A method for obtaining the stroke height of the oil rod in a belt-driven pumping unit

Abstract

This invention relates to a method for obtaining the stroke height of a belt-driven pumping unit. The method involves iteratively calculating the linear motion zone and the semi-circular reversing zone of the crank 1 during the up and down strokes, respectively. Trigonometric functions are used to calculate the projection elevation of the crank 1 position corresponding to the pulse in the semi-circular reversing zone onto the trajectory axis of the pumping unit suspension point, thus obtaining the reversing zone height. The linear motion zone during the up and down strokes is still processed using geometric iteration. Compared with existing technologies, this invention simplifies the calculation method for the stroke height of a belt-driven pumping unit, allowing the acquisition of instantaneous stroke height data required for real-time dynamometer card plotting using a PLC control system.

Description

Technical Field

[0001] This invention relates to the field of oil and gas engineering, and in particular to a method for obtaining the stroke height of the oil rod in a belt-driven pumping unit. Background Technology

[0002] Belt-driven pumping units are internationally leading long-stroke, slow-stroke, purely mechanically driven pumping units. They are simple to operate, easy to maintain, and safe to use. Their excellent oil extraction performance and reliable mechanical properties make them the most widely used type of beamless pumping unit in the world. Currently, the rod stroke height parameter acquisition method used in dynamometer card technology for belt-driven pumping units mainly includes sensor measurement and sprocket coaxial target disk detection. The sensor measurement method, due to the simultaneous operation of two or more sensors, has high circuit power consumption and can only be implemented via wired connection. The sprocket coaxial target disk detection method typically includes three methods: "full-stroke geometric average iteration method," "partition geometric iteration method," and "fast Fourier series fast iteration algorithm." The "full-stroke geometric average iteration method" is suitable for low-performance PLC-CPUs, but the calculated instantaneous speed has a certain error. The "partition geometric iteration method" cannot be used for real-time dynamometer card plotting and instantaneous sprint speed control and protection. The "fast Fourier series fast iteration algorithm" is suitable for 32-bit single-chip microcomputer embedded control systems, which PLC-CPUs cannot handle. Summary of the Invention

[0003] To address the aforementioned problems, this invention discloses a method for obtaining the stroke height of a belt-driven pumping unit's rod, which reduces the CPU's computing power requirements and can accurately calculate the stroke height in real time.

[0004] To achieve the above objectives, the present invention adopts the following solution: a method for obtaining the stroke height of the oil rod of a belt-driven pumping unit, comprising the following steps:

[0005] S1. Obtain the current chain drive ratio k1 of the belt-driven pumping unit, the reduction ratio k2 of the gearbox, the pitch circle radius R of the sprocket, the rated stroke height H, and the number of holes m of the rotation signal detection target plate;

[0006] S2. Calculate the total number of rotational pulses N per stroke, using the following formula:

[0007] N = k1 × k2 × m;

[0008] S3. Calculate the pulse division value D. g The calculation formula is as follows:

[0009]

[0010] S4. Calculate the total number of reversing point pulses in four intervals: N1 for the downstroke semicircular reversing zone, N2 for the upstroke straight zone, N3 for the upstroke semicircular reversing zone, and N4 for the downstroke straight zone.

[0011] S5. Calculate the real-time stroke height of each zone based on the zones defined in step S4, which are as follows:

[0012] Real-time stroke height h1 in the downward semi-circular reversing zone, h1=R[1-sin(α)]=R·[1-sin(n×D)] g )],0≤n≤N1

[0013] Real-time stroke height h2 in the straight upward stroke zone

[0014] Real-time stroke height h3 in the upward semi-circular reversing zone.

[0015]

[0016] Real-time stroke height h4 in the straight downward stroke zone

[0017] Where n is the number of real-time pulses per stroke, N C The rated number of pulses in the semi-circular commutation zone of the stroke is calculated using the following formula:

[0018] α is the angle between the line connecting the center of crank (1) and the center of upper sprocket (2) and P1, α = n × D g β is the angle between the line connecting the center of crank (1) and the center of lower sprocket (3) and P3.

[0019] In step S4

[0020] Compared with the prior art, the present invention simplifies the method of calculating the stroke height of belt-driven pumping units, thereby enabling the acquisition of instantaneous stroke height data required for real-time dynamometer plotting by adopting a PLC control system. Attached Figure Description

[0021] Figure 1 This is a diagram illustrating the calculation model of the downward-facing semi-circular reversing zone in this invention.

[0022] Figure 2 This is an illustration of the calculation model for the upward straight line zone in this invention;

[0023] Figure 3 This is an illustration of the calculation model for the upward-striking semi-circular reversing zone in this invention;

[0024] Figure 4This is an illustration of the calculation model for the downward straight line zone in this invention. Detailed Implementation

[0025] This invention obtains the reversing zone height by iteratively calculating the linear motion zone and the upper and lower semicircular reversing zone of crank 1, respectively, and using trigonometric functions to calculate the projection elevation of the crank 1 position corresponding to the pulse in the upper and lower semicircular reversing zone onto the axis of the hydraulic rod suspension point trajectory. The linear motion zone of the up and down strokes is still processed using geometric iteration.

[0026] To facilitate understanding of the technical solution of this invention, a schematic diagram of the calculation model is provided, dividing the crank motion trajectory into four regions according to a complete stroke. The order of the crank motion trajectory is as follows: Figures 1 to 4 .

[0027] Therefore, a method for obtaining the rod stroke height of a belt-driven pumping unit includes the following steps:

[0028] First, obtain the current chain drive ratio K1 of the belt-driven pumping unit, the reduction ratio K2 of the gearbox, the pitch circle diameter R of the sprocket, the rated stroke height H, and the number of holes m of the rotation signal detection target plate.

[0029] Next, calculate the total number of rotational pulses N per stroke, using the following formula:

[0030] N = k1 × k2 × m.

[0031] Then calculate the pulse division value using the following formula:

[0032]

[0033] Next, the total number of commutation point pulses is calculated for each partition:

[0034] P1 to P2 is the downward-thrusting semi-circular commutation zone. The total number of pulses N1 is the cumulative total number of pulses in this zone. P1 is the starting point, at which point the real-time pulse count n = 0. P2 is the ending point of the downward-thrusting semi-circular commutation zone, at which point the pulse count... Where N C This represents the rated number of pulses in the semi-circular commutation zone of the stroke. Within this zone, 0 ≤ n ≤ N1.

[0035] P2 to P3 is the upward linear zone. The total number of pulses N2 is the cumulative number of pulses from the starting point P1 to the end of this zone. P3 is the end point of the upward linear zone. In this interval, N1 < n ≤ N2.

[0036] The upward semi-circular commutation zone from P3 to P4 is defined by the total number of pulses N3, which is the cumulative total number of pulses from the starting point P1 to the end of this zone. P4 is the end point of the upward semi-circular commutation. In this interval, N2 < n ≤ N3.

[0037] In the straight-line region from P4 to P1, the total number of pulses N4 is the cumulative number of pulses from the starting point of P1 to the end of this region. When a complete stroke ends, N4 = N. In this region, N3 < n ≤ N4.

[0038] Finally, the real-time stroke height h in each zone is calculated:

[0039] The real-time stroke height in the downward semi-circular reversing zone is h = h1, h1 = R[1-sin(α)] = R·[1-sin(n×D)]. g )], 0≤n≤N1;

[0040] The real-time stroke height in the straight upward stroke zone is h = h2.

[0041] The real-time stroke height in the upward semi-circular reversal zone is h = h3.

[0042]

[0043] The real-time stroke height in the straight-line downward stroke zone is h = h4.

[0044] Where n is the number of real-time pulses per stroke, N C The rated number of pulses in the semi-circular commutation zone of the stroke is calculated using the following formula:

[0045] α is the angle between the line connecting the center of crank 1 and the center of upper sprocket 2, and the line connecting P1 and the center of upper sprocket 2, with the starting point of this angle being P1 and the ending point being P2, and α = n × D. g .

[0046] β is the angle between the line connecting crank 1 and the center of lower sprocket 3, and the line connecting P3 and the center of lower sprocket 3, with the starting point of this angle being P3 and the ending point being P4.

[0047] Taking a certain type of belt-driven oil pumping unit as an example, the chain drive ratio k1 = 6.19; the gearbox reduction ratio k2 = 31.069; the sprocket pitch circle diameter R = 426mm; the rated stroke height H = 7747mm; and the number of holes in the rotation signal detection target plate m = 3.

[0048] The total number of rotational pulses per stroke is N = k1 × k2 × m = 6.19 * 31.069 * 3 = 576.95, which is rounded up to 577.

[0049] Pulse division value

[0050] Total number of pulses in the downward semi-circular commutation zone from P1 to P2 Take 46.

[0051] P2 to P3, total number of pulses in the upward linear region Take 288.

[0052] P3 to P4, total number of pulses in the upward semi-circular commutation zone

[0053]

[0054] The total number of pulses in the downstroke linear region from P4 to P1 is N4 = N = 577.

[0055] Calculate the real-time stroke height, from P1 to P2:

[0056] When n = 10, h1 = 426 * [1 - sin(3.86 * 10)] = 160 mm

[0057] When n = 23, h1 = 426 * [1 - sin(3.86 * 23)] = 0 mm

[0058] When n = 40, h1 = 426 * [1 - sin(3.86 * 40)] = 212 mm

[0059] When n = 46, h1 = 426 * [1 - sin(3.86 * 46)] = 408 mm

[0060] From P2 to P3:

[0061] When n = 47

[0062] When n = 150

[0063] When n = 288

[0064] From P3 to P4:

[0065] When n = 289

[0066]

[0067] When n = 312

[0068]

[0069] When n = 358

[0070]

[0071] From P4 to P1:

[0072] When n = 359

[0073] When n = 460

[0074] When n = 576

[0075] The above method is simple and convenient, reducing the computational requirements while still obtaining the stroke height data needed for real-time dynamometer diagrams. Furthermore, it makes it possible to achieve instantaneous speed optimization control and protection for each motion region of the stroke under a PLC control system.

[0076] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for obtaining the stroke height of the oil rod in a belt-driven oil pumping unit, characterized in that, Includes the following steps: S1. Obtain the current chain drive ratio k1 of the belt-driven pumping unit, the reduction ratio k2 of the gearbox, the pitch circle radius R of the sprocket, the rated stroke height H, and the number of holes m of the rotation signal detection target plate; S2. Calculate the total number of rotational pulses N per stroke, using the following formula: ； S3. Calculate the pulse division value D. g The calculation formula is as follows: ； S4. Calculate the total number of reversing point pulses in four intervals: N1 for the downstroke semicircular reversing zone, N2 for the upstroke straight zone, N3 for the upstroke semicircular reversing zone, and N4 for the downstroke straight zone. Among them, P1 to P2 is the downward-thrusting semi-circular commutation zone, the total number of pulses N1 is the cumulative total number of pulses in this zone, P1 is the starting point, at this time the real-time pulse count at the commutation point n=0, and P2 is the ending point of the downward-thrusting semi-circular commutation zone. P2 to P3 is the upward straight line zone. The total number of pulses N2 is the cumulative number of pulses from the starting point of P1 to the end of this zone. P3 is the end point of the upward straight line zone. P3 to P4 is the upward semi-circular reversal zone, and the total number of pulses N3 is the cumulative total number of pulses from the starting point of P1 to the end of this interval; P4 to P1 is the downstroke straight line region, and the total number of pulses N4 is the cumulative total number of pulses from the starting point of P1 to the end of this interval; S5. Calculate the real-time stroke height of each zone based on the zones defined in step S4, which are as follows: Real-time stroke height h1 in the downward semi-circular reversing zone. , 0≤n≤N1, Real-time stroke height h2 in the straight upward stroke zone N1<n≤N2, Real-time stroke height h3 in the upward semi-circular reversing zone. ,N2<n≤N3, Real-time stroke height h4 in the straight downward stroke zone N3 < n ≤ N4 Where n is the number of real-time pulses per stroke, N C The rated number of pulses in the semi-circular commutation zone of the stroke is calculated using the following formula: ; α is the angle between the line connecting the center of crank (1) and the center of upper sprocket (2) and P1. β is the angle between the line connecting the center of crank (1) and the center of lower sprocket (3) and P3. .

2. The method for obtaining the stroke height of the oil rod in a belt-driven pumping unit according to claim 1, characterized in that, In step S4 ; ; ; .

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