Beam-pumping unit belt slipping discrimination method

Abstract

The invention relates to a belt slipping judgment method for a beam-pumping unit, which belongs to the field of oil extraction in oil fields and comprises the following steps of: calculating a theoretical operation period of operation of an oil beam of the beam-pumping unit according to attribute data of the beam-pumping unit, calculating the actual operation cycle of the oil beam of the oil pumping unit according to the collected oil beam inclination angle curve data of the oil pumping unit; if the difference value between the theoretical operation cycle and the actual operation cycle is larger than or equal to a first threshold value, the relation between the high-frequency component and a second threshold value is judged, if the high-frequency component is larger than or equal to the second threshold value, it is judged that the pumping unit belt has a slipping fault, and the operation condition of the belt is indirectly judged by detecting the operation cycle of the pumping unit oil beam. The operation of mounting a sensor on the belt pulley is avoided, and the running stability and safety of the belt are guaranteed. The operation state of the belt is determined through the combination of the judgment operation cycle and the high-frequency component, misjudgment of belt operation is avoided, and the accuracy of judgment of the pumping unit belt is improved.

Description

Technical Field

[0001] The invention belongs to the field of oil field production, and in particular relates to a method for judging belt slippage of a beam pumping unit. Background Art

[0002] The beam pumping unit is the most important equipment in the current surface oil production equipment at home and abroad. The belt is one of the important components of the beam pumping unit. It, together with the motor and the reduction box, constitutes the transmission device of the pumping unit to realize the power transmission from the motor to the crankshaft.

[0003] Since the belt is made of rubber material, it has great elasticity, and the instability of underground production will cause the load to fluctuate. If the load increases, the belt will slip. In addition, the pumping unit is in outdoor production for a long time, and is often affected by rain, snow, fog and other weather conditions, so the belt slip is very likely to occur. In addition, because the actual layout of oil wells is relatively scattered, the belt slip phenomenon cannot be discovered in time. If the belt slip phenomenon cannot be discovered and handled in time, the belt will be worn off as long as it slips continuously for about 5-10 minutes, and in severe cases, fire accidents and other safety issues may even occur.

[0004] At present, the main method in China to determine whether the pulley is slipping is through manual regular inspections. Since most oil wells are scattered in the field, there are often problems such as delayed detection of slippage and large manual workload. To solve the above problems, Patent Publication No. CN106444569A discloses a method and device for protecting the pumping unit belt. The method collects the rotation speed of the pumping unit pulley by installing a Hall sensor on the pumping unit pulley, and determines whether the belt is slipping by comparing it with the set threshold. Installing equipment on the pulley is likely to affect the operating status of the equipment itself, which may cause operating obstacles to the pulley. Summary of the invention

[0005] The purpose of the present invention is to provide a method for determining belt slippage of a beam pumping unit, so as to solve the technical problem in the prior art that arranging a sensor on a pulley affects the operation of the equipment.

[0006] To achieve the above-mentioned purpose, the present invention provides a technical solution for a method for determining belt slippage of a beam pumping unit:

[0007] A method for distinguishing belt slippage of a beam pumping unit comprises the following steps: calculating a theoretical operation cycle of the oil beam of the pumping unit based on attribute data of the pumping unit, and calculating an actual operation cycle of the oil beam of the pumping unit based on collected oil beam inclination operation curve data of the pumping unit; if the difference between the theoretical operation cycle and the actual operation cycle is greater than or equal to a first threshold, determining a relationship between a high-frequency component of an oil beam inclination operation curve in the oil beam inclination operation curve data and a second threshold; and if the high-frequency component is greater than or equal to the second threshold, determining that a belt slippage fault occurs in the pumping unit.

[0008] The beneficial effects are: by detecting the operation cycle of the oil beam of the pumping unit to indirectly judge the operation of the belt, the operation of installing a sensor on the pulley is avoided, and the stability and safety of the belt operation are guaranteed. By combining the judgment of the operation cycle and the high-frequency component to determine the operation status of the belt, the misjudgment of the belt operation is avoided, and the accuracy of the judgment of the pumping unit belt is improved.

[0009] As a further improvement, the calculation method of the actual operating cycle is as follows: the time interval between the maximum or minimum inclination angle and the adjacent maximum or minimum inclination angle is obtained from the oil beam inclination operating curve, and it is used as the actual time to complete the stroke, and the actual time to complete the stroke is used as the actual operating cycle.

[0010] The beneficial effect is: the value of the actual operation cycle is obtained by calculating the oil beam inclination operation curve. Since the oil beam inclination operation curve is data that can be obtained by the equipment provided by the oil pump, the operation of adding equipment to the oil pump to obtain data is avoided, thereby improving the stability of the oil pump operation.

[0011] As a further improvement, the average time value of N consecutive completed strokes is taken as the actual operation cycle.

[0012] The beneficial effect is that the accuracy of the acquired actual operation cycle data is improved by taking the average value.

[0013] As a further improvement, the difference between the theoretical operating cycle and the actual operating cycle is greater than or equal to the first threshold, which is expressed by the formula: |T0-T1|≥T0×m%, where T0 is the theoretical operating cycle, T1 is the actual operating cycle, and m% is a percentage constant.

[0014] The beneficial effect is: by calculating the change rate of the actual operation cycle relative to the theoretical operation cycle, it is possible to detect whether the current oil beam equipment of the oil pump is operating normally, further judge the operating status of the oil pump belt, and realize the detection of the oil pump belt status.

[0015] As a further improvement, the high-frequency component acquisition method is as follows: the oil beam inclination curve is replaced with frequency data, and within the set time, the number of high-frequency signals and the number of low-frequency signals are obtained according to the frequency data, and the high-frequency component is calculated according to the number of high-frequency signals and the number of low-frequency signals. The calculation formula of the high-frequency component is: N = n 高 / (n 高 +n 基 ), where n 高 is the number of high-frequency signals, n 基 is the reference frequency signal number; high frequency is a frequency greater than or equal to twice the reference frequency, and low frequency is a frequency less than twice the reference frequency.

[0016] The beneficial effect is that too much high frequency indicates that the oil beam is operating abnormally, and the high-frequency component is used to represent the proportion of high frequency occurrence to further judge the operating status of the oil beam.

[0017] As a further improvement, the calculation formula for the theoretical operating cycle is: T0 = k×p / (1-s)×f, k is the reduction ratio of the reduction box, p is the number of motor poles, f is the AC frequency, and s is the slip ratio.

[0018] The beneficial effect is that the value of the theoretical value operation cycle of the property data calculator of the oil pumping unit is used as the reference data of the actual operation cycle to observe the state of the oil pumping unit.

[0019] As a further improvement, when the pumping unit belt slips, a warning signal is issued.

[0020] The beneficial effect is that when a fault is detected, a warning signal is used to remind the staff to carry out maintenance.

[0021] As a further improvement, m%∈(2%, 5%).

[0022] As a further improvement, the value range of the second threshold is (4%, 6%). BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the method for judging the slippage of the pumping unit belt in the present invention;

[0024] Figure 2 It is a structural schematic diagram of the application of the method for distinguishing oil pump belt slippage in the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0026] Example of method for judging belt slippage of beam pumping unit:

[0027] like Figure 1 As shown, the method for judging the belt slippage of the beam pumping unit includes the following steps:

[0028] 1) The theoretical operation cycle of the oil beam of the oil pumping unit is calculated according to the attribute data of the oil pumping unit, and the actual operation cycle of the oil beam of the oil pumping unit is calculated according to the collected oil beam inclination curve data of the oil pumping unit.

[0029] The calculation formula of the theoretical operation cycle is:

[0030] T0=k×p / (1-s)×f

[0031] k is the reduction ratio of the reduction box, p is the number of motor pole pairs, s is the slip ratio, and f is the AC frequency. The slip ratio refers to the speed difference between the motor speed and the synchronous speed of the three-phase asynchronous motor of the pumping unit.

[0032] Calculation method of actual operation cycle: obtain the oil beam inclination operation curve, obtain the actual operation time of the maximum or minimum inclination and the adjacent maximum or minimum inclination from the curve as the actual time to complete the stroke, and take the average time value of N consecutive completed strokes as the actual operation cycle.

[0033] Specifically: compare the sizes of the inclination angle values ​​in order of their sampling moments; when the maximum inclination angle appears for the first time, record the sampling moment t1 of the first maximum inclination angle, and then continue to compare the sizes of the subsequent inclination angle values; when the minimum inclination angle appears for the first time, record the sampling moment t2 of the first minimum inclination angle, and then continue to compare the sizes of the subsequent inclination angle values; when the maximum inclination angle appears for the second time, record the sampling moment t3 of the second maximum inclination angle; the oil pump is in the downstroke process during the time period between the sampling moment t1 and the sampling moment t2, and is in the upstroke process during the time period between the sampling moment t2 and the sampling moment t3, so T1=t3-t1.

[0034] 2) If the difference between the theoretical operating cycle and the actual operating cycle is less than the first threshold, no processing is performed; if the difference between the theoretical operating cycle and the actual operating cycle is greater than or equal to the first threshold, the relationship between the high-frequency component in the oil beam inclination curve and the second threshold is judged. If the high-frequency component is greater than or equal to the second threshold, it is determined that the pumping unit belt has a slipping fault.

[0035] The first threshold T is m% of the theoretical operation cycle, and the difference between the theoretical operation cycle and the actual operation cycle is greater than or equal to the first threshold T, which is expressed by the formula:

[0036] |T0-T1|≥T0×m% or |(T0-T1) / T0|≥m% or |T0-T1|≥T

[0037] Wherein, T0 is the theoretical operation cycle, T1 is the actual operation cycle, T is the first threshold, m% is the percentage constant, m%∈(2%, 5%). The difference between the theoretical operation cycle and the actual operation cycle is greater than or equal to the first threshold. The purpose of this judgment is to detect whether there is any abnormality in the operation of the oil beam.

[0038] High-frequency component acquisition method: The oil beam inclination curve is converted into frequency data through Fourier transform and frequency domain analysis. Within the set time, the number of high-frequency signals and low-frequency signals are obtained according to the frequency data. The high-frequency component is expressed by the formula: N = n 高 / (n 高 +n 基 ), where n 高 is the number of high-frequency signals, n 基 is the number of low-frequency signals; high frequency is a frequency greater than or equal to twice the reference frequency, and low frequency is a frequency less than twice the reference frequency.

[0039] The setting time refers to three times the operating cycle of the pumping unit. The pumping unit cycle spans a large range, ranging from 10s to 60s. If the common cycle is about 12s, the setting time is about 30-40s. Select the corresponding setting time according to different pumping units. The fundamental frequency refers to the frequency domain value obtained by Fourier transforming the inclination signal in the time domain. Most frequencies are concentrated near a certain frequency as the fundamental frequency. Due to differences in inclination thresholds and other factors, different pumping units have different corresponding fundamental frequencies.

[0040] The value range of the second threshold is (4%, 6%). In the operation data of the oil beam inclination angle, the high frequency indicates that the time interval of an oil beam operation cycle relative to the low-frequency operation cycle is smaller, which means that the oil beam is faster than the normal operation speed, indicating that the oil pump has a fault. During the operation of the oil pump, if there is no belt slippage, the inclination operation curve is a smooth sine wave-like curve in the time domain. After Fourier transform, it is near the base frequency in the frequency domain; if the belt slippage occurs, there will be a spike similar to "burrs" in the time domain, and a high-frequency component will be displayed in the frequency domain, excluding the influence of external vibration. When the high-frequency component exceeds a certain threshold, it is judged that the belt slippage occurs.

[0041] 3) When the pumping unit belt slips, a warning signal is issued.

[0042] The warning signal can be any form of data such as sound, light, etc. It can be a voice broadcast of the fault, or it can be a prompt through a warning light. The alarm level is divided according to different period differences or the proportion of high-frequency components or the size of the high-frequency signal number, and different alarm signal strengths are set according to different alarm levels.

[0043] By detecting the operation cycle of the oil beam of the pumping unit, the operation of the belt can be indirectly judged, avoiding the operation of installing sensors on the pulley, ensuring the stability and safety of the belt operation. By combining the judgment of the operation cycle and high-frequency components to determine the operation status of the belt, misjudgment of the belt operation is avoided, and the accuracy of the judgment of the pumping unit belt is improved.

[0044] In addition, if Figure 2As shown, the method can be designed to be applied in a processor, and the operating data and attribute data of the oil pump are collected through the existing processor, and the attribute data includes data such as motor power, motor pole pair number, transmission ratio, motor box reduction ratio, etc. The collected data is processed, calculated and analyzed according to the beam pump belt slippage judgment method, and an alarm signal is output according to the calculation result. In the process of data processing, calculation and analysis, the same processor is used to collect data, and the function can be divided inside the processing; or the data is transmitted to the host computer, and the host computer performs the data calculation, data analysis and alarm signal output part of the above beam pump belt slippage judgment method.

[0045] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for determining belt slippage of a beam pumping unit, characterized in that: The method comprises the following steps: The theoretical operation cycle of the oil beam of the oil pumping unit is calculated according to the attribute data of the oil pumping unit, and the actual operation cycle of the oil beam of the oil pumping unit is calculated according to the collected operation curve data of the oil beam inclination of the oil pumping unit; If the difference between the theoretical operating cycle and the actual operating cycle is greater than or equal to the first threshold, the relationship between the high-frequency component in the oil beam inclination angle operating curve data and the second threshold is judged. If the high-frequency component is greater than or equal to the second threshold, it is determined that the oil pump belt has a slip fault.

2. The method for determining belt slippage of a beam pumping unit according to claim 1, characterized in that: Calculation method of actual operation cycle: obtain the time interval between the maximum or minimum inclination and the adjacent maximum or minimum inclination from the oil beam inclination operation curve, and use it as the actual time to complete the stroke. The actual time to complete the stroke is the actual operation cycle.

3. The method for determining belt slippage of a beam pumping unit according to claim 2, characterized in that: The average time value of N consecutive completed strokes is taken as the actual operation cycle.

4. The method for determining belt slippage of a beam pumping unit according to claim 1, characterized in that: The difference between the theoretical operation cycle and the actual operation cycle is greater than or equal to the first threshold, which is expressed by the formula: |T0-T1|≥T0×m%, where T0 is the theoretical operation cycle, T1 is the actual operation cycle, and m% is a percentage constant.

5. The method for determining belt slippage of a beam pumping unit according to claim 1, characterized in that: Method for obtaining high-frequency components: replace the oil beam inclination curve with frequency data, obtain the number of high-frequency signals and low-frequency signals according to the frequency data within the set time, and calculate the high-frequency components according to the number of high-frequency signals and low-frequency signals. The calculation formula for the high-frequency components is: N = n 高 / (n 高 +n 基 ), where n 高 is the number of high-frequency signals, n 基 is the reference frequency signal number; The high frequency is a frequency greater than or equal to twice the reference frequency, and the low frequency is a frequency less than twice the reference frequency.

6. The method for determining belt slippage of a beam pumping unit according to claim 1, characterized in that: The calculation formula for the theoretical operating cycle is: T0 = k×p / (1-s)×f, k is the reduction ratio of the reduction box, p is the number of motor poles, f is the AC frequency, and s is the slip ratio.

7. The method for determining belt slippage of a beam pumping unit according to any one of claims 1 to 3, 5 and 6, characterized in that: It also includes sending out a warning signal when a slipping failure occurs in the pumping unit belt.

8. The method for determining belt slippage of a beam pumping unit according to claim 4, characterized in that: m％∈(2％，5％)。 9. The method for determining belt slippage of a beam pumping unit according to claim 1, characterized in that: The value range of the second threshold is (4%, 6%).

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