Discover the IHRDC Energy Glossary_beta

Walkie

A type of motor-driven pallet jack that the operator walks along with to guide and control

Wall-fired Furnace

A furnace that has burners installed along the shell walls

Warmup Burner

A burner that is used to increase boiler temperature during the warmup stage of startup

Washer

A flat thin ring or a perforated plate used in joints or assemblies to ensure tightness, prevent leakage, or relieve friction

Waste Activated Sludge

Sludge that is removed and disposed of during the activated sludge process

Wastewater

Water left over from a process that may be contaminated with pollutants.

Water Base Mud

A drilling fluid in which water is the major liquid phase, as well as the wetting phase.

Water Base Mud, Water Base Drilling Fluid

A water base mud is a drilling fluid in which water is the major liquid phase, as well as the wetting phase.

Water Breakthrough

Water breakthrough is a description of reservoir conditions under which a fluid, previously isolated or separated from production, gains access to a producing wellbore. The term is most commonly applied to water or gas breakthrough, where the water or gas injected to maintain reservoir pressure via injection wells breaks through to one or more of the producing wells.

Water Contact

The elevation above which fluids other than water, such as oil and gas, can be found in the pores of a rock.

Water Cushion

A water cushion is a volume of water placed in a tubing string prior to conducting a drill stem test or opening a well to flow with a formation tester. The water cushion is designed to reduce and control the pressure drawdown applied to the reservoir when the downhole valve or tester valve is opened to initiate flow.

Water Cut

Water cut is the ratio of water produced compared to the volume of total liquids produced.

Water Draw Method

The method used to calibrate a physical prover. Water flows into a calibrated container as the displacer makes a trip.

Water Drive

Water drive is a reservoir drive mechanism whereby the oil is driven through the reservoir by an active aquifer.

Water Flood

Water flood is a method of secondary hydrocarbon recovery in which water is injected into the reservoir formation to displace some of the residual oil.

Water Flood, Waterflood

Water flood is a method of secondary hydrocarbon recovery in which water is injected into the reservoir formation to displace some of the residual oil.

Water Flood, Waterflood, Water Injection

Water flood is a method of secondary hydrocarbon recovery in which water is injected into the reservoir formation to displace some of the residual oil.

Water Hammer

The slamming of accumulated condensate against a piping wall

Water Saturation

The fraction of water in a given pore space, expressed in volume/volume, percent, or saturation units. Unless otherwise stated, water saturation refers to the fraction of formation water in the undisturbed zone, corresponding to the effective porosity.

Water Seal

A type of turbine seal that uses water to fill the opening between the turbine shaft and the casing to prevent leakage

Water Siphon

The device by which the water level in the unit is maintained.

Water Tube Boiler

A type of boiler in which tubes are used to transport water and steam

Water Vapor

Water in a gaseous form. Water can exist in three phases: gas, liquid, and solid.

Water reactive chemicals

Chemicals that will react with water to release a gas that is either flammable or presents a health hazard

Water testing

Testing the mechanical integrity of a tank by filling the tank with water and then checking the tank for leaks or other signs of damage; also called hydroelectric or hydro testing.

Water tube

A tube through which water and steam are distributed in a water tube boiler

Water tube boilers

A type of boiler in which tubes are used to transport water and steam

Water wash

A piece of equipment in which water is mixed with neutralized reactor effluent to absorb entrained caustic.

Water-Wet

The tendency of one fluid to spread on, or adhere to, a solid surface in the presence of other immiscible fluids. Many rocks are water-wet. A water-wet area contains profuse amounts of water but no recoverable hydrocarbons.

Water-reactive

A chemical that reacts with water to release a gas that is either flammable or presents a health hazard.

Water-wet Formation

In water-wet formations, a thin film of water coats the surface of the formation matrix.

Water/Oil Interface

The level at which the layers of water and crude meet in a desalter.

Waterflood

An improved oil recovery technique that involves injecting water into a producing reservoir to increase production and enhance movement of oil to producing wells. Use of water to increase oil production is known as secondary recovery.

Waterwalls

Vertical tubes, filled with a water/steam mixture, that line the inside of a boiler furnace

Watt

The unit of electric power, equal to the rate of energy transfer when one ampere of current flows through an electrical potential difference of one volt at unity power factor.

Watt-hour

The basic unit used to measure electrical energy. Watt-hours are determined by multiplying power by time. One watt-hour is the amount of energy used when one watt of power is delivered to an electrical device for one hour.

Watt-hour (Wh)

An electrical energy unit of measure equal to 1 watt of power supplied to, or taken from, an electric circuit steadily for 1 hour.

Waveform

A graphic representation of a voltage varying over time

Waveform Analysis

Waveform analysis is the determination of the amplitude and phase of the components of a complex waveform, either mathematically or by means of electronic instruments.

Weak Point, Weakpoint

The weak point is a piece of steel cable placed inside a logging head that is designed to break at a pre-determined tension. If the logging tool becomes stuck in the borehole, there is a danger that the logging cable will break at surface, since this is the place of maximum tension. It is difficult to fish a long length of tangled cable in the borehole. The weak point is designed to break before the cable, so that the latter can be retrieved, leaving only the logging tool and head in the borehole.

Wearing Ring

A replaceable ring that can be mounted on either the impeller or the casing of a centrifugal pump; designed to prevent leakage from the volute back to the suction eye

Wearing Rings

Replaceable rings on the casing or the impeller of a centrifugal pump that wear as the pump operates

Webinar

A digital seminar where presenters discuss a specific subject, reaching viewers worldwide. Participants can either join these sessions live or view the recorded version at a later time at their convenience.

Weight

The downward force exerted by an object as a result of gravity.

Weight Transference

The temporary movement of a forklift's center of gravity due to changes in momentum

Weir

A dam-like device or flat restriction installed across a channel to maintain and control liquid level and flow. In metering, a notched restriction that causes liquid level to rise for conversion to a flow rate. In glycol systems, a dam in the contactor or reboiler that holds glycol level above bubble cap slots or fire tubes.

Welding

A process in which heat is used to melt metal surfaces for the purpose of joining them together

Well Completion

The process of making a well ready for production or injection after drilling operations.

Well Kick

A kick is a well control problem in which the pressure found within the drilled rock is higher than the mud hydrostatic pressure acting on the borehole or rock face. When this occurs, the greater formation pressure tends to force formation fluids into the wellbore. This forced fluid flow is called a kick.

Well Log Correlation

Well log correlation is the identification and connection of equivalent patterns and/or values between log curves of adjacent wells.

Well Logging, Geological Well Logging

Well logging is the practice of making a detailed record (a well log) of the geologic formations penetrated by a borehole. The log may be based either on visual inspection of samples brought to the surface or on physical measurements made by instruments lowered into the hole.

Well Logging, Geological Well Logging, Well Logs

The practice of making a detailed record (a well log) of the geologic formations penetrated by a borehole, based either on visual inspection of samples brought to the surface (mud log) or on physical measurements made by instruments lowered into the hole (wireline logging or logging while drilling).

Well Stimulation

A treatment performed to enhance the productivity of a well, by either hydraulic fracturing or matrix treatments.

Well Stream

All fluids produced at the wellhead, e.g., gas, liquid vapors, water, oil, etc.

Well Terminology

An Exploration Well is the first well drilled on an exploration prospect. If there is a discovery then several Appraisal Wells (or Delineation Wells) are drilled to confirm the extent of the discovery, the size of the reservoir and the quality of reservoir environment. These wells are typically drilled vertically. In offshore prospects, they are often abandoned after drilling the appraisal wells.

Figure 1: Figure of Well Terminology

Well Test

The measurement of production from a well in a given length of time under controlled conditions.

Well Testing

Well testing is the execution of data acquisition activities to broaden the knowledge and understanding of hydrocarbons properties and characteristics of the reservoir. The test will also provide information about the state of the particular well tested. The overall objective is identifying the reservoir's capacity to produce hydrocarbons.

Well tractors

A well tractor is a self-propelled robotic device used in highly deviated wellbores to drive tools down towards the toe of the well.

Wellbore

The hole drilled by a drilling rig to explore for or develop oil and/or natural gas. Also referred to as a well or borehole.

Wellbore Storage

Wellbore storage is the afterflow of fluids into the well bore after the well is shut-in at the wellhead. During wellbore storage, reservoir effects are masked or distorted, making it impossible to quantify well properties such as permeability, skin and P*.

Wellsite Geologist

A specialist who analyzes samples from an oil well as it is being drilled, recommends decisions on coring, reports on hydrocarbon shows, and liaises with drilling engineers and the company office.

Western Union Splice

A type of splice that is often used to join small, solid conductors together in a linear run

Wet Glycol (or Rich Glycol)

Glycol that has absorbed water.

Wet chemistry

See Intermittent monitoring.

Wet gas

Natural gas that contains an appreciable amount of heavier hydrocarbons (natural gas liquids), which are often liquid.

Wet scrubber

A scrubber that uses a liquid to remove contaminants from a gas or vapor stream.

Wet-type filter

A filter that is coated with a sticky substance that holds contaminants against the filter material; also called an adhesive-type filter.

Wettability

The tendency of a liquid to spread on, or adhere to, a solid surface in the presence of other immiscible fluids.

Wettability, Oil-wet, Water-wet

Wettability is the tendency of one fluid to spread on, or adhere to, a solid surface in the presence of other immiscible fluids. Rocks can be oil-wet or water-wet.

Wettability, Water Wet, Oil Wet

Wettability is the tendency of one fluid to spread on, or adhere to, a solid surface in the presence of other immiscible fluids.

Wheel

In a turbine, a round hub containing a set of rotating blades

Whole Number

A number that describes a whole object or an entire quantity.

Winch

A hand-powered or motor-driven lifting device designed to lift and move a load using a wire rope or chain. In wireline logging, it is used to pick up the logging tool string attached to the wireline cable.

Winder

A mechanical take-up reel that stores measuring tape; the tape is connected to a float inside a container and is released or retracted by the winder as level changes.

Wiper

The circular seat in a ball valve

Wiper Rings

Rings located in the distance piece surrounding the piston rod that form a seal to prevent cylinder gas from passing to the crankcase and crankcase lubricant from passing to the cylinder, while also removing lubricants from the rod.

Wire Connector

A cone-shaped solderless connector that has a steel spring inside it. Also called a wire nut.

Wire Rope

A type of rope that is made of individual wires of iron or steel that are wrapped into strands, which are then wound around a central core

Wire Rope Clip

A fitting that is used to clamp two sections of wire rope together

Wireline

An electrical cable used to lower tools into and out of the wellbore and to transmit downhole condition data. Wireline relates to any aspect of logging that employs such a cable.

Wireline Formation Pressure Test

The wireline formation pressure measurement is acquired by inserting a probe into the borehole wall and performing a mini-drawdown and build up by withdrawing a small amount of formation fluid and then waiting for the pressure to build up to the formation pore pressure.

Wireline Formation Tester

A tool run on an electric logging cable that pushes a probe into the formation, allowing production into a small closed chamber. It is primarily used to obtain formation pressures at chosen locations, and with an accurate quartz gauge, order-of-magnitude permeability estimates may be obtained. Variations have been developed to acquire formation fluid samples.

Wireline Logging

Wireline logging is the acquisition of geological and geophysical data as a function of the wellbore depth by lowering a string of one or more logging instruments on the end of a wireline into a borehole.

Wireline Logging Run, Wireline Logging Survey Run

Wireline logging is the acquisition of geological and geophysical data as a function of the wellbore depth by lowering a string of one or more logging instruments on the end of a wireline into a borehole.

Wireline Tractor Conveyance, Tractor

A wireline tractor conveyance, or tractor, is a device for assisting a logging tool to descend a deviated or irregular profile wellbore.

Wireline, Wireline Cable

Wireline relates to any aspect of logging that employs an electrical cable to lower tools into the borehole and to transmit data.

Wiring Diagram

A drawing or graphic representation that shows the physical locations of components, the physical relationships between them, and where electrical connections are made.

Withdrawal profile

The withdrawal profile usually consists of a constant rate (plateau) period followed by a period of declining rates

Withdrawal rate

The amount of gas that can be delivered (withdrawn) from a storage facility on a daily basis

Witness testimony [evidence]

A statement about the employee's ability to perform a task can be obtained from someone who has worked closely with the employee, e.g., a line manager or supervisor. This may be useful where the Assessor is not in a position to observe an employee's performance directly. It can also be used for assessing competencies that have to be demonstrated over a period of time, such as working safely and working as part of a team.

Word Address

An address that refers to one or more complete 16-bit words, rather than to a single bit of a word

Word Instruction

An instruction that acts on a group of bits rather than on a single bit

Word Module

A type of I/O module that handles a relatively large number of input or output bits simultaneously

Work

A force applied to an object times the distance that the object travels

Work A Tank

To gauge and test a lease tank.

Work Commitment

This term refers to Contractor's commitment to the owner of the oil and gas rights, outlining the specific work that will be guaranteed during the exploration phase. The commitment is usually made in both money amounts and the type of exploration to be undertaken (seismic surveys, exploration wells etc.). This commitment is usually divided into two or three exploration stages (about two years each) during the Exploration Period. The Work Commitment represents the minimum expenditure that a company may make during each stage - it can certainly spend more and often does. If more funds are spent in one stage, the excess normally can be credited to the next stage.

Work practice controls

Controls that reduce the likelihood of exposure by altering the manner in which a task is performed (e.g., prohibiting recapping of needles by a two-handed technique).

Work product [evidence]

Evaluation of work products used in conjunction with observation. Examples include a part manufactured on a machine or by hand, documents (a report, process logs, permit to work, etc.), a completed task (e.g., repaired or maintained equipment).

Working Interest

The legal and revenue interest in an oil and gas lease after payment of royalties, representing the ownership interest that manages operations and pays all capital and operating costs. It is the right granted to the lessee to explore for, produce, and own oil, gas, or other minerals.

Working Power

Voltage and current that performs work.

Working drawings

Drawings that are used in the actual construction of a building or part of a building; also referred to as blueprints and construction drawings

Workover Operations

Workover operations mean the work conducted on wells after the initial well-completion operation for the purpose of maintaining or restoring the productivity of a well. Well completion/well workover means those operations following the drilling of a well that are intended to establish or restore production.

Worm

A cylindrical gear that has teeth shaped like the threads on a screw 1

Worm Gear

The gear in a motor operator that engages and is driven by the worm

Wound Rotor

A rotor that has conducting coils wound to match the stator windings

Wrist Pin

A pin placed in a pre-positioned hole in the crank to hold the pitman arm to the crank.

Wrist Pin Bearing

A tapered or spherical roller bearing that allows rotary motion between the crank and the pitman arm.

Wye Connection

A connection in a three-phase AC system (also called a star connection) in which one end of each of the three phase windings is connected to a common point and the load is connected to the free ends of the coils, which connect to the three phase lines.

Wye-connected Stator

A stator in which the coils are connected through a common point; also called a star-connected stator

wave swash

Wave swash refers to the movement of water from a wave that breaks onto a beach and then recedes back into the sea. Swash is a dynamic process that involves both an uprush (onshore flow) and a backwash (offshore flow).

wavelets transform

A wavelet transform creates a representation of the signal in both time and frequency domains, which allows efficient access of localized information about the signal.

weathering layer

A weathering layer is a rock layer at or near the surface, usually marked by a sharp transition, in which the seismic velocities are substantially lower than in the less weathered, hard rock layers beneath it.

well prognosis

A well prognosis is a detailed description of the likely geological sequence to be encountered in the well, together with associated data acquisition objectives and operational procedures.

whipstock

A whipstock is a curved steel wedge used in drilling operations to start a new branch of a well, or wellbore, or to deflect the drill bit for directional drilling.

wildcat

An exploration well that is drilled in an area in which little is known about the subsurface geology.

winnowed

Winnowing is the process by which wind or water removes finer material from a coarser sediment. This process can improve the sorting of sediment.

wiping

Wiping is an additional operation when drilling a borehole that may be done to part or all of the open borehole, to ensure the borehole is the diameter and quality expected. For example, wiping (or a wiper trip) may be done when issues, such as insufficient hole cleaning, have occurred or are suspected.