Absolute Open Flow Potential- The highest rate of potential when a well’s Bottomhole flowing pressure is equal to zero.
Artificial Lifting- Methods used to produce fluids in downhole situations where a well is dead or to up the production rate of existing producing wells.
Bag- type Protectors- Bag type or bladder-type protectors utilize a positive barrier between the motor oil and well fluid. The bag is flexible and expands to accommodate changing pressures within the well.
Best Efficiency Point (BEP)- The point at which a pump runs at optimum efficiency within the designed range of the unit.
Cable- Three phase copper conducting cable containing three leads that run from the surface of a well downhole to the ESP motor. Cable comes in many different sizes all being used with different voltage needs for different downhole conditions.
Centrifugal Pumps- A non-positive displacement type of pump that uses an impeller spinning on a shaft. The impeller takes in fluid through an opening located centrally about the axis of rotation then expels it through vanes along its outer diameter. The impeller can either be open or closed vane by design. Impellers are used in series to increase pressure and used in parallel to increase flow.
Coiled Tubing Installations- The opposite of a tubing deployed installation where instead of jointed tubing used to install the Electric Submersible Pump (ESP) they use a continuous string of coiled tubing.
Compression Pumps- A type of centrifugal pump that has “fixed” as opposed to “floating” impellers in the axial direction. The impellers are compressed through their central hub on the pumps shaft via a compression device. Most of the high-flow, high-lift pumps are of this type.
Dual Zone Installations- where a well has two open zones and wish them to be produced by a single string of tubing and ESP unit. This is uncommon but does occur in some instances where using two separate tubing strings and ESP units are not plausible.
Floating Impellers- This is the ESP pump where all of the axial thrust is put on the downthrust washers as opposed to a compression pump that puts all of the axial thrust on the main thrust bearing located in the protector.
Flowing Bottomhole Pressure- The pressure at the bottom of the well that is measured once the well flow becomes stable. Typically this is reported in pounds per square inch or head in feet.
Flowing Well- When a well in the early stages of its life naturally flows fluid to the surface simply using the pressure from the bottom of the well.
Fluid Flow Velocity- The velocity, typically in feet/sec, of the fluid flowing past the outside of the motor to the intake of an ESP installation. This velocity must be known because if it is too high erosion the equipment will occur. If it is too low the motor will overheat and fail.
Fluid over Pump- The amount of fluid in feet sitting above an ESP when a well is either in a static or producing state
Free Gas Handling Ability- The ability of an ESP pump to move well fluids from a well that contain high contents of gas in the well fluids that can potentially gas lock pumps.
Gas/Liquid Ratio- The actual mixture of gas and oil in the well stream above the pump.
Gassy Wells- Wells that produce high volumes of natural gas within the producing fluid level column in a well.
Head Capacity Curve- A pump curve that shows flow rate vs. head capacity and is used in the process of sizing an ESP. Units for flow rate (Q) are typically barrels per day (bpd) and head is shown either in feet (ft) or pounds per square inch (psi).
Induction Motors- The primary type of motors used in ESP applications. They can also be referred to as a “squirrel-cage” or asynchronous motor.
Inflow Performance Relationship- This is the performance of a well with regards to the amount of production a well is prepared to give up as far as gas and oil flow rates.
Inverted Units- An ESP unit where the motor is put at the top of the unit instead of the bottom which cuts out the need for a motor lead extension and allows the motor to be tied directly into the cable string.
Isolation Chambers- The chambers within a protector on an ESP unit that separate the well fluids form the motor oil on an ESP unit.
Measured Depth- The total depth of a pump in a well that helps with the sizing of the ESP unit
Metal Armor- Armor that is coiled around ESP cable to protect the conductors from the downhole conditions in a well. Most armor is either stainless steel or Monel.
Mohs Scale- The scale of testing the scratch resistance of softer materials by scratching them with harder materials.
Motor Lead Extension- A section of flat cable that is used to run from the top of the pump to the pothead on the motor and is spiced directly into the main cable string
Natural Gas Separation- The process that consists of separating the natural gas from the rest of the fluids being produced in a well.
Net Positive Suction Head Available- The amount of positive head pressure that is available at the pump intake for a given system. Typically this is measured at the intake of the pump prior to the impeller and is reported in units of pounds per square inch (psi) or as a fluid height (ft).
Net Positive Suction Head Required- The amount of positive head pressure that is required to keep the pump from cavitating. This information is provided by the pump manufacturer. Typically this is measured at the intake of the pump prior to the impeller and is reported in units of pounds per square inch (psi) or as a fluid height (ft).
Power Efficiency- The ratio that describes how efficient a given system is operating when comparing power provided to power used taking into account various system losses. System losses in an ESP system can be electrical, hydraulic or mechanical. It is typically reported as a percent.
Power Factor- The ratio of Real Power to Apparent Power in an AC electrical power system. It is a dimensionless number between 0 and 1 and is typically reported as a percent.
Productivity Index- The amount of oil produced per day per decreasing well bottom-hole pressure. Units of oil are typically barrels and pressure is either pounds per square inch (psi) or head pressure in feet (ft).
Protector/Seal Section- It is the component(s) in an ESP string that offsets the axial load between the pump and motor. It also isolates and allows for expansion of the oil in the ESP motor. It is typically located between the pump and motor in the ESP string.
Protector Thrust Bearing- The bearing located within the Protector that offsets the axial thrust load from the pump to the motor.
Pump Intake Pressure- The pressure measured at the intake of the pump during operation. Units are typically pounds per square inch (psi).
Radial Flow Impeller- An impeller used in ESP’s that take in fluid axially intake and discharge it radially. Typically used in lower volume pumps.
Rotary Gas Separator- A device used in High-Gas wells that separates the gas out of the flowing fluid and allows it to flow between the well casing and ESP pipe.
Shrouded Well Installations- Installations where a short section of pipe is used to cover, or “shroud” the ESP unit. The can be done to either act as a reverse flow gas separator or to insure cooling liquid is always in contact with the motor casing.
Silicone Controlled Rectifiers- SCR’s are four layer solid state devices that are used in electronic to control current. They are used in ESP applications to better control the DC waveform.
Stage Diffuser- The outer portion of a centrifugal pump stage that is generally fixed in the pump housing that acts as the pump stator. It provides the flow path for the fluid to the next stage in a mult-stage pump.
Stages- The primary component in an ESP that consist of both an impeller and diffuser. The size of these components usually dictates the amount of flow produced for a given pump. More stages are added if more pressure is required
Static Bottomhole Pressure- The pressure at the bottom of a well hole created by the static fluid level in the well. Typically is measured in units of pounds per square inch (psi).
Surface Casing Pressure- The pressure measured at the surface of the well casing. Values can then be used when calculating Bottomhole pressures when no downhole instrumentation is present. Units are typically reported as pounds per square inch (psi) or head pressure in feet (ft).
Surface Voltage- The voltage that is available at the surface of a well. This information is needed when calculating losses due to cable lengths.
Switchboards- An electronic controller that is part of the surface equipment that is used to control the ESP motor. Switchboards do not offer variable speed control.
Tandem Motors- When two or three more ESP motors are used in assembled in series but wired in parallel for the purpose of increasing power output.
Tandem Pumps- Where two ESP pumps are put together to accommodate for downhole conditions where excessive amounts of fluid need to be moved.
Three Phase Electric Power- This is the most common type of electric power transmission used worldwide for the purpose of transmitting AC power. In this system three different conductors carry three separate alternating currents (AC) of the same frequency that are out of phase with one another.
Three Phase Step Transformer- An electrical device that is used to either increase or decrease voltage that is going from the service head to the controller. The voltage is either “stepped” up or down depending upon the ESP requirements.
Total Dynamic Head- The pressure measurement of fluid that is to be pumped from a well taking into account all hydraulic frictions losses. Units are typically pounds per square inch (psi) or height of fluid (ft).
True Vertical Depth- The measurement in a well that reports the overall depth in the vertical direction neglecting any paths that are horizontal.
Tubing Deployed Installations- Individual joints of tubing are deployed to install standard ESP units. This is the most popular method of installing ESP units.
Variable Speed Drive- An electronic controller that is part of the surface equipment that is used to control the ESP motor. Unlike Switchboards these do offer variable speed control by varying the frequency.
Water/Oil Ratio- The ratio of water to oil that is produced from a given well. This value is typically reported as a percent.
Zone Production- The area that is at the bottom of a well hole that is producing fluid and can either be single or multiple.