How To Calculate The Downhole Head Of A Well Pump

Oct 04, 2024

Submersible pumps for wells are important equipment for deep well water extraction. When in use, the entire unit submerges into the water to extract groundwater to the surface. Simply put, it means lifting a certain weight of groundwater from underground to a location on the surface where water is needed. The volume of groundwater lifted per unit time is the flow rate, and the height lifted to the surface is the head (which should be considered the main part of the head, including pipeline resistance and outlet pressure requirements, and will not be discussed in detail here).
So, is the lifting height underground the installation position of the water pump or the water level of the well? Next, I will introduce it to you.
Firstly, let's understand two terms - static water level and dynamic water level:
The water level of a well is the elevation of the water surface of the well. There are two types of water levels: static water level and dynamic water level. The water level elevation before starting up for pumping is called the static water level. When starting up for pumping, the water level of the well decreases with the pumping time, and this change in water level elevation is called the dynamic water level.
How to calculate the downhole head of a well pump
The water level elevation at which the water output of the pump is relatively stable and the water level stabilizes at a certain depth without further decline is called the stable dynamic water level. The commonly referred dynamic water level refers to a stable dynamic water level. The vertical height from static water level to dynamic water level, which is the depth of water level drop during the pumping process, is called water level drop or pumping drop.
How to calculate the downhole head of a well pump
So, if the height difference between the water level of the well and the ground during the operation of the water pump is used as the lifting height, the head should be based on the dynamic water level.
If the head is selected based on the installation position of the water pump, it will be too large, which will first cause cost waste in equipment procurement: the electric pump needs to be purchased large, the pipeline and cables need to be lengthened, and electricity will be consumed during operation; At the same time, it also causes excessive flow and overload during the operation of the water pump, which can easily lead to motor burnout.
If the static water level is used as the head for selection, it will cause the selected head to be too low, resulting in insufficient water flow or no water pumping during operation.
Therefore, considering the groundwater level difference, it is necessary to choose the dynamic water level for deep well pumps! Moving water level! Moving water level!