A control method for a remote terminal unit for balancing and regulating an oil pumping unit

Abstract

The present invention discloses a control method for a remote terminal unit (RTU) for balancing and adjusting an oil pumping unit. The method comprises the following steps: S1: sensor data collection: load sensor B1 outputs a 4-20mA signal, which is connected by a wire to the analog input (AI) terminal of RTUA15 to collect load data at the well suspension point; displacement sensor B2 outputs a 4-20mA signal, which is connected by a wire to the analog input (AI) terminal of RTUA15 to collect displacement data at the well suspension point; electrical parameter sensor A14 outputs an RS485 signal, which is connected by a serial cable to the RS485 port of RTUA15 to collect relevant electrical quantity data; S2: edge computing and analysis; S3: balance calculation; and S4: local control. The present invention provides an intelligent RTU device for controlling the well suspension point based on dynamometer diagrams and electrical parameter analysis. This shortens the closed-loop control link for the well suspension point, enabling intelligent control such as local balancing, intermittent control, and variable frequency speed regulation, significantly improving system operational stability.

Description

Technical Field

[0001] The invention relates to the field of production control of pumping wells, and in particular to a control method for a remote terminal unit for balancing and regulating an oil pumping well. Background Art

[0002] At present, pumping wells mainly operate at industrial frequency, and the balance cannot be directly adjusted. This has the following problems: First, 24-hour industrial frequency operation consumes a lot of energy; second, the unbalanced operation of the pumping unit can easily cause the motor to burn out. Therefore, there is an urgent need for an intelligent control RTU device for pumping wells. Through edge analysis and calculation based on the pumping well indicator diagram and electrical parameters, it can intelligently send control instructions to ensure that the pumping unit operates in the optimal state. Summary of the Invention

[0003] The main purpose of the present invention is to provide a method for controlling a remote terminal unit for balancing and regulating an oil pumping unit, which can effectively solve the problems in the background technology.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for controlling a remote terminal unit for balancing and adjusting an oil pumping unit includes the following steps:

[0006] S1: Sensor data collection: Load sensor B1 outputs a 4-20mA signal, which is connected to the analog input (AI) terminal of RTUA15 via a wire to collect the load data of the pumping well suspension point. Displacement sensor B2 outputs a 4-20mA signal, which is connected to the analog input (AI) terminal of RTUA15 via a wire to collect the displacement data of the pumping well suspension point. Electrical parameter sensor A14 outputs an RS485 signal, which is connected to the RS485 port of RTUA15 via a serial cable to collect the relevant electrical quantity data of the pumping well.

[0007] S2: Edge computing analysis: This includes calculations of fullness and balance. The fullness of a pumping unit well refers to the ratio of the effective stroke of the pump barrel to the actual stroke of the pumping unit well. The calculation method for the effective stroke and fullness is as follows:

[0008] a: Maximum load point P of the fixed ground dynamometer U (U U , F U ), minimum load point PD (U D , F D), the ground dynamometer diagram is drawn by 200 sets of load and displacement data, and its data set Ω = {(U0, F0), (U1, F1), ..., (U199, F199)}. Therefore, it is easy to obtain: load data set Ω1 = [F0, F1, ..., F199], displacement data set Ω2 = [U0, U1, ..., U199], and by applying the maximum function MAX(Ω1) and the minimum function MIN(Ω1), the maximum load point P can be obtained. U (U U ,F U ) and the minimum load point P D (U D ,F D );

[0009] b: Determine the effective stroke length: With load as the ordinate (y-axis) and displacement as the abscissa (x-axis), the ground dynamometer diagram can be drawn in two-dimensional coordinates, and △F=(F U -F D ) / 5, let y1=F D +△F,y2=F U -△F, plot y1 and y2 in the coordinate system of the indicator diagram, and obtain four intersection points P that intersect with the indicator diagram i (U i ,F i )、P j (U j , F j )、P m (U m , F m )、P n (U n , F n ), take S pt =U n -U m , S ps =U j -U i , then the effective stroke S of the ground dynamometer diagram is P =min(S pt ,S ps );

[0010] c: Determine the fullness;

[0011] d: Stroke frequency adjustment and intelligent intermittent control method: including pumping unit stroke frequency adjustment method and pumping unit intermittent control method. The pumping unit stroke frequency adjustment method is: when the filling degree is within the range of [0.5, 0.9], the frequency is adjusted by frequency conversion speed regulation. In the actual production process, as the formation fluid supply changes, the filling degree also changes, generally changing in the range of 0%-100%. Given the output frequency range of the pumping unit well inverter [freq_down, freq_up], freq_down, freq_up can be set manually, then the output frequency can be calculated as follows: freq = (freq q_up - freq_down) * fullness + freq_down, the inverter output frequency changes linearly with the fullness, so that when the pump fullness is large, oil is pumped quickly and the output frequency reaches the maximum freq_up; when the pump fullness is small, oil is pumped slowly and the output frequency reaches the minimum freq_down. The pumping unit inter-spacing control method is: when the fullness is less than 0.5, the intelligent inter-spacing control mode is adopted. The inter-spacing of pumping units is generally based on a 24-hour cycle. The specific production time and well stop time are as follows: production time = 24 hours * fullness, well stop time = 24 hours - 24 hours * fullness;

[0012] S3: Balance calculation: including the following steps:

[0013] A: The power diagram is drawn from 200 sets of power and displacement data. The data set Ω = {(U0, P0), (U1, P1), ..., (U199, P199)}. Therefore, it is easy to obtain: load data set Ω3 = [P0, P1, ..., P199], displacement data set Ω4 = [U0, U1, ..., U199];

[0014] B: average power of upstroke within one stroke;

[0015] C: Balance calculation of a single power graph;

[0016] D: Calculate the balance of the pumping well. The balance adjustment method is as follows: When the balance exceeds the range of [0.8, 1.2], it indicates that the pumping well is currently unbalanced. At this time, the wellhead RTU controls the balancing motor to automatically adjust the balance of the pumping well according to the established balancing strategy. After a period of adjustment, further evaluation is performed to form a closed-loop control.

[0017] S4: Local control: The wellhead RTU A15 is connected to the balancing contactor A11 through the digital output terminal (DO) to realize the balance adjustment function of the pumping well. The wellhead RTU A15 is connected to the frequency conversion circuit contactor A3 through the digital output terminal (DO) and is connected to the frequency converter A9 through the RS485 interface to realize the frequency conversion start and stop control and adjustment function of the pumping well. The wellhead RTU A15 is connected to the power frequency circuit contactor A4 through the digital output terminal (DO) to realize the power frequency start and stop control function of the pumping well.

[0018] Preferably, the electrical power data related to the pumping well include active power P, reactive power Q, power factor cosψ, active power Pa, Pb, Pc of each phase, reactive power Qa, Qb, Qc of each phase, total active power, total reactive power, total apparent power, etc.

[0019] Beneficial effects

[0020] Compared with the prior art, the present invention provides a method for controlling a remote terminal unit for balancing and regulating an oil pumping unit, which has the following beneficial effects:

[0021] 1. The present invention is an intelligent control RTU device for pumping wells based on dynamometer diagrams and electrical parameter analysis. It shortens the closed-loop control link of the pumping wells, realizes intelligent control such as local balance adjustment, intermittent control and variable frequency speed regulation, and greatly improves the operating stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a new sensor deployment diagram of the present invention;

[0023] Figure 2 It is a control cabinet deployment diagram of the present invention;

[0024] Figure 3 It is a schematic diagram of the data acquisition and control circuit of the present invention;

[0025] Figure 4 is a diagram of a method for calculating fullness of the present invention;

[0026] Figure 5 is a power diagram of the present invention;

[0027] Figure 6 This is a diagram of the stroke frequency adjustment method of the present invention;

[0028] Figure 7 It is a diagram of the stroke frequency adjustment method of the present invention.

[0029] In the figure: B0, control cabinet; B1, load sensor; B2, displacement sensor; A1, variable frequency power supply circuit breaker; A2, industrial frequency power supply circuit breaker; A3, variable frequency circuit contactor; A4, industrial frequency circuit contactor; A6, current transformer; A9, frequency converter; A11, balancing contactor; A13, balancing power supply circuit breaker; A14, electrical parameter sensor; A15, wellhead RTU. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] like Figure 1-7 The present invention relates to a method for controlling a remote terminal unit for balancing and regulating an oil pumping unit, comprising the following steps:

[0032] S1: Sensor data collection: Load sensor B1 outputs 4-20mA signal, which is connected to the analog input (AI) terminal of RTUA15 through a wire to realize the collection of load data of the suspension point of the pumping unit. Displacement sensor B2 outputs 4-20mA signal, which is connected to the analog input (AI) terminal of RTUA15 through a wire to realize the collection of displacement data of the suspension point of the pumping unit. Electrical parameter sensor A14 outputs RS485 signal, which is connected to the RS485 port of RTUA15 through a serial line to realize the collection of relevant electrical data of the pumping unit. The relevant electrical data of the pumping unit well include active power P, reactive power Q, power factor cosψ, active power Pa, Pb, Pc of each phase, reactive power Qa, Qb, Qc of each phase, total active power, total reactive power, total apparent power, etc. The sensor is installed as follows: Figure 1 shown.

[0033] S2: Edge computing analysis: This includes calculations of fullness and balance. The fullness of a pumping unit well refers to the ratio of the effective stroke of the pump barrel to the actual stroke of the pumping unit well. The calculation method for the effective stroke and fullness is as follows:

[0034] a: Maximum load point P of the fixed ground dynamometer U (U U , F U ), minimum load point PD (U D , F D), the ground dynamometer diagram is drawn by 200 sets of load and displacement data, and its data set Ω = {(U0, F0), (U1, F1), ..., (U199, F199)}. Therefore, it is easy to obtain: load data set Ω1 = [F0, F1, ..., F199], displacement data set Ω2 = [U0, U1, ..., U199], and by applying the maximum function MAX(Ω1) and the minimum function MIN(Ω1), the maximum load point P can be obtained. U (U U ,F U ) and the minimum load point P D (U D ,F D );

[0035] b: Determine the effective stroke length: With load as the ordinate (y-axis) and displacement as the abscissa (x-axis), the ground dynamometer diagram can be drawn in two-dimensional coordinates, such as Figure 2 As shown, take △F=(F U -F D ) / 5, let y1=F D +△F,y2=F U -△F, plot y1 and y2 in the coordinate system of the indicator diagram, and obtain four intersection points P that intersect with the indicator diagram i (U i ,F i )、P j (U j , F j )、P m (U m , F m )、P n (U n , F n ), take S pt =U n -U m , S ps =U j -U i , then the effective stroke S of the ground dynamometer diagram is P =min(S pt ,S ps );

[0036] c: Determine the fullness;

[0037] d: Stroke frequency adjustment and intelligent intermittent control method: including the pumping unit stroke frequency adjustment method and the pumping unit intermittent control method, wherein the pumping unit stroke frequency adjustment method is: when the fullness is within the range of [0.5, 0.9], the frequency conversion speed regulation method is used to adjust the stroke frequency. In the actual production process, as the formation fluid supply changes, the fullness also changes accordingly, generally changing within the range of 0%-100%. Given the output frequency range of the pumping well inverter [freq_down, freq_up], freq_down, freq_up can be set manually, then the output frequency can be calculated as follows: freq = (freq_up-freq_down) * fullness + freq_down, so that the inverter output frequency changes linearly with the fullness, thereby achieving rapid oil pumping when the pump fullness is large, and the output frequency reaches the maximum freq_up. When the pump fill level is low, the pumping speed is slow, and the output frequency reaches the minimum freq_down. The pumping unit intermittent control method is: when the fill level is less than 0.5, the pumping unit intermittent control mode is adopted. The pumping unit intermittent well cycle is generally 24 hours. The specific production time and well downtime are as follows: production time = 24 hours * fill level, well downtime = 24 hours - 24 hours * fill level;

[0038] S3: Balance calculation: including the following steps:

[0039] A: The power diagram is drawn from 200 sets of power and displacement data. The data set Ω = {(U0, P0), (U1, P1), ..., (U199, P199)}. Therefore, it is easy to obtain: load data set Ω3 = [P0, P1, ..., P199], displacement data set Ω4 = [U0, U1, ..., U199];

[0040] B: average power of upstroke within one stroke;

[0041] C: Balance calculation of a single power graph;

[0042] D: Calculate the balance of the pumping well. The balance adjustment method is as follows: When the balance exceeds the range of [0.8, 1.2], it indicates that the pumping well is currently unbalanced. At this time, the wellhead RTU controls the balancing motor to automatically adjust the balance of the pumping well according to the established balancing strategy. After a period of adjustment, further evaluation is performed to form a closed-loop control.

[0043] S4: Local control: The wellhead RTU A15 is connected to the balancing contactor A11 through the digital output terminal (DO) to realize the balance adjustment function of the pumping well. The wellhead RTU A15 is connected to the frequency conversion circuit contactor A3 through the digital output terminal (DO) and is connected to the frequency converter A9 through the RS485 interface to realize the frequency conversion start and stop control and adjustment function of the pumping well. The wellhead RTU A15 is connected to the power frequency circuit contactor A4 through the digital output terminal (DO) to realize the power frequency start and stop control function of the pumping well.

[0044] The present invention is an intelligent control RTU device for pumping wells based on dynamometer diagrams and electrical parameter analysis. It shortens the closed-loop control link of the pumping wells, realizes intelligent control such as local balance adjustment, intermittent control and variable frequency speed regulation, and greatly improves the operating stability of the system.

[0045] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling a remote terminal unit for balancing and adjusting an oil pumping unit, characterized in that: The following steps are included: S1: Sensor data collection: Load sensor B1 outputs a 4-20mA signal, which is connected to the analog input (AI) terminal of RTUA15 via a wire to collect the load data of the pumping well suspension point. Displacement sensor B2 outputs a 4-20mA signal, which is connected to the analog input (AI) terminal of RTUA15 via a wire to collect the displacement data of the pumping well suspension point. Electrical parameter sensor A14 outputs an RS485 signal, which is connected to the RS485 port of RTUA15 via a serial cable to collect the relevant electrical quantity data of the pumping well. S2: Edge computing analysis: This includes calculations of fullness and balance. The fullness of a pumping unit well refers to the ratio of the effective stroke of the pump barrel to the actual stroke of the pumping unit well. The calculation method for the effective stroke and fullness is as follows: a: Maximum load point P of the fixed ground dynamometer U (U U , F U ), minimum load point PD (U D , F D ), the ground dynamometer diagram is drawn by 200 sets of load and displacement data, and its data set Ω = {(U0, F0), (U1, F1), ..., (U199, F199)}. Therefore, it is easy to obtain: load data set Ω1 = [F0, F1, ..., F199], displacement data set Ω2 = [U0, U1, ..., U199], and by applying the maximum function MAX(Ω1) and the minimum function MIN(Ω1), the maximum load point P can be obtained. U (U U ,F U ) and the minimum load point P D (U D ,F D ); b: Determine the effective stroke length: With the load as the y-axis and the displacement as the x-axis, the ground dynamometer diagram can be drawn in two-dimensional coordinates, and △F=(F U -F D ) / 5, let y1=F D +△F,y2=F U -△F, plot y1 and y2 in the coordinate system of the indicator diagram, and obtain four intersection points P that intersect with the indicator diagram i (U i ,F i )、P j (U j , F j )、P m (U m , F m )、P n (U n , F n ), take S pt =U n -U m , S ps =U j -U i , then the effective stroke S of the ground dynamometer diagram is P =min(S pt ,S ps ); c: Determine the fullness; d: Stroke frequency adjustment and intelligent intermittent control method: including pumping unit stroke frequency adjustment method and pumping unit intermittent control method. The pumping unit stroke frequency adjustment method is: when the filling degree is within the range of [0.5, 0.9], the frequency is adjusted by frequency conversion speed regulation. In the actual production process, as the formation fluid supply changes, the filling degree also changes, generally changing in the range of 0%-100%. Given the output frequency range of the pumping unit well inverter [freq_down, freq_up], freq_down, freq_up can be set manually, then the output frequency can be calculated as follows: freq = (freq q_up - freq_down) * fullness + freq_down, the inverter output frequency changes linearly with the fullness, so that when the pump fullness is large, oil is pumped quickly and the output frequency reaches the maximum freq_up; when the pump fullness is small, oil is pumped slowly and the output frequency reaches the minimum freq_down. The pumping unit inter-spacing control method is: when the fullness is less than 0.5, the intelligent inter-spacing control mode is adopted. The inter-spacing of pumping units is generally based on a 24-hour cycle. The specific production time and well stop time are as follows: production time = 24 hours * fullness, well stop time = 24 hours - 24 hours * fullness; S3: Balance calculation: including the following steps: A: The power diagram is drawn from 200 sets of power and displacement data. The data set Ω = {(U0, P0), (U1, P1), ..., (U199, P199)}. Therefore, it is easy to obtain: load data set Ω3 = [P0, P1, ..., P199], displacement data set Ω4 = [U0, U1, ..., U199]; B: average power of upstroke within one stroke; C: Balance calculation of a single power graph; D: Calculate the balance of the pumping well. The balance adjustment method is as follows: When the balance exceeds the range of [0.8, 1.2], it indicates that the pumping well is currently unbalanced. At this time, the wellhead RTU controls the balancing motor to automatically adjust the balance of the pumping well according to the established balancing strategy. After a period of adjustment, further evaluation is performed to form a closed-loop control. S4: Local control: The wellhead RTU A15 is connected to the balancing contactor A11 through the digital output terminal (DO) to realize the balance adjustment function of the pumping well. The wellhead RTU A15 is connected to the frequency conversion circuit contactor A3 through the digital output terminal (DO) and is connected to the frequency converter A9 through the RS485 interface to realize the frequency conversion start and stop control and adjustment function of the pumping well. The wellhead RTU A15 is connected to the power frequency circuit contactor A4 through the digital output terminal (DO) to realize the power frequency start and stop control function of the pumping well.

2. A method for controlling a pumping unit balance adjustment remote terminal unit according to claim 1, characterized in that: The electrical quantity data related to the pumping well include active power P, reactive power Q, power factor cosψ, active power Pa, Pb, Pc of each phase, reactive power Qa, Qb, Qc of each phase, total active power, total reactive power, and total apparent power.

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