Electric submersible screw pump temperature control method and device for heavy oil well and medium

Abstract

The invention discloses an electric submersible screw pump temperature control method and device for a heavy oil well and a medium. The method comprises the steps that pressure data of downhole fluid of an electric submersible screw pump and current data of a downhole motor of the electric submersible screw pump are periodically collected; performing pressure feature recognition on the liquid supply state corresponding to the electric submersible screw pump to determine a first feed-forward compensation control signal; according to the current data, carrying out load characteristic identification on the electric submersible screw pump so as to determine a second feedforward compensation control signal; based on the real-time temperature data, the rotating speed of the motor is subjected to partition feedback correction, so that a first electric submersible screw pump rotating speed control signal is obtained; and performing feedforward compensation on the first electric submersible screw pump rotating speed control signal based on the first feedforward compensation control signal and / or the second feedforward compensation control signal to obtain a second electric submersible screw pump rotating speed control signal. By means of the method, the technical problem that an existing control method for the rotating speed of the motor of the heavy oil underground electric submersible screw pump cannot meet the requirement for dynamic balance of motor heat dissipation and output is solved.

Description

Technical Field

[0001] This application relates to the field of crude oil extraction technology, and in particular to a method, equipment and medium for temperature control of electric submersible screw pumps for heavy oil wells. Background Technology

[0002] Heavy oil resources account for a significant proportion of global oil and gas reserves. When using electric submersible screw pumps to lift heavy oil, the motor is typically located at the bottom of the unit, relying on well fluid flowing over its casing for cooling. The motor's heat dissipation efficiency directly depends on the fluid velocity and state flowing over its surface. In actual heavy oil well production, heavy oil has poor fluidity, and the resistance to its flow from the formation into the wellbore is high. The fluid velocity in the motor region within the wellbore is usually lower than the design critical value.

[0003] In existing technologies, for heavy oil well production, the pump speed is typically reduced to match the low fluid supply capacity of the formation. When the motor speed decreases, the screw pump's displacement decreases accordingly, and the fluid flow velocity across the motor surface also slows down. This reduction in motor speed further degrades the motor's heat dissipation performance. In other words, when the motor speed decreases, the low fluid production of the pump body results in insufficient fluid flow velocity on the motor surface, further affecting heat dissipation and causing the motor temperature to rise at low speeds. Chinese patent CN202411236309.0 discloses a downhole intelligent oil production pump and system. The motor drives the screw pump according to the operating parameters indicated by the control signal. The screw pump is used to pump oil-bearing fluid from the well through tubing, or to pump surface cleaning fluid into the well through tubing. The surface control cabinet receives coded data from the controller, monitors the downhole operating conditions, and controls the motor's operating status based on the monitoring results. However, in practical applications, this patent cannot dynamically control the motor temperature of the screw pump. Therefore, there is an urgent need for a temperature control method for electric submersible screw pumps in heavy oil wells that can provide real-time feedback on downhole motor temperature and fluid flow status, and dynamically adjust motor heat dissipation to balance the needs of heat dissipation and production. Summary of the Invention

[0004] This application provides a method, equipment, and medium for temperature control of electric submersible screw pumps in heavy oil wells, which solves the technical problem that the existing methods for controlling the motor speed of electric submersible screw pumps in heavy oil wells cannot meet the dynamic balance between motor heat dissipation and production.

[0005] In a first aspect, embodiments of this application provide a method for temperature control of an electric submersible pump (ESP) in heavy oil wells. The method comprises: periodically acquiring pressure data of the fluid at the bottom of the ESP well and current data of the ESP downhole motor; based on the pressure data, performing pressure feature identification on the fluid supply state corresponding to the ESP to determine a first feedforward compensation control signal; based on the current data, performing load feature identification on the ESP to determine a second feedforward compensation control signal; periodically acquiring real-time temperature data of the ESP downhole motor, and based on the real-time temperature data, performing zoned feedback correction on the motor speed to obtain a first ESP speed control signal; and performing feedforward compensation on the first ESP speed control signal based on the first feedforward compensation control signal and / or the second feedforward compensation control signal to obtain a second ESP speed control signal.

[0006] In one implementation of this application, periodically acquiring pressure data of the fluid at the bottom of the ESP pump and current data of the ESP pump's downhole motor specifically includes: periodically acquiring the static pressure parameters and dynamic pressure parameters of the fluid at the bottom of the ESP pump, and performing low-pass filtering on the static pressure parameters and dynamic pressure parameters to obtain pressure data; periodically acquiring the current signal of the ESP pump's downhole motor, and performing moving average filtering on the current signal to obtain current data.

[0007] In one implementation of this application, pressure feature identification is performed on the liquid supply state corresponding to the electric submersible screw pump based on pressure data to determine the first feedforward compensation control signal. Specifically, this includes: calculating the pressure change rate corresponding to the pressure data and determining a pressure change threshold based on the pressure change rate to determine the liquid supply state; wherein the types of liquid supply states include: liquid shortage and pump blockage; when the liquid supply state is liquid shortage, a corresponding speed adjustment curve is matched based on the pressure change rate, and a liquid shortage compensation control signal corresponding to the electric submersible screw pump is determined according to the speed adjustment curve; when the liquid supply state is pump blockage, the motor speed of the electric submersible screw pump is increased by a preset step size to obtain pressure feedback data during the motor speed increase; the pressure change trend of the pressure feedback data is judged, and if the pressure change trend is upward, overload protection is performed on the electric submersible screw pump; if the pressure change trend is downward, the motor speed of the electric submersible screw pump is increased by a step size until the pressure feedback data reaches a preset normal threshold, thereby determining the first feedforward compensation control signal.

[0008] In one implementation of this application, load characteristic identification is performed on the electric submersible screw pump based on current data to determine a second feedforward compensation control signal. Specifically, this includes: calculating the current standard deviation within a preset time window and detecting abnormal fluctuations in the current standard deviation to determine if the electric submersible screw pump is passing through an intermittent heavy oil section; wherein, abnormal fluctuations include: increased current fluctuation amplitude and low fluctuation frequency; when the electric submersible screw pump is passing through an intermittent heavy oil section, the minimum motor speed threshold of the electric submersible screw pump is increased until the abnormal fluctuations are eliminated, thus obtaining a speed threshold control compensation signal; the current data is detected... Based on the current overload state, the motor speed of the electric submersible screw pump is reduced by a preset step size to obtain current feedback data during the motor speed reduction period. The current change trend corresponding to the current feedback data is judged. If the current change trend is rising, the electric submersible screw pump is overload protected. If the current change trend is falling, the motor speed of the electric submersible screw pump is reduced by a preset step size until the current feedback data reaches a preset normal threshold, and the current feedback compensation signal is determined. Based on the speed threshold control compensation signal and the current feedback compensation signal, the second feedforward compensation control signal is determined.

[0009] In one implementation of this application, the motor speed is partitioned and feedback-corrected based on real-time temperature data to obtain a first electric submersible screw pump speed control signal. Specifically, this includes: partitioning the real-time temperature data to determine the correction threshold corresponding to the real-time temperature data; wherein the correction threshold includes a target temperature and a warning temperature; when the real-time temperature data is less than or equal to the target temperature, increasing the inverter output frequency of the electric submersible screw pump by a preset step size until a preset wellhead production target is reached, thus determining a first threshold speed control signal for the electric submersible screw pump; when the real-time temperature data is greater than or equal to the warning temperature, performing overload protection on the electric submersible screw pump; when the real-time temperature data is greater than the target temperature and less than the warning temperature, calculating the temperature difference between the real-time temperature data and the target temperature, and calculating the output term corresponding to the PID controller of the electric submersible screw pump based on the temperature difference; wherein the output term includes a proportional term, an integral term, and a derivative term; and superimposing the output term with the current speed of the electric submersible screw pump to obtain the first electric submersible screw pump speed control signal.

[0010] In one implementation of this application, the output term of the PID controller of the electric submersible screw pump is calculated based on the temperature difference value. Specifically, this includes: determining the proportional term by proportional gain processing based on the temperature difference value; calculating the integral value corresponding to the temperature difference value according to a preset integral coefficient to obtain the integral term; and calculating the differential value corresponding to the temperature difference value based on a preset differential coefficient to determine the differential term.

[0011] In one implementation of this application, a first electric submersible screw pump speed control signal is feedforward compensated based on a first feedforward compensation control signal and / or a second feedforward compensation control signal to obtain a second electric submersible screw pump speed control signal. Specifically, this includes: superimposing the first feedforward compensation control signal and / or the second feedforward compensation control signal with the first electric submersible screw pump speed control signal to obtain a feedforward compensated speed control signal; and applying speed limiting constraints to the feedforward compensated speed control signal to obtain the second electric submersible screw pump speed control signal.

[0012] In one implementation of this application, after performing feedforward compensation on the first electric submersible screw pump speed control signal based on the first feedforward compensation control signal and / or the second feedforward compensation control signal to obtain the second electric submersible screw pump speed control signal, the method further includes: sending the second electric submersible screw pump speed control signal to the control terminal of the electric submersible screw pump, and executing the second electric submersible screw pump speed control signal through the control terminal to obtain the speed update data of the electric submersible screw pump.

[0013] Secondly, embodiments of this application also provide a temperature control device for an electric submersible screw pump for heavy oil wells, characterized in that the device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to implement a temperature control method for an electric submersible screw pump for heavy oil wells.

[0014] Thirdly, embodiments of this application also provide a non-volatile computer storage medium for temperature control of an electric submersible screw pump for heavy oil wells, storing computer-executable instructions, characterized in that, when the computer-executable instructions are executed, they can realize a method for temperature control of an electric submersible screw pump for heavy oil wells.

[0015] This application provides a method, equipment, and medium for temperature control of an electric submersible screw pump in heavy oil wells. By acquiring the downhole fluid pressure and operating parameters of the electric submersible screw pump in real time, and performing parallel processing of feedforward compensation control signals and speed control signals, it solves the technical problem that the existing control methods for the motor speed of electric submersible screw pumps in heavy oil wells cannot meet the dynamic balance between motor heat dissipation and production. It realizes feedforward compensation for the adjustment of the electric submersible screw pump motor speed, improves the rationality of the allocation between motor heat dissipation and speed requirements, and reduces the probability of overheating of the electric submersible screw pump motor. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A flowchart illustrating a method for temperature control of an electric submersible screw pump in a heavy oil well, as provided in this application embodiment; Figure 2 This is a schematic diagram of the internal structure of an electric submersible screw pump temperature control device for heavy oil wells, provided as an embodiment of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] This application provides a method, equipment, and medium for temperature control of an electric submersible screw pump in heavy oil wells. By acquiring the downhole fluid pressure and operating parameters of the electric submersible screw pump in real time, and performing parallel processing of feedforward compensation control signals and speed control signals, it solves the technical problem that the existing control methods for the motor speed of electric submersible screw pumps in heavy oil wells cannot meet the dynamic balance between motor heat dissipation and production. It realizes feedforward compensation for the adjustment of the electric submersible screw pump motor speed, improves the rationality of the allocation between motor heat dissipation and speed requirements, and reduces the probability of overheating of the electric submersible screw pump motor.

[0019] The technical solutions proposed in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0020] Figure 1 This is a flowchart illustrating a method for temperature control of an electric submersible screw pump in a heavy oil well, as provided in an embodiment of this application. Figure 1 As shown in the figure, the temperature control method for an electric submersible screw pump in a heavy oil well provided in this application embodiment specifically includes the following steps: Step 101: Periodically collect pressure data of the fluid at the bottom of the ESP pump and current data of the ESP pump's downhole motor.

[0021] For example, bottomhole fluid pressure data typically includes static pressure representing the fluid level and dynamic pressure reflecting the dynamics of viscous fluids, while the current data of the downhole motor of an electric submersible screw pump mainly represents the motor's load fluctuations. Since signal acquisition in heavy oil wells requires noise filtering, low-pass filtering is needed for static and dynamic pressure parameters, and moving average filtering is used for current signals to preserve pressure and current characteristics.

[0022] Specifically, the pressure data of the fluid at the bottom of the ESP pump and the current data of the ESP pump's downhole motor are periodically acquired, including: periodically acquiring the static pressure parameters and dynamic pressure parameters of the fluid at the bottom of the ESP pump, and performing low-pass filtering on the static pressure parameters and dynamic pressure parameters to obtain pressure data; periodically acquiring the current signal of the ESP pump's downhole motor, and performing moving average filtering on the current signal to obtain current data.

[0023] In one embodiment, the static and dynamic pressure parameters of the fluid at the bottom of the electric submersible screw pump, which are periodically acquired, change relatively slowly. Conventional RC low-pass filtering can effectively filter out high-frequency turbulence noise, and in the process of filtering out noise, the overall trend of pressure decrease or increase can be preserved.

[0024] It is important to note that for static and dynamic pressure parameters, the filter intensity should not be too high to avoid losing the characteristics of rapid pressure changes and causing a lag in the feedforward compensation response.

[0025] Furthermore, for the current signal of the downhole motor of the ESP (Electric Submersible Pump) acquired periodically, it is necessary to identify its fluctuation amplitude and frequency in order to determine situations such as low-frequency large fluctuations caused by pumping heavy oil. Therefore, the current signal can be denoised by using a moving average filter, which can effectively eliminate high-frequency random noise while preserving the signal shape and amplitude.

[0026] Step 102: Based on the pressure data, perform pressure feature identification on the liquid supply status corresponding to the electric submersible screw pump to determine the first feedforward compensation control signal.

[0027] For example, the feedforward compensation control signal is used to adjust the speed in advance based on the preceding indicators of pressure and current before the motor temperature changes, in order to achieve a more suitable speed or temperature requirement. Regarding pressure data, this application identifies the pressure characteristics of the fluid supply state corresponding to the electric submersible screw pump, analyzes the abnormal fluid supply caused by rapid decreases and increases in the pressure of the bottom-hole fluid corresponding to the electric submersible screw pump, and realizes the generation of compensation control signals for the abnormal fluid supply portion of the electric submersible screw pump.

[0028] Specifically, based on pressure data, pressure characteristics are identified for the fluid supply status corresponding to the electric submersible screw pump to determine the first feedforward compensation control signal. This includes: calculating the pressure change rate corresponding to the pressure data and determining a pressure change threshold based on the pressure change rate to determine the fluid supply status; the types of fluid supply status include: fluid shortage and pump blockage; when the fluid supply status is fluid shortage, the corresponding speed adjustment curve is matched based on the pressure change rate, and the fluid shortage compensation control signal corresponding to the electric submersible screw pump is determined according to the speed adjustment curve; when the fluid supply status is pump blockage, the motor speed of the electric submersible screw pump is increased by a preset step size to obtain pressure feedback data during the motor speed increase; the pressure change trend of the pressure feedback data is judged, and if the pressure change trend is rising, overload protection is provided for the electric submersible screw pump; if the pressure change trend is falling, the motor speed of the electric submersible screw pump is increased by a step size until the pressure feedback data reaches a preset normal threshold, thus determining the first feedforward compensation control signal.

[0029] In one embodiment, in the liquid supply state corresponding to the electric submersible screw pump, the abnormal state can be determined by calculating the pressure change rate corresponding to the pressure data.

[0030] If the inlet pressure drops continuously within a short period, it indicates a fluid shortage, posing a risk of fluid shortage to the electric submersible screw pump. This corresponds to a weakening of the formation's fluid supply capacity or a drop in the wellbore fluid level. Even if the pump motor temperature is within the normal range, it will still trigger an active speed reduction demand.

[0031] The motor speed is reduced according to a smooth deceleration curve (the step size can be adjusted according to the pump parameters). The purpose is to reduce the pump's displacement, wait for the liquid level to recover, and prevent the flow velocity on the motor surface from slowing down further due to pump cavitation. The speed reduction is related to the rate and magnitude of pressure drop. The faster and greater the pressure drop, the more the motor needs to reduce its speed.

[0032] Furthermore, if the inlet pressure rises abnormally in a short period of time and the rate of increase exceeds the safety threshold (the safety threshold for the rate of increase can be adjusted according to the pump body parameters), it is determined that there may be a blockage at the pump suction end, or that a high-viscosity heavy oil section has suddenly entered, resulting in a sharp increase in flow resistance.

[0033] Due to the risk of pump blockage, directly reducing the motor rotation speed of the electric submersible screw pump may exacerbate the blockage problem. Therefore, this application adopts a trial-and-error speed increase method, which rapidly increases the motor speed with a small preset step size. By utilizing the pump's suction force to break through the blockage or push out the heavy oil section, the risk of pump blockage is gradually eliminated.

[0034] During the gradual increase of motor speed, the inlet pressure is monitored simultaneously. If the inlet pressure begins to decrease, it indicates that the increase in motor speed can break through the blockage or push out the heavy oil section, reducing the blockage. Conversely, if the inlet pressure begins to rise and the motor current also increases due to blockage, the system immediately switches to motor overload protection mode. This protection mode is used to prevent motor overload and can be implemented through extreme speed reduction or shutdown alarm.

[0035] Step 103: Based on the current data, identify the load characteristics of the electric submersible screw pump to determine the second feedforward compensation control signal.

[0036] For example, the feedforward compensation control signal is used to adjust the speed in advance based on leading indicators of pressure and current before the motor temperature changes, in order to achieve a more suitable speed or temperature requirement. This application realizes the generation of compensation control signals for abnormal load parts of the electric submersible screw pump by identifying the load characteristics of the pump and analyzing current fluctuations and continuous abnormal values.

[0037] Specifically, based on the current data, load characteristics of the electric submersible screw pump are identified to determine the second feedforward compensation control signal. This includes: calculating the current standard deviation of the current data within a preset time window and detecting abnormal fluctuations in the current standard deviation to determine if the electric submersible screw pump is passing through an intermittent heavy oil section; where abnormal fluctuations include: increased current fluctuation amplitude and low fluctuation frequency; when the electric submersible screw pump is passing through an intermittent heavy oil section, the minimum motor speed threshold of the electric submersible screw pump is increased until the abnormal fluctuations are eliminated, thus obtaining a speed threshold control compensation signal; detecting the current overload status of the current data, and based on the current overload status, reducing the motor speed of the electric submersible screw pump by a preset step size to obtain current feedback data during the motor speed reduction period; judging the current change trend corresponding to the current feedback data, and if the current change trend is increasing, overload protection is provided for the electric submersible screw pump; if the current change trend is decreasing, the motor speed of the electric submersible screw pump is reduced by a step size until the current feedback data reaches a preset normal threshold, thus determining the current feedback compensation signal; and determining the second feedforward compensation control signal based on the speed threshold control compensation signal and the current feedback compensation signal.

[0038] In one embodiment, by performing time-domain analysis on the current signal, the current standard deviation within the corresponding time window is calculated, and abnormal fluctuations in the current standard deviation are detected. When a significant increase in the current fluctuation amplitude and a low fluctuation frequency are detected, it is determined that an intermittent heavy oil section is passing through the electric submersible screw pump.

[0039] During the passage of intermittent heavy oil through the ESP (Electric Submersible Screw Pump), the flow rate can be accelerated by increasing the motor speed. However, considering that excessive motor speed can also cause motor temperature to rise, this application adopts an increased minimum motor speed threshold to ensure that the ESP has sufficient energy to push the intermittent heavy oil section without causing the motor temperature to become too high. This prevents the intermittent heavy oil section from accumulating on the motor surface or inside the pump. After the current fluctuation returns to normal (the current standard deviation falls back to within the preset threshold range), the lower limit of the motor speed smoothly returns to the original set value.

[0040] Furthermore, the current overload status of the detected current data is determined, and based on the current overload status, the motor speed of the electric submersible screw pump is reduced by a preset step size to obtain current feedback data during the motor speed reduction period.

[0041] After determining that a continuous overload state has been entered, the motor will not immediately reduce its speed drastically. Instead, it will reduce its speed in a step-by-step manner with preset small steps. The speed reduction step can be set to 2% to 5% of the current operating speed. After each speed reduction step is completed, a fixed observation and waiting period is adopted. The waiting time is usually set to 30 to 60 seconds to balance the time delay of the downhole fluid flowing from the pump outlet to the motor surface and the response lag of the temperature sensor.

[0042] The current is compared with the reference current before the speed reduction. If a significant downward trend in the current is detected, it is determined that the current overload is mainly caused by excessive fluid viscosity, and the motor speed reduction is effective. Based on this speed, the next step of speed reduction is executed, and the step-by-step speed reduction is repeated until the current falls back to the safe range, at which point the second feedforward compensation control signal is determined.

[0043] Furthermore, once the current returns to a safe range, maintain the motor speed at a stable rate and continue to check the wellhead fluid production and motor temperature.

[0044] Step 104: Periodically collect real-time temperature data of the downhole motor of the electric submersible screw pump, and based on the real-time temperature data, perform zoned feedback correction on the motor speed to obtain the first electric submersible screw pump speed control signal.

[0045] For example, by using the real-time temperature data of the motor, it is possible to intuitively determine whether the motor is overheating. Based on the real-time temperature data, this application performs zoned feedback correction on the motor speed, thereby achieving preliminary control of the motor at the current temperature and ensuring that the motor can be maintained within a safe operating temperature range.

[0046] Specifically, based on real-time temperature data, the motor speed is partitioned and feedback corrected to obtain the first electric submersible screw pump speed control signal. This includes: partitioning the real-time temperature data to determine the correction threshold corresponding to the real-time temperature data; the correction threshold includes: target temperature and warning temperature; when the real-time temperature data is less than or equal to the target temperature, increasing the inverter output frequency of the electric submersible screw pump by a preset step size until a preset wellhead production target is reached, thus determining the first threshold speed control signal of the electric submersible screw pump; when the real-time temperature data is greater than or equal to the warning temperature, performing overload protection on the electric submersible screw pump; when the real-time temperature data is greater than the target temperature and less than the warning temperature, calculating the temperature difference between the real-time temperature data and the target temperature, and calculating the output term corresponding to the PID controller of the electric submersible screw pump based on the temperature difference; the output term includes: proportional term, integral term, and derivative term; and superimposing the output term with the current speed of the electric submersible screw pump to obtain the first electric submersible screw pump speed control signal.

[0047] Furthermore, based on the temperature difference, the output term corresponding to the PID controller of the electric submersible screw pump is calculated, specifically including: determining the proportional term based on the temperature difference through proportional gain processing; calculating the integral value corresponding to the temperature difference according to the preset integral coefficient to obtain the integral term; and calculating the differential value corresponding to the temperature difference according to the preset differential coefficient to determine the differential term.

[0048] In one embodiment, the real-time collected motor temperature data is first subjected to feedback partitioning processing, and the control range of the current temperature is determined according to a preset temperature threshold. The correction threshold includes, but is not limited to, the target temperature and the warning temperature. The target temperature is usually set as the lower limit of the motor's rated operating temperature or the economic operating temperature. The warning temperature can be obtained by subtracting a safety margin from the highest continuous operating temperature allowed by the motor's insulation class, and is used to indicate the critical state where enhanced heat dissipation is required.

[0049] When the real-time temperature data is less than or equal to the target temperature, it is determined that the motor heat dissipation is sufficient. The production demand is adjusted first, and the frequency of the inverter of the electric submersible screw pump is gradually increased by a preset step size, thereby increasing the motor speed.

[0050] After the motor speed is increased, the rate of change of motor temperature is monitored. If the motor temperature does not show a rapid upward trend and the wellhead production has not reached the preset target, the speed increase process will be repeated until the set maximum speed limit or wellhead production target is reached, thereby determining the first threshold speed control signal at this time.

[0051] When the real-time temperature data is greater than or equal to the warning temperature, the motor is determined to be in an overheating risk state, and the overload protection logic is immediately triggered. In this state, the motor is driven to run at a preset safe forced cooling speed, forcibly increasing the fluid velocity flowing over the motor surface to quickly cool it down. After the temperature drops below the target temperature and remains stable for a period of time, the protection mode is exited.

[0052] When the real-time temperature data is greater than the target temperature but less than the warning temperature, the system enters the dynamic balance adjustment zone and activates the PID controller for fine feedback correction. First, the temperature difference between the real-time temperature and the target temperature is calculated; this temperature difference is used as the input to the PID controller.

[0053] Based on the temperature difference, the three output terms of the PID controller are calculated as follows: the proportional term, which is obtained by processing the temperature difference with proportional gain and is used to respond quickly to the current deviation; the integral term, which calculates the cumulative amount of the temperature difference over time according to the preset integral coefficient and is used to eliminate long-term steady-state errors; and the derivative term, which calculates the rate of change of the temperature difference based on the preset derivative coefficient and is used to apply adjustment in advance according to the temperature change trend to suppress temperature fluctuations.

[0054] Summing the proportional, integral, and derivative terms yields the total output correction of the PID controller. This correction is then superimposed on the current speed of the electric submersible screw pump to obtain the dynamically adjusted first electric submersible screw pump speed control signal. This application achieves a dynamic balance between heat dissipation and lifting efficiency by continuously fine-tuning the motor temperature to maintain it consistently near the target temperature.

[0055] Furthermore, the specific implementation method for calculating each output term of the PID controller based on the temperature difference is as follows: the proportional term is obtained by multiplying the temperature difference by the proportional gain coefficient, and the value of the proportional gain coefficient can be preset according to the thermal response characteristics of the motor and the actual sensitivity requirements.

[0056] The integral term is obtained by integrating the temperature difference over time and then multiplying it by the integration coefficient. The integration operation is implemented by accumulating at discrete sampling points using a numerical integration method. The integration coefficient determines the correction strength for the accumulated deviation. The differential term is obtained by calculating the rate of change of the temperature difference at the current moment and then multiplying it by the differential coefficient. The rate of change is approximately calculated by dividing the difference between the current sample value and the previous sample value by the sampling period. Its differential coefficient is used to adjust the response strength to the temperature change trend.

[0057] Step 105: Based on the first feedforward compensation control signal and / or the second feedforward compensation control signal, perform feedforward compensation on the first electric submersible screw pump speed control signal to obtain the second electric submersible screw pump speed control signal.

[0058] Specifically, based on the first feedforward compensation control signal and / or the second feedforward compensation control signal, the first electric submersible screw pump speed control signal is fedforward compensated to obtain the second electric submersible screw pump speed control signal. This specifically includes: superimposing the first feedforward compensation control signal and / or the second feedforward compensation control signal with the first electric submersible screw pump speed control signal to obtain a feedforward compensated speed control signal; and applying speed limiting constraints to the feedforward compensated speed control signal to obtain the second electric submersible screw pump speed control signal.

[0059] Furthermore, after performing feedforward compensation on the first electric submersible screw pump speed control signal based on the first feedforward compensation control signal and / or the second feedforward compensation control signal to obtain the second electric submersible screw pump speed control signal, the method further includes: sending the second electric submersible screw pump speed control signal to the control terminal of the electric submersible screw pump, and executing the second electric submersible screw pump speed control signal through the control terminal to obtain the speed update data of the electric submersible screw pump.

[0060] In one embodiment, firstly, compensation signals from different feedforward logic modules are received simultaneously in each control cycle. The first feedforward compensation control signal is triggered by the inlet pressure change rate to deal with abnormal liquid supply (such as the risk of liquid shortage or pump blockage). The second feedforward compensation control signal is triggered by the motor current fluctuation characteristics to deal with sudden load changes (such as the passage of heavy oil section or continuous overload). The two feedforward compensation signals exist in the form of dynamic bias, which is numerically represented as a positive value (speed increase) or a negative value (speed decrease). Its amplitude is determined according to the specific operating conditions. The first electric submersible screw pump speed control signal generated by feedback control is received. This signal is a basic speed command obtained after fine adjustment of the motor real-time temperature by PID.

[0061] Then, by signal superposition, the above-mentioned feedforward compensation signal and the first speed control signal are algebraically superimposed to form the feedforward compensation speed control signal. If a certain feedforward signal is not triggered, its corresponding compensation amount is zero.

[0062] To ensure that the superimposed result does not cause the speed command to exceed the safe operating range of the equipment, a speed limit constraint is imposed on the feedforward compensation speed control signal. The speed limit includes an upper limit constraint and a lower limit constraint: the upper limit constraint is typically set to 90% to 100% of the motor's rated maximum speed to prevent damage to the equipment from overspeed operation; the lower limit constraint is set to a minimum allowable speed based on well conditions to avoid excessively low speeds leading to poor heat dissipation or insufficient pump efficiency. After amplitude limiting processing, the second electric submersible screw pump speed control signal is obtained.

[0063] Furthermore, after generating the second electric submersible screw pump speed control signal, this signal is sent to the ground-based frequency converter control terminal of the electric submersible screw pump via a fieldbus or analog output channel. Upon receiving the speed command, the frequency converter adjusts the output frequency and voltage according to the command value, driving the downhole motor to rotate at the target speed. The actual speed feedback, current, temperature, and other data during motor operation are continuously collected and compared with the command values ​​to form a closed-loop monitoring system.

[0064] Furthermore, if excessive speed deviation or equipment malfunction is detected during execution, the protection logic is re-triggered to ensure the safety of the entire control process.

[0065] The above are embodiments of the method proposed in this application. Based on the same inventive concept, embodiments of this application also provide a temperature control device for an electric submersible screw pump for heavy oil wells, the structure of which is as follows: Figure 2 As shown.

[0066] Figure 2 This is a schematic diagram of the internal structure of an electric submersible screw pump temperature control device for heavy oil wells, provided as an embodiment of this application. Figure 2 As shown, the device includes: at least one processor 201; and a memory 202 communicatively connected to the at least one processor; wherein the memory 202 stores instructions executable by the at least one processor, which are executed by the at least one processor 201 to enable the at least one processor 201 to implement a method for temperature control of an electric submersible screw pump for heavy oil wells.

[0067] Some embodiments of this application provide corresponding to Figure 1 A non-volatile computer storage medium for temperature control of an electric submersible screw pump in heavy oil wells, storing computer-executable instructions that, when executed, enable a temperature control method for an electric submersible screw pump in heavy oil wells.

[0068] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments for IoT devices and media are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0069] The systems, media, and methods provided in this application are one-to-one correspondences. Therefore, the systems and media also have similar beneficial technical effects as their corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the systems and media will not be repeated here.

[0070] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0071] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0072] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0073] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0074] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0075] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0076] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage, other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0077] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0078] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for temperature control of an electric submersible screw pump for heavy oil wells, characterized in that, The method includes: Periodically collect pressure data of the fluid at the bottom of the electric submersible screw pump and current data of the downhole motor of the electric submersible screw pump; Based on the pressure data, pressure characteristics are identified for the liquid supply state corresponding to the electric submersible screw pump to determine the first feedforward compensation control signal. Based on the current data, the load characteristics of the electric submersible screw pump are identified to determine the second feedforward compensation control signal; Real-time temperature data of the downhole motor of the electric submersible screw pump is periodically collected, and the motor speed is corrected by partition feedback based on the real-time temperature data to obtain the first electric submersible screw pump speed control signal; Based on the first feedforward compensation control signal and / or the second feedforward compensation control signal, the first electric submersible screw pump speed control signal is fedforward compensated to obtain the second electric submersible screw pump speed control signal.

2. The method for temperature control of an electric submersible screw pump for heavy oil wells according to claim 1, characterized in that, Periodically collect pressure data of the fluid at the bottom of the ESP pump and current data of the ESP pump's downhole motor, specifically including: The static pressure and dynamic pressure parameters of the fluid at the bottom of the electric submersible screw pump are periodically collected, and the static pressure and dynamic pressure parameters are low-pass filtered to obtain the pressure data. The current signal of the downhole motor of the electric submersible screw pump is periodically acquired, and the current signal is processed by moving average filtering to obtain the current data.

3. The method for temperature control of an electric submersible screw pump for heavy oil wells according to claim 1, characterized in that, Based on the pressure data, pressure characteristics are identified for the fluid supply status corresponding to the electric submersible screw pump to determine the first feedforward compensation control signal, specifically including: Calculate the pressure change rate corresponding to the pressure data, and determine the pressure change threshold based on the pressure change rate to determine the liquid supply status; wherein, the types of liquid supply status include: liquid shortage, pump blockage; When the liquid supply state is in the case of liquid shortage, based on the pressure change rate, a corresponding speed adjustment curve is matched, and the liquid shortage compensation control signal corresponding to the electric submersible screw pump is determined according to the speed adjustment curve. When the pump is blocked in the liquid supply state, the motor speed of the electric submersible screw pump is increased by a preset step size to obtain pressure feedback data during the motor speed increase. Determine the pressure change trend of the pressure feedback data, and if the pressure change trend is upward, perform overload protection on the electric submersible screw pump; When the pressure change trend is decreasing, the motor speed of the electric submersible screw pump is increased by the step size until the pressure feedback data reaches the preset normal threshold, and the first feedforward compensation control signal is determined.

4. The method for temperature control of an electric submersible screw pump for heavy oil wells according to claim 1, characterized in that, Based on the current data, load characteristic identification is performed on the electric submersible screw pump to determine the second feedforward compensation control signal, specifically including: The standard deviation of the current data within a preset time window is calculated, and abnormal fluctuations in the standard deviation are detected to determine whether the electric submersible screw pump is passing through an intermittent heavy oil section; wherein, the abnormal fluctuations include: increased current fluctuation amplitude and low fluctuation frequency; When the electric submersible screw pump passes through an intermittent heavy oil section, the minimum speed threshold of the electric submersible screw pump motor is increased until the fluctuation abnormality is eliminated, thereby obtaining a speed threshold control compensation signal; The current overload status of the current data is detected, and based on the current overload status, the motor speed of the electric submersible screw pump is reduced by a preset step size to obtain current feedback data during the reduction of the motor speed. Determine the current change trend corresponding to the current feedback data, and if the current change trend is upward, perform overload protection on the electric submersible screw pump; When the current change trend is decreasing, the motor speed of the electric submersible screw pump is reduced by the step size until the current feedback data reaches the preset normal threshold, and the current feedback compensation signal is determined. The second feedforward compensation control signal is determined based on the speed threshold control compensation signal and the current feedback compensation signal.

5. The method for temperature control of an electric submersible screw pump for heavy oil wells according to claim 1, characterized in that, Based on the real-time temperature data, the motor speed is corrected by zonal feedback to obtain the first electric submersible screw pump speed control signal, specifically including: The real-time temperature data is partitioned into feedback zones to determine the correction thresholds corresponding to the real-time temperature data; wherein the correction thresholds include: target temperature and warning temperature. When the real-time temperature data is less than or equal to the target temperature, the frequency of the inverter of the electric submersible screw pump is increased by a preset step size until the preset wellhead production target is reached, and the first threshold speed control signal of the electric submersible screw pump is determined. If the real-time temperature data is greater than or equal to the warning temperature, the electric submersible screw pump will be overload protected. When the real-time temperature data is greater than the target temperature and less than the warning temperature, the temperature difference between the real-time temperature data and the target temperature is calculated, and based on the temperature difference, the output term corresponding to the PID controller of the electric submersible screw pump is calculated; wherein, the output term includes: proportional term, integral term, and derivative term; The output item is superimposed with the current speed of the electric submersible screw pump to obtain the speed control signal of the first electric submersible screw pump.

6. The method for temperature control of an electric submersible screw pump for heavy oil wells according to claim 5, characterized in that, Based on the temperature difference, the output term corresponding to the PID controller of the electric submersible screw pump is calculated, specifically including: Based on the temperature difference value, the proportional term is determined through proportional gain processing; The integral value corresponding to the temperature difference is calculated according to the preset integral coefficient to obtain the integral term; Based on the preset differential coefficients, the differential value corresponding to the temperature difference is calculated, and the differential term is determined.

7. The method for temperature control of an electric submersible screw pump for heavy oil wells according to claim 1, characterized in that, Based on the first feedforward compensation control signal and / or the second feedforward compensation control signal, feedforward compensation is performed on the first electric submersible screw pump speed control signal to obtain the second electric submersible screw pump speed control signal, specifically including: The first feedforward compensation control signal and / or the second feedforward compensation control signal are superimposed with the first electric submersible screw pump speed control signal to obtain the feedforward compensation speed control signal. The feedforward compensation speed control signal is subjected to speed limit constraints to obtain the second electric submersible screw pump speed control signal.

8. The method for temperature control of an electric submersible screw pump for heavy oil wells according to claim 1, characterized in that, After performing feedforward compensation on the first electric submersible screw pump speed control signal based on the first feedforward compensation control signal and / or the second feedforward compensation control signal to obtain the second electric submersible screw pump speed control signal, the method further includes: The second electric submersible screw pump speed control signal is sent to the control terminal of the electric submersible screw pump, and the second electric submersible screw pump speed control signal is executed through the control terminal to obtain the speed update data of the electric submersible screw pump.

9. A temperature control device for an electric submersible screw pump in a heavy oil well, characterized in that, The device includes: At least one processor; And, a memory communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor, which are executed by the at least one processor to enable the at least one processor to implement a method for temperature control of an electric submersible screw pump for heavy oil wells as described in any one of claims 1-8.

10. A non-volatile computer storage medium for temperature control of an electric submersible screw pump in heavy oil wells, storing computer-executable instructions, characterized in that... When the computer-executable instructions are executed, they can realize the electric submersible screw pump temperature control method for heavy oil wells as described in any one of claims 1-8.

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