Electric submersible pumps are mechanical oil extraction devices that pump underground fluid out to the surface level. These include submersible motors, protectors, separators and submersible centrifugal pumps. An electric submersible pump unit typically comprises three parts:
1.Underground part: A submersible pump, a separator, a protector, a submersible motor and submersible cables;
2.Surface installation:
Fixed-frequency drive: A step-down transformer and a control cabinet;
Variable-frequency drive: A step-down transformer, an inverter and a step-up transformer;
3.Auxiliaries: A centralizer, a temperature and a pressure tester, a one-way valve, a well top penetrator and a junction box.
Characteristics of an Electric Submersible Pump:
1)Large-discharge fluid collection is the typical feature of this oil extraction process. However, electric submersible pumps are also frequently used in low fluid-yield oil wells at present.
2)This pump re-injects water in oil well in the upstream water layer into the downstream water injection layer.
3)It is easily operated and managed and helps beautify the environment and reduces noise.
4)It is satisfactorily used for oil extraction in inclined wells, horizontal wells and marine application.
5)The corrosion and waxing are easily removed.
6)The construction provides sound flexibility for incorporating underground pressure and temperature testing devices, from which signals are transmitted up to the surface level through the cables to enable measurement and reading.
7)The power frequency can be regulated with a variable frequency device to accommodate the decrement or changes in the well output, though this requires considerable investment.
8)It provides a considerable mean time between failures and a comparatively high production time effect for oil wells.
