Pumping well working fluid level depth calculation method, pumping unit control system and control method

Abstract

The invention discloses a rod pumped well working fluid level depth calculation method, a pumping unit control system and a pumping unit control method, which effectively, intelligently and automatically regulate and control the operation speed of a pumping unit according to the real-time working fluid level depth, improve the oil well yield, improve the pump efficiency and reduce the invalid energy consumption. The underground working fluid level is calculated by applying parameters such as motor acting, balance block acting, sucker rod weight, underground fluid column weight and the like. The calculation method is applied to an operation control device of the oil pumping unit, the underground working fluid level depth can be automatically calculated in real time and compared with the required fluid level depth, and the operation speed of the oil pumping unit is logically regulated and controlled according to the comparison result. According to the operation control device of the pumping unit, the driver is installed, the controller is used for programming and calculating the working fluid level depth, sending out an instruction according to a comparison result and controlling the driver to adjust the output frequency, so that the operation speed of the motor is controlled, the operation speed of the pumping unit is controlled, and the stroke frequency of a pumping unit well is changed.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic monitoring and control, and in particular to a method for calculating the dynamic liquid level depth of a pumping unit well, a method for calculating the dynamic liquid level depth of a pumping unit well, an oil pumping control system and a control method. Background Art

[0002] In the production of the oil industry, pumping wells account for more than 90% of the total number of production wells. Therefore, the efficient production of pumping wells determines the oil production and the cost of oil products. Whether the pumping unit running speed is reasonable depends on whether the real-time dynamic liquid level depth of the oil well is reasonable. In the production of pumping wells, efforts are made to obtain the dynamic liquid level depth in order to reasonably adjust the pumping unit running speed, achieve the designed production pressure difference, and achieve stable production. If the pumping unit runs too fast, the liquid level depth will increase, the formation will produce too large a production pressure difference, and the formation is prone to sand production, resulting in production problems such as stuck pumps and empty pumping; if the pumping unit runs too slowly, the liquid level depth will decrease, the formation will produce too small a production pressure difference, resulting in production failing to meet production requirements, and the oil field crude oil production will decrease. Therefore, the monitoring of the dynamic liquid level position of the oil well is the most important technical parameter for the production of pumping wells.

[0003] At present, the method of monitoring the liquid level of the pumping well mainly uses an echometer, which uses sound waves for testing. However, this method has two disadvantages. First, the echo technology is restricted by the conditions of the wellbore (such as dead oil, foam, pipe wall deformation, etc.) and produces errors; second, the product is large in size and high in investment cost, which consumes a lot of manpower and material resources and cannot achieve real-time monitoring of all oil wells. Therefore, traditional manual monitoring methods can no longer meet the current digital production needs of oil fields. It is necessary to find a monitoring method to replace the traditional liquid level monitoring method and display the dynamic liquid level of the pumping well in real time to achieve efficient, effective and intelligent operation of the oil well.

[0004] At present, the existing Chinese patent CN114183125A has been published. It is a driving end sensing type pumping well dynamic liquid level test method. It specifically discloses that the relationship between the plunger load and the stroke is established on the basis of synchronously measuring the suspension point load and displacement to obtain a pump work diagram, and the dynamic liquid level depth is obtained by using the pump work diagram. The dynamic liquid level of the oil well is an important indicator reflecting the formation fluid supply capacity, and is an important basis for the oil field to determine the reasonable subsidence and formulate a reasonable work system. It provides a device and method that can continuously test the dynamic liquid level, but it still has the following shortcomings: a work diagram tester must be added, and the load data can only be obtained by mechanical testing. At the same time, the added work diagram tester must be calibrated and maintained regularly to operate normally.

[0005] After understanding and consulting technical literature, it is found that there is no product in China that can calculate the dynamic liquid level depth of the pumping unit in real time based on the ground pumping unit data (balance block, crank, sucker rod combination), wellhead casing pressure, oil pressure, current, voltage and other data, and intelligently control the speed of the pumping unit based on the calculated dynamic liquid level depth data. Summary of the invention

[0006] The purpose of the present invention is to provide a method for calculating the dynamic liquid level depth of a pumping unit well, a pumping unit operation control system and a control method, by applying parameters such as the work done by the motor, the work done by the balance block, the weight of the sucker rod and the weight of the downhole liquid column to calculate the downhole dynamic liquid level. Furthermore, by applying the calculation method to the pumping unit operation control system, the downhole dynamic liquid level depth is automatically calculated in real time, and according to the geological requirements for the dynamic liquid level depth, the operating speed of the pumping unit is automatically and logically adjusted in real time.

[0007] The technical solution adopted by the present invention is:

[0008] A method for calculating the dynamic liquid level depth of a pumping well comprises the following steps:

[0009] Step A: Calculate the average pulling force F during the upward movement of the donkey head by collecting the production parameters of the oil pumping unit;

[0010] Step B: By collecting the production parameters of the pumping unit, calculate the theoretical pulling force F of the donkey head when the liquid level is at the pump hanging depth and the pipe is full of liquid. 假设 ;

[0011] Step C: Calculate the dynamic liquid level depth L by collecting the production parameters of the pumping unit f When the distance from the liquid surface to the pump barrel is H, that is, when the submergence is H, the upward force F exerted by the lower liquid at the pump hanging depth on the piston is 沉没 , assuming the pump hanging depth is L, through the formula F 沉没 =F 假设 -F gets the dynamic liquid level depth L f Simplify the calculation formula;

[0012] Step D: Enter the real-time distance value from the liquid surface to the pump barrel, i.e., the sinking degree H, to obtain the real-time dynamic liquid surface depth value.

[0013] The step A specifically includes the following steps: first, measuring the stroke length L of the pumping well 冲程 , the size of the balance block, the size of the crank and the distance X from the inside of the balance block to the center of the crank shaft pnq Then, the average output voltage U and average output current I of the donkey head during the upward movement are collected; finally, the average pulling force F of the donkey head during the upward movement is obtained by the following formula: W 电机 W is the work done by the motor during the donkey's upward movement.平衡块 : The balance block and crank do work during the donkey's upward movement.

[0014] The step B specifically includes the following steps: First, collect and measure the sucker rod gravity F 杆 , sucker rod diameter d 杆 , sucker rod density ρ 杆 , sucker rod length L 杆 , Pump piston cross-sectional area S 活塞 , oil pipe inner cross-sectional area S 管内 and the inner diameter of the oil pipe D IN ; Read the wellhead oil pressure Po and the wellhead casing pressure Pc; Secondly, calculate the theoretical pulling force F of the donkey head through the formula 假设 , F 假设 =G 杆 +G 液 +P O ×S 管内 ; The following formulas are used for calculation: The sinking degree H exerts an upward force F on the piston. 沉没 The specific formula is as follows: 沉没 =(ρ 液 ×g×H+P C )×S 活塞 .

[0015] The calculation formula of the dynamic liquid level depth in step C is simplified as follows: Where: S 活塞 is the cross-sectional area of ​​the pump piston, g is the gravity constant, L is the pump hanging depth, and Pc is the wellhead casing pressure.

[0016] The oil pumping control system involved in the method for calculating the dynamic liquid level depth of the oil pumping unit includes a driver. The oil pumping control system is controlled by a controller to issue control operation instructions, and the driver frequency modulation is used to control the operating speed of the motor in the oil pumping unit system, thereby changing the stroke frequency of the oil pumping unit to achieve automatic and efficient operation of the oil pumping unit system.

[0017] The logic method for controlling the operation of the pumping unit based on the pumping unit well dynamic liquid level calculation method comprises the following steps:

[0018] The real-time dynamic liquid level depth value is calculated by collecting the production parameters of the oil pump in real time; then it is compared with the set range threshold of the ideal liquid level depth. If the calculated dynamic liquid level depth value is within the range threshold, the current operating speed of the oil pump is maintained; otherwise, the judgment is continued. If it is greater than the set threshold range, the operating speed of the oil pump is reduced proportionally; if it is less than the set threshold range, the operating speed of the oil pump is increased proportionally; finally, the controller sends a command to the driver to modulate the frequency, the motor speed changes, the pump changes the stroke, and then the production parameters change, and cyclic control is performed.

[0019] The present invention provides a calculation method for calculating the downhole dynamic liquid level by applying parameters such as the work done by the motor, the work done by the balance block, the weight of the sucker rod and the weight of the downhole liquid. The parameters used in the calculation method are real-time data on site, and the downhole dynamic liquid level can be calculated in real time. It does not rely on external instruments such as external dynamometers, and is calculated entirely based on the technical parameters of existing equipment. It is suitable for all beam pumping wells, and can better reflect the adaptability advantage of the method for remote deserts and areas with harsh climates. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a flow chart of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the system of the present invention;

[0023] Figure 3 A schematic diagram of the structure of a balancing block in the embodiment of the present invention;

[0024] Figure 4 Schematic diagram of the central angle of the balancing block in the embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0026] like Figure 1 and 2As shown, in the control system of the present invention, a motor driver is installed, and a controller is programmed to calculate the dynamic liquid level depth and issue instructions based on the comparison results. The motor driver outputs the frequency, thereby controlling the running speed of the motor, and then controlling the running speed of the pumping unit, that is, changing the stroke frequency of the pumping unit well.

[0027] A method for calculating the dynamic liquid level depth of a pumping well comprises the following steps:

[0028] Step A: Calculate the average pulling force F during the upward movement of the donkey head 9 by collecting the production parameters of the pumping unit; the step A specifically includes the following steps: First, measure the stroke length L of the pumping unit well. 冲程 , the size of the balance block 1, the crank size and the distance X from the inside of the balance block to the center of the crank shaft pnq Then, the average output voltage U and average output current I of the donkey head 9 during the upward movement are collected; finally, the average pulling force F of the donkey head 9 during the upward movement is obtained by the following formula: W 电机 The motor does work during the upward movement of the donkey head 9, and the W balance block: the balance block 1 and the crank do work during the upward movement of the donkey head 9.

[0029] Step B: Calculate the theoretical pulling force F of the donkey head 9 when the liquid level is at the pump hanging depth and the pipe is full of liquid by collecting the production parameters of the pumping unit. 假设 The step B specifically comprises the following steps: First, collect and measure the gravity F of the sucker rod 3 杆 , the diameter d of the sucker rod 3 杆 , the density of the sucker rod 3 ρ 杆 , the length of the sucker rod 3 L 杆 , the cross-sectional area S of the pump piston 6 活塞 , the inner cross-sectional area S of the oil pipe 2 管内 and the inner diameter D of the oil pipe 2 IN ; Read the wellhead oil pressure Po and the wellhead casing pressure Pc; Secondly, calculate the theoretical pulling force F of the donkey head through the formula 假设 , F 假设 =G 杆 +G 液 +P O ×S 管内 ; The following formulas are used for calculation: The sinking degree H exerts an upward force F on the piston. 沉没 The specific formula is as follows: 沉没 =(ρ 液 ×g×H+P C )×S 活塞 .

[0030] Step C: Calculate the dynamic liquid level depth L by collecting the production parameters of the pumping unit f When the distance from the liquid surface 4 to the pump barrel is H, that is, when the submergence is H, the upward force F exerted by the lower liquid at the pump hanging depth on the piston is 沉没 , assuming the pump hanging depth is L, through the formula F 沉没 =F 假设 -F gets the dynamic liquid level depth L f Simplified calculation formula: The calculation formula for the dynamic liquid level depth in step C is simplified to Where: S 活塞 is the cross-sectional area of ​​the pump piston, g is the gravity constant, L is the pump hanging depth, and Pc is the wellhead casing pressure.

[0031] Step D: Enter the real-time distance value from the liquid surface to the pump barrel, i.e., the sinking degree H, to obtain the real-time dynamic liquid surface depth value.

[0032] The above method of the present application can realize rapid calculation of the dynamic liquid level, and the calculation process is simple and accurate, without the need for complex layout drawings as an aid, thereby improving efficiency.

[0033] The pumping control system involved in the method for calculating the dynamic liquid level depth of the pumping unit includes a driver. The pumping control system is controlled by a controller to issue a control operation instruction, and the driver frequency modulation controls the running speed of the motor in the pumping system through the output cable 8, thereby changing the stroke frequency of the pumping unit and realizing automatic and efficient operation of the pumping system. The system of the present application can change the frequency of pumping oil by adding a driver to the existing system, and then realize the improvement of the efficiency of pumping oil by combining our calculation method.

[0034] The logic method for controlling the operation of the pumping unit based on the pumping unit well dynamic liquid level calculation method comprises the following steps:

[0035] The real-time dynamic liquid level depth value is calculated by collecting the production parameters of the oil pump in real time; then it is compared with the set range threshold of the ideal liquid level depth. If the calculated dynamic liquid level depth value is within the range threshold, the current operating speed of the oil pump is maintained; otherwise, the judgment is continued. If it is greater than the set threshold range, the operating speed of the oil pump is reduced proportionally; if it is less than the set threshold range, the operating speed of the oil pump is increased proportionally; finally, the controller sends a command to the driver to modulate the frequency, the motor speed changes, the pump changes the stroke, and then the production parameters change, and cyclic control is performed.

[0036] The calculation process of the method for calculating the oil pumping dynamic liquid level in the present invention is as follows:

[0037] F×L 冲程 =W 电机 +W 平衡块…………………………(1)

[0038] Where:

[0039] F: average pulling force of the donkey head during upward movement, N;

[0040] L 冲程 : stroke length, m;

[0041] W 电机 : The motor does work when the donkey head moves upward, J;

[0042] W balance block: the work done by the balance block and crank during the ass head ascending, J;

[0043]

[0044] W 平衡块 =G 平衡块 ×D 平衡块 ×n+2×G 曲柄 ×L q ……………………(3)

[0045] G 平衡块 : weight of the balance block, N;

[0046] D 平衡块 : Distance from the center of gravity of the balance block to the output shaft of the gearbox, m;

[0047] n: number of balancing blocks;

[0048] L q : crank length;

[0049] G 曲柄 : weight of the balance block, N;

[0050] U: output voltage, V;

[0051] I: output current, A;

[0052] From (1), (2) and (3), we can get:

[0053]

[0054] Assuming that the liquid level is below the pump hanging depth, as shown in the figure, the pipe between the oil layer 7 below the liquid level 4 is filled with a mixture of oil, gas and water 5. Ignoring the friction force, the theoretical pulling force of the donkey head is F 假设 :

[0055] F 假设 =G 杆 +G 液 +P O ×S 管内 ………………(5)

[0056] F 假设 : Theoretical pulling force of the donkey head, N;

[0057] G 杆 : Weight of sucker rod, N;

[0058] G 液 : Liquid gravity when lifting, N;

[0059] P O : Wellhead oil pressure, Pa;

[0060] S 管内 : Cross-sectional area of ​​the oil pipe, m 2 ;

[0061] D 平衡块 : Distance from the center of gravity of the balancing block to the center of the rotating shaft, m.

[0062]

[0063]

[0064]

[0065] D ON : outer diameter of pump piston, m;

[0066] d 杆 : sucker rod diameter, m;

[0067] D in : inner diameter of the oil pipe, m;

[0068] ρ 杆 : Sucker rod density, kg / m 3 ;

[0069] L 杆 : sucker rod length, m;

[0070] ρ 液 : Density of mixed liquid.

[0071] ρ 液 =ρ o +(ρ w -ρ o )×f w

[0072] ρ O : Density of crude oil, kg / m 3 ;

[0073] ρ W : Water density, kg / m 3 ;f

[0074] f W: moisture content, %;

[0075] If the depth of the moving liquid surface is L f , the distance from the liquid surface to the pump barrel is H, which is called the submergence. The upward force of the submergence on the piston is F. 沉没 :

[0076] F 沉没 =(ρ 液 ×g×H+P C )×S 活塞 …………………………(9)

[0077] ρ 液 : Liquid density, kg / m 3 ;

[0078] g: constant, 9.8N / kg;

[0079] H: sinking degree, m;

[0080] Pc: wellhead casing pressure, Pa;

[0081] S 活塞 : Pump piston cross-sectional area, m 2 .

[0082] H=LL f ………………………………………………(10)

[0083] L: Pump hanging depth, m.

[0084] again:

[0085] F 沉没 =F 假设 -F…………………………………………(11)

[0086] Combining equations (4), (5), (9), (10) and (11), we get:

[0087]

[0088] The dynamic liquid level depth L of the pumping well is calculated by formula (12): f .

[0089] From the above calculation method, we can see that the method for obtaining the liquid level depth in the invention does not rely on external instruments such as external dynamometers, but is calculated entirely based on the technical parameters of existing equipment. It is applicable to all beam pumping wells and can better demonstrate its unique technical advantages in remote deserts and areas with harsh climates.

[0090] The following is an example of a specific practical example:

[0091] Downhole pipe string and wellhead parameters

[0092]

[0093] Surface pumping equipment parameters

[0094]

[0095] For the above-mentioned actual equipment parameters, the process of using the calculation method of this application is as follows:

[0096] 1. Assume that the liquid surface is loaded at the suspension point of the pump

[0097] F 假设 =G 杆 +G 液 +F 油

[0098]

[0099]

[0100]

[0101] F 假设 =G 杆 +G 液 +F 油 =104983+11089+1910=117982N

[0102] 2. The calculation formula of the balance weight and center of gravity is as follows: Figure 3 and Figure 4 As shown,

[0103] Distance from the center of gravity of the balance block to the rotation axis:

[0104]

[0105] Crank center angle:

[0106]

[0107] Radius of balance weight:

[0108]

[0109] Balance weight area:

[0110]

[0111] Single balance weight:

[0112] G 平衡块 =7800×9.8×S×D q

[0113] 3. Balance block and crank work

[0114] W p =G 平衡块 ×2×X pq ×n×2+L q ×K q ×D q ×7800×9.8×L q

[0115] n: the number of identical balancing blocks on each side

[0116] Angle:

[0117]

[0118] Radius of balance weight:

[0119]

[0120] Balance weight area:

[0121]

[0122] G 平衡块 =7800×9.8×S×D q =7800×9.8×0.18×1.41=19438.7N

[0123]

[0124] W P =G 平衡块 ×2×X pq ×n×2+L q ×K q ×D q ×7800×9.8×L q

[0125] =19438.7×2×1.822×2×3+3×0.18×0.55×7800×9.8×3

[0126] =268129.25J

[0127] 4. Actual pulling force on the donkey head

[0128]

[0129] F 沉没 =F 假设 -F=117982-92841.9=25140.1N

[0130] 5. Dynamic liquid level depth

[0131]

[0132] That is: the dynamic liquid level depth is 1429.01 meters.

[0133] The calculated dynamic liquid level depth is 1429.01m, and the actual measured dynamic liquid level depth of the oil well is 1398.4m. The error is 30.61 meters, which can fully meet the technical requirements of production application.

[0134] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific protection scope of the present invention.

[0135] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0136] Note that the above are only preferred embodiments of the present invention and the principles of the application technology. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the specific embodiments described herein, and may include more other effective embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for calculating the dynamic liquid level depth of a pumping well, characterized in that: The steps include: Step A: Calculate the average pulling force F during the upward movement of the donkey head by collecting the production parameters of the oil pumping unit; Step B: By collecting the production parameters of the pumping unit, calculate the theoretical pulling force F of the donkey head when the liquid level is at the pump hanging depth and the pipe is full of liquid. 假设 ; Step C: Calculate the dynamic liquid level depth L by collecting the production parameters of the pumping unit f When the distance from the liquid surface to the pump barrel is H, that is, when the submergence is H, the upward force F exerted by the lower liquid at the pump hanging depth on the piston is 沉没 , assuming the pump hanging depth is L, through the formula F 沉没 =F 假设 -F gets the dynamic liquid level depth L f Simplify the calculation formula; Step D: Enter the real-time distance value from the liquid surface to the pump barrel, i.e., the sinking degree H, to obtain the real-time dynamic liquid surface depth value.

2. The method for calculating the dynamic liquid level of a pumping well according to claim 1, characterized in that: The step A specifically includes the following steps: first, measuring the stroke length L of the pumping well 冲程 , the size of the balance block, the size of the crank and the distance X from the inside of the balance block to the center of the crank shaft pnq Then, the average output voltage U and average output current I of the donkey head during the upward movement are collected; finally, the average pulling force F of the donkey head during the upward movement is obtained by the following formula: W 电机 The motor does work when the donkey head moves upwards, W balance block: the balance block and crank do work when the donkey head moves upwards.

3. The method for calculating the dynamic liquid level depth of a pumping well according to claim 1, characterized in that: The step B specifically includes the following steps: First, collect and measure the sucker rod gravity F 杆 , sucker rod diameter d 杆 , sucker rod density ρ 杆 , sucker rod length L 杆 , Pump piston cross-sectional area S 活塞 , oil pipe inner cross-sectional area S 管内 and the inner diameter of the oil pipe D IN ; Read the wellhead oil pressure Po and the wellhead casing pressure Pc; Secondly, calculate the theoretical pulling force F of the donkey head through the formula 假设 , F 假设 =G 杆 +G 液 +P O ×S 管内 ; The following formulas are used for calculation: The sinking degree H exerts an upward force F on the piston. 沉没 The specific formula is as follows: F sink = (ρ liquid × g × H + P C )×S 活塞 .

4. The method for calculating the dynamic liquid level depth of a pumping well according to claim 1, characterized in that: The calculation formula of the dynamic liquid level depth in step C is simplified as follows: Where: S 活塞 is the cross-sectional area of ​​the pump piston, g is the gravity constant, L is the pump hanging depth, and Pc is the wellhead casing pressure.

5. The oil pumping control system involved in the method for calculating the dynamic liquid level depth of the oil pumping well according to claim 1 is characterized in that: The pumping unit control system includes a driver, in which a controller sends out control operation instructions, and controls the running speed of the motor in the pumping unit system through the driver frequency modulation, thereby changing the stroke frequency of the pumping unit to realize automatic and efficient operation of the pumping unit system.

6. A logic method for controlling the operation of a pumping unit based on the method for calculating the dynamic liquid level of a pumping unit according to claim 1, characterized in that: The steps include: The real-time dynamic liquid level depth value is calculated by collecting the production parameters of the oil pump in real time; then it is compared with the set range threshold of the ideal liquid level depth. If the calculated dynamic liquid level depth value is within the range threshold, the current operating speed of the oil pump is maintained; otherwise, the judgment is continued. If it is greater than the set threshold range, the operating speed of the oil pump is reduced proportionally; if it is less than the set threshold range, the operating speed of the oil pump is increased proportionally; finally, the controller sends a command to the driver to modulate the frequency, the motor speed changes, the pump changes the stroke, and then the production parameters change, and cyclic control is performed.

Images