<P> The subsurface components generally include a pump portion and a motor portion, with the motor downhole from the pump . The motor rotates a shaft that, in turn, rotates pump impellers to lift fluid through production tubing to the surface . These components must reliably work at high temperatures of up to 300 ° F (149 ° C) and high pressures of up to 5,000 psi (34 MPa), from deep wells of up to 12,000 feet (3.7 km) deep with high energy requirements of up to 1000 horsepower (750 kW). The pump itself is a multi-stage unit with the number of stages being determined by the operating requirements . Each stage includes an impeller and diffuser . Each impeller is coupled to the rotating shaft and accelerates fluid from near the shaft radially outward . The fluid then enters a non-rotating diffuser, which is not coupled to the shaft and contains vanes that direct fluid back toward the shaft . Pumps come in diameters from 90mm (3.5 inches) to 254mm (10 inches) and vary between 1 metre (3 ft) and 8.7 metres (29 ft) in length . The motor used to drive the pump is typically a three phase, squirrel cage induction motor, with a nameplate power rating in the range 7.5 kW to 560 kW (at 60 Hz). </P> <P> ESP assemblies may also include: seals coupled to the shaft between the motor and pump; screens to reject sand; and fluid separators at the pump intake that separate gas, oil and water . ESPs have dramatically lower efficiencies with significant fractions of gas, greater than about 10% volume at the pump intake, so separating gas from oil prior to the pump can be important . Some ESPs include a water / oil separator which permits water to be reinjected downhole . As some wells produce up to 90% water and fluid lift is a significant cost, reinjecting water before lifting it to the surface can reduce energy consumption and improve economics Given ESPs' high rotational speed of up to 4000 rpm (67 Hz) and tight clearances, they are not very tolerant of solids such as sand . </P> <P> There are at least 15 brands of oilfield ESPs used throughout the world . </P> <P> Submersible pump cable are designed for use in wet ground or under water, with types specialized for pump environmental conditions . </P>

Difference between open well and borehole submersible pump