Since the introduction of frequency converters in China in the 1980s, it has played an increasingly important role in the national economy and people’s daily lives, and has been widely used in the production of companies and in people’s lives. Inverter is widely used, mainly due to its excellent energy-saving characteristics and speed regulation characteristics. China's energy consumption is one of the highest in the world. To solve the problem of product energy consumption, in addition to other related technical issues need to be improved, frequency control has become an effective measure to save energy and improve product quality. Frequency control technology is a major means of saving electricity today, improving process flow to improve product quality, improve the environment, and promote technological progress. The frequency conversion speed regulation is recognized as the most promising speed regulation method at home and abroad for its excellent speed regulation and braking performance, high efficiency, high power factor and power saving effect, wide application range and many other advantages.
The main function of the inverter is to convert the power frequency power supply (50Hz or 60Hz) into AC power of various frequencies to realize the variable speed operation of the motor. Because the frequency converter has the advantages of small size, light weight, high precision, advanced technology, rich functions, complete protection, high reliability, easy operation, strong versatility, easy to form closed-loop control, etc., and the system composed of it has better The energy-saving effect has been welcomed by the steel, nonferrous metals, petroleum, petrochemical, power, coal, urban water supply and wastewater treatment industries.
The rapid development of China's economy cannot be separated from the rapid development of the pillar industries of the national economy such as steel, petroleum, petrochemicals, electricity, and machinery. However, we must realize that the high economic growth in China is a large consumption of domestic production resources and a huge environment. The premise of pollution, this fully shows that China's economic development is a huge hidden danger, it is unsustainable and unscientific. In recent years, more and more concepts such as sustainable development, energy saving, and environmental protection have appeared in China's economic development, and have gradually become the vane of China's economic development in the future.
Oilfields have a unique background as a special industry, because our oilfields are mostly low-permeability low-energy, low-yield oilfields, and unlike the oilfields in the Middle East, they have strong self-injection capabilities. Most oilfields rely on water injection pressure oil. Into the well, and then pumping the oil from the formation uplift. Changing oil from water to oil from electricity is a reality in China's oil fields. Electricity charges account for a large proportion of China's oil exploitation costs. Therefore, the oil industry attaches great importance to saving electricity.
In China's oil exploitation, mechanical oil production wells account for the vast majority of them, and rod oil production accounts for more than 90% of total mechanical oil production. More than 70% of the country's oil production is completed by a rod pumping unit. Its energy consumption accounts for one-third of the oil field's energy consumption. The country's oil fields consume about 4.2 billion yuan annually. Since each oilfield needs several thousand new wells to be put into production every year, together with the original equipment renewal, several thousand pumping units will be added each year. Pumping units play an important role in China’s oil exploitation.
Shanghai Hongbao Electric Automation Co., Ltd. invested a large amount of funds and manpower in the two years of 2007-2008 to develop high-performance, current vector type AC frequency converters and pumping unit intelligent controllers suitable for oil extraction and mechanical oil recovery. . After nearly one year of field tests and data collection in the Hailar Oilfield, Daqing Oilfield, it was proved that the intelligent control system for pumping units produced by Shanghai Hongbao Electric Automation Co., Ltd. is suitable for use in low-permeability, low-energy, and low-yield oil fields in China, with obvious power-saving effects and systems. The improvement of efficiency is one of the more advanced oil extraction technologies in China. It has been praised by oil extraction experts and has obtained the appraisal report for this project.
Beam Pumping Unit Working Principle
The principle of operation of the beam pumping unit is that the AC motor drives the oil pump at a constant speed and reciprocates along the direction of gravity, thereby pumping crude oil from the hundreds of wells down to the surface of the well. The analysis of its load characteristics shows that its inertia is large, and the viscosity of different wells is very different. When the viscosity of the oil is large, the efficiency of the pump also becomes low, and it is often difficult to start. The load is a cyclic load again. The load characteristics of the ascending and descending travels are also different. In order to adapt to these complicated working conditions, the configuration of the pumping unit and its actual working condition can only be large horse-drawn carts. The beam-type pumping unit moves repeatedly up and down, one stroke is lifted once, and its power comes from two relatively large steel sliders driven by the motor. When the slider is lifted, it acts like a lever and feeds the oil machine rod. In the well, when the slider is lowered, the oil production rod raises the oil to the wellhead. Because the motor rotates at a certain speed, the slider decreases and the load is reduced. The energy generated by the motor dragging cannot be attracted by the load, and it is bound to find the energy consumption channel, resulting in the motor. Entering the state of regenerative power generation and feeding excess energy back into the grid, causing bus voltage of the main circuit to increase, which will inevitably impact the entire grid, resulting in a decrease in the quality of the grid power supply and a reduction in the power factor. Frequent high-voltage shocks will damage the motor and cause production. Reduced efficiency and increased maintenance are extremely detrimental to the energy saving and consumption reduction of pumping equipment, and cause greater economic losses to enterprises. The beam-type pumping unit introduces two large-mass steel sliders, leading to many problems such as the large starting shock of the pumping unit.
In addition to the above two issues, the special geographic environment of oilfield production determines that the oil extraction equipment has its unique operating characteristics: large oil reserves in the early stage of oil well extraction, sufficient liquid supply, and can be run at high frequency to improve efficiency and ensure higher oil production. In the middle and late period, due to the reduction of oil reserves, it is easy to cause shortage of liquid supply. If the motor is still running at industrial frequency, it is bound to waste energy and cause unnecessary losses. In this case, the actual working conditions must be taken into consideration, and the motor speed should be properly reduced to reduce the stroke. Increase the filling rate.
The working principle and features of the pumping unit intelligent control system produced by Shanghai Hongbao Electric Automation Co., Ltd. are:
I. Applicable well conditions
l Wells that need to work intermittently
l Oil wells that frequently change well conditions (eg: gas injection wells, injection wells)
l wells often broken
l Horizontal wells
l High gas well
l Well performance below design capability
Second, characteristics
l Self-learning function, automatic identification of downhole conditions
l With industrial frequency and variable frequency, manual and automatic selection of a variety of work modes
l Automatically keep the fluid level in the borehole constant
l Vector control inverter AC motor drive
l Allow continuous change of motor speed
l Suitable for standard motors and high slip motors.
l outdoor standard box
l Wide operating temperature range, temperature controlled fan switch
l The pump can be placed deeper into the well. (Because the working strength of the sucker rod is reduced), the stroke length can be increased, the output can be increased, and the pump efficiency can be increased.
l Improve reliability, reduce maintenance, and increase equipment life, including sucker rods, casing, and oil pumps in oil pump systems. Transmission gearboxes, belts, motors, etc.
Third, the technical specifications
1, the motor power range P ≤ 7.5 ~ 75KW
2, the rated power frequency: 50Hz
3, input power supply voltage Three-phase AC, 380-440 V ± 10%
4, the output voltage frequency 10HZ ~ 60HZ
5, the normal operating temperature range -40 ° C ~ +50 ° C
6, storage and transportation temperature -40 ° C ~ +60 ° C
7, relative humidity ≤ 90%, altitude is less than 2000m
8, protection class IP40
Fourth, the working principle
The controller achieves three levels of closed-loop control by collecting motor torque, output power, and downhole fluid level. The motor torque is the inner ring, the output power is the middle ring, and the downhole fluid level is the outer ring. The use of advanced scientific algorithms to achieve the best condition control of the motor and controller.
The outer ring of the liquid outer ring control system refers to the liquid level as the control object, macro-control the average speed of the motor and the working gap of the well, the control for the hour-level control; output power in the ring control refers to the output power as the control object, the output The power is controlled in minutes, in order to ensure the fullness of the downhole pump body; the motor torque inner loop control refers to the motor torque as the control object, and the output motor torque is controlled in seconds, in order to ensure the reasonable force of the sucker rod, At the same time, the DC bus voltage of the drive power supply should not be too high.
The controller has a triple self-learning function. The first one is a self-learning function for the motor parameters and structural characteristics. Through learning, the controller and the motor are optimally matched. The second is the controller's learning of the downhole working conditions, including the downhole. The liquid level, initial average power, motor torque variation and other parameters, through the learning to make the best match between the controller and the pumping system; the third is the self-learning correction in the work process, through the learning process in the normal work process The understanding of the downhole working conditions is continuously revised to ensure that the pumping unit system is always operating in the correct state.
Identifying the pump fullness automatically adjusts the pumping parameters. Pumping unit full-closed-loop frequency conversion intelligent control device realizes closed-loop control according to the linear relationship between the output power of the motor and the fullness of the pump. The real-time output power of the motor is measured in the control cabinet, and the working status of the pumping system is identified according to the power and overcomes Use load-displacement sensors for various problems.
The frequency converter unit is the implementation unit of the frequency conversion speed regulation technology and is one of the most important components of the entire system. This system is equipped with vector type HB-H9 series high performance frequency converters. HB-H9 series high-performance inverter is a follow-on general-purpose inverter and is equipped with vector control on the V/F control. Real-time detection of motor power and output torque. Inverter rated voltage 380-440V, rated power range 4-75Kw, overload capacity: 200% * 60 seconds.
The main control board unit is a system control center with a single-chip microcomputer as its core. It is used for data acquisition, calculation, comparison, and transmission of control signals to the inverter. The main control board adopts a 4-layer industrial PCB design, and all industrial-grade devices are selected. , Suitable for ambient temperature -20 ~ 65 °C.
Fifth, the use of effects
1. Current comparison
The following test data was obtained from the field test conducted by Hailar Co., Ltd., Daqing Oilfield. The test flow was as follows: The first step was to test the test data without using the pumping unit intelligent frequency conversion control system, and the second step was to use the pumping unit intelligent frequency conversion control. After the system test data, then compare the test data before and after.
Table 1: Before and after current change table using intelligent variable frequency control system of pumping unit
Hashtag
April 20
April 21
April 22
April 23
Bay 14-B 58-57
I on = 37A
I lower = 33A
Stroke = 3.0
Punches = 4
I on = 36A
I lower = 31A
Stroke = 3.0
Punches = 4
I on = 12A
I lower = 12A
Frequency = 29-43Hz
Punches = 4
I on = 9A
I lower = 6A
Frequency = 26-37Hz
Punches = 3
Bei 14-B59-56
I on = 41A
I lower = 36A
Stroke = 3.0
Punches = 4
I on = 42A
I lower = 36A
Stroke = 3.0
Punches = 4
I on = 9A
I lower = 3A
Frequency = 29-33 Hz
Punches = 2
I on = 11A
I lower = 8A
Frequency = 27-37Hz
Punches = 2.5
Bei 14-X 66-62
I on =57A
I lower = 41A
Stroke = 3.0
Punches = 5
I on = 51A
I lower = 43A
Stroke = 3.0
Punches = 5
I on = 17A
I lower = 12A
Frequency = 33-46 Hz
Punches = 4.5
I on = 15A
I lower = 16A
Frequency = 25-42Hz
Punches = 4
Bei 14-X 64-64
I on = 24A
I lower = 28A
Stroke = 3.0
Punches = 5
I on = 24A
I lower = 29A
Stroke = 3.0
Punches = 5
I on = 13A
I next = 17A
Frequency = 28-46Hz
Punches = 4
I on = 14A
I lower = 13A
Frequency = 25-41 Hz
Punches = 4
The above table shows the current measurement for four different wells. On April 20 and April 21, the current value was measured before using the pumping unit intelligent frequency conversion system. It was used on April 22 and April 23. The current value measured after pumping unit intelligent frequency conversion system. It can be seen that the use of pumping unit intelligent frequency conversion system, the current down the stroke has a significant decline.
2 Analysis of dynamometer charts
The dynamometer diagram is a closed curve formed by the curve of load versus displacement. The dynamometer diagram representing the relationship between the suspension point load and the displacement is called a ground dynamometer chart or a polished rod dynamometer chart. In actual work, the measured ground power diagram is used as the main basis for analyzing the working status of the deep well pump.
Fig.1 Comprehensive test of oil well test using B14-B59-56 before pumping unit intelligent frequency conversion system
Figure 2 B14-B59-56 well test comprehensive record after using pumping unit intelligent frequency conversion system
Fig. 3 Comprehensive test of well test before B14-X64-64 using pumping unit intelligent frequency conversion system
Fig. 4 B14-X64-64 well test comprehensive record after using pumping unit intelligent frequency conversion system
It can be seen from the comprehensive records of the pumping well test that before the intelligent frequency conversion control system of the pumping unit was used, the analysis result of the ground power diagram showed that the liquid supply was insufficient and the liquid could not fill the working cylinder. After using the pumping smart frequency conversion control system, The analysis of the ground power diagram showed that the liquid supply was normal.
3 Analysis of Pumping System Efficiency
Table 2 is the daily production volume of pumping units with different well numbers, actual lifting height, active power, reactive power, apparent power, tons of power consumption, 100 meters of power consumption per ton of liquid, system efficiency value. Determination. The figures in the figure are all measured in the field of Daqing Oilfield. Table 3 shows the data values ​​measured after using the pumping unit intelligent frequency conversion control system. Then compare the data before and after, to illustrate the changes in the efficiency of the pumping system.
Table 2 System efficiency summary before using pumping unit intelligent frequency conversion system
Hashtag
Bei 14-B58-57
Bei 14-B59-56
Bei 14-X64-64
Bei 14-X66-62
model
CYJY12-3-53HB
CYJY12-3-53HB
CYJY10-3-37HB
CYJY10-3-37HB
motor model
MW/FD-CJF-14
MW/FD-CJF-14
TYG250M-8
ZYCYT250M-8/12
Rated power (KW)
45
45
40
37
Production fluid (t)
1
1
1.3
1.3
1.8
1.8
5
5
Actual lift
Height (m)
1807
1807
1883
1883
1454
1454
1666
1666
Active power
(KW)
6.55
6.35
5.17
4.62
7.38
7.45
7.06
7.43
Reactive power
(KW)
20.21
21.49
19.61
19.32
3.88
5.89
19.86
19.71
inspecting power
(KV·A)
21.57
21.49
21.25
20.87
9.93
11.12
22.4
22.5
Ton of liquid power consumption
(KWh)
157.2
157.1
95.4
85.3
98.4
99.4
33.9
35.6
Ton of liquid 100 meters
Power consumption (KWh)
8.70
8.69
5.06
4.53
6.76
6.80
2.03
2.13
System efficiency
(%)
3.13
3.23
5.37
6.01
4.02
3.99
13.39
12.72
Table 3 System efficiency summary after using pumping unit intelligent frequency conversion system
Hashtag
Bei 14-B58-57
Bei 14-B59-56
Bei 14-X64-64
Bei 14-X66-62
model
CYJY12-3-53HB
CYJY12-3-53HB
CYJY10-3-37HB
CYJY10-3-37HB
motor model
MW/FD-CJF-14
MW/FD-CJF-14
TYG250M-8
ZYCYT250M-8/12
Rated power (KW)
45
45
40
37
Production fluid (t)
1
1
1.3
1.3
1.8
1.8
5
5
Actual lift
Height (m)
1807
1807
1883
1883
1454
1454
1666
1666
Active power
(KW)
4.78
3.64
3.97
4.28
3.76
4.74
4.54
3.60
Reactive power
(KW)
4.62
3.68
3.97
4.17
3.16
3.74
4.72
3.90
inspecting power
(KV·A)
6.66
5.18
5.62
5.98
4.94
6.07
6.55
5.32
Ton of liquid power consumption
(KWh)
87.3
114
79
73.3
50.2
63.2
17.3
21.8
Ton of liquid 100 meters
Power consumption (KWh)
4.8
6.3
4.2
3.8
3.4
4.3
1.1
1.3
System efficiency
(%)
5.63
4.28
6.99
6.49
7.88
6.29
20.8
26.2
As can be seen from the above two tables, the well number is B14-B58-57, the model is CYJY12-3-53HB, and the motor model is MW/FD-CJF-14 before the intelligent variable frequency control system for the pumping unit is used. The liquid consumption per ton of liquid is 157 KWh, and the system efficiency is 3.13%. After the intelligent variable frequency control system of pumping unit is used, the electricity consumption per ton of liquid is 87.3 KWh and the system efficiency is 5.63%. The well number is Beibei 14-X64-64, the model is CYJY10-3-37HB, the motor model TYG250M-8 has a ton liquid power consumption of 98.4KWh, the system efficiency is 4.02%, and the pumping unit intelligent frequency conversion control system is used. After that, the liquid consumption per ton of liquid was 50.2 KWh and the system efficiency was 7.88%. The well number is Beibei 14-X66-62, the model is CYJY10-3-37HB, the motor model is ZYCYT250M-8/12, the ton liquid power consumption is 33.9KWh, the system efficiency is 12.72%, and the intelligent frequency conversion of the pumping unit is used. After the control system, the electricity consumption per ton of liquid was 17.3 KWh and the system efficiency was 20.8%. It can be seen that the use of pumping unit intelligent variable frequency control system, the consumption of tons of liquid power has decreased, the system efficiency has increased, indicating that the pumping unit intelligent frequency conversion control system has obvious energy-saving, increase production, improve the effectiveness of the effect, is our country One of the more advanced oil extraction technologies.
The intelligent control system of the pumping unit produced by Shanghai Hongbao Electric Automation Co., Ltd. is different from the simple frequency conversion control system in the past; 1 It uses the characteristics of the current vector inverter and the intelligent control system to perform torque, power, current, etc. on the pumping unit motor. Control is performed so that the motor does not generate electricity when the steel slider of the pumping unit descends, and the rotation speed of the motor can be automatically adjusted according to the downhole conditions so that the oil production efficiency can be optimized. 2 DC, input and output reactors are installed in the intelligent pumping unit control system to effectively prevent the inverter from contaminating the motor and inverter to the power grid and increase the power factor.
At present, the intelligent pumping unit control system produced by Shanghai Hongbao Electric Automation Co., Ltd. has begun mass production. The products have been sold to Daqing Oilfield, Hailar Oilfield, and Karamay Oilfield in Xinjiang.