Application of ABB inverter in oil field water injection pump

Oil field water injection is an important and effective inverter measure inverter to maintain high and stable yield in many oilfields in China. The method is to focus on the distribution of oil in the ground to the oil well, and then extract it. Because oil Daqing oil oilfield oil is a fault block oil field, each block has a small water injection, Application water Application injection Application volume changes with the mining conditions, need to adjust, most of the water injection station there is a problem with the actual traffic flow rate is not matched. Because of the high pressure and water quantity, the water injection motor is high energy consumption and high energy consumption. It is a very effective energy saving measure to realize the variable speed regulation of the motor.

Current mode of control flow

High pressure water injection valve control to adjust the flow and pressure. According to the technological requirements, are not allowed to run long time small displacement, otherwise the temperature inside the pump increased cause cavitation and mechanical burned past was forced to adopt large reflux method decreases the temperature rise, caused a lot of power consumption, causing a lot of energy loss to the oil fields.

In the condition of the original design system, the {TodayHot} water is injected with two water injection pump. In the transformation of the frequency conversion speed control, the energy consumption of the water injection system in this condition is mainly controlled by the throttle. Through the analysis, only through the combination of injection quantity, reduce the water pressure, reduce the pressure difference between the valve control, can achieve the purpose of saving energy and reducing consumption.

Principle of variable frequency system description

Because the actual flow rate of the pump is smaller than the rated flow of the pump, so the power saving potential is relatively large. In the system, the water injection control of water injection pump is controlled by the feedback pressure value of the converter and the pressure value of the inverter. The operation parameters of the inverter are transferred to computer workstation through the internal computer interface and communication protocol. At the same time, the system can be detected and controlled by PID.

Comparison of frequency converter control system with original system

1)    using frequency conversion control mode, it is easy to operate, without manual adjustment of the intake valve, greatly reducing the labor intensity of workers, improve the work efficiency

2)    starting with low noise, the motor starts slowly at the start of the process, and reaches the setting frequency after 20 seconds. The starting current is very small, the impact of the power grid is reduced, and the service life of the motor is prolonged.

3)    system uses a drag two control methods, using pressure transducer feedback current signal (4 ~ 20mA) to the inverter central processing unit (CPU), and the PID control to form a closed loop control system. The output frequency of the size by the role of processor control, so that the motor speed automatically increased or reduced; when the pressure exceeds the set of target value (>5%) of which the first motor to power frequency operation, the inverter starting second motor frequency conversion, to maintain constant water pressure. This will not only reduce the motor power, but also improve the efficiency of the pump, saving energy.

4)    ordinary power frequency control mode (the original control mode) can not achieve the purpose of this {HotTag} sample, its start and stop the need to operate, but also need to adjust the valve switch to meet the requirements of the working conditions, that is, time and effort, and prone to operating errors, resulting in unnecessary loss. Power frequency operation control mode of the motor speed is not adjustable, and the starting current is large, when the pressure exceeds the required pressure value of the water valve to adjust the size of the water supply pressure. At this time the motor is still running at full load, the excess power is consumed on the valve, the energy waste is very big.

From the above actual conditions, the use of variable frequency speed control approach to meet the needs of production, making the water injection pump can not only large flow, but also small flow, both high pressure, can also be low pressure operation. Can use the pressure closed loop or closed-loop control of water injection pressure or flow, in the injection station condition changes, the frequency converter can make the injection pump automatically adjust the water injection pressure or flow. At this point, the pump outlet valve is fully open, so that the pressure difference between the pump is zero. In this way, both to save energy, and reduce the maintenance of the valve. It also improves the automation level of the system, reduces the noise of the system, improves the working environment and reduces the labor intensity of the workers. Using frequency conversion speed regulation to obtain the actual need of water flow, not only save energy, improve the operating level of the system, the inverter automatically adjust the speed according to the demand, and smooth and stable, reduce the labor intensity of the workers, the operation parameters of the pump can be improved, and the system efficiency is improved.