Application of the hottest Delta Electromechanical

Delta mechanical and electrical industry science formulates the technical circuit of key fields. The application of green paper in oilfield water injection station

1 introduction

in order to compensate for the decline of formation pressure in the process of oilfield oil production, it is necessary to use water injection technology to maintain formation pressure for oil production. Water injection pressure is an important parameter that determines the reasonable development of oil fields and the state of surface pipelines and equipment. Due to the complex and diverse process conditions that need to be adapted in the water injection process and electromechanical equipment configuration design, there is an engineering margin in the water injection process design and electromechanical equipment configuration. These technological conditions include: the increase of water injection wells in later development; The pressure of oil storage formation and the distribution of oil, gas and water are constantly changing; Increase or decrease of the number of open and close wells; The impact of well flushing and insufficient water supply, etc. The uncertainty of process conditions causes the fluctuation of water injection pressure, the uneven and unstable water injection volume, and the difficulty of water injection pressure control, which brings difficulties to the stable and high production of oilfield production and management. Because it is difficult to accurately predict and control the requirements of oilfield water injection, considering the needs of oilfield development, the equipment margin is usually designed according to the maximum possible demand of the oilfield, especially in the design of water injection system. The oil field water injection equipment is driven by centrifugal pump motor, and the high-power system often operates in the light load and low efficiency state of the big horse and trolley. The water injection pressure is manually controlled by the pump outlet gate, that is, the pump displacement is adjusted by changing the pipe characteristic curve. The matching of pump and motor is difficult to operate at the best working point of the pump. The pipe efficiency is low, and the power loss is as high as more than 50%

variable frequency constant pressure technology can effectively stabilize the water injection process and greatly reduce the power consumption of large margin fan pump projects. The technical route of the constant pressure variable frequency automatic control system of the water injection station is to make full use of the existing production facilities to adjust the motor speed of the water injection equipment to achieve stable pressure and flow for water injection. At the same time, the soft start and soft stop function replaces the decompression start, which makes the start and stop of the motor stable, reduces the impact on Electrical and mechanical equipment, and will not cause dramatic changes in pipe pressure, flow and flow rate, without valve interception. Therefore, it is extremely beneficial to prevent cavitation, water hammer and surge, and can prolong the maintenance cycle and service life of pipes, pumps and valves. It has great economic and social benefits to complete the automatic control system, build the demand information platform, improve the sewage treatment effect, strengthen the supervision and management mechanism, minimize the labor intensity of post employees, and improve the enterprise information management level

2 system composition and function design

the structure of the control system is shown in Figure 1. The system is divided into two levels, namely, the field level and the control level. The process flow display and control are realized through the human-machine interface (HMI)

Figure 1 system structure

delta electromechanical products are selected as the core automation equipment of the system. The control level is the key to realize the system function, and its main function is the hub layer between HMI (Human-Computer Interaction Interface) and field level. Accept the parameters or commands set by HMI, control the water injection production process, and transmit the on-site status to HMI. The control part is integrated by Delta PLC and touch screen. It consists of dvp-32eh00r (CPU unit), dvp-04ad-h (analog input module), analog dvp-04da-h (digital output module) and dop-a80thtd (touch screen). The control level equipment is installed in the electric control cabinet in the control room. The CPU module dvp-32eh00r of Delta PLC has an RS232 and an RS485 communication interface, and the dop-a80thtd touch screen has an RS232 interface and a USB interface. The touch screen communicates with the controller through RS232 serial port

field level is the basis for realizing system functions. The field level is composed of intelligent integrated pressure transmitter and frequency converter. Honeywell pressure transmitter is selected as the integrated pressure transmitter of intelligent plastic parts regardless of material, and delta VFD series frequency converter is selected as the frequency converter. One 160kW and two 75kW on-site water injection motors (one for standby), so one 160kW vfd-1600f43a and 75KW vfd-750f43a are selected as frequency converters to form one drive one and one drive two schemes respectively, see Figure 2. One PLC is used to control two frequency converters to drive two water injection motors for variable-frequency horizontal pressure water injection. The field level control adopts shielded cable connection. The intelligent integrated pressure transmitter converts the pressure signal into Ma signal and inputs it to the analog input module dvp-04ad-h. the control quantity output by the controller PLC is converted into Ma signal through the analog output module wear-resistant dvp-04ad-h and input into two frequency converters to realize the constant pressure water injection frequency conversion control of two water injection motors

3 process flow and control system design

the principle of horizontal pressure water injection process automation system is shown in Figure 2. The system adopts three control modes: automatic operation, manual frequency conversion operation and power frequency operation

Figure 2 Schematic diagram of automatic control system

3.1 automatic operation

the system automatically starts the first frequency converter and uses PID to control the water injection pressure of the water injection pump. If the output pressure of one pump cannot meet the pressure requirements, the system will automatically start the second frequency converter to meet the pressure requirements

3.2 manual frequency conversion operation

the frequency converter can be started separately in manual mode through the button on the control panel, which can flexibly control the frequency conversion output. Meet the control requirements in complex situations

3.3 power frequency operation

after the frequency converter starts the motor and operates to the power frequency frequency, use the contactor to switch the motor off the frequency converter and put it into power frequency operation, as shown in Figure 2. The frequency converter acts as a soft start clamp for high-power motors

through the above three control methods, the normal operation of the water injection motor can be guaranteed to meet the requirements of uninterrupted production

3.4 human machine interface design

the process flow chart is shown in Figure 3, the control parameters are shown in Figure 4, and the controller parameter settings are shown in Figure 5

Figure 3 process flow chart

Figure 4 control parameters

Figure 5 controller parameter setting

4 Conclusion

the water injection system is controlled by the PLC, touch screen and frequency converter of Zhongda company, and the control structure of a single automation platform is simple; Remarkable energy-saving benefits; Convenient for personnel operation. The project has attracted the attention of oilfield enterprises and received favorable comments. The project embodies the concept of energy-saving automation of Zhongda products, especially the advantages of Zhongda electromechanical products in the complete system control engineering

Guo Yunping

Harbin electromechanical business department

0451 － 1004

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