Rod pumped well working condition monitoring knowledge base construction method based on theoretical electric power reconstruction

Abstract

The invention provides a rod-pumped well working condition monitoring knowledge base construction method based on theoretical electric power reconstruction, and belongs to the technical field of oil field informatization construction. Actually-measured electric power curves of all working conditions of a rod-pumped well and corresponding oil pumping unit parameters are obtained, and an electric power historical data set is formed; establishing a relational expression among the suspension center displacement, the suspension center load, the electric power and the crank angle; establishing an electric power to suspension point indicator diagram model, and calculating a suspension point indicator diagram corresponding to the actually measured electric power curve; a theoretical indicator diagram generation method is adopted, and the suspension point indicator diagram obtained through calculation is converted into a theoretical indicator diagram; establishing a suspension point indicator diagram to electric power conversion model, and calculating a theoretical electric power curve corresponding to the theoretical indicator diagram; and extracting shape features of the theoretical electric power curve and the actually measured electric power curve, and establishing a rod-pumped well working condition monitoring knowledge base by utilizing an electric power historical data set. The theoretical electric power curve can be automatically calculated according to the actually measured electric power curve, and expert participation is not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield information construction, and in particular relates to a method for constructing a knowledge base for monitoring the working conditions of a pumping well based on theoretical electric power curve reconstruction. Background Art

[0002] The main equipment for oil production in pumping wells is located thousands of meters underground. It is affected by factors such as high temperature and high pressure for a long time. The working conditions are complex and changeable. Once the abnormal working conditions cannot be discovered and effectively handled in time, it will not only affect the efficiency of oil production, but may even cause serious damage to the pumping wells. Therefore, timely and accurate monitoring of the working conditions of pumping wells is of great significance to the efficient and safe production of oil fields. The traditional method is based on the theoretical dynamometer diagram. It realizes the working condition monitoring of pumping wells by drawing the hanging point dynamometer diagram and analyzing the geometric characteristics of the hanging point dynamometer diagram. The drawing of the hanging point dynamometer diagram requires the installation of load and displacement sensors on the pumping unit. However, the installation steps of the load and displacement sensors are cumbersome and require regular calibration, resulting in the high installation and maintenance costs of the monitoring method based on the hanging point dynamometer diagram. With the continuous advancement of oilfield informatization construction, the motor control cabinets of most pumping wells have been equipped with terminal monitoring equipment, which can realize the real-time acquisition of electrical parameters such as electric power without the need to install additional sensors. Electrical parameters such as electric power are easy to obtain and contain rich information about changes in the operating conditions of pumping wells. Therefore, they have become an important data source for the current research on monitoring methods for pumping well conditions.

[0003] The Chinese patent "CN106337681A A method for diagnosing the working condition of a pumping well based on an electric power diagram" provides another method for monitoring the working condition of a pumping well. This patent first converts the curve of the change of electric power over time into an electric power diagram with displacement as the horizontal coordinate and electric power as the vertical coordinate. Secondly, for each working condition, multiple typical electric power diagrams are selected to form an electric power diagram. Finally, the measured electric power is converted into an electric power diagram and classified into the category corresponding to the electric power diagram with similar features in the electric power diagram, thereby realizing the working condition monitoring of the pumping well.

[0004] The Chinese patent "CN111322058A Method and device for determining the working condition of a pumping well based on an electrical parameter curve" provides another method for monitoring the working condition of a pumping well. This patent introduces the concept of a standard electrical parameter curve, and regards a historical electrical power curve of a normal working condition as a standard electrical parameter curve. By comparing the peak value and trough value of the measured electrical parameter curve with the standard electrical parameter curve, the monitoring of the working conditions such as the fluid supply condition and the rod breakage of the pumping well can be realized.

[0005] The above method does not provide a method for selecting an electric power diagram or a standard electric parameter curve. If an electric power diagram or a standard electric parameter curve of a normal operating condition is arbitrarily selected, an abnormal operating condition close to the diagram or curve will be judged as a normal operating condition, while a normal operating condition that is significantly different from the diagram or curve will be judged as an abnormal operating condition, resulting in a misclassification problem, thereby reducing the accuracy of monitoring the operating conditions of the pumping well. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present application proposes a method for constructing a knowledge base for monitoring the working conditions of a pumping well based on theoretical electric power reconstruction. The present application establishes an electric power-to-hanging point dynamometer diagram model and a hanging point dynamometer diagram-to-electric power model based on the least squares method, and combines the method for generating the theoretical dynamometer diagram to provide a method for reconstructing a theoretical electric power curve, thereby solving the problem of misclassification caused by the selection of electric dynamometer diagrams or standard electric parameter curves based on expert experience. In addition, the present application establishes a knowledge base for monitoring the working conditions of a pumping well by extracting the shape characteristics of the theoretical electric power curve and the measured electric power curve and analyzing the relationship between the two and the working conditions, thereby realizing the monitoring of multiple working conditions of a pumping well based on the measured electric power curve. The theoretical electric power curve reconstructed by the present application is calculated from the theoretical dynamometer diagram, so the reconstructed theoretical electric power curve and the theoretical dynamometer diagram have the same important position in the research of the method for monitoring the working conditions of a pumping well.

[0007] This application proposes a method for constructing a knowledge base for monitoring the working conditions of a pumping well based on theoretical electrical power reconstruction, including:

[0008] Obtain the measured electric power curves of various working conditions of the pumping well and the corresponding pumping unit parameters to form an electric power history data set;

[0009] Establish the relationship between suspension point displacement, suspension point load, electric power and crank angle;

[0010] According to the relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle, a model of converting the electric power to the suspension point indicator diagram is established, and the suspension point indicator diagram corresponding to the measured electric power curve is calculated;

[0011] The method of generating the theoretical dynamometer diagram is adopted to transform the calculated suspension point dynamometer diagram into the theoretical dynamometer diagram;

[0012] According to the relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle, a suspension point dynamometer diagram to electric power conversion model is established to calculate the theoretical electric power curve corresponding to the theoretical dynamometer diagram;

[0013] The shape characteristics of the theoretical electric power curve and the measured electric power curve are extracted, and the knowledge base for monitoring the working condition of the pumping well is established using the electric power historical data set.

[0014] The obtained measured electric power curves of various working conditions of the pumping well and the corresponding pumping unit parameters constitute an electric power history data set, including:

[0015] The electric power curves and their corresponding pumping unit parameters under normal, insufficient liquid supply, gas influence, gas lock, rod break, fixed valve leakage and floating valve leakage conditions are collected to form an electric power history data set.

[0016] The relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle is established, including:

[0017] Establish the relationship between the suspension point displacement and the crank angle;

[0018] Establish the relationship between the suspension point load, crank angle and suspension point load torque;

[0019] Establish the relationship between the suspension point load torque and the electric power.

[0020] The method of establishing an electric power-to-suspension point dynamometer diagram model based on the relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle, and calculating the suspension point dynamometer diagram corresponding to the measured electric power curve includes:

[0021] According to the relationship between the suspension point load torque and the electric power, a model of converting the electric power to the suspension point load torque is established to calculate the suspension point load torque corresponding to the measured electric power;

[0022] According to the relationship between the crank angle and the suspension point load torque, a crank angle to torque factor model is established to calculate the torque factor corresponding to the crank angle;

[0023] According to the relationship between the suspension point load and the suspension point load torque, a suspension point load torque conversion model is established to calculate the suspension point load corresponding to the suspension point load torque;

[0024] According to the relationship between suspension point displacement and crank angle, a crank angle to suspension point displacement model is established to calculate the suspension point displacement corresponding to the crank angle.

[0025] The method for generating the theoretical dynamometer diagram is to convert the calculated suspension point dynamometer diagram into the theoretical dynamometer diagram, including:

[0026] Calculate the slopes of the loading and unloading sections of the theoretical dynamometer diagram;

[0027] Calculate the upper load line of the theoretical dynamometer diagram;

[0028] Calculate the lower load line of the theoretical dynamometer diagram;

[0029] According to the loading section and unloading section slopes, the upper load line and the lower load line of the theoretical dynamometer diagram, a theoretical dynamometer diagram corresponding to the calculated suspension point dynamometer diagram is generated.

[0030] The method of establishing a suspension point dynamometer diagram to electric power model and calculating a theoretical electric power curve corresponding to the theoretical dynamometer diagram includes:

[0031] According to the relationship between suspension point displacement and crank angle, a suspension point displacement to crank angle model is established to calculate the theoretical crank angle corresponding to the theoretical suspension point displacement;

[0032] According to the crank angle to torque factor model, the torque factor of the pumping unit corresponding to the theoretical crank angle is calculated;

[0033] According to the relationship between the suspension point load and the suspension point load torque, a suspension point load to suspension point load torque model is established to calculate the theoretical suspension point load torque corresponding to the theoretical suspension point load;

[0034] According to the relationship between the suspension point load torque and the electric power, a suspension point load to electric power model is established to calculate the theoretical electric power corresponding to the theoretical suspension point load torque.

[0035] The method of extracting the shape features of the theoretical electric power curve and the measured electric power curve and establishing a knowledge base for monitoring the working conditions of the pumping well using the electric power history data set includes:

[0036] Determine the key features of the theoretical electrical power curve;

[0037] Determine key features of measured electrical power curves;

[0038] Determine the relationship between theoretical electric power curve characteristics, measured electric power curve characteristics and operating conditions;

[0039] According to the key features of the theoretical electric power curve, the key features of the measured electric power curve, the characteristics of the theoretical electric power curve, the relationship between the characteristics of the measured electric power curve and the working conditions, a knowledge base for monitoring the working conditions of the pumping well is established using the electric power historical data set.

[0040] Beneficial effects:

[0041] 1. This application proposes a method for constructing a knowledge base for monitoring the operating conditions of a pumping well based on theoretical electric power reconstruction. This method automatically calculates the theoretical electric power curve based on the measured electric power curve without the need for expert participation, thus avoiding the problem of improper selection of electric power diagrams or standard electric parameter curves due to subjective factors such as insufficient expert experience.

[0042] 2. This application proposes a method for constructing a knowledge base for monitoring the operating conditions of a pumping well based on theoretical electric power reconstruction. This method calculates the hanging point dynamometer diagram using the least squares method based on the discrete sequence of measured electric power data, thereby solving the problem of the upper and lower dead points in the hanging point dynamometer diagram not being closed.

[0043] 3. This application proposes a method for constructing a knowledge base for monitoring the operating conditions of a pumping well based on theoretical electric power reconstruction. This method makes full use of the information of the theoretical electric power curve and the measured electric power curve to improve the accuracy of monitoring the operating conditions of the pumping well.

[0044] 4. This application proposes a method for constructing a knowledge base for monitoring the operating conditions of a pumping well based on theoretical electrical power reconstruction. This method automatically calculates characteristic parameters based on historical data sets of each operating condition, avoiding subjective errors caused by methods such as expert experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flow chart of a method for constructing a knowledge base for monitoring the working conditions of a pumping well based on theoretical electric power reconstruction according to an embodiment of the present application;

[0046] Figure 2 The measured electric power curve diagram of the embodiment of the present application;

[0047] Figure 3 Schematic diagram of the dimensions of the oil pumping unit according to the embodiment of the present application;

[0048] Figure 4 The suspension point indicator diagram under various working conditions of the embodiment of the present application and the generated theoretical indicator diagram;

[0049] Figure 5 Theoretical electric power curve diagram of the embodiment of the present application;

[0050] Figure 6 Schematic diagram of the characteristics of the theoretical electric power curve extracted by the embodiment of the present application;

[0051] Figure 7 Schematic diagram of the characteristics of the measured electric power curve extracted by the embodiment of the present application;

[0052] Figure 8 Measured electric power curves and reconstructed theoretical electric power curves under various working conditions in the embodiments of the present application. DETAILED DESCRIPTION

[0053] The specific implementation of the present application is further described in detail below in conjunction with the drawings and examples.

[0054] The present application proposes a method for constructing a knowledge base for monitoring the working conditions of oil pumping wells based on theoretical electric power reconstruction. First, the theoretical electric power curve is reconstructed by establishing an electric power-to-hanging point dynamometer diagram, a hanging point dynamometer diagram-to-electric power model, and a theoretical dynamometer diagram generation model. Secondly, the relationship between the extracted theoretical electric power curve characteristics, the measured electric power curve characteristics and various working conditions is analyzed to formulate working condition monitoring rules. Finally, the historical data sets of various working conditions are used to automatically calculate the thresholds of the extracted features to establish a knowledge base for monitoring the working conditions of oil pumping wells.

[0055] Example:

[0056] This embodiment proposes a method for constructing a knowledge base for monitoring the working conditions of a pumping well based on theoretical electrical power reconstruction. Figure 1 As shown, including:

[0057] Step S1: obtaining the measured electric power curves of various working conditions of the pumping well and the corresponding pumping unit parameters to form an electric power history data set;

[0058] In this embodiment, the electric power curves of 7 common working conditions, including normal, insufficient liquid supply, gas influence, gas lock, rod break, fixed valve leakage and floating valve leakage, and their corresponding pumping unit parameters are collected to form an electric power history data set, wherein the collected electric power curves are discrete sequences obtained by sampling at equal intervals. This electric power history data set contains n1 insufficient liquid supply conditions, n2 gas influence conditions, n3 gas lock conditions, n4 floating valve leakage conditions, n5 fixed valve leakage conditions, n6 rod break conditions and n7 normal conditions. Let n = n1 + n2 + ... + n7, then this electric power history data set can be described as:

[0059]

[0060] T={T1,T2,…,T q}

[0061] Among them, S m is the collected electric power historical data set, is the i-th electric power curve in the electric power history data set, n is the number of collected electric power curves, q is the number of sampling points of the electric power curve, and T is the set of sampling points. The collected electric power curves are as follows: Figure 2 shown.

[0062] Step S2: establishing a relationship between suspension point displacement, suspension point load, electric power and crank angle, to provide theoretical support for the electric power to suspension point dynamometer diagram model and the suspension point dynamometer diagram to electric power model;

[0063] In this embodiment, the relationship between the suspension point displacement and the crank angle is first established, and then the relationship between the suspension point load, the crank angle and the electric power is established. The specific process is as follows:

[0064] Step S2.1: Establishing a relationship between the suspension point displacement and the crank angle;

[0065] In this embodiment, each crank angle of the pumping unit has a unique suspension point displacement corresponding thereto, but each suspension point displacement may have two crank angles corresponding thereto, namely:

[0066] PR=(ψ b -ψ)A (1)

[0067]

[0068] θ2=mod(2π-θ+κ,2π) (7)

[0069]

[0070] Among them, PR is the suspension point displacement, ψ is the angle between the line between the center of the gearbox output shaft and the center of the bracket bearing and the rear arm of the walking beam, and ψ b is the ψ value when the suspension point is at the bottom dead center, γ is the angle between the line between the center of the crank pin and the center of the bracket bearing and the line between the center of the gearbox output shaft and the center of the bracket bearing, κ is the angle between the line between the center of the gearbox output shaft and the center of the bracket bearing and the vertical direction, θ2 is the crank rotation angle starting from the line between the center of the gearbox output shaft and the center of the bracket bearing, counterclockwise as the positive direction, θ is the crank rotation angle starting from the vertical direction, clockwise as the positive direction; A is the length of the front arm of the pumping unit walking beam, C is the length of the rear arm of the pumping unit walking beam, P is the length of the connecting rod, L is the length from the center of the crank pin to the center of the bracket bearing, K is the length from the center of the gearbox output shaft to the center of the bracket bearing, I is the horizontal distance from the center of the gearbox output shaft to the center of the bracket bearing, and R is the crank radius; J is a piecewise function, indicating that when the crank angle is less than π, γ is a positive value, and when the crank angle is greater than π, γ is a negative value. The pumping unit size diagram is shown in Figure 3 shown.

[0071] Step S2.2: Establishing a relationship between the suspension point load, crank angle and suspension point load torque;

[0072] In this embodiment, the suspension point load torque can be calculated by multiplying the torque factor and the suspension point load at the same crank angle, that is,

[0073] M r =TF(PRL-SUB) (9)

[0074]

[0075] α=π-(θ2-θ3) (11)

[0076] β=π-ψ-θ3 (12)

[0077]

[0078] Among them, M r is the suspension point load torque, PRL is the suspension point load, SUB is the structural unbalanced weight, TF is the torque factor of the pumping unit, α is the angle between the crank and the connecting rod, β is the angle between the walking beam and the connecting rod, and θ3 is the angle between the connecting rod and the line from the center of the reduction box output shaft to the center of the bracket bearing.

[0079] When the pumping unit parameters are determined, the relationship between the torque factor and the crank angle can be determined according to formula (10). The torque factor describes the force transmission process from the load at the suspension point to the suspension point load torque at the center of the crankshaft. The load at the suspension point transmits the force to the center of the crankpin through the walking beam, connecting rod and crank. The force transmitted to the center of the crankpin will generate a torque at the center of the crankshaft. The torque generated is the suspension point load torque.

[0080] Step S2.3: Establish a relationship between the suspension point load torque and the electric power.

[0081] In this embodiment, the relationship between the suspension point load torque and the electric power is as follows:

[0082]

[0083] M e =M net i g i b (15)

[0084] M net =M r -M b (16)

[0085] M b =M bmax sinθ (17)

[0086] Among them, M b To balance the torque, M e is the motor load torque, M net is the net crank torque, n N is the rated speed, P m is the motor power, M r is the suspension load torque, P m is the electric power, i g is the gearbox transmission ratio, i b is the pulley reduction ratio, n N is the rated speed of the motor; M bmax is the maximum balancing torque, that is, the product of the sum of the weights of the balancing block and the crank pin and the balancing radius. The weight of the balancing block, the weight of the crank pin and the crank radius are the parameters of the pumping unit.

[0087] Step S3: establishing an electric power-to-suspension point dynamometer diagram model according to the relationship between the suspension point displacement, suspension point load, electric power and crank angle, and calculating the suspension point dynamometer diagram corresponding to the measured electric power curve;

[0088] In this embodiment, taking the ith electric power curve data in the electric power data set as an example, the suspension point load value corresponding to each electric power value in the ith electric power curve data is calculated. First, a model of electric power to suspension point load torque is established, then a crank angle to pumping unit torque factor model and a suspension point load torque to suspension point load model are established, and finally a crank angle to suspension point displacement model is established, thereby completing the establishment of the suspension point indicator diagram, including:

[0089] Step S3.1: According to the relationship between the suspension point load torque and the electric power, a model of converting the electric power to the suspension point load torque is established to calculate the suspension point load torque corresponding to the measured electric power;

[0090] In this embodiment, the suspension point load torque corresponding to each electric power is calculated according to the relationship between the suspension point load torque and the electric power (14)-(17), that is,

[0091]

[0092] in, is the suspension load torque value corresponding to the jth sampling point in the i-th electric power curve, is the crank angle corresponding to the jth sampling point in the i-th electric power curve.

[0093] Step S3.2: According to the relationship between the crank angle and the suspension point load torque, a crank angle to torque factor model is established to calculate the torque factor corresponding to the crank angle;

[0094] In this embodiment, the torque factor of the pumping unit corresponding to each crank angle is calculated according to equations (7), (10)-(13), that is,

[0095]

[0096] in, is the torque factor corresponding to the jth sampling point in the i-th electric power curve, is the α value corresponding to the jth sampling point in the i-th electric power curve, is the β value corresponding to the jth sampling point in the i-th electric power curve, is the θ3 value corresponding to the jth sampling point in the i-th electric power curve, is the θ2 value corresponding to the jth sampling point in the i-th electric power curve, is the γ value corresponding to the jth sampling point in the i-th electric power curve, is the L value corresponding to the jth sampling point in the ith electric power curve.

[0097] Step S3.3: According to the relationship between the suspension point load and the suspension point load torque, a suspension point load torque conversion model is established to calculate the suspension point load corresponding to the suspension point load torque;

[0098] In this embodiment, according to the relationship between the suspension point load and the suspension point load torque (9), the suspension point load corresponding to each suspension point load torque is calculated using the least squares method, that is,

[0099]

[0100] in, is the optimal suspension point load value corresponding to the jth sampling point in the i-th electric power curve, is the suspension point load variable corresponding to the jth sampling point in the i-th electric power curve; They represent the upper and lower limits of the allowable suspension point load respectively, and χ is the threshold parameter.

[0101] Step S3.4: According to the relationship between the suspension point displacement and the crank angle, a crank angle to suspension point displacement model is established to calculate the suspension point displacement corresponding to the crank angle.

[0102] In this embodiment, the suspension point displacement corresponding to each crank angle is calculated according to the relationship between the suspension point displacement and the crank angle (1)-(8).

[0103]

[0104] in, is the suspension point displacement corresponding to the jth sampling point in the i-th electric power curve, is the ψ value corresponding to the jth sampling point in the ith electric power curve.

[0105] With the suspension point displacement as the horizontal axis and the suspension point load as the vertical axis, draw the suspension point indicator diagram corresponding to the measured electric power curve. The calculated suspension point indicator diagram is as follows: Figure 4 shown.

[0106] Step S4: using a method for generating a theoretical dynamometer diagram, converting the calculated suspension point dynamometer diagram into a theoretical dynamometer diagram;

[0107] In this embodiment, the theoretical dynamometer diagram is a parallelogram consisting of an upper load line, a lower load line, a loading section, and an unloading section, and is an important theoretical basis for judging the working conditions of the pumping well. Therefore, the calculated suspension point dynamometer diagram is converted into a theoretical dynamometer diagram, including:

[0108] Step S4.1: Calculate the slopes of the loading and unloading sections of the theoretical dynamometer diagram;

[0109] In this embodiment, the slopes of the loading section and the unloading section are equal in the theoretical dynamometer diagram. The calculated suspension point dynamometer diagram starts from the suspension point displacement at the bottom dead center and takes the upper stroke n. u The average slope of the sampling points is calculated. u It is the number of sampling points when the sucker rod string is deformed during the upstroke.

[0110] Step S4.2: Calculate the upper load line of the theoretical dynamometer diagram;

[0111] In this embodiment, the upper load line of the theoretical dynamometer diagram is the average suspension point load value of all sampling points from the sampling point corresponding to the maximum suspension point load in the upstroke to the sampling point corresponding to the top dead center.

[0112] Step S4.3: Calculate the lower load line of the theoretical dynamometer diagram;

[0113] In this embodiment, the lower load line of the theoretical dynamometer diagram is the average suspension point load value of all sampling points from the sampling point corresponding to the minimum suspension point load of the downstroke to the sampling point corresponding to the top dead center.

[0114] Step S4.4: Generate a theoretical dynamometer diagram corresponding to the calculated suspension point dynamometer diagram according to the slopes of the loading section and the unloading section, the upper load line, and the lower load line of the theoretical dynamometer diagram.

[0115] In this embodiment, a parallelogram can be determined based on the calculated slopes of the loading section and the unloading section, the upper load line and the lower load line. This parallelogram is the generated theoretical dynamometer diagram. Taking the i-th data as an example, the j-th load data and displacement data in the generated theoretical dynamometer diagram are respectively and The suspension point indicator diagram of each working condition and the generated theoretical indicator diagram are as follows: Figure 4 shown.

[0116] Step S5: establishing a suspension point dynamometer diagram to electric power model according to the relationship between the suspension point displacement, suspension point load, electric power and crank angle, and calculating a theoretical electric power curve corresponding to the theoretical dynamometer diagram;

[0117] In this embodiment, taking the ith data as an example, the theoretical electric power value corresponding to each sampling point in the theoretical dynamometer diagram is calculated. First, the theoretical crank angle corresponding to each theoretical suspension point displacement is calculated using the least squares method, then the torque factor corresponding to each theoretical crank angle and the theoretical suspension point load torque corresponding to each theoretical suspension point load are calculated, and finally the theoretical electric power corresponding to each theoretical suspension point load torque is calculated, including:

[0118] Step S5.1: According to the relationship between the suspension point displacement and the crank angle, a suspension point displacement to crank angle model is established to calculate the theoretical crank angle corresponding to the theoretical suspension point displacement;

[0119] In this embodiment, according to the relationship between the suspension point displacement and the crank angle (1)-(8), the least square method is used to calculate the theoretical crank angle corresponding to each theoretical suspension point displacement, that is,

[0120]

[0121] in, is the optimal theoretical crank angle corresponding to the jth sampling point in the i-th electric power curve, is the theoretical suspension point displacement corresponding to the jth sampling point in the i-th electric power curve, is the crank angle variable corresponding to the jth sampling point in the i-th electric power curve, and are the upper and lower limits of the allowed crank angle respectively. When located at the upstroke sampling point, when When located in the downstroke sampling point,

[0122] Step S5.2: Calculate the torque factor of the pumping unit corresponding to the theoretical crank angle according to the crank angle to torque factor model;

[0123] In this embodiment, the torque factor corresponding to each theoretical crank angle is calculated according to the relationship between the torque factor of the oil pumping unit and the crank angle established by equation (18).

[0124] Step S5.3: According to the relationship between the suspension point load and the suspension point load torque, a suspension point load to suspension point load torque model is established to calculate the theoretical suspension point load torque corresponding to the theoretical suspension point load;

[0125] In this embodiment, the theoretical suspension point load torque corresponding to each theoretical suspension point load is calculated according to formula (9), that is,

[0126]

[0127] in, is the theoretical suspension point load torque corresponding to the jth sampling point in the i-th electric power curve.

[0128] Step S5.4: According to the relationship between the suspension point load torque and the electric power, a suspension point load to electric power conversion model is established to calculate the theoretical electric power corresponding to the theoretical suspension point load torque.

[0129] In this embodiment, the theoretical electric power corresponding to each theoretical suspension point load torque is calculated according to the relationship between the suspension point load torque and the electric power (14)-(17), that is,

[0130]

[0131] in, is the theoretical electric power value corresponding to the jth sampling point in the i-th electric power curve.

[0132] The theoretical electric power curve is established with the theoretical electric power value as the ordinate and the sampling time as the abscissa. The established theoretical electric power curve is as follows: Figure 5 shown.

[0133] Step S6: extracting shape features of the theoretical electric power curve and the measured electric power curve, and establishing a knowledge base for monitoring the working conditions of the pumping well.

[0134] In this embodiment, the key features of the theoretical electric power curve and the measured electric power curve are first determined, and then the relationship between the theoretical electric power curve features, the measured electric power curve features and the working conditions is determined. Finally, the characteristic parameters of the working condition monitoring knowledge base are determined according to the electric power historical data set, including:

[0135] Step S6.1: Determine key features of the theoretical electric power curve;

[0136] In this embodiment, the extracted theoretical electric power curve features are shown in Table 1. Figure 6 shown.

[0137] Table 1 Theoretical electric power curve characteristics extracted

[0138]

[0139] Step S6.2: determining key features of the measured electric power curve;

[0140] In this embodiment, the extracted measured electric power curve features are shown in Table 2. Figure 7 shown.

[0141] Table 2 Extracted measured power curve characteristics

[0142]

[0143]

[0144] Step S6.3: Determine the relationship between the theoretical electric power curve characteristics, the measured electric power curve characteristics and the operating conditions;

[0145] In this embodiment, the relationship between the theoretical electric power curve characteristics, the measured electric power curve characteristics and the working conditions is shown in Table 3, where x1, x2…x 10 is the characteristic parameter. The measured electric power curve of each working condition and the reconstructed theoretical electric power curve are as follows Figure 8 shown.

[0146] Table 3 Relationship between theoretical power curve characteristics, measured power curve characteristics and operating conditions

[0147]

[0148] Step S6.4: Based on the key features of the theoretical electric power curve, the key features of the measured electric power curve, the features of the theoretical electric power curve, the relationship between the features of the measured electric power curve and the working conditions, a knowledge base for monitoring the working conditions of the pumping well is established using the electric power history data set.

[0149] In this embodiment, the characteristic parameters x1, x2…x of the working condition monitoring knowledge base are calculated by using the relationship between the constructed electric power data set and the determined theoretical electric power curve characteristics, the measured electric power curve characteristics and the working condition. 10 .

[0150] For the characteristic parameter x1, the historical electric power data of n1 insufficient liquid supply conditions are concentrated. The minimum value of is determined, that is

[0151]

[0152] in, Represents the i-th electric power curve in the insufficient liquid supply condition data set value.

[0153] For characteristic parameters x2, x3, x4, x5, the historical electric power data of n2 gas-affected operating conditions are concentrated. and The minimum and maximum values ​​of

[0154]

[0155] in, Represents the i-th electric power curve in the gas-affected operating condition data set value, Represents the i-th electric power curve in the gas-affected operating condition data set value.

[0156] For characteristic parameters x6, x7, according to the historical electric power data of n3 gas lock conditions, and The minimum value of is determined, that is

[0157]

[0158] in, Represents the i-th electric power curve in the gas lock condition data set value, Represents the i-th electric power curve in the gas-affected operating condition data set value.

[0159] For characteristic parameters x8, x9, the electric power data of n4 floating valve leakage conditions are concentrated Minimum and The maximum value is determined, that is

[0160]

[0161]

[0162] in, Represents the i-th electric power curve in the floating valve leakage condition data set value, Represents the i-th electric power curve in the floating valve leakage condition data set value.

[0163] For the characteristic parameter x 10 , based on the electric power data of n5 fixed valve leakage conditions The maximum value of is determined, that is

[0164]

[0165] in, Represents the i-th electric power curve in the floating valve leakage condition data set value.

[0166] Based on the above established knowledge base for monitoring the working condition of the pumping well, the working condition of the pumping well is monitored in real time. First, the collected measured electric power curve is used to calculate the theoretical electric power curve, and then the features of the measured electric power curve and the theoretical working condition electric power curve are extracted. Finally, the extracted features are input into a computer containing the established knowledge base, and the computer outputs the current working condition type.

[0167] The various embodiments in the present application are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0168] The protection scope of the present application is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the scope and spirit of the present disclosure. If these changes and modifications fall within the scope of the claims of the present disclosure and their equivalents, the intention of the present disclosure also includes these changes and modifications.

Claims

1. A method for constructing a knowledge base for monitoring the working conditions of a pumping well based on theoretical electric power reconstruction, characterized in that: include: Obtain the measured electric power curves of various working conditions of the pumping well and the corresponding pumping unit parameters to form an electric power history data set; Establish the relationship between suspension point displacement, suspension point load, electric power and crank angle; According to the relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle, a model of converting the electric power to the suspension point indicator diagram is established, and the suspension point indicator diagram corresponding to the measured electric power curve is calculated; The method of generating the theoretical dynamometer diagram is adopted to transform the calculated suspension point dynamometer diagram into the theoretical dynamometer diagram; According to the relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle, a suspension point dynamometer diagram to electric power conversion model is established to calculate the theoretical electric power curve corresponding to the theoretical dynamometer diagram; The shape characteristics of the theoretical electric power curve and the measured electric power curve are extracted, and the knowledge base for monitoring the working condition of the pumping well is established using the electric power historical data set.

2. The method for constructing a knowledge base for monitoring the working condition of a pumping well based on theoretical electric power reconstruction according to claim 1 is characterized in that: The obtained measured electric power curves of various working conditions of the pumping well and the corresponding pumping unit parameters constitute an electric power history data set, including: The electric power curves and their corresponding pumping unit parameters under normal, insufficient liquid supply, gas influence, gas lock, rod break, fixed valve leakage and floating valve leakage conditions are collected to form an electric power history data set.

3. The method for constructing a knowledge base for monitoring the working condition of a pumping well based on theoretical electric power reconstruction according to claim 1 is characterized in that: The relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle is established, including: Establish the relationship between the suspension point displacement and the crank angle; Establish the relationship between the suspension point load, crank angle and suspension point load torque; Establish the relationship between the suspension point load torque and the electric power.

4. The method for constructing a knowledge base for monitoring the working condition of a pumping well based on theoretical electric power reconstruction according to claim 1 is characterized in that: The method of establishing an electric power-to-suspension point dynamometer diagram model based on the relationship between the suspension point displacement, the suspension point load, the electric power and the crank angle, and calculating the suspension point dynamometer diagram corresponding to the measured electric power curve includes: According to the relationship between the suspension point load torque and the electric power, a model of converting the electric power to the suspension point load torque is established to calculate the suspension point load torque corresponding to the measured electric power; According to the relationship between the crank angle and the suspension point load torque, a crank angle to torque factor model is established to calculate the torque factor corresponding to the crank angle; According to the relationship between the suspension point load and the suspension point load torque, a suspension point load torque conversion model is established to calculate the suspension point load corresponding to the suspension point load torque; According to the relationship between suspension point displacement and crank angle, a crank angle to suspension point displacement model is established to calculate the suspension point displacement corresponding to the crank angle.

5. The method for constructing a knowledge base for monitoring the working condition of a pumping well based on theoretical electric power reconstruction according to claim 1, characterized in that: The method for generating the theoretical dynamometer diagram is to convert the calculated suspension point dynamometer diagram into the theoretical dynamometer diagram, including: Calculate the slopes of the loading and unloading sections of the theoretical dynamometer diagram; Calculate the upper load line of the theoretical dynamometer diagram; Calculate the lower load line of the theoretical dynamometer diagram; According to the loading section and unloading section slopes, the upper load line and the lower load line of the theoretical dynamometer diagram, a theoretical dynamometer diagram corresponding to the calculated suspension point dynamometer diagram is generated.

6. The method for constructing a knowledge base for monitoring the working condition of a pumping well based on theoretical electric power reconstruction according to claim 1, characterized in that: The method of establishing a suspension point dynamometer diagram to electric power model and calculating a theoretical electric power curve corresponding to the theoretical dynamometer diagram includes: According to the relationship between suspension point displacement and crank angle, a suspension point displacement to crank angle model is established to calculate the theoretical crank angle corresponding to the theoretical suspension point displacement; According to the crank angle to torque factor model, the torque factor of the pumping unit corresponding to the theoretical crank angle is calculated; According to the relationship between the suspension point load and the suspension point load torque, a suspension point load to suspension point load torque model is established to calculate the theoretical suspension point load torque corresponding to the theoretical suspension point load; According to the relationship between the suspension point load torque and the electric power, a suspension point load to electric power model is established to calculate the theoretical electric power corresponding to the theoretical suspension point load torque.

7. The method for constructing a knowledge base for monitoring the working condition of a pumping well based on theoretical electric power reconstruction according to claim 1, characterized in that: The method of extracting the shape features of the theoretical electric power curve and the measured electric power curve and establishing a knowledge base for monitoring the working conditions of the pumping well using the electric power history data set includes: Determine the key features of the theoretical electrical power curve; Determine key features of measured electrical power curves; Determine the relationship between theoretical electric power curve characteristics, measured electric power curve characteristics and operating conditions; According to the key features of the theoretical electric power curve, the key features of the measured electric power curve, the characteristics of the theoretical electric power curve, the relationship between the characteristics of the measured electric power curve and the working conditions, a knowledge base for monitoring the working conditions of the pumping well is established using the electric power historical data set.

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