Submersible electric pump jamming pre-judgment and jam releasing control system and submersible electric pump jamming pre-judgment and jam releasing control method

Abstract

The invention discloses an electric submersible pump jamming pre-judgment and jam releasing control system and a method thereof. The control system comprises a PLC used for receiving data of all sensors and controlling output of a frequency converter, the frequency converter used for controlling operation of the electric submersible pump motor, a voltage and current sensor used for collecting voltage and current of the electric submersible pump motor and an electric submersible pump underground sensor. According to the pre-judgment and jam-releasing method, a plurality of operating parameters such as active power, power factor, rotating speed difference, motor temperature, inlet pressure and outlet pressure of the electric submersible pump are integrated through a pump jam comprehensive evaluation function f (x), and the operating state of the electric submersible pump is quantitatively evaluated in a weighted summation mode. The method has the beneficial effects that the pump jamming state of the electric submersible pump is quantitatively evaluated, and a basis is provided for pump jamming pre-judgment and control; according to the pump jamming comprehensive evaluation function value, the pump jamming risk is pre-judged, the running state is adjusted in time, and the pump jamming occurrence probability is reduced; and corresponding jam releasing control strategies are automatically executed according to different pump jam degrees, so that the jam releasing efficiency is improved.

Description

Technical Field

[0001] This invention relates to a submersible electric pump control system, and more particularly to a submersible electric pump jamming prediction and de-jamming control system and method, belonging to the field of oil and gas development technology. Background Technology

[0002] Submersible electric pumps (SAPs) are commonly used lifting equipment in oil extraction, but pump jamming frequently occurs during operation, severely impacting production efficiency and equipment lifespan. Currently, the commonly used unlocking methods are manual judgment and manual unlocking, which are not only inefficient but also prone to errors. Therefore, there is an urgent need for an intelligent control system capable of adaptively predicting pump jamming risks and automatically unlocking them. Summary of the Invention

[0003] In order to overcome the above-mentioned shortcomings of existing submersible electric pumps in the process of pump jamming and unjamming, the present invention provides a submersible electric pump jamming prediction and unjamming control system and method.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A submersible electric pump (FETP) jamming prediction and de-jamming control system includes a PLC controller for receiving data from various sensors, executing jamming prediction and control algorithms, and controlling the output of a frequency converter; a frequency converter for controlling the operation of the FETP motor; voltage and current sensors for acquiring the three-phase voltage and current of the FETP motor; and downhole sensors for the FETP, including a temperature sensor for the motor, a pressure sensor at the FETP inlet, and a pressure sensor at the FETP outlet.

[0006] A method for predicting and de-carding the control system.

[0007] Define the comprehensive evaluation function f(x) for the pump:

[0008] f(x) = w1 × (P N -P) / P N +w2×(cosφ N -cosφ) / cosφ N +w3×(ss N ) / s N +w4×(TT N ) / T N +w5×(P in -P inN ) / P inN +w6×(P outN -P out ) / P outN

[0009] In the formula:

[0010] P—Active power

[0011] cosφ — Power factor

[0012] s — speed difference

[0013] S = [(Synchronous speed - Actual speed) / Synchronous speed] × 100%

[0014] T - Motor temperature

[0015] P in —Inlet pressure of submersible electric pump

[0016] P out —Submersible pump outlet pressure

[0017] N in the subscript – Rated value of the submersible electric pump

[0018] w1 to w6 are weighting coefficients, and w1+w2+w3+w4+w4+w5+w6=1

[0019] Let the warning threshold be α, and the puncture pump threshold be β.

[0020] When α≤f(x)<β, it is determined that there is a risk of pump jamming, and the early warning control program is executed;

[0021] When f(x)≥β, it is determined that pump jamming has occurred, and the pump jamming control program is executed.

[0022] Furthermore, when α≤f(x)<β, early warning control is executed, including: controlling the frequency converter to reduce the motor speed and increase the torque; and shortening the data acquisition cycle.

[0023] Furthermore, the early warning control includes: controlling the frequency converter to reduce the motor speed by 5% and increase the torque by 10%; the data acquisition cycle is 30 seconds.

[0024] A method for predicting and de-carding the control system.

[0025] When f(x)≥β, perform pump control, including: controlling the frequency converter to perform reverse de-carding; if it fails, perform frequency boosting de-carding; if it still fails, shut down and alarm; shorten the data acquisition cycle;

[0026] If the card is successfully unlocked, gradually restore the normal operating parameters of the submersible pump and continue to monitor the f(x) value.

[0027] Furthermore, the data acquisition cycle of the pump control is 10 seconds; the operating parameters of the submersible electric pump include motor speed and torque.

[0028] Furthermore, the warning threshold α is 0.15 to 0.25; the puncture pump threshold β is 0.35 to 0.65.

[0029] Furthermore, the method for determining the values ​​of the warning threshold α and the puncture pump threshold β includes the following steps:

[0030] S1. Based on the historical operating data of the submersible electric pump, statistically analyze the distribution of each operating parameter under normal operating conditions, early warning operating conditions, and pump jamming conditions, and calculate the distribution range of the comprehensive evaluation function f(x) under normal operating conditions, early warning operating conditions, and pump jamming conditions.

[0031] S2. Within the distribution range of f(x), select appropriate thresholds as the warning threshold α and the clogging threshold β, such that:

[0032] When f(x) < α, more than 95% of the time it is under normal operating conditions;

[0033] When α≤f(x)<β, 70%~80% of the time is a warning condition;

[0034] When f(x)≥β, more than 90% of the time it is a pump-clamping condition.

[0035] S3. Based on the effects of early warning control and pump jamming control, adjust and optimize the values ​​of early warning threshold α and pump jamming threshold β.

[0036] 9. The prediction and unlocking method of the control system according to claim 8, characterized in that: the historical operating data of the submersible electric pump includes at least: active power P, power factor cosφ, speed difference S, motor temperature T, and inlet pressure P. in Outlet pressure P out .

[0037] The beneficial effects of this invention are:

[0038] (1) The proposed comprehensive evaluation function for stuck pumps can quantitatively evaluate the stuck pump status of submersible electric pumps, providing a basis for stuck pump prediction and control;

[0039] (2) Based on the comprehensive evaluation function value of the pump jamming, predict the risk of pump jamming and adjust the operating status in a timely manner to reduce the probability of pump jamming.

[0040] (3) Automatically execute corresponding de-blocking control strategies for different levels of pump jamming to improve de-blocking efficiency;

[0041] (4) Fully automatic intelligent control reduces manual intervention and improves system reliability. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the submersible electric pump jamming prediction and de-jamming control method of the present invention.

[0043] Figure 2 This is a schematic diagram of the submersible electric pump jam prediction and de-jamming control system of the present invention.

[0044] In the diagram: 1. PLC controller, 2. Frequency converter, 3. Voltage and current sensor, 4. Submersible pump downhole sensor, 5. Submersible pump. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments. However, those skilled in the art should understand that the present invention is not limited to the specific embodiments listed, and any embodiment that conforms to the spirit of the present invention should be included within the scope of protection of the present invention.

[0046] See appendix Figure 2 This invention relates to a submersible electric pump jamming prediction and de-jamming control system.

[0047] PLC controller 1 is used to receive data from various sensors, execute pump prediction and control algorithms, and control the inverter output;

[0048] Inverter 2 is used to control the operation of the submersible electric pump motor;

[0049] Voltage and current sensor 3 is used to collect the three-phase voltage and current of the submersible electric pump motor;

[0050] The downhole sensor 4 for the submersible electric pump includes: a temperature sensor for the motor, a pressure sensor at the inlet of the submersible electric pump, and a pressure sensor at the outlet of the submersible electric pump.

[0051] See appendix Figure 1 This invention provides a method for predicting and releasing a stuck submersible electric pump, within its stuck pump prediction and release control system.

[0052] Define the comprehensive evaluation function f(x) for the pump:

[0053] f(x) = w1 × (P N -P) / P N +w2×(cosφ N -cosφ) / cosφ N +w3×(ss N ) / s N +w4×(TT N ) / T N +w5×(P in -P inN ) / P inN +w6×(P outN -P out ) / P outN

[0054] In the formula:

[0055] P—Active power

[0056] cosφ — Power factor

[0057] s — speed difference

[0058] S = [(Synchronous speed - Actual speed) / Synchronous speed] × 100%

[0059] T - Motor temperature

[0060] P in —Inlet pressure of submersible electric pump

[0061] P out —Submersible pump outlet pressure

[0062] N in the subscript – Rated value of the submersible electric pump

[0063] w1 to w6 are weighting coefficients, and w1+w2+w3+w4+w4+w5+w6=1

[0064] Let the warning threshold be α and the puncture pump threshold be β.

[0065] When α≤f(x)<β, it is determined that there is a risk of pump jamming, and the early warning control program is executed.

[0066] When f(x)≥β, it is determined that pump jamming has occurred, and the pump jamming control program is executed.

[0067] When α≤f(x)<β, the early warning control program is executed, including: controlling the frequency converter to reduce the motor speed and increase the torque; and shortening the data acquisition cycle.

[0068] Furthermore, when α≤f(x)<β, the warning control program controls the frequency converter to reduce the motor speed by 5% and increase the torque by 10%; the data acquisition cycle is 30 seconds.

[0069] When f(x)≥β, execute the card pump control program, including: controlling the frequency converter to perform reverse card release.

[0070] If the process fails, the frequency will be increased and the card will be unlocked. If the process still fails, the system will be shut down and an alarm will be triggered. The data acquisition cycle will be shortened.

[0071] If the card is successfully unlocked, gradually restore the normal operating parameters of the submersible pump and continue to monitor the f(x) value.

[0072] Furthermore, when f(x)≥β, the data acquisition cycle of the pump control is 10s; the operating parameters of the submersible electric pump include motor speed and torque.

[0073] The warning threshold α is 0.15 to 0.25;

[0074] The threshold β of the cassette pump is 0.35 to 0.65.

[0075] The method for determining the early warning threshold α and the puncture pump threshold β described in this invention comprises the following steps:

[0076] S1. Based on the historical operating data of the submersible electric pump, statistically analyze the distribution of each operating parameter under normal operating conditions, early warning operating conditions, and pump jamming conditions, and calculate the distribution range of the comprehensive evaluation function f(x) under normal operating conditions, early warning operating conditions, and pump jamming conditions.

[0077] S2. Within the distribution range of f(x), select appropriate thresholds as the warning threshold α and the clogging threshold β, such that:

[0078] When f(x) < α, more than 95% of the time it is under normal operating conditions;

[0079] When α≤f(x)<β, 70%~80% of the time is a warning condition;

[0080] When f(x)≥β, more than 90% of the time it is a pump-clamping condition.

[0081] S3. Based on the effects of early warning control and pump jamming control, adjust and optimize the values ​​of early warning threshold α and pump jamming threshold β.

[0082] Furthermore, the historical operating data of the submersible electric pump includes at least: active power P, power factor cosφ, speed difference S, motor temperature T, and inlet pressure P. in Outlet pressure P out .

[0083] Example 1:

[0084] By analyzing the historical operating data of 100 submersible electric pumps in an oilfield, the distribution range of f(x) under different operating conditions is as follows:

[0085] Normal operating condition: f(x) < 0.15

[0086] Warning condition: 0.15 ≤ f(x) < 0.35

[0087] Pump operating condition: f(x) ≥ 0.35

[0088] Therefore, the initial warning threshold α is set at 0.2, and the pump ignition threshold β is set at 0.5. In practical applications, if the warning control is found to start too early or too late, the value of α can be adjusted appropriately; if the pump ignition control is found to start too early or too late, the value of β can be adjusted appropriately.

[0089] Considering the differences between various oil wells and submersible pump models, and the need for adjustments based on performance in practical applications, the warning threshold α is set between 0.15 and 0.25, with α fluctuating by 0.05 around 0.2; the stuck pump threshold β is set between 0.35 and 0.65, with β fluctuating by 0.15 around 0.5. This range reflects the distribution patterns under different operating conditions while also allowing for parameter adjustments in practical applications.

[0090] It should be noted that the values ​​of α and β are related to the specific oil well conditions and the submersible pump model, and may vary between different oil fields and submersible pump models. In practical applications, appropriate α and β should be selected based on field data and experience, and continuously optimized during operation to effectively prevent or reduce pump jamming.

[0091] Example 2:

[0092] A submersible electric pump (FETP) jamming prediction and de-jamming control system includes: a Siemens S7-200 PLC, an ABB ACS510 frequency converter, voltage and current sensors for acquiring the three-phase voltage and current of the FETP motor, and a motor temperature sensor, a pressure sensor at the FETP inlet, and a pressure sensor at the FETP outlet for acquiring downhole data of the FETP.

[0093] In the comprehensive evaluation function f(x) for the puncture pump, the weight coefficients are: w1 = 0.25, w2 = 0.2, w3 = 0.2, w4 = 0.15, w5 = 0.1, w6 = 0.1; the warning threshold α = 0.2, and the puncture pump threshold β = 0.5.

[0094] The rated parameters of the submersible electric pump used are: rated active power P N =50kW, rated power factor cosφ N =0.85, Rated speed difference S N =4%, rated motor temperature T N =65℃, rated inlet pressure P inN =1.5MPa, rated outlet pressure P outN =10MPa.

[0095] The data under different operating conditions are as follows:

[0096] (1) Under normal operating conditions, when f(x) < 0.2,

[0097] The operating data of the submersible electric pump are: active power P = 45kW, power factor Speed ​​difference S = 4.5%, motor temperature T = 68℃, inlet pressure P in =1.6MPa, outlet pressure P out =9.5MPa.

[0098] Substitute the above data into the comprehensive evaluation function of the pump.

[0099] f(x) = w1 × (P N -P) / P N +w2×(cosφ N -cosφ) / cosφ N +w3×(ss N ) / s N +w4×(TT N ) / T N +w5×(P in -P inN ) / P inN +w6×(P outN -P out ) / P outN

[0100] The calculation yields f(x) = 0.1335, which is less than the warning threshold α = 0.2. Therefore, it is determined to be a normal operating condition, and the system maintains its current operating state with a data acquisition cycle of 60 seconds.

[0101] (2) When the warning condition α≤f(x)<β,

[0102] The operating data of the submersible electric pump are: active power P = 40kW, power factor Speed ​​difference S = 8%, motor temperature T = 70℃, inlet pressure P in =1.8MPa, outlet pressure P out =8MPa.

[0103] Substituting the above data into the comprehensive evaluation function for the pump jamming system, we get f(x) = 0.3268, which is greater than the warning threshold α. Therefore, it is determined that there is a risk of pump jamming, and the system automatically executes warning control.

[0104] The PLC-controlled frequency converter reduces the motor speed by 5% and increases the torque by 10%.

[0105] The PLC shortens the data acquisition cycle to 30 seconds.

[0106] (3) When f(x) ≥ β under the pump operating condition

[0107] Submersible electric pump operating data: Active power P = 35kW, power factor Speed ​​difference S = 10%, motor temperature T = 75℃, inlet pressure P in =2.0MPa, outlet pressure P out =7MPa.

[0108] Substituting the above data into the comprehensive evaluation function for the clogging pump, we get f(x) = 0.5238, which is greater than the clogging pump threshold β. Therefore, it is determined that clogging has occurred, and the system automatically executes clogging pump control.

[0109] PLC controls the frequency converter to perform reverse card unlocking;

[0110] If the reverse card unlocking fails, perform a frequency increase unlocking, increasing the frequency by 50Hz.

[0111] Frequency upgrade and card unlocking failed, power off alarm;

[0112] At the same time, the PLC shortens the data acquisition cycle to 10 seconds.

[0113] When the frequency upgrade and card unlocking are successful, the PLC will gradually restore the operating parameters such as motor speed and torque, and continue to monitor the f(x) value. The PLC will restore the data acquisition cycle to 60s.

[0114] The present invention proposes a comprehensive evaluation function f(x) for predicting and controlling pump jamming in submersible electric pumps. This function integrates multiple operating parameters of the submersible electric pump, such as active power, power factor, speed difference, motor temperature, inlet pressure, and outlet pressure, and quantifies the operating status of the submersible electric pump through weighted summation. When f(x) exceeds a warning threshold, the system determines that there is a risk of pump jamming and executes a warning control program, including measures such as reducing motor speed, increasing torque, and shortening the data acquisition cycle to reduce the probability of pump jamming. When f(x) exceeds the pump jamming threshold, the system determines that pump jamming has occurred and executes a pump jamming control program, including measures such as reversing the pump to release the jamming, increasing the frequency to release the jamming, and shortening the data acquisition cycle to quickly resolve the pump jamming state.

[0115] This invention relates to an adaptive pump jamming prediction and control system and method for submersible electric pumps based on PLC and frequency converter. It can assess the risk of pump jamming in real time, adjust the operating status in advance, and automatically execute de-jamming control. For different degrees of pump jamming, it can automatically execute corresponding de-jamming control strategies to improve de-jamming efficiency, reduce manual intervention, and improve system reliability.

[0116] It should be noted that the above embodiments are examples and not limitations of the present invention, and those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of this patent.

Claims

1. A control system for predicting and resolving stuck pump of electric submersible pump (ESP), comprising: a PLC controller configured to receive data from sensors, execute a stuck pump predicting and resolving algorithm, and control a frequency converter; the frequency converter configured to control the operation of an ESP motor; voltage and current sensors configured to collect three-phase voltage and current of the ESP motor; and ESP downhole sensors including a motor temperature sensor, an ESP inlet pressure sensor, and an ESP outlet pressure sensor. 2.A method for predicting and resolving stuck pump of the control system of claim 1, comprising: defining a stuck pump comprehensive evaluation function f (x) : f (x) = w 1 * P + w 2 * cosφ + w 3 * s + w 4 * T + w 5 * P N + w 6 * cosφ N wherein: P——active power cosφ——power factor s——speed difference S=[(synchronous speed-actual speed) / synchronous speed]×100% T——motor temperature N——rated value of ESP w1 to w6——weight coefficients, w1+w2+w3+w4+w4+w5+w6=1 α——early warning threshold β——stuck pump threshold, wherein: when α≤f (x) <β, it is determined that there is a risk of stuck pump, and an early warning control program is executed; when f (x) ≥β, it is determined that stuck pump has occurred, and a stuck pump control program is executed. 3.The method of claim 2, wherein when α≤f (x) <β, an early warning control is executed, including: controlling the frequency converter to reduce the motor speed and increase the torque; and shortening the data collection period. 4.The method of claim 3, wherein the early warning control includes: controlling the frequency converter to reduce the motor speed by 5% and increase the torque by 10%; and setting the data collection period to 30 seconds. 5.The method of claim 2, wherein when f (x) ≥β, a stuck pump control is executed, including: controlling the frequency converter to perform reverse rotation to resolve stuck pump, if failed, to perform frequency increase to resolve stuck pump, if still failed, to stop and alarm; and shortening the data collection period; and if the stuck pump is resolved, gradually restoring the normal operation parameters of the ESP and continuing to monitor the value of f (x). 6.The method of claim 5, wherein the data collection period of the stuck pump control is 10 seconds; and the operation parameters of the ESP include the motor speed and the torque. 7.The method of claim 2, wherein the early warning threshold α is 0.15-0.25; and the stuck pump threshold β is 0.35-0.

65. f(x) = w1 x (P N -P) / P N +w2 x (cosφ N -cosφ) / cosφ N +w3 x (s-s N ) / s N +w4 x (T-T N ) / T N +w5 x (P in -P inN ) / P inN +w6 x (P outN -P out ) / P outN 8.The method of claim 7, wherein the method for determining the values of the early warning threshold α and the stuck pump threshold β comprises the following steps: S1, according to the historical operation data of the ESP, counting the distribution of each operation parameter under normal condition, early warning condition and stuck pump condition, and calculating the distribution range of the comprehensive evaluation function f (x) under normal condition, early warning condition and stuck pump condition; and S2, selecting appropriate thresholds as the early warning threshold α and the stuck pump threshold β within the distribution range of f (x), so that: when f (x) <α, more than 95% is normal condition; when α≤f (x) <β, 70%-80% is early warning condition. ​ ​ ​ ​ ​ P in Submerged electric pump inlet pressure P out — Submersible electric pump discharge pressure ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ When f(x)≥β, more than 90% is the pump stall condition. S3, according to the effect of early warning control and pump stall control, the value of early warning threshold α and pump stall threshold β is adjusted and optimized.

9. The control system pre-judgment and unblocking method of claim 8, characterized in that: The historical operation data of the submersible electric pump at least includes: active power P, power factor cosφ, speed difference S, motor temperature T, inlet pressure P in , outlet pressure P out .

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