Electric Submersible Pump
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A submersible pump (or electric submersible pump (ESP)) is a device which has a
hermetically sealed A hermetic seal is any type of sealing that makes a given object airtight (preventing the passage of air, oxygen, or other gases). The term originally applied to airtight glass containers, but as technology advanced it applied to a larger categor ...
motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...
close-coupled to the pump body. The whole assembly is submerged in the fluid to be pumped. The main advantage of this type of pump is that it prevents pump cavitation, a problem associated with a high elevation difference between the pump and the fluid surface. Submersible pumps push fluid to the surface, rather than jet pumps, which create a vacuum and rely upon atmospheric pressure. Submersibles use pressurized fluid from the surface to drive a hydraulic motor downhole, rather than an electric motor, and are used in heavy oil applications with heated water as the motive fluid.


History

In. 1928
Armenia Armenia (), , group=pron officially the Republic of Armenia,, is a landlocked country in the Armenian Highlands of Western Asia.The UNbr>classification of world regions places Armenia in Western Asia; the CIA World Factbook , , and ''Ox ...
n oil delivery system engineer and inventor Armais Arutunoff successfully installed the first submersible oil pump in an oil field. In 1929, Pleuger Pumps (today Pleuger Industries) developed the design of the submersible turbine pump, the forerunner of the modern multi-stage submersible pump.


Working principle

Electric submersible pumps are multistage centrifugal pumps operating in a vertical position. Liquids, accelerated by the impeller, lose their kinetic energy in the diffuser, where a conversion of kinetic to pressure energy takes place. This is the main operational mechanism of radial and mixed flow pumps. In the HSP, the motor is a hydraulic motor rather than an electrical motor, and may be closed cycle (keeping the power fluid separate from the produced fluid) or open cycle (mingling the power fluid with the produced fluid downhole, with surface separation). The pump shaft is connected to the gas separator or the protector by a mechanical coupling at the bottom of the pump. Fluids enter the pump through an intake screen and are lifted by the pump stages. Other parts include the radial bearings (bushings) distributed along the length of the shaft, providing radial support to the pump shaft. An optional thrust bearing takes up part of the axial forces arising in the pump, but most of those forces are absorbed by the protector's thrust bearing. There are also screw-type submersible pumps, there is a steel screw which is used as a working element in them. The screw allows the pump to work in
water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
with a high
sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...
content and other mechanical impurities.


Applications

Submersible pumps are found in many applications. Single stage pumps are used for drainage,
sewage pumping Small-scale sewage pumping is normally done by a submersible pump. This became popular in the early 1960s, when a guide rail system was developed to lift the submersible pump out of the pump station for repair, and ended the dirty and sometimes da ...
, general industrial pumping and slurry pumping. They are also popular with Pond filters. Multiple stage submersible pumps are typically lowered down a
borehole A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petro ...
, and most typically used for residential, commercial, municipal and industrial water extraction (abstraction),
water well A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. Th ...
s and in
oil well An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas may ...
s. Other uses for submersible pumps include
sewage treatment Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding envir ...
plants,
seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appro ...
handling,
fire fighting Firefighting is the act of extinguishing or preventing the spread of unwanted fires from threatening human lives and destroying property and the environment. A person who engages in firefighting is known as a firefighter. Firefighters typicall ...
(since it is
flame retardant The term flame retardants subsumes a diverse group of chemicals that are added to manufactured materials, such as plastics and textiles, and surface finishes and coatings. Flame retardants are activated by the presence of an ignition source a ...
cable),
water well A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. Th ...
and deep well drilling, offshore
drilling rigs A drilling rig is an integrated system that drills wells, such as oil or water wells, or holes for piling and other construction purposes, into the earth's subsurface. Drilling rigs can be massive structures housing equipment used to drill wat ...
,
artificial lift Artificial lift refers to the use of artificial means to increase the flow of liquids, such as crude oil or water, from a production well. Generally this is achieved by the use of a mechanical device inside the well (known as pump or velocity strin ...
s, mine
dewatering Dewatering is the removal of water from a location. This may be done by wet classification, centrifugation, filtration, or similar solid-liquid separation processes, such as removal of residual liquid from a filter cake by a filter press as part ...
, and
irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
systems. Pumps in electrical hazardous locations used for combustible liquids or for water that may be contaminated with combustible liquids must be designed not to ignite the liquid or vapors.


Use in oil wells

Submersible pumps are used in
oil production Petroleum is a fossil fuel that can be drawn from beneath the earth's surface. Reservoirs of petroleum was formed through the mixture of plants, algae, and sediments in shallow seas under high pressure. Petroleum is mostly recovered from oil dri ...
to provide a relatively efficient form of "artificial lift", able to operate across a broad range of flow rates and depths.Lyons (ed), ''Standard Handbook of Petroleum & Natural Gas Engineerin'', p. 662 By decreasing the pressure at the bottom of the well (by lowering bottom-hole flowing pressure, or increasing drawdown), significantly more oil can be produced from the well when compared with natural production. The pumps are typically electrically powered, referred to as Electrical Submersible Pumps (ESP) or if hydraulically powered, referred to as Hydraulic Submersible Pumps (HSP). ESP systems consist of both surface components (housed in the production facility, for example an
oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
platform), and sub-surface components (found in the
well A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...
hole). Surface components include the motor controller (often a variable speed controller), surface cables and transformers. The subsurface components are deployed by attaching to the downhole end of a tubing string, while at the surface, and then lowered into the well bore along with the tubing. A high-voltage (3 to 5 kV) alternating-current source at the surface drives the subsurface motor. Until recently, ESPs had been costly to install due to the requirement of an electric cable extending from the source to the motor. This cable had to be wrapped around jointed tubing and connected at each joint. New coiled tubing umbilicals allow for both the piping and electric cable to be deployed with a single conventional coiled tubing unit. Cables for sensor and control data may also be included. 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 and high pressures of up to , from deep wells of up to 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 90 mm (3.5 inches) to 254 mm (10 inches) and vary between and 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). 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 re-injected downhole. As some wells produce up to 90% water, and fluid lift is a significant cost, re-injecting 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. There are at least 15 brands of oilfield ESPs used throughout the world.


Cables

''Submersible pump cable'' are electrical conductors designed for use in wet ground or under water, with types specialized for pump environmental conditions. A submersible pump cable is a specialized product to be used for a submersible pump in a deep well, or in similarly harsh conditions. The cable needed for this type of application must be durable and reliable, as the installation location and environment can be extremely restrictive as well as hostile. As such, submersible pump cable can be used in both fresh and salt water. It is also suitable for direct burial and within well castings. A submersible pump cable's area of installation is physically restrictive. Cable manufacturers must keep these factors in mind to achieve the highest possible degree of reliability. The size and shape of submersible pump cable can vary depending on the usage and preference and pumping instrument of the installer. Pump cables are made in single and multiple conductor types and may be flat or round in cross section; some types include control wires as well as power conductors for the pump motor. Conductors are often color-coded for identification and an overall cable jacket may also be color-coded. Major types of cable include: In 3&4 Core cable as per right side ''SPC types'' image shown, plain Copper/Tinned Copper used as a conductor. * PVC 3&4 Core Cable ** Flat Cable ** Round Cable * Rubber 3&4 Core Cable ** Flat Cable ** Round Cable * Flat Drincable * HO7RN-F Cable


See also

*
Centrifugal pump Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor. They are a sub-class of dynamic ...
*
Eductor-jet pump A vacuum ejector, or simply ejector is a type of vacuum pump, which produces vacuum by means of the Venturi effect. In an ejector, a working fluid (liquid or gaseous) flows through a jet nozzle into a tube that first narrows and then expands in ...
*
Booster pump Booster may refer to: Amusement rides * Booster (Fabbri ride), a pendulum ride * Booster (HUSS ride), an evolution of the Breakdance ride * Booster (KMG ride), a pendulum ride Arts, entertainment, and media Fictional characters *Booster, a cha ...


References

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External links


''Versatile Pump Works Under Water'', July 1947, Popular Science
excellent cutaway drawing of large public water works submersible pump design {{Authority control Pumps Irrigation Oil wells