A method and device for early warning of wire rope fracture of oil pumping unit

Abstract

The present application is applicable to the technical field of steel wire ropes for oil pumping units, and provides a steel wire rope fracture warning method and a warning device for oil pumping units, wherein the steel wire rope fracture warning method for oil pumping units comprises: measuring the cross-sectional area of ​​the steel wire rope at the ith monitoring point of the steel wire rope, measuring the temperature value of the steel wire rope at the ith monitoring point of the steel wire rope, measuring the voltage value of the strain gauge at the ith monitoring point of the steel wire rope, establishing a mathematical model between the deformation amount of the steel wire rope at the ith monitoring point and the corresponding voltage value of the strain gauge, establishing a tension model to which the steel wire rope is subjected when lifting a pull rod and an oil pump, establishing a mathematical model between the modulus of the steel wire rope at the ith monitoring point and the tension to which the steel wire rope is subjected, the deformation of the steel wire rope and the voltage value of the strain gauge, and providing a warning for the fracture of the steel wire rope, thereby solving the problem that the existing steel wire rope fracture warning method cannot accurately consider the influence of the external environment on the steel wire rope and cannot accurately predict the fracture of the steel wire rope.

Description

Technical Field

[0001] The present application belongs to the technical field of steel wire ropes for oil pumping units, and in particular, relates to a steel wire rope fracture early warning method and early warning device for oil pumping units. Background Art

[0002] In mechanical oil production, the main equipment is the pumping unit, sucker rod, oil pump and wire rope. The wire rope connects the sucker rod and the oil pump through a rope hanger. The wire rope is the only carrier for transmitting the power of the ground pumping unit to the downhole oil pump. Therefore, the service life of the wire rope is crucial to the production of crude oil. Due to the connection method of the wire rope and the long-term alternating load, there are some unfavorable factors in the field application that make the wire rope easy to trip and break. Since the load of the pumping unit is not constant, its instability shortens the life of the wire rope and is difficult to calculate. In the existing technology, most oil production workers adopt the method of regularly replacing the wire rope, which leads to a substantial increase in the cost of oil extraction, or directly calculate the service life of the wire rope by calculating the load borne by the wire rope.

[0003] In summary, the existing wire rope breakage early warning method cannot accurately take into account the impact of the external environment on the wire rope, and there is a problem that the wire rope breakage cannot be accurately predicted. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a pumping unit wire rope fracture warning method and warning device, which can solve the problem that the existing wire rope fracture warning method cannot accurately consider the impact of the external environment on the wire rope and cannot accurately predict the wire rope fracture.

[0005] A first aspect of an embodiment of the present application provides a method for early warning of a wire rope breakage of an oil pumping unit, the method comprising:

[0006] Select n monitoring points at equal distances on the wire rope, and set a strain gauge at each monitoring point;

[0007] Measure the cross-sectional area S of the wire rope at the i-th monitoring point i , 0<i≤n, where i is a positive integer and n is a positive integer;

[0008] Measure the temperature value H of the wire rope at the i-th monitoring point i ;

[0009] Measure the voltage value V of the strain gauge at the i-th monitoring point of the wire rope i ;

[0010] Establish the deformation D of the wire rope at the i-th monitoring point i The corresponding voltage value V of the strain gauge i The mathematical model between them is:

[0011]

[0012] Among them, V i is the voltage value of the strain gauge at the i-th monitoring point, D i is the deformation of the wire rope length at the i-th monitoring point, k1 is the correction coefficient of the output voltage, k2 is the cosine component coefficient, k3 is the sine component coefficient, Q i is the voltage sensitivity coefficient of the strain gauge at the ith monitoring point, ω1 is the deformation coefficient of the wire rope, H i is the temperature of the wire rope at the i-th monitoring point;

[0013] Establish a model of the tension F that the wire rope is subjected to when lifting the pull rod and the oil pump;

[0014] The mathematical model between the modulus of the wire rope at the i-th monitoring point and the tension on the wire rope, the deformation of the wire rope and the voltage value of the strain gauge is established as follows:

[0015]

[0016] Among them, E i is the modulus of the wire rope at the i-th monitoring point, F is the tension on the wire rope, a is the acceleration of the wire rope when it is lifted and moves upward, H i is the temperature of the wire rope at the i-th monitoring point,

[0017] When the modulus of the steel wire rope at the i-th monitoring point is greater than or equal to the preset steel wire rope modulus, a steel wire rope breakage warning signal is generated to remind the user to replace the steel wire rope.

[0018] In one embodiment, the pumping unit wire rope fracture early warning method further includes:

[0019] The deformation variables and the voltage output by the strain gauge at at least four monitoring points are monitored at a preset reference temperature, and the correction coefficient k1, the cosine component coefficient k2, the sine component coefficient k3 of the output voltage, and the deformation coefficient ω1 of the wire rope are calculated based on the deformation variables and the voltage output by the strain gauge.

[0020] In one embodiment, the pumping unit wire rope fracture early warning method further includes:

[0021] The total tension on the steel wire rope during the ascent is expressed as:

[0022] F=F1+F2

[0023] Wherein, F is the total tension that the steel wire rope bears when it is lifted and moves upward, F1 is the first tension that the steel wire rope bears when it is lifted and moves upward, and F2 is the second inertia additional tension that the steel wire rope bears when it is lifted and moves upward;

[0024] The mathematical model of the total tension F applied to the wire rope during the ascent is:

[0025]

[0026] in,

[0027] Among them, ρ1 is the density of the wire rope, is the average cross-sectional area of ​​the wire rope, L1 is the total length of the wire rope, ρ2 is the density of the sucker rod, S2 is the cross-sectional area of ​​the sucker rod, L2 is the length of the sucker rod, ρ3 is the density of the oil pump, S3 is the effective cross-sectional area of ​​the oil pump, L3 is the length of the oil pump, ρ4 is the density of crude oil, ρ5 is the density of water, m1 is the proportion coefficient of crude oil, m2 is the proportion coefficient of water, S4 is the effective cross-sectional area of ​​crude oil and water in the oil pump, L4 is the effective length of crude oil and water in the oil pump, g is the acceleration of gravity, and a is the acceleration of the wire rope when it is lifted and moves upward.

[0028] In one embodiment, the mathematical model between the modulus of the steel wire rope at the i-th monitoring point and the tension on the steel wire rope, the deformation of the steel wire rope and the voltage value of the strain gauge is established as follows:

[0029] Among them, E i is the modulus of the wire rope at the i-th monitoring point, F is the tension on the wire rope, a is the acceleration of the wire rope when it is lifted and moves upward, H i is the temperature of the wire rope at the i-th monitoring point;

[0030] The mathematical model between the obtained deformation of the wire rope and the corresponding output voltage value of the strain gauge can be transformed into:

[0031]

[0032] Substituting it into the improved Young's modulus equation, the relationship between the wire rope modulus and voltage can be obtained as follows:

[0033]

[0034] That is, by setting the strain gauge on the wire rope and the degree of deformation of the wire rope when lifting the oil pump, the relationship between the deformation of the wire rope at the ith monitoring point and the corresponding strain gauge output voltage value can be calculated, and then the modulus of the wire rope at the ith monitoring point can be calculated through the strain gauge output voltage value corresponding to the wire rope at the ith monitoring point, the deformation amount and the influence of temperature on the wire rope. Then, when the modulus of the wire rope at this time exceeds the preset wire rope modulus, the wire rope needs to be replaced.

[0035] In one embodiment, it further includes:

[0036] Determine the overall modulus E of the steel wire rope according to the modulus of the steel wire rope at n monitoring points;

[0037] When the overall modulus E is greater than a preset overall modulus threshold, generating the wire rope breakage warning signal;

[0038] Where E = X1E1 + X2E2 + ... + X i E i +…+X n E n

[0039] Among them, X1, X2, …, X i , …, X n is the preset weight coefficient, and X1+X2+…+X i +…+X n =1.

[0040] In one embodiment, the weight coefficient Xi preset for the i-th monitoring point is positively correlated with the distance between the suspension ropes.

[0041] In one embodiment, the selecting n monitoring points at equal distances on the wire rope includes:

[0042] Select n monitoring points on the steel wire rope at equal distances in the vertical direction.

[0043] A second aspect of an embodiment of the present application provides an early warning device, which is used to execute the early warning method for breakage of a steel rope of an oil pumping unit as described in any one of the above items.

[0044] In one embodiment, the early warning device further comprises:

[0045] An alarm is provided, wherein the alarm is used to sound an alarm when the modulus of the steel wire rope exceeds a preset modulus of the steel wire rope.

[0046] The embodiment of the present application provides an early warning method and early warning device for the breakage of a steel wire rope of an oil pumping unit, wherein the early warning method for the breakage of a steel wire rope of an oil pumping unit comprises: selecting n monitoring points at equal distances on the steel wire rope, setting a strain gauge at each monitoring point, measuring the cross-sectional area of ​​the steel wire rope at the ith monitoring point of the steel wire rope, measuring the temperature value of the steel wire rope at the ith monitoring point of the steel wire rope, measuring the voltage value of the strain gauge at the ith monitoring point of the steel wire rope, establishing a mathematical model between the deformation amount of the steel wire rope at the ith monitoring point and the corresponding voltage value of the strain gauge, establishing a tension model to which the steel wire rope is subjected when lifting a pull rod and an oil pump, establishing a mathematical model between the modulus of the steel wire rope at the ith monitoring point and the tension to which the steel wire rope is subjected, the deformation of the steel wire rope and the voltage value of the strain gauge, and giving an early warning of the breakage of the steel wire rope, thereby solving the problem that the existing early warning method for the breakage of the steel wire rope cannot accurately consider the influence of the external environment on the steel wire rope and cannot accurately predict the breakage of the steel wire rope. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0048] Figure 1 This is a schematic diagram of the steps of a method for early warning of wire rope breakage of an oil pumping unit provided by an embodiment of the present application;

[0049] Figure 2 It is a schematic diagram of the monitoring point structure of a method for early warning of wire rope breakage of an oil pumping unit provided by an embodiment of the present application;

[0050] Figure 3 It is a schematic diagram of the number of experiments and errors of a method for early warning of wire rope breakage of an oil pump provided by an embodiment of the present application. DETAILED DESCRIPTION

[0051] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] In mechanical oil production, the main equipment is the pumping unit, sucker rod, oil pump and wire rope. The wire rope connects the sucker rod and the oil pump through a rope hanger. The wire rope is the only carrier for transmitting the power of the ground pumping unit to the downhole oil pump. Therefore, the service life of the wire rope is crucial to the production of crude oil. Due to the connection method of the wire rope and the long-term alternating load it bears, there are some unfavorable factors in the field application that make the wire rope prone to tripping and breaking. Since the load of the pumping unit is not constant, its instability shortens the life of the wire rope and is difficult to calculate. In the existing technology, oil production workers mostly use the method of regularly replacing the wire rope, which leads to a significant increase in the cost of oil extraction, or directly calculate the service life of the wire rope by calculating the load borne by the wire rope. The existing wire rope fracture warning method cannot accurately take into account the impact of the external environment on the wire rope, and there is a problem of not being able to accurately predict the fracture of the wire rope.

[0054] In order to solve the above technical problems, the present application embodiment provides a method for early warning of wire rope fracture of an oil pumping unit, referring to Figure 1 , Figure 2 As shown, the method for early warning of the breakage of a steel rope of an oil pumping unit may include steps S10 to S70.

[0055] Step S10, selecting n monitoring points at equal distances on the wire rope, and setting a strain gauge at each monitoring point;

[0056] Specifically, n monitoring points are selected, and a strain gauge is set at each monitoring point to monitor the conditions of different monitoring points of the wire rope, and then any point of the pumping unit wire rope can be monitored, solving the problem that the existing wire rope breakage early warning method only monitors at one point. Among them, n monitoring points are selected, which can be expressed as N1, N2, ..., N i ,…,N n , 0<i≤n, where i is a positive integer and n is a positive integer.

[0057] Step S20, reference Figure 1 , Figure 2 As shown, the cross-sectional area S of the wire rope at the i-th monitoring point is measured. i , 0<i≤n, where i is a positive integer and n is a positive integer;

[0058] Specifically, in daily life, we generally believe that the cross-sectional area of ​​a wire rope is uniformly distributed. However, strictly speaking, the cross-sectional areas of different sections of a wire rope are different. Moreover, a wire rope generally breaks because of its different cross-sectional areas and breaks at places with relatively small cross-sectional areas. Therefore, measuring the cross-sectional area of ​​the wire rope at different monitoring points of the wire rope can make the calculation result more accurate. In this embodiment, a micrometer can be used to measure the cross-sectional area of ​​the wire rope.

[0059] Step S30, measuring the temperature value H of the wire rope at the i-th monitoring point of the wire rope i ;

[0060] Specifically, the steel wire rope is partially set in the pumping well, partially set in the pumping well, and partially set outside the well, and the temperature value of the steel wire rope at the monitoring point is crucial to the influence of thermal expansion and contraction of the steel wire rope.

[0061] Step S40, measuring the voltage value V of the strain gauge at the i-th monitoring point of the wire rope i ;

[0062] Step S50, establish the deformation amount D of the wire rope at the i-th monitoring point i The corresponding voltage value V of the strain gauge i The mathematical model between them is:

[0063]

[0064] Among them, V i is the voltage value of the strain gauge at the i-th monitoring point, D i is the deformation of the wire rope length at the i-th monitoring point, k1 is the correction coefficient of the output voltage, k2 is the cosine component coefficient, k3 is the sine component coefficient, Q i is the voltage sensitivity coefficient of the strain gauge at the ith monitoring point, ω1 is the deformation coefficient of the wire rope, H i is the temperature of the wire rope at the i-th monitoring point;

[0065] In this embodiment, the strain gauge is an element composed of a sensitive grid and the like for measuring strain. When the deformation of the strain gauge changes, its resistance value changes accordingly. The strain gauge is arranged at the monitoring point of the wire rope and is closely attached to the wire rope. When the wire rope is subjected to tension and its deformation changes, the strain gauge is deformed, and its resistance value also changes. However, since the deformation of the strain gauge is small, it is difficult to measure or the measurement is inaccurate when a slight deformation occurs. By establishing a mathematical model between the deformation of the wire rope and the corresponding voltage value of the strain gauge, the voltage change of the strain gauge can be used to calculate the resistance value. Its deformation variable, and then bring the deformation variable into the mathematical model between the modulus of the wire rope established in step S70 and the tension exerted on the wire rope, the deformation of the wire rope and the voltage value of the strain gauge, so as to calculate the modulus change exerted on the wire rope, and then compare the modulus of the wire rope at the ith monitoring point with the preset modulus of the wire rope. When the modulus of the wire rope at the ith monitoring point is greater than or equal to the preset modulus of the wire rope, it indicates that the wire rope is in danger of breaking and needs to be replaced, which solves the problem that the existing wire rope breakage early warning method cannot accurately take into account the influence of the external environment on the wire rope and cannot accurately predict the breakage of the wire rope.

[0066] Step S60, establishing a model of the tension F that the wire rope is subjected to when lifting the pull rod and the oil pump;

[0067] Specifically, in this implementation, a model of the tension F that the wire rope is subjected to when lifting the pull rod and the oil pump is established. Because the wire rope is not only subjected to the downward pulling force of the pumping rod, the oil pump, and the oil-water mixture in the oil pump during the rising process, but also to the gravity of the wire rope itself and the inertial additional tension of the acceleration on the wire rope during the upward movement, the total tension that the wire rope is subjected to during the rising process is expressed by F as follows:

[0068] F=F1+F2

[0069] Wherein, F is the total tension that the steel wire rope bears when it is lifted and moves upward, F1 is the first tension that the steel wire rope bears when it is lifted and moves upward, and F2 is the second inertia additional tension that the steel wire rope bears when it is lifted and moves upward;

[0070] The mathematical model of the total tension F applied to the wire rope during the ascent is:

[0071]

[0072] in,

[0073] Among them, ρ1 is the density of the wire rope, is the average cross-sectional area of ​​the wire rope, L1 is the total length of the wire rope, ρ2 is the density of the sucker rod, S2 is the cross-sectional area of ​​the sucker rod, L2 is the length of the sucker rod, ρ3 is the density of the oil pump, S3 is the effective cross-sectional area of ​​the oil pump, L3 is the length of the oil pump, ρ4 is the density of crude oil, ρ5 is the density of water, m1 is the proportion coefficient of crude oil, m2 is the proportion coefficient of water, S4 is the effective cross-sectional area of ​​crude oil and water in the oil pump, L4 is the effective length of crude oil and water in the oil pump, g is the acceleration of gravity, and a is the acceleration of the wire rope when it is lifted and moves upward.

[0074] By taking into account the effect of inertia on the tension of the wire rope, the tension on the wire rope can be accurately calculated, making the calculation more accurate.

[0075] Step S70, a mathematical model is established between the modulus of the steel wire rope at the i-th monitoring point, the tension on the steel wire rope, the deformation of the steel wire rope, and the voltage value of the strain gauge:

[0076] Among them, E i is the modulus of the steel wire rope at the i-th monitoring point, F is the tension on the steel wire rope, a is the acceleration of the steel wire rope when it is lifted and moves upward, H i is the temperature of the wire rope at the i-th monitoring point,

[0077] When the modulus of the steel wire rope at the i-th monitoring point is greater than or equal to the preset steel wire rope modulus, a steel wire rope breakage warning signal is generated to remind the user to replace the steel wire rope.

[0078] In this embodiment, according to the mathematical model between the deformation amount of the steel wire rope and the corresponding output voltage value of the strain gauge:

[0079]

[0080] Can be transformed into:

[0081]

[0082] Substituting it into the improved Young's modulus equation, the relationship between the wire rope modulus and voltage can be obtained as follows:

[0083]

[0084] In this example, by setting the strain gauge on the wire rope and the degree of deformation of the wire rope when lifting the oil pump, the relationship between the deformation of the wire rope at the ith monitoring point and the corresponding strain gauge output voltage value can be calculated, and then the modulus of the wire rope at the ith monitoring point can be calculated through the strain gauge output voltage value corresponding to the wire rope at the ith monitoring point, the deformation amount and the influence of temperature on the wire rope. Then, when the modulus of the wire rope at the ith monitoring point is greater than or equal to the preset wire rope modulus, it indicates that the wire rope is in danger of breaking and needs to be replaced, which solves the problem that the existing wire rope breakage early warning method cannot accurately consider the influence of the external environment on the wire rope and cannot accurately predict the wire rope breakage.

[0085] In one embodiment, the pumping unit wire rope fracture early warning method further includes:

[0086] The deformation variables and the voltage output by the strain gauge at at least four monitoring points are monitored at a preset reference temperature, and the correction coefficient k1, the cosine component coefficient k2, the sine component coefficient k3 of the output voltage, and the deformation coefficient ω1 of the wire rope are calculated based on the deformation variables and the voltage output by the strain gauge.

[0087] Specifically, when the temperature of the wire rope is 20°C, the deformation of the wire rope length is 0.1mm, 0.2mm, 0.4mm, 0.6mm, and the voltage output by the strain gauge is 3.9mV, 7.6mV, 15.2mV, and 22.5mV, respectively. V is calculated to be i The parameters in the strain gauge can then be used to obtain the relationship between the strain gauge voltage and the deformation of the wire rope at the monitoring point;

[0088] Calculate V i The parameters in are:

[0089]

[0090] In one embodiment, the pumping unit wire rope fracture warning method further includes: determining the overall modulus E of the wire rope according to the modulus of the wire rope at n monitoring points; generating the wire rope fracture warning signal when the overall modulus E is greater than a preset overall modulus threshold;

[0091] Where E = X1E1 + X2E2 + ... + X i E i +…+X n E n

[0092] Among them, X1, X2, …, X i , …, X n is the preset weight coefficient, and X1+X2+…+X i +…+Xn =1.

[0093] Specifically, in this embodiment, by setting weight coefficients for different monitoring points and determining the overall modulus E of the wire rope according to the modulus of the wire rope at n monitoring points, the overall modulus of the wire rope can be monitored more comprehensively. Then, when the overall modulus of the wire rope is greater than or equal to the preset modulus of the wire rope, it indicates that the wire rope is in danger of breaking and needs to be replaced, which solves the problem that the existing wire rope breakage early warning method cannot accurately take into account the impact of the external environment on the wire rope and cannot accurately predict the breakage of the wire rope.

[0094] In one embodiment, the weight coefficient X preset at the i-th monitoring point is i It is positively correlated with the distance between the suspension ropes.

[0095] In one embodiment, selecting n monitoring points at equal distances on the steel wire rope includes: selecting n monitoring points at equal distances in a vertical direction on the steel wire rope.

[0096] Specifically, the deformation of the monitoring points is different when the distance between them and the suspension rope is different. Therefore, n monitoring points are selected at equal distances in the vertical direction of the wire rope to comprehensively monitor the deformation of the wire rope. When the wire rope is subjected to tension and the deformation changes, the strain gauge is deformed and its resistance value is also deformed. However, due to the small deformation of the strain gauge, it is difficult to measure or inaccurate when it undergoes a slight deformation. By establishing a mathematical model between the deformation of the wire rope and the corresponding voltage value of the strain gauge, its resistance value can be calculated through the change in the voltage value of the strain gauge. The deformation variable can be used to establish the modulus of the wire rope with the tensile force, deformation of the wire rope and the voltage value of the strain gauge in a mathematical model to calculate the modulus change of the wire rope. The modulus of the wire rope at each monitoring point can be compared with the preset modulus of the wire rope. When the modulus of the wire rope at the monitoring point is greater than or equal to the preset modulus of the wire rope, it indicates that the wire rope is in danger of breaking and needs to be replaced. This solves the problem that the existing wire rope breakage early warning method cannot accurately consider the impact of the external environment on the wire rope and cannot accurately predict the breakage of the wire rope.

[0097] In one embodiment, Figure 3 As shown, 20 wire rope breakage prediction experiments were carried out on the same pumping unit using the patented method. It can be seen from the figure that the average error value of wire rope breakage prediction is 1.67%, the variance is 3, and the maximum error is 2.76%. Therefore, the patented method is stable. 20 wire rope breakage prediction experiments were carried out on the same pumping unit using the patented method, and the average value was recorded as the result. It can be seen that the maximum relative error is 1.78, which meets industrial needs.

[0098] An embodiment of the present application provides an early warning device, which is used to execute the early warning method for the breakage of a steel rope of an oil pumping unit as described in any one of the above items.

[0099] In one embodiment, the early warning device further includes: an alarm, wherein the alarm is used to sound an alarm when the modulus of the steel wire rope exceeds a preset modulus of the steel wire rope.

[0100] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0101] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0102] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0103] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for early warning of wire rope breakage of an oil pumping unit, characterized in that: The pumping unit wire rope fracture early warning method comprises: Select n monitoring points at equal distances on the wire rope, and set a strain gauge at each monitoring point; Measure the cross-sectional area S of the wire rope at the i-th monitoring point i , 0<i≤n, where i is a positive integer and n is a positive integer; Measure the temperature value H of the wire rope at the i-th monitoring point i ; Measure the voltage value V of the strain gauge at the i-th monitoring point of the wire rope i ; Establish the deformation D of the wire rope at the i-th monitoring point i The corresponding strain gauge voltage value V i The mathematical model between them is: Among them, V i is the voltage value of the strain gauge at the i-th monitoring point, D i is the deformation of the wire rope at the i-th monitoring point, k1 is the correction coefficient of the output voltage, k2 is the cosine component coefficient, k3 is the sine component coefficient, Q i is the voltage sensitivity coefficient of the strain gauge at the ith monitoring point, ω1 is the deformation coefficient of the wire rope, H i is the temperature of the wire rope at the i-th monitoring point; Establish a model of the tension F that the wire rope is subjected to when lifting the pull rod and the oil pump; The mathematical model between the modulus of the wire rope at the i-th monitoring point and the tension on the wire rope, the deformation of the wire rope and the voltage value of the strain gauge is established as follows: Among them, E i is the modulus of the wire rope at the i-th monitoring point, F is the tension on the wire rope, a is the acceleration of the wire rope when it is lifted and moves upward, H i is the temperature of the wire rope at the monitoring point, When the modulus of the steel wire rope at the i-th monitoring point is greater than or equal to the preset steel wire rope modulus, a steel wire rope breakage warning signal is generated to remind the user to replace the steel wire rope.

2. The method for early warning of wire rope breakage of an oil pumping unit according to claim 1, characterized in that: The pumping unit wire rope fracture early warning method further comprises: The deformation variables and the voltage output by the strain gauge at at least four monitoring points are monitored at a preset reference temperature, and the correction coefficient k1, the cosine component coefficient k2, the sine component coefficient k3 of the output voltage, and the deformation coefficient ω1 of the wire rope are calculated based on the deformation variables and the voltage output by the strain gauge.

3. The method for early warning of wire rope breakage of an oil pumping unit according to claim 2, characterized in that: The pumping unit wire rope fracture early warning method further comprises: The total tension on the steel wire rope during the ascent is expressed as: F=F1+F2 Wherein, F is the total tension that the steel wire rope bears when it is lifted and moves upward, F1 is the first tension that the steel wire rope bears when it is lifted and moves upward, and F2 is the second inertia additional tension that the steel wire rope bears when it is lifted and moves upward; The mathematical model of the total tension F applied to the wire rope during the ascent is: in, ρ1 is the density of the wire rope, is the average cross-sectional area of ​​the wire rope, L1 is the total length of the wire rope, ρ2 is the density of the sucker rod, S2 is the cross-sectional area of ​​the sucker rod, L2 is the length of the sucker rod, ρ3 is the density of the oil pump, S3 is the effective cross-sectional area of ​​the oil pump, L3 is the length of the oil pump, ρ4 is the density of crude oil, ρ5 is the density of water, m1 is the proportion coefficient of crude oil, m2 is the proportion coefficient of water, S4 is the effective cross-sectional area of ​​crude oil and water in the oil pump, L4 is the effective length of crude oil and water in the oil pump, g is the acceleration of gravity, and a is the acceleration of the wire rope when it is lifted and moves upward.

4. The method for early warning of wire rope breakage of an oil pumping unit according to claim 3, characterized in that: The mathematical model between the modulus of the steel wire rope at the i-th monitoring point and the tension on the steel wire rope, the deformation of the steel wire rope and the voltage value of the strain gauge is established as follows: Among them, E i is the modulus of the wire rope at the i-th monitoring point, F is the tension on the wire rope, a is the acceleration of the wire rope when it is lifted and moves upward, H i is the temperature of the wire rope at the i-th monitoring point; The mathematical model between the obtained deformation of the wire rope and the corresponding output voltage value of the strain gauge can be transformed into: By applying it to the mathematical model between the modulus of the wire rope and the tension on the wire rope, the deformation of the wire rope and the voltage value of the strain gauge, the relationship between the modulus of the wire rope and the voltage can be obtained as follows: That is, by setting the strain gauge on the wire rope and the degree of deformation of the wire rope when lifting the oil pump, the relationship between the deformation of the wire rope at the ith monitoring point and the corresponding strain gauge output voltage value can be calculated, and then the modulus of the wire rope at the ith monitoring point can be calculated through the strain gauge output voltage value corresponding to the wire rope at the ith monitoring point, the deformation amount and the influence of temperature on the wire rope. Then, when the modulus of the wire rope at this time exceeds the preset wire rope modulus, the wire rope needs to be replaced.

5. The method for early warning of wire rope breakage of an oil pumping unit according to claim 4, characterized in that: Also includes: Determine the overall modulus E of the steel wire rope according to the modulus of the steel wire rope at n monitoring points; When the overall modulus E is greater than a preset overall modulus threshold, generating the wire rope breakage warning signal; Where E = X1E1 + X2E2 + ... + X i E i +…+X n E n Among them, X1, X2, …, X i , …, X n is the preset weight coefficient, and X1+X2+…+X i +…+X n =1.

6. The method for early warning of wire rope breakage of an oil pumping unit according to claim 5, characterized in that: The preset weight coefficient Xi of the i-th monitoring point is positively correlated with the distance between the suspension ropes.

7. The method for early warning of wire rope breakage of an oil pumping unit according to claim 6, characterized in that: The selection of n monitoring points at equal distances on the wire rope includes: Select n monitoring points on the steel wire rope at equal distances in the vertical direction.

8. An early warning device, characterized in that: The early warning device is used to execute the early warning method for wire rope breakage of an oil pumping unit as described in any one of claims 1 to 7.

9. The early warning device according to claim 8, characterized in that: Also includes: An alarm is provided, wherein the alarm is used to sound an alarm when the modulus of the steel wire rope exceeds a preset modulus of the steel wire rope.

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