Electric Submersible pumps for  oil and gas

In the oil and gas industry, electric submersible pump (ESP) systems are probably best known as an effective artificial lift method of pumping production fluids to the surface. ESPs are especially effective in wells with low bottomhole pressure, low gas/oil ratio, low bubblepoint, high water cut or low API gravity fluids. Over the last several years prior to 2008 ESP technology has developed a reputation as a low-maintenance, cost-effective alternative to vertical turbine, split case and positive displacement pumps in various fluid-movement surface applications in the petroleum industry. This older article by Wood in Pumps and Systems gives a still valuable overview of the options.

Artificial lift uses some means to increase the flow of liquids (i.e., crude oil or water with some amount of gas included) to the surface of a production well. This is usually achieved by (1) a mechanical device inside the well, such as a pump; (2) decreasing the weight of the liquid/gas mixture via high pressure gas or (3) improving the lift efficiency of the well via velocity strings. An artificial lift system is needed in wells with insufficient pressure in the reservoir to boost the liquid to the surface. Also, these systems are sometimes used in flowing wells to increase the naturally occurring flow rate.

More than 60 percent of producing oil wells require some type of assisted lift technology to produce the recoverable oil. Several artificial lift (or pumping) technologies are employed, including plunger lift, beam/sucker rod pumps, gas lift, progressive cavity pumps (PCP) or electric submersible pumps.