Application of ABB frequency converter in oilfield water injection pump
Oilfield water injection is a crucial and effective method used in many Chinese oil fields to maintain high and stable production levels. This technique involves concentrating the dispersed oil within the reservoir and directing it toward the production wells for extraction. In the case of Daqing Oilfield, which is classified as a fault block oilfield, each block has a limited water injection range, requiring frequent adjustments to the injection volume based on changing operational conditions. Most water injection stations face challenges where the rated flow rate does not match the actual flow, leading to inefficiencies.
Due to the high pressure and large volume of water involved in oilfield operations, the motors used for water injection are typically high-power units that run continuously at high energy levels. To address this, variable frequency drives (VFDs) are employed to control the speed of the water injection pumps, enabling precise regulation of the water flow. This approach not only enhances energy efficiency but also significantly reduces power consumption, making it a highly effective energy-saving solution.
In traditional oilfield water injection systems, gate valves are commonly used to regulate flow and pressure. However, prolonged low-flow operation is generally not allowed due to the risk of overheating, cavitation, and mechanical damage to the pump. Historically, operators had to use a large reflow method to manage temperature, which resulted in excessive energy consumption and significant waste.
Under the original system design, two injection pumps were typically used. Without frequency conversion, the main source of energy loss was the throttling effect of control valves. Through analysis, it was found that combining mixing ratios, reducing water pressure, and minimizing the pressure difference across control valves could lead to substantial energy savings.
The principle behind the VFD system is that the actual flow rate of the water injection pump is often lower than its rated capacity, creating significant potential for energy savings. The system uses feedback from a pressure transmitter to compare the measured pressure with a preset value within the inverter. A PID controller then automatically adjusts the frequency to maintain the desired pressure. These operational parameters are transmitted to a computer workstation via internal communication protocols, allowing real-time monitoring and control of system pressure, motor speed, voltage, and current, thereby enabling fully automated and energy-efficient operation.
Compared to the traditional control system, the VFD system offers several advantages. First, it simplifies operation by eliminating the need for manual adjustment of inlet valves, significantly reducing labor intensity and improving work efficiency. Second, the system starts with low noise, as the motor gradually accelerates from a low frequency, reducing electrical stress on the grid and extending the motor’s lifespan. Third, the system employs a one-to-two control mode, using a 4-20mA signal from a pressure transmitter to form a closed-loop control system. When pressure exceeds the set point, the system automatically switches to variable frequency operation, maintaining stable pressure while reducing reactive power and improving overall efficiency.
In contrast, the conventional power frequency control method requires manual intervention for start-up and shutdown, along with constant valve adjustments to meet operational demands. This process is time-consuming, labor-intensive, and prone to errors, leading to unnecessary energy waste. Additionally, the motor runs at full load regardless of demand, with excess power lost through the valve, further increasing energy costs.
By implementing frequency conversion speed control, the water injection system can adapt to varying conditions, offering both high and low flow rates while operating under different pressure settings. Pressure or flow control can be managed through either a pressure or flow feedback loop. When conditions change, the VFD automatically adjusts the injection pressure or flow, keeping the outlet valve fully open and eliminating differential pressure. This not only saves energy but also reduces valve maintenance and improves automation, noise reduction, and working conditions. Ultimately, frequency conversion ensures optimal performance, lowers operational costs, and enhances system reliability.
Chiller is a kind of water cooling equipment, is able to provide constant temperature, constant current, constant pressure cooling equipment. Cold water machine the principle is to a certain amount of water injection machine of the internal water tank, through the mechanism of cold water cooling system will be water cooling, and then have the machine within the cryogenic frozen water injection pump need to cooling equipment, cold water machine the internal heat away, the high temperature cooling of the hot water back into the water again, so exchange cooling cycle, as the function of the cooling equipment.
Water Cooled Ice Machine, Water Cooling Machine,water cooled chiller
Ningbo Haijing Plastic Machine Manufacturing Co. LTD , https://www.chinahaijing.com