Oil pumping unit indicator diagram correction and production and liquid level metering method based on data driving

Abstract

The invention discloses an oil pumping unit indicator diagram correction and production and liquid level metering method based on data driving, and relates to the technical field of oil exploitation, and the method comprises the following steps: S1, obtaining indicator diagram data of an oil field oil pumping unit well, and collecting an original suspension center indicator diagram through a power indicator; s2, obtaining a temperature drift correction coefficient and a null drift correction coefficient according to basic data in the original suspension point indicator diagram, and correcting a load measured by a suspension point to obtain a corrected indicator diagram; s3, displacement of different layers is obtained through operation according to a difference method, loads of time points of different layers are obtained in combination with the Hooke law, and indicator diagrams of different positions of the sucker rod string are obtained; and S4, a pump indicator diagram is calculated in combination with working fluid level iteration and a difference method, and calculation, digital production calculation and liquid level calculation of the oil well working fluid level are completed. According to the method, the precision and accuracy of the indicator diagram can be improved, and a powerful guarantee is provided for oil well digital technology and scientific management development.

Description

Technical Field

[0001] The present invention relates to the field of oil production technology, in particular to the field of automation technology of information collection and data analysis in oil production engineering, and more specifically to a method for correcting a pumping unit dynamometer diagram and calculating production and liquid level based on data drive. Background Art

[0002] During oil production, the operating status of the pumping unit is a key factor influencing oil well production efficiency. To effectively monitor the pumping unit's operation, the dynamometer diagram, a crucial tool for reflecting its operating status, provides a visual representation of the well's load changes, the mechanical condition of the sucker rod system, and the well's internal operating conditions. However, the accuracy of the dynamometer diagram is often affected by various external factors. For example, long-term operation of the dynamometer under conditions such as alternating loads and wide temperature fluctuations can lead to temperature drift and zero drift in the load sensor. This can cause the dynamometer diagram to become offset and distorted, making it unable to accurately reflect the actual operating status of the pumping unit. Therefore, dynamometer diagram calibration is an essential and critical step in the oil well production process.

[0003] Existing dynamometer calibration methods rely primarily on manual judgment and regular manual calibration, increasing the difficulty and labor costs of oilfield management. In particular, failure to promptly detect zero drift and temperature drift in the dynamometer load sensor can severely impact the dynamometer measurement accuracy, potentially rendering the promotion of oil well digitization technology based on the hanging point dynamometer diagram impractical. For example, pump dynamometer diagrams, well dynamic fluid levels, well production, parameter adjustments, and operating condition diagnostics predicted based on the hanging point dynamometer diagrams can suffer from significant accuracy errors. Proposing an online dynamometer correction method is crucial for oil well management and digitization. However, no theoretical or methodological approaches for online, real-time dynamometer correction have been reported, and there is no guarantee that the corrected dynamometer diagrams accurately reflect real-time dynamic fluid level changes and adapt to complex operating conditions with missing data.

[0004] During the operation of the pumping unit, the suspension point power diagram is converted to downhole pump power diagram. Figure 1This has long been a hot research topic among oilfield researchers. Downhole pump dynamometers are essential for accurately calculating oil well production and dynamic fluid levels, and are also a crucial basis for the digitization of pumping wells. Currently, most researchers, both domestically and internationally, have conducted extensive research on dynamic fluid level calculations and pumping unit dynamometer data analysis, using differential or Fourier series methods to solve the Gibbs one-dimensional wave equation. The suspension point displacement and load data of a beam pumping unit are collected, and the suspension point dynamometer diagram is plotted based on these data. The suspension point load is acquired using strain gauges. When using metal strain gauges for measurement, temperature changes can cause output signal offsets. This is because the thermal expansion coefficient of the metal strain gauge material varies with temperature, leading to an unstable relationship between the output signal and temperature, which in turn causes dynamometer diagram anomalies. Furthermore, displacement measurement in the suspension point dynamometer diagram, whether using wired or wireless displacement sensors, can introduce significant errors.

[0005] Therefore, how to provide a data-driven method for correcting the pumping unit indicator diagram and measuring production and liquid level, improve the precision and accuracy of the indicator diagram, and provide a strong guarantee for the development of oil well digital technology and scientific management is a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0006] In view of this, the present invention provides a data-driven method for correcting the dynamometer diagram of an oil well pump and calculating production and liquid level. On the one hand, the temperature drift and zero drift coefficient of the load sensor are corrected by solving the one-dimensional wave equation by an iterative method in combination with the downhole static parameters; on the other hand, the suspension point displacement is corrected in combination with the structural parameters of the oil well pump. The above correction process will greatly improve the precision and accuracy of the dynamometer diagram, providing a strong guarantee for the development of digital technology and scientific management of oil wells.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A data-driven method for correcting a pumping unit's dynamometer diagram and calculating production and liquid level includes the following steps:

[0009] S1. Obtaining the power diagram data of the oilfield pumping well, and collecting the original suspension point power diagram through the power indicator;

[0010] S2. Calculate the temperature drift correction coefficient and the zero drift correction coefficient based on the basic data of the original suspension point dynamometer diagram, and correct the load measured at the suspension point to obtain a corrected dynamometer diagram;

[0011] S3. Obtain the displacement of different layers using the differential method, and obtain the load of different layers at different time points using Hooke's law, and obtain the work diagram of different positions of the sucker rod string;

[0012] S4. Combine the dynamic liquid level iteration and differential method to calculate the pump power diagram, and complete the calculation of the dynamic liquid level of the oil well, digital production and liquid level.

[0013] Optionally, the well condition parameters of the pumping well include: first-stage rod length, first-stage rod diameter, oil pressure, casing pressure, pump diameter, pump depth, water content, stroke, and number of strokes.

[0014] Optionally, before S2, the method further includes: calculating a reference load of a standard dynamometer diagram according to the following formula based on well condition parameters of the pumping well, as a basis for determining whether the dynamometer diagram needs to be corrected;

[0015] P 静上 =P' 杆 +P' 液

[0016] P 静下 =P' 杆

[0017] Where: P 静上 is the reference load of the upper static load line, P 静下 is the reference load of the lower static load line, P′ 杆 is the weight of the sucker rod string in the liquid column, P′ 液 It is the weight of the liquid column in the oil well whose cross-sectional area above the dynamic liquid level is equal to the plunger area.

[0018] Optionally, in S2, the load measured at the suspension point is corrected, specifically comprising the following steps:

[0019] In the up and down strokes, the average acceleration is 0. According to the inertia load waveform, the average load of the up stroke BC section and the down stroke DA section is calculated:

[0020]

[0021] According to the A, B, C, and D points of the suspension load, measure the average load of the upstroke BC section and the downstroke DA section; combine the calculated average load of the upstroke BC section and the downstroke DA section to calculate T according to the following formula: f and P of ;

[0022]

[0023] According to the obtained T f and P of , correct the load measured at the suspension point to obtain the corrected dynamometer diagram;

[0024] Where: is the calculated value of the average load on the upstroke, is the calculated value of the average load of the downstroke, is the measured value of the average load on the upstroke, is the measured value of the average load during the downstroke; P′ 杆 is the weight of the sucker rod string in the liquid column, P′ 液 P is the weight of the liquid column with a cross-sectional area equal to the plunger area above the dynamic liquid level in the oil well, 油 is the wellhead oil pressure, F is the cross-sectional area of ​​the pump plunger, ρ 液 is the density of the produced liquid, g is the acceleration of gravity, h is 沉 is the submergence of the pump, P t is the casing pressure, T f is the temperature drift correction coefficient, P of is the zero drift correction coefficient.

[0025] Optionally, in S3, obtaining the work diagrams of different positions of the sucker rod string specifically includes the following steps:

[0026] Take the rod column micro unit Δx and analyze it from the spatial and temporal directions respectively. Define the spatial direction downward as the positive direction. The load on the rod column micro unit Δx includes the micro unit self-weight f w , micro unit inertia force f a (x, t), micro-element damping force f v (x, t) and the micro-unit internal forces f(x, t) and f(Δx+x, t), are expressed as follows:

[0027]

[0028] According to the balance of forces, we can obtain:

[0029] f(Δx+x,t)-f(x,t)=f a (x,t)+f v (x,t)-f w

[0030] After sorting, we get the one-dimensional wave equation:

[0031]

[0032] For the same-level sucker rod string, the rod string is divided into m units along the axis with equal steps, the step size is Δx, and each unit is represented by the subscript i, i = 0, 1, 2, 3, ..., m; the time is divided into n units with equal steps, the time step is Δt, and each time point is represented by the subscript j, j = 0, 1, 2, 3, ..., n;

[0033] Newton's forward interpolation formula is:

[0034]

[0035] Get the central difference:

[0036]

[0037] Similarly, we can get the second-order central difference formula of u to x:

[0038]

[0039] The displacement equation of the homogeneous section of the sucker rod string is obtained by combining the equations:

[0040]

[0041] The first layer of the differential network is the suspension point displacement, and the calculation formula of the suspension point load is:

[0042]

[0043] The calculation formula for the second layer displacement of the differential network is:

[0044]

[0045] Starting from the third layer, in the process of calculating the displacement using the formula, the periodic boundary conditions of the following formula are used to calculate the displacement of each time point downward using the differential grid form;

[0046] u i,0 =u i,n ,u i,1 =u i,n+1

[0047] The displacement of different layers is obtained by differential calculation, and the load of different layers at different time points is obtained by combining Hooke's law, so that the work diagram of different positions of the sucker rod string can be obtained.

[0048] Where: ρ 杆 is the density of the steel sucker rod, A is the cross-sectional area of ​​the sucker rod, g is the acceleration of gravity, v is the viscosity coefficient, E is the elastic modulus of the sucker rod, and c is the wave velocity; u i,j is the displacement of the i-th node on the column at time j, f 0,j It is the first layer load of the differential network.

[0049] Optionally, in S4, when the calculation of the dynamic liquid level of the oil well, the digital production and liquid level are completed, the specific steps are as follows:

[0050] Within the framework of the suspension point load correction model, by using the oil well dynamic liquid level or submergence as a known boundary condition and combining iterative differential algorithms for the dynamic liquid level of the suspension point dynamometer diagram, high-precision inversion of the downhole dynamic liquid level and adaptive calibration of the load sensor's temperature drift and zero drift coefficients can be achieved simultaneously when the theoretical prediction value and the actual calculation result reach a convergence threshold.

[0051] When the dynamic liquid level of the oil well is iterated in a cycle, the dynamic liquid level depth of the oil well is calculated through the load characteristics:

[0052]

[0053] Convert the corrected suspension point work diagram to the pump work diagram to obtain the upper and lower load differences in the pump work diagram:

[0054]

[0055] The production calculation formula in the actual production process is:

[0056] Q 实 =1440·(S pe ·F-ΔQ)·N

[0057] The calculation method for the loss per stroke is:

[0058]

[0059] P c =ρ 液 gh 挂 +P 油

[0060] Where: H is the calculated dynamic liquid level, ΔP is the upper and lower load difference in the pump power diagram, F is the cross-sectional area of ​​the plunger, ρ 液 is the density of the produced liquid, g is the acceleration due to gravity, is the average load on the pump stroke diagram, is the average load of the lower stroke of the pump diagram, Q 实 To predict production, S pe is the effective stroke of the oil well pump plunger, ΔQ is the leakage of the oil well pump per stroke, N is the number of strokes, D p is the diameter of the oil well pump plunger, δ is the average value of the concentric clearance of the plunger pump barrel, P d is the pump discharge pressure, P c is the pump suction pressure, μ is the fluid dynamic viscosity, l z is the plunger length, e is the eccentricity, is the average speed of the upstroke, h 沉 is the submergence of the pump, h 挂 is the pump hanging depth, is the wellhead oil pressure, Wellhead casing pressure.

[0061] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a data-driven method for correcting the dynamometer diagram of a pumping unit and calculating production and liquid level, which achieves the following beneficial effects:

[0062] This invention utilizes physical sensors such as strain gauges, displacement sensors, and temperature sensors for data acquisition, and performs signal processing via a computer. It proposes an online correction algorithm for the load sensor's temperature drift and zero drift. This algorithm effectively and automatically corrects the dynamometer diagram collected by the dynamometer, significantly improving the precision and accuracy of dynamometer testing. This method provides a better basis for determining the operating condition of the pumping unit and, in turn, optimizes its efficiency. This method is primarily applied to dynamometer diagram correction and production and liquid level measurement for beam pumping units, enabling digital oil production from these units. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0064] Figure 1 A schematic diagram of the motion mechanism of the oil pumping unit provided by the present invention;

[0065] Figure 2 A flow chart of the motion parameter sorting algorithm provided by the present invention;

[0066] Figure 3 The displacement curve of the suspension point of the oil pumping unit provided by the present invention;

[0067] Figure 4 The oil well actual measured suspension point work diagram provided by the present invention;

[0068] Figure 5 A flow chart of the data-driven method for correcting the pumping unit's dynamometer diagram and calculating production and liquid level provided by the present invention;

[0069] Figure 6 A schematic diagram of the upward offset of the load generated by the power diagram provided by the present invention;

[0070] Figure 7 A schematic diagram of a downward offset of a load on a power diagram provided by the present invention;

[0071] Figure 8 Schematic diagram of temperature drift and zero drift generated by the power diagram load provided by the present invention;

[0072] Figure 9 A schematic diagram of the force acting on the rod micro-unit provided by the present invention;

[0073] Figure 10 A grid diagram for solving a one-dimensional wave equation using the difference method provided by the present invention;

[0074] Figure 11The iterative method provided by the present invention is used to cyclically solve the pump work diagram, dynamic liquid level and production flow chart;

[0075] Figure 12 The present invention provides the modified front and rear suspension point power diagram and pump power diagram. DETAILED DESCRIPTION

[0076] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments 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.

[0077] Explanation of terms:

[0078] Suspension point work diagram: The work done by the changes in the load at the polished rod suspension point of the pumping well and the ground displacement are simplified into a closed geometric figure. By considering the influence of temperature drift, zero drift and friction load on the suspension point work diagram, the pump work diagram is inverted to achieve production and liquid level measurement and intelligent parameter adjustment of the pumping well.

[0079] Pump performance diagram: The load and displacement information of the downhole pump when the pumping unit is running. The pump performance diagram can reflect the working condition of the downhole pump, the production status of the oil well and potential failures.

[0080] Dynamic liquid level: When the pumping well is in normal production, there is a liquid level in the annular space between the oil pipe and casing. This liquid level is the dynamic liquid level. The position of the dynamic liquid level is generally expressed by the depth measured from the wellhead.

[0081] The dynamometer diagram for a pumping well is composed of the displacement and load at the suspension point. Displacement is typically measured using a wire-type displacement sensor or a wireless displacement sensor. If the wireless displacement sensor uses an accelerometer, it obtains acceleration data at the suspension point and then calculates displacement by integrating it twice over time. The cumulative error from this integration (especially over long periods of time) can lead to significant errors in the calculated displacement. Even if the acceleration signal is small, multiple integrations can cause the error to grow, leading to discrepancies between the measured and actual displacements.

[0082] The operating principle of a pumping unit reveals that its primary motion steering mechanism is a crank-rocker mechanism, which converts the circular motion of the crank into reciprocating linear motion between top and bottom dead centers. The kinematic characteristics of the four-bar linkage are fundamental to determining the basic kinematic parameters of the pumping unit. Establishing a precise kinematic model for the suspension point based on the unit's structural parameters allows for the correction of the unit's suspension point displacement.

[0083] exist Figure 1In the schematic diagram of the beam pumping unit's structure and motion, R is the crank radius, P is the connecting rod length, C is the length of the beam's rear arm, K is the base rod length, A is the length of the beam's front arm, and I is the horizontal projection of the base rod. For ease of analysis, the positive directions of the angles in the diagram are defined as follows: (1) The crank angle θ is measured from the 12 o'clock position and is positive in the clockwise direction; (2) The reference angles θ2, θ3, and θ4 of each member are measured from the base rod OO1 and are positive in the counterclockwise direction.

[0084] The bottom dead center is the zero point of displacement, and upward is the positive direction of displacement. The displacement S at any time is:

[0085]

[0086] The above method of calculating the motion law of the suspension point has been widely used. However, when performing the dynamic analysis of the suspension point, it is often overlooked that the kinematic law of the suspension point is calculated based on the crank being at 12 o'clock, which is ahead of the bottom dead center of the pumping unit. Therefore, it is necessary to follow the Figure 2 The motion parameters are reordered starting from the bottom dead center, where i represents the sequence number of the motion parameters, S represents the displacement value of any point position, and num represents the total number of motion parameters.

[0087] according to Figure 3 The displacement curve of the pumping unit suspension point and Figure 4 The measured suspension point work diagram of the oil well shown in the figure shows that both the measured displacement value and the suspension point work diagram are too large or too small. Therefore, in order to better analyze the pumping unit suspension point work diagram and invert the suspension point work diagram to obtain the pump work diagram, it is necessary to correct the suspension point displacement.

[0088] To achieve this goal, the present invention discloses a data-driven method for correcting the pumping unit dynamometer diagram and calculating production and liquid level. Figure 5 As shown, the following steps are included:

[0089] S1. Obtaining the power diagram data of the oilfield pumping well, and collecting the original suspension point power diagram through the power indicator;

[0090] S2. Calculate the temperature drift correction coefficient and the zero drift correction coefficient based on the basic data of the original suspension point dynamometer diagram, and correct the load measured at the suspension point to obtain a corrected dynamometer diagram;

[0091] S3. Obtain the displacement of different layers using the differential method, and obtain the load of different layers at different time points using Hooke's law, and obtain the work diagram of different positions of the sucker rod string;

[0092] S4. Combine the dynamic liquid level iteration and differential method to calculate the pump power diagram, and complete the calculation of the dynamic liquid level of the oil well, digital production and liquid level.

[0093] Based on the above process, this embodiment mainly solves the problem of inaccurate displacement and load measured by the dynamometer. The error of the wire displacement sensor comes from human operation or environmental wind load, and the error of the wireless displacement sensor comes from the error of the acceleration sensor's two-time integration. That is, no matter what displacement sensor is used, the displacement measurement error cannot be completely eliminated. Since the load sensor is affected by factors such as alternating loads and large changes in ambient temperature for a long time, temperature drift and zero drift are inevitable in the load sensor. Temperature drift solves the problem of large difference in upper and lower loads on the dynamometer diagram, and zero drift solves the problem of overall upper and lower offset of the dynamometer diagram. It can effectively and automatically correct the dynamometer diagram collected by the dynamometer, greatly improving the precision and accuracy of the dynamometer diagram test, and better providing a basis for judging the working condition of the oil pump.

[0094] Next, Figure 5 The process shown is described in detail to further understand the technical solution.

[0095] (1) Measurement principle and correction of load at suspension point of power diagram

[0096] According to the actual situation of the oil well, the following reasonable assumptions are made:

[0097] 1) The annulus of the rod and tube during the upstroke is filled with well fluid;

[0098] 2) The rod string combination and the water content of the well fluid are known;

[0099] 3) The measuring rod of the load sensor of the suspension point dynamometer does not undergo plastic deformation and does not lose its elasticity;

[0100] 4) The average value of the dynamic load during the up and down strokes is approximately 0;

[0101] 5) Suspension point diagram to eliminate broken rod and pump valve failures.

[0102] Principle of suspension point load strain measurement:

[0103] P=a*ε+b

[0104] Where: a is the elastic coefficient, b is the zero point coefficient, and ε is the strain value;

[0105] According to the above-mentioned suspension load strain test principle, when the a and b coefficients drift, the suspension load is a relative value. Therefore, the actual value of the suspension load can be written as:

[0106] P 实 =T f ·P 测 +P of

[0107] Where: T f is the temperature drift correction coefficient, P of is the zero drift correction coefficient, P测 is the load measurement value of the load sensor.

[0108] Then, in S2, the load measured at the suspension point is corrected, specifically including the following steps:

[0109] In the up and down strokes, the average acceleration is 0. According to the inertia load waveform, the average load of the up stroke BC section and the down stroke DA section is calculated:

[0110]

[0111] According to the A, B, C, and D points of the suspension load, measure the average load of the upstroke BC section and the downstroke DA section; combine the calculated average load of the upstroke BC section and the downstroke DA section to calculate T according to the following formula: f and P of ;

[0112]

[0113] According to the obtained T f and P of , correct the load measured at the suspension point to obtain the corrected dynamometer diagram;

[0114] Where: is the calculated value of the average load on the upstroke, is the calculated value of the average load of the downstroke, is the measured value of the average load on the upstroke, is the measured value of the average load during the downstroke; P′ 杆 is the weight of the sucker rod string in the liquid column, N; P' 液 P is the weight of the liquid column with a cross-sectional area equal to the plunger area above the dynamic liquid level in the oil well, N; 油 is the wellhead oil pressure, Pa; F is the cross-sectional area of ​​the pump plunger, m 2 ρ 液 is the density of the produced liquid, kg / m 3 ; g is the acceleration due to gravity, 9.87N / kg; h 沉 is the submergence of the pump, m; P t is the casing pressure, Pa.

[0115] Well parameters for pumping wells include: first-stage rod length, first-stage rod diameter, oil pressure, casing pressure, pump diameter, pump depth, water content, stroke, and stroke frequency. Based on these well parameters, the reference load of the standard dynamometer diagram is calculated using the following formula to determine whether the dynamometer diagram needs to be calibrated.

[0116] P 静上 =P' 杆 +P' 液

[0117] P 静下 =P' 杆

[0118] Where: P 静上 is the reference load of the upper static load line, P 静下 is the reference load of the lower static load line, P′ 杆 is the weight of the sucker rod string in the liquid column, N; P' 液 The weight of the liquid column in the oil well whose cross-sectional area above the dynamic liquid level is equal to the plunger area, N.

[0119] When the work diagram is Figure 6 When the power diagram is shown as Figure 7 When the power diagram is shown as Figure 8 As shown in the figure, the load sensor has serious temperature drift and zero drift and needs to be calibrated.

[0120] (2) Suspension point power diagram calculation pump power diagram model

[0121] In S3, the work diagrams of different positions of the sucker rod string are obtained, which specifically includes the following steps:

[0122] like Figure 9 As shown, the rod column micro unit Δx is taken and analyzed from the spatial and temporal directions respectively. The spatial direction is defined as the downward positive direction. The load on the rod column micro unit Δx includes the micro unit self-weight f w , micro unit inertia force f a (x, t), micro-element damping force f v (x, t) and the micro-unit internal forces f(x, t) and f(Δx+x, t). The expressions of the above forces are:

[0123]

[0124] from Figure 9 According to the balance relationship of forces, we can get:

[0125] f(Δx+x,t)-f(x,t)=f a (x,t)+f v (x,t)-f w

[0126] After sorting, we get the one-dimensional wave equation:

[0127]

[0128] Where: ρ 杆 The density of steel sucker rod is 7850kg / m 3 ; A is the cross-sectional area of ​​the sucker rod, mm2 ; d is the diameter of the sucker rod, mm; g is the acceleration due to gravity, m / s 2 ; v is the viscosity coefficient, μ is the viscosity of the well fluid, Pa·s; E is the elastic modulus of the sucker rod, 2.01× 11 Pa; c is the wave speed,

[0129] The wave equation contains the second-order partial derivative of displacement with respect to position and the second-order derivative of displacement with respect to time. Two initial conditions and two boundary conditions are required to solve the wave equation.

[0130] For the same-level sucker rod string, the rod string is divided into m units along the axis with equal steps, the step length is Δx, and each unit is represented by the subscript i, i = 0, 1, 2, 3, ..., m; the time is divided into n units with equal steps, the time step is Δt, and each time point is represented by the subscript j, j = 0, 1, 2, 3, ..., n; then, u i,j represents the displacement of the i-th node on the column at time j.

[0131] Newton's forward interpolation formula is:

[0132]

[0133] Get the central difference:

[0134]

[0135] Similarly, we can get the second-order central difference formula of u to x:

[0136]

[0137] The displacement equation of the homogeneous section of the sucker rod string is obtained by combining the equations:

[0138]

[0139] The first layer of the differential network is the suspension point displacement, and the suspension point load f 0,j The calculation formula is:

[0140]

[0141] The calculation formula for the second layer displacement of the differential network is:

[0142]

[0143] Starting from the third layer, in the process of calculating the displacement using the formula, the periodic boundary conditions of the following formula are used to calculate the displacement of each time point downward using the differential grid form;

[0144] u i,0 =u i,n ,ui,1 =u i,n+1

[0145] Based on the difference method, the displacement of different layers is obtained, and then the load of different layers at different time points is obtained by combining Hooke's law. The work diagram of the sucker rod at different positions (abscissa displacement, ordinate load) can be obtained, and the grid diagram of the wave equation can be solved as follows: Figure 10 shown.

[0146] In the process of solving the pump performance diagram using the difference method, the required well parameters are shown in Table 1.

[0147] Table 1 Required well parameters

[0148] parameter unit parameter unit Sucker rod diameter mm Plunger diameter mm Sucker rod length m Pump hanging depth m Moisture content ％ oil pressure MPa Casing pressure MPa rush min-1

[0149] Because downhole operating conditions are complex and variable, we focused on the morphological correlation between the pump dynamometer and the suspension-point dynamometer. During data preprocessing, we performed feature analysis on the suspension-point dynamometer to systematically eliminate interference samples from conditions such as spontaneous flow, pump valve lock failure, abnormal pump barrel wear, sucker rod fracture, gas lock, and pump sticking. These abnormal operating conditions can all be effectively identified and eliminated through morphological diagnosis of the suspension-point dynamometer, resulting in the pump dynamometer.

[0150] (3) Dynamic liquid level calculation, digital production and liquid level calculation

[0151] Since the dynamic liquid level or submergence of the oil well is unknown, the dynamic liquid level iteration and differential method are combined to calculate the pump work diagram to achieve the calculation of the dynamic liquid level of the oil well, digital production and liquid level measurement.

[0152] In the framework of the suspension point load correction model, by taking the dynamic liquid level or submergence of the oil well as the known boundary condition and combining the dynamic liquid level iterative difference algorithm of the suspension point indicator diagram, when the theoretical prediction value and the actual calculation result reach the convergence threshold, the high-precision inversion of the downhole dynamic liquid level and the adaptive calibration of the load sensor temperature drift and zero drift coefficient can be achieved simultaneously. The calculation process is as follows: Figure 11 As shown, H0 is the predicted dynamic liquid level, and H is the calculated dynamic liquid level;

[0153] When the dynamic liquid level of the oil well is iterated in a cycle, the dynamic liquid level depth of the oil well is calculated through the load characteristics:

[0154]

[0155] Convert the corrected suspension point work diagram to the pump work diagram to obtain the upper and lower load differences in the pump work diagram:

[0156]

[0157] The liquid production of an oil well is related to the suspension stroke, plunger diameter, etc. However, in the actual production process, oil well pumps inevitably produce leakage. The production calculation formula is:

[0158] Q 实 =1440·(S pe ·F-ΔQ)·N

[0159] The leakage of pumping wells mainly considers the leakage between the plunger and the pump barrel. The calculation method of the leakage per stroke is:

[0160]

[0161] P d =ρ 液 gh 沉 +P 套

[0162] P c =ρ 液 gh 挂 +P 油

[0163] Where: ΔP is the difference between the upper and lower loads in the pump power diagram; F is the cross-sectional area of ​​the plunger, m 2 ρ 液 is the density of the produced liquid, g is the acceleration due to gravity; is the average load on the stroke of the pump diagram, kN; is the average load of the lower stroke of the pump diagram, kN; Q 实 To predict the output; S pe is the effective stroke of the oil well pump plunger, m; ΔQ is the leakage of the oil well pump per stroke, m 3 / times; N is the number of strokes, min -1 ;D p is the diameter of the oil well pump plunger, m; δ is the average concentric clearance of the plunger pump barrel, m; P d is the pump discharge pressure, kPa; P c is the pump suction pressure, kPa; μ is the fluid dynamic viscosity, kPas; l z is the plunger length, m; e is the eccentricity, m; is the average speed of the upstroke, m / s; h 沉 is the submergence of the pump, h 挂 is the pump hanging depth, m; is the wellhead oil pressure, Wellhead casing pressure.

[0164] (4) In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the following is a detailed description with reference to specific examples.

[0165] The dynamometer has temperature drift and zero drift problems due to the strain gauge. The method for automatically correcting the collected dynamometer diagram effectively includes the following steps:

[0166] 1. Obtain the power diagram data of the oilfield pumping well (Table 2), collect the suspension point power diagram through the power indicator, and obtain the original suspension point power diagram, such as Figure 12 The closed curve drawn by the orange curve.

[0167] Table 2 Well parameters collected in the case

[0168] Well condition parameters Well 1 Well 2 Well 3 Well 4 Well 5 Length of first pole (m) 518.81 1106.19 1200.20 1456.86 9.14 First-stage rod diameter (mm) 22 22 22 19 28 Secondary rod length (m) 697.27 — — — 810.02 Secondary rod diameter (mm) 19 — — — 28 Length of third pole (m) 200.46 — — — — Diameter of third-level rod (mm) 22 — — — — Oil pressure (Mpa) 0.61 0.67 0.42 0.38 0.44 Casing pressure (Mpa) 0.62 0.70 0.70 0.40 0.63 Pump diameter (mm) 28 44 44 38 83 Pump depth (m) 1434.97 1106.19 1200.20 1471.92 830.71 Moisture content (%) 20.3 64.2 28.5 72.0 99.8 Stroke (m) 2.07 1.58 1.88 3.16 4.01 <![CDATA[Stroke frequency (min -1 )]]> 5.64 1.87 2.93 3.48 2.82

[0169] Taking Well 3 as an example, according to the well parameters, the formula: Calculate P and use it as the basis for judging the dynamometer diagram.

[0170] Calculate the average load of the BC section and the average load of the AD segment Then by and and and Compare them separately. If the errors of both are less than 10%, it is considered that the power diagram is normal and no power diagram correction is required; if the errors of both are greater than 10%, it is considered that power diagram correction is required.

[0171] 2. Based on the measured data, calculate: average load of upstroke Average load on downstroke Measured Measured Solve the following equation: T f ≈-0.094, P of ≈31726.3;

[0172]

[0173] The obtained T f and P of Substitute P 实 =T f ·P 测 +P of , the load measured at the suspension point can be corrected to obtain a dynamometer diagram containing only the friction load correction, such as Figure 12 The closed curve drawn by the blue curve.

[0174] 3. According to the steps in the above part (2), the displacement of different layers is obtained by differential calculation, and the load of different layers at different time points is obtained by combining Hooke's law. The work diagram of the sucker rod at different positions can be obtained. The obtained pump work diagram is Figure 12 The closed curve drawn by the red curve.

[0175] 4. According to

[0176]

[0177] Calculated: H 预测 =1064.65m, ΔP=15000N;

[0178] according to

[0179] Q 实 =1440·(S pe ·F-ΔQ)·N

[0180]

[0181] Calculated: ΔQ = 0.00107, Q 实 =7.54(m 3 / d).

[0182] Through the above technical solution, an intelligent compensation algorithm was developed to address the thermal drift phenomenon of strain-type dynamometers. The dynamometer diagram morphology was corrected through dynamic load feature reconstruction technology, and the relative error of load measurement can be controlled within ±1.5%, significantly improving the engineering confidence level of pumping well operating condition diagnosis.

[0183] The comparison results between the measured data and the predicted data of the five wells are shown in Table 3, with Well 3 used as an example for verification.

[0184] Table 3 Statistics of measured and predicted values ​​of production and liquid level

[0185]

[0186] From the accuracy rate = (1 - |predicted value - actual value| / actual value) × 100%, we can calculate: dynamic liquid level accuracy = 97.89%, production accuracy = 91.35%.

[0187] When using the pump dynamometer to calculate production and dynamic liquid level, the accuracy can reach over 90%, solving the temperature drift and zero drift problems caused by the strain gauge of the dynamometer. It can effectively and automatically correct the dynamometer diagram collected by the dynamometer, greatly improving the precision and accuracy of the dynamometer diagram test, and better providing a basis for judging the working condition of the pumping unit.

[0188] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0189] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A data-driven method for correcting the pumping unit dynamometer diagram and calculating production and liquid level, characterized in that: The following steps are involved: S1. Obtaining the power diagram data of the oilfield pumping well, and collecting the original suspension point power diagram through the power indicator; S2. Calculate the temperature drift correction coefficient and the zero drift correction coefficient based on the basic data of the original suspension point dynamometer diagram, and correct the load measured at the suspension point to obtain a corrected dynamometer diagram; S3. Obtain the displacement of different layers using the differential method, and obtain the load of different layers at different time points using Hooke's law, and obtain the work diagram of different positions of the sucker rod string; S4. Combine the dynamic liquid level iteration and differential method to calculate the pump power diagram, and complete the calculation of the dynamic liquid level of the oil well, digital production and liquid level.

2. The method for correcting the pumping unit dynamometer diagram and calculating production and liquid level based on data drive according to claim 1, characterized in that: The well condition parameters of the pumping well include: first-stage rod length, first-stage rod diameter, oil pressure, casing pressure, pump diameter, pump depth, water content, stroke, and stroke frequency.

3. The method for correcting the pumping unit dynamometer diagram and calculating production and liquid level based on data drive according to claim 1, characterized in that: Before S2, the method further includes: calculating the reference load of the standard dynamometer diagram according to the following formula based on the well condition parameters of the pumping well, as a basis for judging whether the dynamometer diagram needs to be corrected; P 静上 =P′ 杆 +P′ 液 P 静下 =P′ 杆 Where: P 静上 is the reference load of the upper static load line, P 静下 is the reference load of the lower static load line, P′ 杆 is the weight of the sucker rod string in the liquid column, P′ 液 It is the weight of the liquid column in the oil well whose cross-sectional area above the dynamic liquid level is equal to the plunger area.

4. The method for correcting the pumping unit dynamometer diagram and calculating production and liquid level based on data drive according to claim 1, characterized in that: In S2, the load measured at the suspension point is corrected, specifically including the following steps: In the up and down strokes, the average acceleration is 0. According to the inertia load waveform, the average load of the up stroke BC section and the down stroke DA section is calculated: According to the A, B, C, and D points of the suspension load, measure the average load of the upstroke BC section and the downstroke DA section; combine the calculated average load of the upstroke BC section and the downstroke DA section to calculate T according to the following formula: f and P of ; According to the obtained T f and P of , correct the load measured at the suspension point to obtain the corrected dynamometer diagram; Where: is the calculated value of the average load on the upstroke, is the calculated value of the average load of the downstroke, is the measured value of the average load on the upstroke, is the measured value of the average load during the downstroke; P′ 杆 is the weight of the sucker rod string in the liquid column, P′ 液 P is the weight of the liquid column with a cross-sectional area equal to the plunger area above the dynamic liquid level in the oil well, 油 is the wellhead oil pressure, F is the cross-sectional area of ​​the pump plunger, ρ 液 is the density of the produced liquid, g is the acceleration of gravity, h is 沉 is the submergence of the pump, P t is the casing pressure, T f is the temperature drift correction coefficient, P of is the zero drift correction coefficient.

5. The method for correcting the pumping unit dynamometer diagram and calculating production and liquid level based on data drive according to claim 1, characterized in that: In S3, the work diagrams of different positions of the sucker rod string are obtained, which specifically includes the following steps: Take the rod column micro unit Δx and analyze it from the spatial and temporal directions respectively. Define the spatial direction downward as the positive direction. The load on the rod column micro unit Δx includes the micro unit self-weight f w , micro unit inertia force f a (x, t), micro-element damping force f v (x, t) and the micro-unit internal forces f(x, t) and f(Δx+x, t), are expressed as follows: According to the balance of forces, we can obtain: f(Δx+x,t)-f(x,t)=f a (x,t)+f v (x,t)-f w After sorting, we get the one-dimensional wave equation: For the same-level sucker rod string, the rod string is divided into m units along the axis with equal steps, the step size is Δx, and each unit is represented by the subscript i, i = 0, 1, 2, 3, ..., m; the time is divided into n units with equal steps, the time step is Δt, and each time point is represented by the subscript j, j = 0, 1, 2, 3, ..., n; Newton's forward interpolation formula is: Get the central difference: Similarly, we can get the second-order central difference formula of u to x: The displacement equation of the homogeneous section of the sucker rod string is obtained by combining the equations: The first layer of the differential network is the suspension point displacement, and the calculation formula of the suspension point load is: The calculation formula for the second layer displacement of the differential network is: Starting from the third layer, in the process of calculating the displacement using the formula, the periodic boundary conditions of the following formula are used to calculate the displacement of each time point downward using the differential grid form; in i,0 =in i,n ,in i,1 =in i,n+1 The displacement of different layers is obtained by differential calculation, and the load of different layers at different time points is obtained by combining Hooke's law, so that the work diagram of different positions of the sucker rod string can be obtained. Where: ρ 杆 is the density of the steel sucker rod, A is the cross-sectional area of ​​the sucker rod, g is the acceleration of gravity, v is the viscosity coefficient, E is the elastic modulus of the sucker rod, and c is the wave velocity; u i,j is the displacement of the i-th node on the column at time j, f 0,j It is the first layer load of the differential network.

6. The method for correcting the dynamometer diagram and calculating the production and liquid level of a pumping unit based on data drive according to claim 1, characterized in that: In S4, when calculating the dynamic liquid level of the oil well, digitally calculating production and calculating the liquid level, the specific steps are as follows: Within the framework of the suspension point load correction model, by using the oil well dynamic liquid level or submergence as a known boundary condition and combining iterative differential algorithms for the dynamic liquid level of the suspension point dynamometer diagram, high-precision inversion of the downhole dynamic liquid level and adaptive calibration of the load sensor's temperature drift and zero drift coefficients can be achieved simultaneously when the theoretical prediction value and the actual calculation result reach a convergence threshold. When the dynamic liquid level of the oil well is iterated in a cycle, the dynamic liquid level depth of the oil well is calculated through the load characteristics: Convert the corrected suspension point work diagram to the pump work diagram to obtain the upper and lower load differences in the pump work diagram: The production calculation formula in the actual production process is: The calculation method for the loss per stroke is: P d =ρ 液 gh 沉 +P 套 P c =ρ 液 gh 挂 +P 油 Where: H is the calculated dynamic liquid level, ΔP is the upper and lower load difference in the pump power diagram, F is the cross-sectional area of ​​the plunger, ρ 液 is the density of the produced liquid, g is the acceleration due to gravity, is the average load on the pump stroke diagram, is the average load of the lower stroke of the pump diagram, Q 实 To predict production, S pe is the effective stroke of the oil well pump plunger, ΔQ is the leakage of the oil well pump per stroke, N is the number of strokes, D p is the diameter of the oil well pump plunger, δ is the average value of the concentric clearance of the plunger pump barrel, P d is the pump discharge pressure, P c is the pump suction pressure, μ is the fluid dynamic viscosity, l z is the plunger length, e is the eccentricity, is the average speed of the upstroke, h 沉 is the submergence of the pump, h 挂 is the pump hanging depth, is the wellhead oil pressure, Wellhead casing pressure.

Images