore and pumping unit.

[0067] As an alternative technical solution, the main control module can use an STM32 series microcontroller, or other microcontrollers, digital signal processors, or embedded processors with timing acquisition, serial communication, and data processing capabilities. The energy metering module can use a 7022EU three-phase energy metering chip, or other energy metering chips capable of measuring three-phase voltage, current, power, power factor, and energy. The isolation communication module can use isolated RS485 communication, or CAN, Ethernet, wireless communication, or other industrial communication methods. The parameter storage module can use EEPROM, or Flash, ferroelectric memory, or other power-off retention memory. The sampling interval, number of sampling points, number of standard curve points, and number of segmented upload points can all be adjusted according to the stroke rate, stroke, and on-site communication conditions of different pumping unit models.

[0068] The meanings of the English abbreviations and special codes in this invention are as follows: RS485: A differential serial communication bus commonly used in industrial settings, suitable for data transmission over long distances; Modbus: An industrial communication protocol that can be used for data interaction between the main control module and the configuration panel, host computer or remote terminal. CRC16: 16-bit Cyclic Redundancy Check code, used for error detection in communication data frames; EEPROM: Electrically Erasable Programmable Read-Only Memory, used to retain parameters when power is off; MCU: Microcontroller Unit, also known as the main control chip; SPI: Serial Peripheral Interface, used for data communication between the main control module and the power metering module; I 2 C: Integrated circuit bus, used for data communication between the main control module and the parameter storage module; USART: Universal synchronous / asynchronous transceiver, used for serial communication between the main control module and the communication module; DC-DC: A direct current voltage conversion module used to achieve direct current voltage conversion or isolated power supply; PCB: Printed circuit board, used to carry and connect various electronic components; Phase A, Phase B, and Phase C: The three phase lines of a three-phase alternating current; Suspension point dynamometer diagram: A closed curve formed by the displacement of the pumping unit suspension point as the abscissa and the suspension point load as the ordinate, used to reflect the load and displacement changes of the ground suspension point of the pumping unit within one operating cycle; Torque factor: In the four-bar linkage of an oil pumping unit, it is a mechanism parameter used to represent the conversion relationship between the suspension point load and the crankshaft torque, and its value varies with the crank angle; Crank balancing torque: The balancing torque generated at the crankshaft by the crank balancing device of the pumping unit, which varies periodically with the crank angle; Load correction parameters: Parameters used to correct the influence of transmission efficiency, structural load, friction load, or field calibration deviation on the suspension point load inversion results.

[0069] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point, characterized in that, It includes a three-phase voltage sampling module, a three-phase current sampling module, an energy metering module, a main control module, and a communication module; The three-phase voltage sampling module is connected to the three-phase power supply line of the pumping unit motor to collect three-phase voltage signals, and inputs the voltage sampling signals after proportional conversion, filtering and protection processing into the power metering module. The three-phase current sampling module is connected to the current sampling circuit set on the three-phase power supply line of the pumping unit motor. It is used to collect three-phase current signals and input the current sampling signals after sampling, filtering and protection processing into the power metering module. The power metering module is connected to the three-phase voltage sampling module, the three-phase current sampling module and the main control module respectively. It is used to obtain real-time electrical parameter data including at least active power based on the voltage sampling signal and the current sampling signal, and transmit the real-time electrical parameter data to the main control module. The main control module includes a timing acquisition unit, a power curve processing unit, a suspension point motion calculation unit, a suspension point load inversion unit, and a wellbore and oil pump basic parameter calculation unit; The timing acquisition unit is used to continuously read the active power output by the power metering module according to the preset sampling interval, and store multiple active power sampling points in the order of sampling time to form the original power curve; The power curve processing unit is used to extract one pumping unit operating cycle from the original power curve according to the preset or externally input single-cycle sampling point number, and to perform interpolation, smoothing and curve start-point rearrangement on the extracted power curve to obtain a standard single-cycle power curve with a uniform number of points. The suspension point motion calculation unit is used to calculate the suspension point displacement and torque factor based on the geometric parameters of the four-bar linkage of the pumping unit, the crank rotation direction, and the crank angle corresponding to each sampling point. The suspension point load inversion unit is used to convert the active power of each sampling point into crankshaft torque based on the standard single-cycle power curve and pumping unit stroke, and to calculate the suspension point load corresponding to each sampling point by combining the crank balance torque, torque factor and load correction parameters. The wellbore and pump foundation parameter calculation unit is used to generate a dynamometer diagram of the pumping unit suspension point with the suspension point displacement as the abscissa and the suspension point load as the ordinate. The communication module is connected to the main control module and the external terminal respectively, and is used to upload real-time electrical parameter data, power curve and suspension point dynamometer diagram data, and to receive operating parameters sent by the external terminal.

2. The device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point according to claim 1, characterized in that, The timing acquisition unit generates active power sampling cycles through a timer and stops the current acquisition after the number of active power sampling points reaches a preset number. The timer generates a timing signal every 2ms, and after accumulating 35 timing signals, a 70ms active power sampling interval is formed. 500 active power sampling points are continuously acquired to form the original power curve.

3. The device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point according to claim 1, characterized in that, The power curve processing unit extracts one pumping unit operating cycle from the original power curve based on the number of sampling points per cycle. It then uses linear interpolation to convert the extracted power curve into a standard single-cycle power curve containing 150 power points and performs multi-point smoothing. The power curve processing unit also calculates the power change rate between adjacent power points and rearranges the starting points of the standard single-cycle power curve based on the power change rate and the power change characteristics of the pumping unit's upstroke and downstroke, thus determining the upstroke and downstroke intervals.

4. The device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point according to claim 1, characterized in that, The geometric parameters of the four-bar linkage of the pumping unit include at least one of the following: walking beam front arm length, walking beam rear arm length, connecting rod length, crank radius, horizontal dimension of the base rod, vertical dimension of the base rod, and crank offset angle; the suspension point motion calculation unit is used to establish the motion relationship of the four-bar linkage of the pumping unit based on the geometric parameters, and to calculate the walking beam swing angle, suspension point displacement, and torque factor corresponding to each sampling point within one cycle of crank rotation.

5. The device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point according to claim 1, characterized in that, The suspension point load inversion unit determines the crank angular velocity based on the pumping unit stroke, calculates the crankshaft torque based on the active power and crank angular velocity at each sampling point, calculates the crank balance torque varying with the crank angle based on the crank balance parameters, crank angle, and crank offset angle, and calculates the suspension point load based on the crankshaft torque, crank balance torque, torque factor, and load correction parameters. For the upstroke and downstroke, corresponding load correction parameters are used respectively. When the absolute value of the torque factor is less than a preset threshold or the change between adjacent suspension point loads exceeds a preset limit, at least one of linear interpolation, curve fitting, amplitude limiting, and smoothing processing is performed on the suspension point load in the corresponding sampling interval based on the adjacent effective suspension point load points and power change characteristics.

6. The device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point according to claim 1, characterized in that, The main control module also includes a well condition parameter calculation unit; the well condition parameter calculation unit is used to calculate at least one of the following based on the upper stroke load, lower stroke load and suspension point displacement characteristics in the suspension point indicator diagram, and in combination with pump diameter, oil pressure, casing pressure, water cut and friction load correction parameters: dynamic fluid level, effective stroke and filling degree.

7. The device for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point according to claim 1, characterized in that, It also includes a parameter storage module, a local debugging module, and a power conversion and zoned power supply module connected to the main control module. The parameter storage module is used to store the geometric structural parameters, crank balance parameters, wellbore and pump basic parameters, communication parameters, sampling parameters, and power metering calibration parameters of the four-bar linkage of the pumping unit. The local debugging module is used to set parameters, read data, and debug the device through at least one of Bluetooth communication, serial communication, button or display modules. The communication module adopts an RS485 communication structure, and the communication data frame adopts CRC16 verification. The power conversion and zoned power supply module is used to provide working power to the three-phase voltage sampling module, three-phase current sampling module, power metering module, main control module, communication module, parameter storage module, and local debugging module.

8. A method for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point, characterized in that, Includes the following steps: S1. Collect the three-phase voltage signal and three-phase current signal in the power supply line of the pumping unit motor, and obtain real-time electrical parameter data including at least active power based on the three-phase voltage signal and three-phase current signal. S2. Continuously read the active power according to the preset sampling interval, and store multiple active power sampling points in the order of sampling time to form the original power curve; S3. Based on the preset or externally input single-cycle sampling point number, extract one pumping unit operating cycle from the original power curve, and perform interpolation, smoothing, power change rate calculation and curve start-point rearrangement on the extracted power curve in sequence to obtain a standard single-cycle power curve with a uniform number of points, and determine the upstroke interval and downstroke interval. S4. Based on the geometric parameters of the four-bar linkage of the pumping unit, the crank rotation direction, and the crank angle corresponding to each sampling point, calculate the suspension point displacement and torque factor corresponding to each sampling point. S5. Determine the crank angular velocity based on the pumping unit stroke, convert the active power at each sampling point in the standard single-cycle power curve into crank shaft torque, calculate the crank balance torque based on the crank balance parameters, crank angle and crank offset angle, and calculate the suspension load corresponding to each sampling point by combining the crank shaft torque, crank balance torque, torque factor and load correction parameters. S6. When the absolute value of the torque factor is less than the preset threshold or the change between adjacent suspension point loads exceeds the preset limit, at least one of the following processes is performed on the suspension point load in the corresponding sampling interval: interpolation, fitting, amplitude limiting, and smoothing, based on the characteristics of adjacent effective suspension point loads and power changes. S7. Generate the dynamometer diagram of the pumping unit suspension point with the suspension point displacement as the abscissa and the suspension point load as the ordinate.

9. The method for acquiring electrical parameters of an oil pumping unit and inverting a suspension point dynamometer diagram according to claim 8, characterized in that, In step S2, 500 active power sampling points are continuously collected at a sampling interval of 70ms. In step S3, the truncated single-cycle power curve is converted into a standard single-cycle power curve including 150 power points by linear interpolation. The acquisition start command and operating parameters issued by the external terminal are received through RS485 communication with CRC16 verification, and at least one of the following is uploaded to the external terminal: real-time electrical parameter data, original power curve, standard single-cycle power curve, suspension point displacement, suspension point load, and suspension point dynamometer diagram data.

10. The method for acquiring electrical parameters of an oil pumping unit and inverting a dynamometer diagram at a suspension point according to claim 8, characterized in that, After generating the suspension point indicator diagram, based on the upper stroke load, lower stroke load, and suspension point displacement characteristics in the suspension point indicator diagram, and combined with pump diameter, oil pressure, casing pressure, water content, and friction load correction parameters, at least one of the following is calculated: dynamic fluid level, effective stroke, and degree of filling.

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