Main performance parameters of water injection pump selection
Water injection pumps mainly include centrifugal pumps and reciprocating pumps. Reciprocating pumps can be divided into booster pumps and ordinary pumps according to the inlet pressure, and can be divided into clean water injection pumps, sewage injection pumps and polymer injection pumps according to the medium.
1. Water injection pump selection requirements
(1) The reciprocating pump should be selected for the small displacement water injection pump, and the centrifugal pump should be selected for the large displacement water injection pump. If there are reciprocating pumps with parameters that meet the needs and the price is right, the reciprocating pump should be used first; otherwise, the centrifugal pump should be used.
(2) When polymer injection, reciprocating pump with stroke less than 100min-1 should be selected.
2. Management requirements for water injection pumps
(1) Not only concerned about the operating conditions of the water injection pump, but also the efficiency of the water injection system. When the pipeline pressure loss is large, consider installing a booster pump at the end.
(2) When conditions permit, several water injection stations can be networked, and one of the stations can use a frequency converter to adjust the displacement of one pump, and the other pumps will work at full load.
(3) Due to the high pressure of the water injection pump, attention should be paid to the reliability of safety devices, such as overpressure alarm, pump shutdown, and pressure relief.
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The main performance parameters of water injection pump selection
A considerable part of the power consumption of the oilfield water injection system is the power consumption of the water injection pump. Therefore, improving the operating efficiency of the water pump has a special significance for the control of production costs and the improvement of economic benefits. In actual operation, there are many factors that make the outlet pump unable to operate in the high-efficiency area. This requires analyzing the composition of the energy loss of the pump. Only by grasping the shortcomings of each link can the pump avoid undue energy loss during operation and effectively improve the actual operating efficiency of the pump.
Head, flow, speed, power and efficiency are the five main parameters describing the performance of a water pump.
(1) Head: also known as head, which means the height of the liquid that the pump lifts. From the energy point of view, it refers to the increase in energy per unit weight of liquid after passing through the pump. It is usually expressed by H. The unit of liquid column is usually meter water column, which is customarily referred to as meter (m).
(2) Flow rate: also known as water delivery volume, refers to the volume of liquid delivered by the pump per unit time. It is often expressed as Q, and the unit is cubic meter per hour (m3/h), or cubic meter per second (m3/s).
(3) Rotation speed: The number of rotations of the pump shaft per minute, usually expressed as n, and the unit is revolutions per minute (r/min).
(4) Power: The power of the pump mostly refers to the shaft power, that is, the power delivered by the motor to the pump shaft under a certain flow and head when the pump is running. It is often represented by N and the unit is kilowatts (kW). The effective power is the work done by the pump on the liquid flowing into the pump in a unit time, which can be calculated according to the flow and head.
(5) Efficiency: When the pump is working, it consumes a part of energy (called mechanical loss) due to the friction of bearings, packing, impeller or piston, etc. The liquid flows from the inlet to the outlet of the pump, and it also needs friction and local resistance on the way. A part of energy is consumed (called flow loss). Therefore, the power (shaft power) transmitted by the motor to the pump shaft cannot all become effective power. The ratio of effective power to shaft power is the efficiency of the pump. According to different working principles, pumps can be divided into centrifugal and plunger types. Among them, centrifugal pumps are more common. They drive liquid to flow through the rotation of the impeller, which is also called vane pumps; while plunger pumps are It is a kind of reciprocating pump that promotes the flow of liquid through the reciprocating action of the piston. It is generally referred to as a reciprocating pump. Its pump efficiency is much higher than that of a centrifugal pump. The actual operating efficiency can reach more than 85% and the energy saving effect is obvious.
