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C Chart

An attribute control chart used to plot the number of defects per item, or sample

CAD

An acronym for "computer-aided design? CAD equipment is commonly used to create original drawings, which can then be reproduced as needed.

CAPEX

Capital expenditures.

CAS Identification Number

A number assigned by the Chemical Abstracts Service to designate a single substance or a substance with a complex structure that has a unique chemical name

CAS number

A unique number assigned to a chemical by the Chemical Abstracts Service.

CAT Scan

A CAT scan, produces an image of the internal structure of a cross-sectional slice through an object by reconstructing a matrix of x-ray attenuation coefficients.

CAT Scanning

CAT scanning is a non-destructive x-ray technology.

CEMF

Counter-electromotive Force: The electrical force produced by a motor as it turns; typically used as feedback to control the speed of a DC motor

CEMTREC

The Chemical Transportation Emergency Center.

CMS Online

IHRDC's proprietary competency management software.

CPR

Cardiopulmonary resuscitation - A method of restoring a shock victim's breathing and heartbeat to normal.

CPVC

Chlorinated polyvinyl chloride, a type of rigid plastic piping that withstands greater pressure/temperature than PVC; used for hot and cold water distribution and for chemical process piping.

CRT

Cathode ray tube; an electron beam tube in which the beam can be focused on a luminescent screen and varied in both position and intensity to produce a visible pattern

CUSUM

A process control system that keeps a running total of the difference between the average value of a variable and its aim, or desired value

Cable

In wireline logging, a cable used to lower tools into the well and transmit signals, consisting of a central section with conductors surrounded by metal, load-bearing armor. In electrical work, two or more insulated conductors bound together in a common covering; a large conductor.

Cable Clips

Devices used to attach a length of wire or cable to a housing or frame

Cable Ties

Plastic straps that can be used to tie together bundles of individual wires to keep them neatly organized

Cable, Wireline Cable

The cable is used to lower wireline logging tools into the well and through which signals from the measurements are passed. The cable consists of a central section with conductors surrounded by a metal, load-bearing armor.

Calcium Carbide

Calcium carbide, also known as calcium acetylide, is a chemical compound with the chemical formula of CaC2.

Calibrate

To adjust an analyzer before use; helps ensure accurate measurements.

Calibration

The process of comparing and, if necessary, restoring the accuracy of a measurement tool or controller to a standard.

Calibration, Tool Calibration

Calibration is a method of adjusting a data set against a control that has properties to which the data set should conform. Tool calibration is the process of establishing the relationship between a measuring device and the units of measurement. This is done by comparing a device, or the output of an instrument, to a standard having known measurement characteristics.

Caliper

A measurement tool that has adjustable legs or jaws

Caliper, Caliper Log

A caliper log is a representation of the measured diameter of a borehole along its depth.

Candidate

A member of the workforce (employee) whose performance in the workplace is to be assessed.

Cap Rock

An impermeable shale, anhydrite, or salt that forms a seal above the reservoir so that fluids cannot migrate upwards.

Capacitance

A physical property of all circuits that opposes changes in voltage; the ability to store electrical energy in the form of an electrostatic field. Measured in farads and typically represented by a capital C in electrical formulas.

Capacitance Filter

A filter circuit that smooths out a pulsating DC voltage. The circuit stores energy as the rectifier's output pulse increases and releases the stored energy as the rectifier's output pulse begins to decrease.

Capacitance Probes

Metal rods that extend into a tank to provide level measurements based on changes in the electrical capacitance between two surfaces separated by a dielectric (non-conducting) liquid.

Capacitive Power

Non-working power that is a result of charging current, such as the charging current required to energize long high-voltage lines.

Capacitive Reactance

The opposition to AC current flow provided by a capacitance, measured in ohms. Typically represented as XC in electrical formulas.

Capacitor

A passive component that stores energy in the form of an electrostatic field, used to control and/or increase the amount of capacitance in an electrical circuit.

Capacitor Bank

Equipment used to improve power factor by offsetting excessive demand for inductive power.

Capacitor-Input (pi) Filter

A filter circuit that combines the operation characteristics of a capacitance filter and an inductance filter.

Capacity

The maximum load weight that equipment can support or lift, or the amount of electric power for which a generator, turbine, transformer, transmission circuit, station, or system is rated by the manufacturer.

Capacity charts

Charts provided by a crane manufacturer that list and explain vital information about a crane's operating capabilities and lifting capacities

Capillary Action, Capillarity, Capillary

Capillary action, or capillarity, is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity.

Capillary Bound Water

Capillary bound water is immobile water held by capillary forces in regions of microporosity.

Capillary Force

Capillary force is the differential force between adhesion and gravity.

Capillary Pressure

The pressure differential between two immiscible fluid phases occupying the same pores, caused by interfacial tension between the two phases. It results from interactions of forces acting within and between fluids and their bounding solids, and must be overcome to initiate flow.

Capture Cross-section

The effective cross-sectional area that an atom of an isotope presents to absorption of neutrons, and is a measure of the probability of neutron capture. The unit of measure is cm²/cm³ = 10³ c.u., where c.u. is the capture unit.

Capture Cross-sections

Capture cross-sections are a measure of the probability that a neutron, or gamma ray, will be captured by an atom.

Capture Gamma Ray

A capture gamma ray is generated by the capturing of a thermal neutron by a chlorine atom.

Carbon Dioxide

A chemical compound (CO2) made up of molecules each having one carbon atom covalently double-bonded to two oxygen atoms. At room temperature it is a colorless gas, heavier than oxygen, that does not support combustion.

Carbon Seal

A seal consisting of carbon rings that are held against the turbine shaft by springs

Carbon adsorption system

A system that uses particles of activated carbon to remove organic compounds and eliminate foul odors from a gas stream.

Carbon capture and storage (CCS)

Process by which carbon dioxide emissions are captured and removed from the atmosphere and then stored, normally via injection into a secure underground geological formation.

Carbon dioxide equivalents (CO2e)

The quantity that describes, for a given mixture and amount of greenhouse gas, the amount of CO2 that would have the same global warming potential (GWP) when measured over a specified timescale (generally 100 years).

Carbon dioxide system

A type of fire protection system that uses carbon dioxide to blanket a fire and to extinguish it by removing its source of oxygen.

Carbon intensity

The quantity of greenhouse gas emissions associated with producing an intermediate or final product. For the oil and gas industry, carbon intensity is commonly expressed in units of Tonnes CO2e per product volume (e.g. Tonnes CO2e/bbl or Tonnes CO2e/MCF).

Carbon monoxide

A colorless, odorless, poisonous gas produced by the incomplete combustion of materials that contain carbon, such as fuels in internal combustion engines. Mild poisoning causes symptoms such as nausea, dizziness and headaches, while severe poisoning can result in brain or heart damage and death.

Carbon sequestration

The fixation of atmospheric carbon dioxide in a carbon sink through biological or physical processes.

Carbon sink

A reservoir that absorbs or takes up released carbon from another part of the carbon cycle. The four sinks, which are regions of the Earth within which carbon behaves in a systematic manner, are the atmosphere, terrestrial biosphere (usually including freshwater systems), oceans and sediments (including fossil fuels).

Carbon/Oxygen Log

A carbon-oxygen (C/O) log measures the carbon content of a formation and its contained fluids. The ratio of the carbon to the oxygen measurement, or C/O, enables the evaluation of differences in the water and oil saturations independent of the formation water salinity.

Carbonate

A sedimentary rock whose main mineral constituents are calcite and dolomite. Carbonate deposition occurs in shallow-water platforms, shelves, ramps, warm shallow seas, atolls, and deepwater basins, and is a product of precipitation rather than sediment transportation.

Carburizing Flame

An oxy-fuel gas welding torch flame that bums excess acetylene. Characterized by a white streak, or "feather", "inside a bright blue "outer flame envelope."

Carcinogen

Any substance that has been found to cause cancer.

Career Path

A feature in CMS Online that allows employees to compare their assessment results for their current job title against the requirements for all other job titles in the career path.

Carpal tunnel syndrome

An MSD that results when tendinitis or any other swelling in the wrist puts pressure on the median nerve as it passes through the carpal tunnel. The carpal tunnel is a small opening in the wrist through which the median nerve and nine tendons that connect the muscles in your arm to the bones of your hand pass. Early symptoms of carpal tunnel syndrome include a tingling or a numb sensation in any of the first three fingers or the thumb.

Carried Working Interest

This represents a situation where one working interest owner covers all or part of the capital costs for exploration, and potentially development, on behalf of another company. The carrying party is repaid out of the carried party's subsequent production cash flow. Note that the “carried” owner does not take the risk of exploration because it does not make an investment during exploration. Repayment is made only out of the profits made from production. On the other hand, the carrying party usually receives an uplift on its investment (i.e. 1.5 - 4.0 times its investment) from the carried party's cash flow.

Carrier Gas

A gas used to carry or transport a sample through a gas chromatograph and its column.

Carrier air

A supply of air used to provide aeration to catalyst in the spent catalyst standpipe.

Carrier solvent

In liquid extraction, the liquid in which the solute is dissolved.

Carryover

A condition where gas carries liquid (glycol or amine solution) out of a vessel.

Cartridge

In wireline logging, the section of a tool that contains the telemetry, electronics, and power supplies, as distinct from the sonde that contains the measurement sensors. In safety, a filter containing a chemical absorbing material used to remove airborne particles and low concentrations of hazardous gas from the air.

Cartridge Fuse

A fuse enclosed in an insulating cylindrical casing to confine the arc when the fuse opens, composed of a fuse link, a casing, and two contact points.

Cartridge respirator

A type of air purifying respirator that uses a cartridge to remove airborne particles and low concentrations of a hazardous gas.

Cascade Control

A type of process control consisting of a master (primary) control loop and a slave (secondary) control loop, where the output of the primary loop becomes the set point of the secondary loop.

Cascaded Loops

A system of master (primary) and slave (secondary) control loops. The primary loop output is the set point of the secondary loop.

Cascading Drain System

Arrangement of drain lines so that drips flow from heater to heater in a train, or string, of heaters

Cascading Vent System

Arrangement of vent lines so that air and non-condensible gases flow from heater to heater in a train, or string, of heaters, then on to a common vent line that is usually connected to the de-aerator or the main condenser

Case temperature for 60 seconds

Usually specified as an absolute maximum. It is meant to be used as guide for automated soldering processes.

Cased Hole

The portion of the wellbore that has had metal casing placed and cemented to protect the open hole from fluids, pressures, and wellbore stability problems.

Casing

Large-diameter, thick-walled steel pipe lowered into an open borehole and cemented in place to isolate formation fluids (such as fresh water), prevent borehole collapse, and withstand forces such as collapse, burst, and tensile failure.

Casing Shoe

The casing shoe is the bottom of the casing string, including the cement around it.

Cat Cracking

A petroleum refinery process in which heavy oil is passed through metal chambers called catalytic crackers or cat-crackers, under pressure and high temperature in the presence of catalysts. This boiling breaks up heavy, large, and more complex long-chain oil molecules into lighter, smaller, and simpler short-chain molecules, such as those of gasoline.

Cat cracked gasoline

A high-quality gasoline feed from a cat cracker that is sent to the gasoline blending area.

Cat cracker

A reactor process system that uses relatively low pressures, high temperatures, and a fluidized catalyst to break (crack) long-chain hydrocarbons in gas oils and other fractions into more valuable shorter-chain hydrocarbon products.

Catalyst

A substance that increases or decreases the rate of a chemical reaction without being significantly affected by or becoming part of the final product.

Catalyst Burn

After unit preparation, the next major step in catalyst regeneration, in which air is used to burn carbon deposits off of the catalyst.

Catalyst Regeneration

The process of burning, or oxidizing, the carbon deposits off of a catalyst.

Catalyst circulation

The flow of catalyst between the reactor and the regenerator of a fluid catalytic cracking unit.

Catalyst-to-oil ratio

A comparison of the amount of catalyst to the amount of charge entering the cat cracker riser.

Catalysts

Materials that speed up or slow down chemical reactions.

Catalytic Reforming

Reforming processes that are accelerated or enhanced by exposing the process stock to catalysts under controlled conditions.

Catalytic cracker

A reactor system used to break down relatively large hydrocarbons into smaller hydrocarbons.

Catalytic reaction section

The section of a sulfur recovery unit in which sulfur is removed from a mixture that contains H₂S and SO₂.

Catalytic reactor

A reactor in a sulfur recovery unit in which H₂S and SO₂ are reacted over a catalyst.

Catalytic reformer

A unit that uses a catalyst to reform the naphtha fraction into more valuable products.

Catastrophic Failure

This type of ESD damage causes some sort of permanent damage, such as an oxide failure or a metal melt.

Catch Basin

A tray or other type of vessel for capturing water or spills of other liquids

Cathode

The part of a corrosion cell at which chemical reactions take place that use the electrons that were released at the anode.

Cathodic protection

A means of protecting an above ground storage tank from corrosion.

Cation

A positively charged ion—an atom or molecule in which the total number of electrons is less than the total number of protons, giving it a net positive electrical charge.

Cation Exchange Capacity

A measure of the ability of clays (such as montmorillonite, chlorite, illite, and kaolinite) to exchange cations between the clay surfaces and surrounding water. It is the number of exchangeable cations per dry weight that a rock is capable of holding at a given pH value. Commonly termed the shale factor in mud logging.

Cation Exchange Capacity (CEC)

Cation exchange capacity is the quantity of positively-charged ions (cations) that a clay mineral can accommodate on its negatively-charged surface.

Cations

Positively charged ions.

Caustic

Corrosive, capable of destroying or eating away by chemical reaction. Opposite of acidic. A solid or liquid having these properties.

Caustic soda

See Sodium hydroxide.

Caustic treater

A piece of equipment that uses a solvent caustic material to absorb mercaptans from an alkylation feed stream.

Caustic wash

Acid removal equipment used to neutralize sulfuric acid carried over in the reactor effluent.

Caustic washing

The process of using caustic on a product before or after a treatment or refining step.

Cavitation

The formation and subsequent collapse of vapor bubbles inside a centrifugal pump, often at the pump inlet, which sounds like marbles rattling around inside the pump.

Cell

A section of a forced-draft or induced-draft cooling tower that can be operated independently

Celsius

A temperature scale with the freezing point of water at O°C and the boiling point of water at 100°C.

Cement

A viscous adhesive used to bond plastic fittings to plastic pipe in order to form leak-proof joints.

Cement Bond

Cement bond is a bond of cement between the exterior casing wall and the adjacent formation. Cement Bond Log (CBL) A cement bond log is a log that uses the variations in amplitude of an acoustic signal traveling down the casing wall between a transmitter and receiver to determine the quality of cement bond on the exterior casing wall.

Cement Bond Log

A cement bond log documents an evaluation of the integrity of cement work performed on an oil or gas well.

Cement Bond Log (CBL)

A cement bond log is a log that uses the variations in amplitude of an acoustic signal traveling down the casing wall between a transmitter and receiver to determine the quality of cement bond on the exterior casing wall.

Cementation Exponent or Cementation Factor

The exponent of porosity, m, in the relation of formation factor, F, to porosity, ϕ. In the Archie equation, F = 1/ϕᵐ.

Cementation Exponent, Porosity Exponent

The exponent of porosity, m, in the relation of formation factor, F, to porosity, ϕ. In the Archie equation, F = 1/ϕᵐ. H. Guyod termed m the cementation exponent because m was observed to be higher in cemented rock. Another term for this is the porosity exponent.

Cementing

Cementing is the process of placing cement outside of casing strings to cement the casing to the formation.

Center Tap

A tap that is connected to the electrical center of a winding.

Center of Gravity

The point at which an object's weight is concentrated, or the single point on which an object could be balanced and not tip in any direction. For empty forklifts, it is generally just below the operator's seat; for symmetrical loads, it is at the middle of the load.

Centralized

A centralized logging tool is one which is run in the center of the borehole.

Centralizer, Centralized

A centralizer is hardware to position equipment in the center (centralized) of a borehole.

Centrifugal Pump

A pump that uses centrifugal force to move liquid through a system.

Centrifugal Separator

A type of moisture separator that relies on centrifugal force to separate moisture from steam; also called a cyclone separator

Centrifugal fan

A fan that moves air by centrifugal action, that is, by spinning air outward from the center of the shaft; typically used to produce higher pressures than axial fans.

Centrifugal force

An outward radial force that tends to impel or throw materials outward from a center of rotation.

Centrifuge

A device or instrument that uses centrifugal force to separate materials in a mixture into layers according to their different densities.

Centrifuge Test

A test to determine percentage of BS&W in oil samples. Same as shake-out or grind-out test.

Cetane Number

A measure of a diesel fuel's ignition quality, or how easily the fuel can be ignited by compression in an engine.

Chalk

A soft, white, porous sedimentary rock; a form of limestone composed of the mineral calcite.

Channel Valve

A suction or discharge valve that has plates in channels which lift and seat by differential pressure to control gas flow. This valve is used for high pressure compression requirements.

Channeling

A problem in which feed material does not flow evenly through a catalyst bed due to a buildup of carbon or scale on the catalyst.

Chapter

A division of the NEC that contains information about a specific topic. The NEC has nine chapters.

Characteristic Impedance

The impedance of an infinitely long length of transmission line

Characterization

The process by which an input or output is modified to improve the response of a process control loop

Charge

The fundamental unit of electricity: the excess or deficiency of electrons in a body. In electrical formulas, charge is typically represented by a small q or a capital Q.

Charge Heater

A furnace in which crude is heated until its temperature is high enough for distillation to occur.

Charge preparation

The process of preheating hydrocarbon feed streams prior to processing them in a cat cracking unit's riser; may also include treating the charge to reduce the effects of accumulated metals.

Charge stream

The feedstream of hydrocarbons supplied to a cat cracker for processing.

Charge tank

See Feed tank.

Charge-coupled Device

An integrated circuit containing an array of linked, or coupled, capacitors.

Charging

The process of adding raw materials to a reactor.

Chart Recorder

A device used to produce charts that provide information about process variables

Chassis Ground

A ground within an oscilloscope, often to the chassis. A chassis ground is usually unable to dissipate large electrical currents.

Check Shot Survey

A check shot survey is a type of borehole seismic data designed to measure the seismic travel time from the surface to a known depth. The compressional wave velocity of the formations in a wellbore can be measured directly by lowering a geophone to each formation of interest, sending out a source of energy from the surface and recording the resultant signal.

Check Valve

A valve designed to allow fluid or gas flow in only one direction and block flow in the opposite direction, protecting equipment and systems from backflow conditions.

Chemical Hygiene Officer

An employee who is designated by the employer, and who is qualified by training or experience, to provide technical guidance in the development and implementation of the provisions of the Chemical Hygiene Plan.

Chemical Hygiene Plan

A written program developed and implemented by the employer that sets forth procedures, equipment, personal protective equipment, and work practices that 1. are capable of protecting employees from the health hazards presented by hazardous chemicals used in that particular workplace and 2. meet the requirements of paragraph (e) of the OSHA Lab Standard.

Chemical Oxidation

A gas sweetening process whereby a solution is mixed with hydrogen sulfide to form a solid sulfur compound.

Chemical Sewer

An underground piping system designed to collect wastes or spilled chemicals and route them to devices such as retention ponds

Chemical intermediate

A chemical that can be used to make other products.

Chlorides

Chemicals that are injected into a reforming process in order to promote the isomerization and hydrocracking reactions.

Chloridization

Step in catalyst regeneration in which chlorides are restored to the surface of the catalyst after the primary and secondary burns.

Chlorine

Chlorine is a chemical element with the symbol Cl and atomic number 17.

Chop Mode Control

A vertical control that allows an oscilloscope to display two low-frequency signals, usually under 20 kilohertz, simultaneously. This is done by chopping up and displaying segments of both signals.

Chopper

A rapid switching circuit typically used in small DC controllers and in some older-style AC inverter controllers

Chromatogram

An X-Y graph that shows the results of a chromatographic analysis

Chromatograph

An analytical device that separates the components in a multi-component mixture according to how easily the components pass through a separation column, often used to measure the concentration of various gases in a complex gas mixture.

Chromatography

A separation technique for separating a mixture by passing it in solution or suspension through a medium in which the components move at different rates based on their interaction with a stationary material held inside a column.

Chronic

Lasting for a long period of time or marked by frequent recurrence. A chronic condition is usually defined as one lasting three months or more.

Chronic effects

Effects that develop after prolonged or repeated exposure to a hazardous chemical over a period of time

Chronic health effect

An adverse health effect that occurs after repeated or long-term exposure to a health hazard, which may not appear until months or years after exposure and may have a long duration.

Chronic health effects

Health problems that occur only after repeated or longduration exposure to a chemical, or health effects that may develop after a long period of time.

Chuck

A device with internal jaws that grip the shank of a drill bit or other attachment and hold the bit or attachment in a power drill or other power tools

Chuck key

A device used to tighten or loosen the jaws of a chuck

Circle

A closed curved line around a center point

Circuit

A complete path for current flow that connects an electrical source to equipment, including a voltage source and resistance.

Circuit Breaker

A protective device that can be opened manually or automatically to protect a circuit from excessive current, providing a means of isolating loads from a source of electrical power. It can be reset after tripping.

Circuit Loading

The unintentional interaction of a probe and an oscilloscope with the circuit being tested, which distorts the signal

Circular Chart

A chart made on a circle of paper that can be used to show operating conditions over a period of time

Circular Mil

The area of a circle with a diameter of 1 mil (0.001 inches)

Circular Mil System

A system used to indicate the size of wires; sizes range from 250,000 circular mils (smallest) to 2,000,000 circular mils (largest)

Circular saw

A power saw that has a disc-shaped, circular blade. The cutting edge of the blade is along the circumference of the blade. Also called a Skilsaw, a cutoff saw, a utility saw, or a builder's saw.

Circumference

The distance around the curved line that forms a circle

Cirrhosis

A disease of the liver in which normal liver cells are damaged and replaced by scar tissue, decreasing the amount of normal liver tissue. The scar tissue interferes with the flow of blood through the liver, and the loss of normal liver tissue leads to loss of liver function.

Clamp

A fastener that binds or presses parts together

Clapper Element

A relay element that operates when an electromagnetic field attracts a hinged plate to close contacts

Clarification

A process used to remove suspended solids from water or wastewater, typically by adding chemicals to cause small particles to clump together and settle out.

Clarifier

A vessel or tank that, with the aid of chemicals, promotes the natural settling out (sedimentation) of solid particles and/or bacteria from wastewater or other liquids.

Clarity

A measure of how clear, or transparent, a substance is

Class A Fire

A classification for fires that involve wood, paper, rags, or other similar materials

Class B Fire

A classification for fires that are caused by chemicals or flammable liquids

Class C Fire

A classification for electrical fires

Class D Fire

A classification for fires that involve flammable metals such as magnesium and phosphorous

Clastic Rocks

Rocks composed of small fragments (clasts) of other rocks, which determine the composition and texture of the clastic rock.

Clastic Rocks, Clastics, Clastic

Clastic rocks are rocks which are composed of small fragments of other rocks. These fragments, known as clasts, determine the composition and texture of the clastic rock.

Claus reaction

A sulfur recovery reaction in which a portion of H₂S is burned to produce SO₂, and the two are combined to produce sulfur and water.

Clay

A fine-grained rock that combines one or more clay minerals with traces of metal oxides and organic matter. Clays are plastic due to their water content and become hard, brittle, and non-plastic upon drying.

Clay Fines

Clay fines are very small clay particles in the size range 44 to 74 microns.

Clay Porosity

Clays have high porosities due to the structured nature of clay minerals. They can hold a large volume of liquids per volume of bulk material, but they do not release liquids rapidly and therefore have low hydraulic conductivity.

Clay Sheets

Clay sheets are comprised of a stack of two, or three, layers of aluminum octahedra or silica tetrahedra lattices.

Clay-bound Water

Water within the clay lattice or near the surface within the electrical double layer. This water does not move when fluid is flowed through the rock.

Clean Air Act

An Environmental Protection Agency regulation that identifies a number of potentially hazardous pollutants and sets limits on the amounts of these pollutants that can be emitted.

Clean Formation

A formation with no significant shale content.

Clearance Pocket

A device which allows adjustment of a compressor's capacity. It can be a fixed-volume or variable-volume pocket.

Clearances

The spaces around a variable speed controller required for proper cooling during normal operation

Clinker Grinder

A device that uses heavy metal rollers to crush large chunks of bottom ash into smaller particles

Closed Heater

A heater that typically uses a shell and tube design to keep steam separated from condensate or feedwater

Closed Impeller

An impeller whose vanes are enclosed by shrouds on both sides

Closed Loop

An automatic process control system in which the input device, controller, and output device are connected so that they form a closed circuit with feedback, where the signal is fed back from the output to the input and then back to the output.

Closed loop gain

The gain of an op amp circuit.

Closing Gauge

Measurement of oil level in lease tank following a transfer or run. May be called bottom gauge.

Closure

Closure occurs when the displacements determined between each adjacent pair of curves, taken cylindrically (1-2, 2-3, 3-4, 4-1), have an algebraic sum of zero.

Cloud Point

The temperature at which wax crystals begin to form in a fuel.

Cluster Analysis

Cluster analysis, or clustering, is the task of grouping a set of objects in such a way that objects in the same group are more similar to each other than to those in other groups.

Clustering

Clustering means that, if at any level in the well, the majority of the possible dips agree with each other and agree with the majority of the dips at adjacent levels in the well, then those are the most probable dips to use.

Clutch Key

A rectangular piece of metal that transfers rotation from one component of gear train to another

Coach

A person (usually a lead technician) who checks on progress and provides support to an assessment candidate (employee) as appropriate.

Coaching

Coagulation

The first step of clarification, in which chemicals are added to water to form sticky masses that cause small, suspended solids to combine into larger clumps.

Coal Bed Methane (CBM), also termed Coal Seam Gas (CSG)

Natural gas, usually primarily methane, contained in coal deposits, whether or not stored in the gaseous phase.

Coal bed methane (CBM)

Natural gas extracted from coal beds.

Coalesce

Combining of water droplets into larger droplets so they will settle out of oil.

Coarse measurement tools

Measurement tools that are reasonably accurate to between 1/64 inch and 1/100 inch (English)

Coax

A cable with two concentric conductors separated by an insulator. Commonly used for PLC network connections.

Coaxial Cable

A type of cable that has one conductor in the middle and one surrounding it in the form of a sheath. Coaxial cable can carry very high frequencies long distances with little attenuation.

Cohesive Force

A molecular force that exists between like molecules

Coil

In ladder diagrams, the part of an output device that moves the switch contact

Coiled Tubing

A long, continuous length of metal pipe, normally 1" to 3.25" in diameter, wound on a spool or large reel for easy transport and storage. It is straightened prior to pushing into a wellbore and is used for well interventions, well repair or workover activities, and sometimes as production tubing. Coiled tubing is often used to run well logs.

Coke

Carbon deposits, consisting of carbon, hydrogen, and sulfur, that can build up on a catalyst.

Coking

The accumulation of carbon deposits on the inside walls of furnace tubes, which can restrict fluid flow and cause heat transfer problems.

Coking unit

A unit that produces sponge coke by heating the pitch, or bottoms, from the residuum fraction to crack the remains.

Cold Flow

Cold flow is compression-induced wireline cable deformation.

Cold Startup

The startup of a boiler that has been out of service for an extended period of time, which has allowed metal components to cool down to room temperature

Cold work

Any work that does not involve a source of ignition.

Collapsed Height

The distance from the floor to the top of the mast of a forklift when the forks and the mast are fully lowered

Collector

One element of a transistor. In a bi-polar transistor, the collector is one of the poles.

Colloid, Colloidal

A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance.

Color Intensity

The strength of a particular color

Color bar label

A labelling system that uses color-coded sections to rate the health hazards, flammability, and physical hazards for a chemical and indicates appropriate personal protective equipment. Officially called a Hazardous Material Identification System (HMIS) color bar label.

Colorimeter

An analyzer that measures the color intensity of a solution

Colpitts Oscillator

An LC oscillator that produces a sinusoidal wave. The tuned circuit has two capacitors connected in series with a tap between them.

Column

The part of a chromatograph where the components in a sample mixture are separated

Combinable Magnetic Resonance (CMR)

Combinable magnetic resonance (CMR) logging is a proprietary nuclear magnetic resonance (NMR) service developed by Schlumberger.

Combination Coupling

A type of fitting that is used to join two different types of conduit together

Combined Operations

Calculations that include more than one type of mathematical operation

Combustible liquid

Any liquid having a flashpoint at or above 100°F (37.8°C) but below 200°F (93.3°C), except any mixture having components with flashpoints of 200°F or higher that make up 99% or more of the total volume.

Combustible material

A material that can be ignited and can fuel a fire, but does not ignite as easily or burn as rapidly as a flammable material.

Combustibles analyzer

An analyzer used to measure the concentration of combustible gases in an area.

Combustion

A heat-producing chemical reaction that occurs when fuel, oxygen, and heat are combined.

Combustion Air System

The system that supplies the air necessary for the proper combustion of fuel in a boiler

Come-along

A Lifting device operated by a handle on a ratchet; also called a ratchet lift.

Common Chain

A type of chain used in rigging that consists of interlocked welded links of forged steel

Common Emitter Amplifier

An amplifier circuit in which the input signal is applied to the base, the output signal is taken from the collector, and the emitter is common to both the input and the output.

Common Mode Choke

A device used to reduce electrical noise in the cabling connecting a variable speed controller and its motor.

Common mode rejection

A characteristic of op amp circuits: with any two equal voltages applied to the input terminals, the circuit will have an output of 0 volts. That voltage is known as the common mode voltage.

Common point

See Signal common.

Common-mode input capacitance

Input capacitance a common-mode source would see to ground.

Common-mode input impedance

The parallel sum of the small-signal impedance between each input terminal and ground.

Common-mode input voltage

The average voltage at the input pins.

Common-mode rejection ratio

The ratio of differential voltage amplification to common-mode voltage amplification, measured by determining the ratio of a change in input common-mode voltage to the resulting change in input offset voltage.

Communication Channel

A pathway for sending and receiving transfer trip signals

Commutative

Changing the order of the inputs does not change the result of the operation.

Commutator

The electrical connection in a DC motor between the brushes and the armature windings; a metal ring that changes alternating current to direct current.

Compaction Trend, Sediment Compaction Trend

The compaction trend is the increasing density of formation rocks with their burial. As layers are piled one upon another, the sediments beneath are buried. The weight of these layers compacts the sediment grains.

Comparator

An op amp circuit that is used to compare voltages in order to determine which has a greater value.

Compass

A navigational instrument for determining direction relative to the Earth's magnetic poles. It consists of a magnetized pointer (usually marked on the North end) free to align itself with Earth's magnetic field.

Compensated Neutron Log

The compensated neutron log tool makes thermal and epithermal neutron measurements to calculate porosity and identify lithology and the presence of gas.

Compensation

A probe adjustment for passive probes that balances the capacitance of the probe with the capacitance of an oscilloscope

Compensation component

Any component used in an op amp circuit to compensate for the op amp's less-than-ideal characteristics. The components may be in side the chip or external to the chip.

Competence

The ability to perform activities to required standards.

Competency

The combination of awareness, knowledge, skills and experience that enables performance to the required standard in the job, that is, what workers should know and do to perform their jobs safely and effectively.

Competency Development Plan [formerly Learning Plan]

Identifies the training needed to fill prioritized gaps between the employee's current skills and those required of the position, including the training type and expected time required to fill the requirement.

Competency Library

Competency Management System (CMS)

A process that assesses an employee's skills against those required in the job, and then develops a Competency Development Plan to prioritize and close any skill gaps identified.

Competency Model (CM) or Job Competency Model (JCM)

Competency Role

A set of tasks and responsibilities related to one aspect of a jobholder's job that the jobholder is required to know and have the skills to perform. One or more competency role may be linked to a job title for the assessment process.

Competency Role Builder (CRB)

A feature of CMS Online, accessible from Content Development on the left navigation menu. CMS Online uses the concept of roles for the development of competency models. One or more competency role can be linked to a single job title, or assigned directly to an employee. They can be built as a group, as well as for the individual roles within a family.

Competency Role Family (CRF)

A group of jobs that involve similar work and require similar training, skills and knowledge, but at different levels of expertise. The family is based on function and not organizational structure.

Competency Specialist

Competency Unit (CU)

A combination of a general statement and a series of specific statements covering four levels of performance or proficiency. These statements contain the specific responsibilities, tasks and skills identified for each competency.

Complementation

Logic inversion

Completion

The process of making a well ready for production or injection after drilling operations, which involves installing permanent equipment such as a wellhead and often includes hydraulic fracturing.

Completion Interval

Completion interval is the reservoir interval that is open to the borehole and connected to the surface facilities for production or injection.

Completion, Well Completion

A completion is an operation on an oil and gas well to open up the reservoir to production.

Compliance

Compound Motor

A DC motor that contains two different types of fields: a series field, which is connected in series with the armature, and a shunt field, which is connected in parallel with the armature

Compound annual growth rate (CAGR)

The average year-over-year growth rate of a metric over a specific period of time.

Compressed Gas Cylinder

Steel cylinders that contain compressed gases such as oxygen and acetylene. Also called bottles.

Compressed gas

A gas or mixture of gases having, in a container, an absolute pressure exceeding 40 psi at 70°F, or exceeding 104 psi at 130°F, or a liquid having a vapor pressure exceeding 40 psi at 100°F.

Compression Connector or Terminal

A connector or terminal that is installed by crimping or compressing the device onto a conductor. Also called a crimp-on connector.

Compression Load

The load (or force) on the piston rod as it travels toward the head end of the cylinder.

Compression Loading

The forces acting on a sucker rod during the downstroke because of the weight of the rods above it. Compression loading forces the rod together along its vertical axis.

Compression Unit

The part of the compressor which compresses the gas. It contains the cylinder, valves and piston.

Compressional Velocity

Compressional velocity is the velocity of compressional waves.

Compressional Wave

A compressional wave (P wave) is an elastic body wave, or sound wave, in which particles oscillate in the direction the wave propagates. P-waves are the waves studied in conventional seismic data.

Compressional Wave (P-wave)

A compressional (P-wave) wave is an elastic body wave, or sound wave, in which particles oscillate in the direction the wave propagates. P-waves are the waves studied in conventional seismic data.

Compressive Strength of Formation Rock

The compressive strength of a formation rock is the maximum load applied to crush the rock divided by the cross-sectional area.

Compressor

A device used to move gases and increase gas pressure. In refrigeration systems, it is the component that adds energy to the refrigerant to increase its temperature and pressure and move it through the system.

Compressor Capacity

The amount or volume of gas that a compressor moves in a given period of time.

Compressor Loading

Opening and closing appropriate valves on the compressor, or on each stage of the compressor, until the compressor is compressing gas in all stages.

Compressor Unloading

Opening and closing appropriate valves on the compressor so that the compressor is no longer compressing gas in any of the cylinders.

Compton Scattering

A gamma ray interaction in which the gamma ray collides with an electron, transferring part of its energy to the electron while itself being scattered at a reduced energy. It occurs with high probability at intermediate gamma ray energies (between 75 keV and 10 MeV in sedimentary formations). The total reduction due to Compton scattering depends on the electron density of the material, forming the basis for the density log.

Computer Platform

A computer platform is a computer or hardware device and/or associated operating system, or a virtual environment, on which software can be installed and run.

Concentrated solution

A solution that contains a relatively large amount of solute per unit volume of solution.

Concentration

The amount of one material dissolved in another material in a solution, or the amount of a contaminant in a certain volume of air.

Condensate

In petroleum, a mixture of hydrocarbons that exist in the gaseous phase at original reservoir temperature and pressure but become liquid at surface conditions. Also, light liquid hydrocarbons with varying proportions of propane, butane, pentane and heavier fractions. In power generation, water that is condensed from steam and collected in a condenser.

Condensate and Feedwater System

A system of heat exchangers, pumps, pipes, and valves that directs and contains the flow of condensate from the condenser to the boiler at the proper rate to support normal boiler operation.

Condensate-Feedwater System

The system that removes condensate from a condenser and sends it back to a boiler as feedwater

Condensation

The phase change from a gas to a liquid at the dew point temperature; the conversion of vapor into liquid droplets.

Condense

To change from a gaseous state to a liquid state.

Condenser

A heat exchanger that removes heat from vapor (such as steam or refrigerant) and converts it into a liquid. In power plants, it condenses exhaust steam from the turbine so the resulting condensate can be pumped back to the boiler for reuse.

Condenser Circulation Water System

The support system that supplies cooling water to a condenser

Conductance

Ability of a circuit to conduct current.

Conductance Probes

Metal rods that are mounted at the top of a tank and extend into it to different depths. As liquid reaches a probe, a circuit is energized or de-energized, and a relay operates to initiate or terminate an action.

Conduction

The primary mode of heat transfer within a solid or between solids in contact, occurring as a result of the collision of molecules or physical contact between objects.

Conductive devices

Electrical equipment or components that carry electric current.

Conductivity

A measure of how easily electrical current flows through a material; the inverse of resistivity.

Conductivity Probes

Electrical probes that initiate an action, such as activating an alarm, in response to changes in the level of a liquid

Conductivity, Electrical Conductivity

The reciprocal of electrical resistivity; measures a formation's ability to conduct an electric current.

Conductor

A material that offers very little resistance to electron flow, allowing electric current to pass through easily. In metallic conductors such as copper or aluminum, the movable charged particles are electrons.

Conduit Body

A type of coupling that has a removable cover, allowing access to conductors for installation and maintenance

Cone roof tank

A vertical, cylindrical tank with a roof that slopes gradually to a peak, forming a vertical cone. One type of atmospheric tank.

Cone-roof tank

A vertical cylindrical atmospheric tank with a roof that gradually slopes to a peak, forming a vertical cone.

Configuration

The setting up or programming of a process control instrument to match the process conditions it will measure, including device ID, engineering units, LRV/URV, damping, calculation and output mode, and other parameters for smart devices.

Confined space

A space that is large enough for a worker to enter and perform work, has limited or restricted means for entry or exit (e.g., tanks, vessels, silos, storage bins, hoppers, vaults, and pits), and is not designed for continuous employee occupancy. It may be deficient in oxygen.

Confined space entry

Going inside a decommissioned storage tank to clean it out or to make repairs and inspections.

Conical mixer

A mixer that consists of a cone-shaped housing and a screw-shaped impeller. Also called a cone and screw mixer.

Conjugate Faults, Fractures

Faults/fractures organized into two intersecting sets with opposite shear sense are commonly referred to as conjugate faults/fractures.

Connate Fluids

Liquids that were trapped in the pores of sedimentary rocks as they were deposited. These liquids are largely composed of water but also contain many mineral components as ions in solution.

Connate Fluids, Connate Water

Liquids that were trapped in the pores of sedimentary rocks as they were deposited, largely composed of water but also containing many mineral components such as ions in solution.

Connate Water

Connate water is the water which was trapped in the sedimentary rocks' pores during deposition.

Connection Diagram

A drawing that shows the general physical locations of all major components and the connection points of all wires within a single unit

Connector

A device used to physically and electrically join together two or more electrical conductors.

Connectors

Devices used to join different parts of a personal fall arrest system together.

Conservator-type sealed power transformer

A power transformer that uses an expansion tank, called a conservator tank, above the transformer, to prevent air and moisture from entering the transformer enclosure.

Constant

A letter, number, or symbol whose value does not change

Construction drawing

A drawing used in the construction of all or part of a building; sometimes referred to as a blueprint or a working drawing

Contact Angle

The contact angle is the angle, conventionally measured through the liquid, where a liquid/vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid.

Contact stress

An ergonomic risk factor associated with contact between sensitive body tissue and a hard or sharp object. Examples of contact stress include leaning against workstation edges, pressing tool handles into the palms, or pounding with the hand. Contact stress commonly affects soft tissues and can inhibit blood flow, tendon and muscle movement, and nerve function.

Contactor

In electrical systems, a large electromagnetic relay or switch inside a motor controller that directly controls the power to a motor; also called a motor starter. In gas processing, a component in an amine treatment unit where sour gas contacts lean amine and acid gases are absorbed.

Contactor (Absorber)

A vertical pressure vessel where gas and amine are brought together to remove acid gases from natural gas.

Contactor (or Absorber)

A vertical pressure vessel where gas and glycol are brought together to remove water vapor from the gas.

Contacts

The parts of a switch, relay, or electromagnetic device that touch to form a path for current and are separated to interrupt current flow.

Contaminants

Impurities in the air.

Contaminated

The presence, or reasonably anticipated presence, of blood or other potentially infectious materials on an item or surface.

Contingent Resources

Contingent Resources are the quantities of petroleum estimated to be potentially recoverable from known accumulations from a given date forward, but the associated development projects are not yet considered mature enough for commercial development due to one, or more, contingencies.

Continuous Level Measurement

A system of level measurement that gives a numerical reading of level at all times.

Continuous Reforming

A type of catalytic reforming in which the catalyst moves through the reactors and is regenerated in a separate regeneration vessel while the reactors continue to operate.

Continuous Sample

A sample taken using a special sampler which takes samples of the stream proportional to flow volume; the most expensive but most accurate method.

Continuous Side-By-Side Correlations

Continuous side-by-side (CSB) correlations only consider displacements computed from the side-by-side buttons on the dipmeter tool pads.

Continuous Wave Telemetry

Continuous wave telemetry systems create a carrier frequency that is transmitted through the mud. They encode data using the phase shifts of the carrier.

Continuous emissions monitoring

A method of source sampling in which emissions of certain chemicals are measured as they occur.

Continuous total dissipation

Usually specified as an absolute maximum. It is the power that can be dissipated by the op-amp package, including the load power. This parameter may be broken down by ambient temperature and package style in a table.

Continuous-Type Deposit

An accumulation that is pervasive throughout a large area and not significantly affected by hydrodynamic or buoyancy influences. Examples include basin-centered gas, shale gas, gas hydrates, natural bitumen, and oil shale accumulations.

Contour lines

Topographic lines that show the rise and fall of Land elevation on a drawing such as a site plan

Contract

To decrease in volume or size.

Contract/License Periods

The term of a license agreement or contract may be 20-30 years with the right to negotiate an extension thereafter. It is normally divided into the initial Exploration Period, and if success is achieved, it is followed by the Exploitation Period, during which the field is developed and production takes place. A Reconnaissance Period may be allowed by Operators in advance of negotiating or bidding on one or more blocks. The Exploitation Period is usually divided into a Development Period, during which the field is planned and constructed, followed by the Production Period.

Control Algorithm

A set of procedures used to move a process variable closer to its setpoint

Control Devices

Devices that adjust or change the operating conditions of a system

Control Output

The action of a control device, such as a valve, motor drive, metering pump, etc. that affects a process under the direction of a loop controller

Control Panel

The nerve center of a LACT unit which starts, monitors and stops the unit.

Control Relay

A small relay designed to control other small devices

Control Unit

Instrumentation in a system of level measurement or control that, upon receiving an electrical signal, converts the signal into an indication of level or into another signal that is used to initiate or terminate an action.

Control Valve

A valve used to control the flow of fluid in a piping system; often operated automatically in response to the value of a process variable.

ControlLogix

An Allen-Bradley family of programmable logic controllers developed specifically for networking and distributed control

ControlNet

Allen-Bradley's proprietary network for connecting multiple remote I/O racks, processors, PLC systems, and HMIs in a plant-wide system

Controlled Circulation

A type of circulation that uses mechanical devices such as pumps to move steam and water through boiler tubes.

Controlled Variable

The process variable that a control loop is designed to keep at the set point; usually also the measured process variable.

Controller

Any device that receives input information, makes decisions, and produces an output control action. Examples include PLCs, process loop controllers, servo and motor controllers, and the controller part of a variable speed drive. Also, a device that operates automatically to regulate a variable (such as rate of flow) in response to another variable (such as liquid level).

Controller Gain

The parameter that determines the proportional relationship between control output and error input; the inverse of proportional band. Often expressed as the change in controller output divided by the change in input.

Convection

A heat transfer process that involves the movement of fluid (liquid or gas), where heat is transferred within the fluid as a result of currents.

Convection Section

The part of a furnace in which the tubes are not in a direct line of sight with the burner flames; the area of a furnace between the radiant section and the stack

Conventional Gas

Natural gas, trapped by buoyancy, occurring in a porous and permeable reservoir rock, either in the gaseous phase or dissolved in crude oil.

Conventional Resources

Discrete petroleum accumulations related to localized geological structural features and/or stratigraphic conditions, typically with each accumulation bounded by a down-dip contact with an aquifer, contained in rocks with relatively high matrix permeability and normally having relatively high recovery factors.

Conventional distillation

Distillation in which a liquid mixture's components, which have different boiling points, are separated by vaporizing part of the mixture in a distillation column at or above atmospheric pressure.

Conversion

The percent of the volume of the charge feed stream in a cat cracker that is changed into other products.

Conversion Table

A data table used to find equivalents between units

Converter

A section of an AC inverter controller that converts the applied AC into DC

Cooler

A piece of equipment in the feed preparation section that cools the feed stream before it is sent to the reaction section.

Cooling Tower

A structure or device in which water is broken up into drops and cooled by air flowing through it. Mechanical draft cooling towers rely on fans; natural draft cooling towers use the tendency of warm air to rise.

Cooling-Degree-Days

The number of degrees that a given day's average temperature is above 65°F (15.5°C in European countries)

Copolymer

A long-chain molecule made from two or more different types of smaller molecules.

Copper Drag

A condition that leaves flakes of copper at the trailing edges of the commutator segments in a DC motor

Copper Oxide

A film that forms on the surfaces of copper contacts; a poor conductor of electricity

Core

The center of an object, such as the metal structure about which transformer windings are wound. In petroleum, cylindrical samples of rock collected either from the full diameter of the borehole using a special coring drill bit, or as smaller perpendicular samples from the side of the borehole using special wireline tools.

Core (rotor)

The part of a cylindrical rotor having grooved longitudinal slots in which windings are embedded; concentrates and directs the magnetic field in the rotor.

Core (stator)

The part of a stator, usually made of laminated iron, that supports the stator winding and concentrates and directs the magnetic field within the stator.

Core Analysis

A set of techniques for measuring well conditions downhole by studying physical samples of reservoir rocks. Core analysis generally gives the most accurate insight into porosity, permeability, and other important characteristics of the well.

Core Barrel

A barrel positioned immediately above the core bit that retains the core after it has been cut, normally consisting of two main parts: a core-retaining inner barrel and a protective outer barrel.

Core Bit

The tool used to core rock.

Core Competencies

Competencies that typically apply across an organization at different organizational levels or in different environments. Examples could be Presentation Skills, Enterprise Resource Planning (ERP) System, Safe Working Practices, Environmental Awareness, etc.

Core Monitor

A device used to measure the amount of particulate matter in the hydrogen inside a hydrogen-cooled generator

Core Plug Sample

Core samples that are normally drilled from full diameter cores.

Core, Coring

A core is a cylindrical sample of geologic formation taken during the drilling of a well. Coring is the process to acquire a core.

Corrective Action Process

A formal, documented process designed to eliminate or reduce the frequency of nonconformances.

Correlation Coefficient

A correlation coefficient is a measure of agreement between two curves.

Correlation Information

Correlation information is used to determine the attitude of bedding planes with respect to the dipmeter tool.

Correlogram

A correlogram is an image of correlation statistics.

Corrosion

An electrochemical reaction that deteriorates and weakens metal surfaces, which can eat away the metal of equipment such as above ground storage tanks.

Corrosive

Any material that eats away another material by electrical or chemical action

Corrosives

Chemicals that cause visible destruction of or irreversible alteration in living tissue by chemical action

Cost Oil

The percentage of production (e.g. 40%) that a PSC Contractor receives to repay its capital, operating and, if permitted, interest costs. In some cases, the Operator is allowed to recover an uplift (e.g.120%) of costs with the additional amount referred to as an Investment Credit. The Cost Oil quantity is converted to dollars using one or more reference crude market prices.

Coulomb

The amount of excess charge on the positive side of a capacitance of one farad charged to a potential difference of one volt.

Coulomb Force

The Coulomb force, also called the electrostatic force or Coulomb interaction, is the attraction or repulsion of particles or objects because of their electric charge.

Coulomb forces

The attraction or repulsion of particles or objects because of their electric charge; also called the electrostatic force or Coulomb interaction.

Counterbalance

Any force equally counteracting another. On a beam pumping unit it is the weight used to balance the weight of the sucker rod string.

Counterbalance Valve

A pressure control valve that is used to support a hoisted load or prevent a load from dropping

Counterflow

A fluid flow pattern in a heat exchanger such that two fluids flow past each other in opposite direction. Also called reverse flow.

Counterion, Counter-ion

A counterion is the ion that accompanies an ionic species in order to maintain electric neutrality.

Counterweight

A weight that is built into the body of a forklift that is used to offset the load's weight and help prevent the forklift from tipping over.

Coupled Physico-chemical System

A Physico-chemical system is a system involving parameters such as the water temperature, pH, dissolved oxygen, conductivity, salinity, nitrate, sulfate, chloride, total hardness, calcium and magnesium elements.

Coupling

In electronics, the method of connecting two circuits together—directly coupled via wire, or indirectly (AC) coupled through a capacitor or transformer. In conduit work, a fitting used to join two lengths of the same type of conduit together.

Coupling Capacitor Voltage Transformer (CCVT)

A device used to put a transfer trip signal onto a line or remove a transfer trip signal from a line

Coventurer

A coventurer is an organization which takes an equity share in an oilfield property and the various associated activities.

Cracked gas

The hydrocarbon vapors produced by a cat cracking unit.

Cracked gas plant

A unit that recovers light end products from unstabilized cat-cracked gasoline.

Cracking

A process in which large hydrocarbon molecules are decomposed into smaller molecules, creating undesired light ends and coke.

Cracking Pressure

The pressure at which a spring-biased valve begins to open and allow fluid to flow through

Crane

Any of several types of mobile or stationary machines used for lifting and moving loads from one place to another

Creutzfeld-Jacob disease

A rare, fatal brain disorder which causes a rapid, progressive dementia and associated neuromuscular disturbances or jerks. Although CJD can be genetic in origin, it's also transmittable through contact with infected tissue.

Crimper

A tool used to apply compression to attach a terminal or connector to a conductor

Critical Point

The point at which the density of water and the density of steam are the same; 705 degrees Fahrenheit and 3206 psi

Critical Water Saturation

Critical water saturation is defined as the water saturation at which the corresponding water phase relative permeability falls below a threshold value.

Cross-Connection Box

Patch panels that use patch cords to reverse the transmit-receive polarity. That is, data coming into the panel from one device on that device's transmit fiber crosses over to go out to another device on its receive fiber.

Cross-bedding

Layering within a stratum that is at an angle to the main bedding plane, where the original depositional layering is tilted but not as a result of post-depositional deformation. Sometimes termed cross-stratification.

Cross-bedding, Cross-beds

Cross-bedding is horizontal units that are internally composed of inclined layers. The original depositional layering is tilted, and the tilting is not a result of post-depositional deformation.

Cross-flow

In reservoir engineering, a condition where two production zones with dissimilar pressure characteristics communicate during production, with fluid from the high-pressure zone flowing preferentially to the low-pressure zone. In heat exchangers, a fluid flow pattern in which two fluids flow past each other at right angles.

Cross-functional Team

A group of employees from a similar hierarchical level, but from different work areas/groups/functions, who come together to accomplish a task.

Cross-tightening

A pattern for tightening flange bolts to ensure even compression on a gasket.

Crosshead

Device which converts rotary motion into reciprocating motion.

Crosstalk

A condition where the signal on one twisted pair of conductors is picked up on another pair in the same cable. Also, the ratio of the change in output voltage of a driven channel to the resulting change in output voltage from an undriven channel.

Crown Block

The fixed set of pulleys, or sheaves, located at the top of the derrick, over which the drilling line (a large-diameter wire rope) is threaded.

Crude Distillation Unit

A unit in a refinery in which distillation is used to physically separate crude into different groups of hydrocarbons.

Crude Oil

Petroleum that exists in the liquid phase in natural underground reservoirs and remains liquid at atmospheric temperature and pressure.

Crude oil (crude)

The liquid form of petroleum.

Crude oil distillation unit (crude unit)

The unit in a refinery where incoming crude is physically separated into groups of hydrocarbons.

Cryogenic

A term relating to very low temperatures (less than -50°F / -73°C to -150°F / -100°C). Used in the processing of natural gas to remove natural gas liquids.

Cryogenic tank

A tank that has been modified to contain liquids at temperatures below -100 degrees Fahrenheit.

Crystallization

The removal of a solid from a solution by increasing the solution's concentration above its saturation point so that crystals form.

Cumulative Data

Information concerning the time-integrated total of some variables. For example, how much water or electricity has been used from some baseline time to the present

Current

The movement or flow of electrons (free electrons through a conductor), measured in amperes. The unit commonly used to specify current is the ampere, and in electrical formulas, current is typically represented by a capital I.

Current (Electric)

A flow of electrons in an electrical conductor. The strength or rate of movement of the electricity is measured in amperes.

Current Limiting Fuse

A fuse that limits the amount of time that current is allowed to pass through it

Current transformer

A transformer that reduces higher line current to a proportional lower current and supplies the lower current to protective relays or to instruments that monitor or measure the line current.

Curriculum Learning

Provides the ability to create and deliver a curriculum of learning to CMS Online users. It also allows users to register for or launch courses through the CMS Online interface.

• Delivers a predefined learning curriculum to the end user
• Displays the curriculum in sequential learning blocks
• Allows the end user to open each block independently to see the list of courses and activities
• Allows the end user to view their training status and launch training within one view

Cursor

An on-screen marker on an oscilloscope that can be aligned with a waveform to enable a user to take accurate measurements

Custody Transfer

An event when products are received from or delivered to another party.

Custom Data Monitor

A software troubleshooting tool that allows you to build a table that displays specific PLC data in real time

Custom Data Monitors

A software troubleshooting tool that allows you to build a table that displays specific PLC data in real time

Cut Points

The temperatures at which fractions separate.

Cut and Thread, Cut and Thread Fishing Technique

Cut and thread is a fishing technique for recovering wireline stuck in a wellbore. In cut and thread operations, the wireline is gripped securely with a special tool and cut at the surface. The cut end is threaded through a stand of drill pipe. While the pipe hangs in the wellbore, the wireline is threaded through another stand of drill pipe, which is screwed onto the stand in the wellbore. The process is repeated until the stuck wireline is recovered.

Cutaneous hazards

Chemicals that affect the skin

Cutback Asphalt

A type of liquid asphalt produced by mixing straight-run asphalt with lighter distillates or oily distillates.

Cutoff

A state in which an amplifier is not conducting at all.

Cuts

See Fractions.

Cutting

A welding application that burns metal surfaces apart

Cuttings

Small pieces of rock that break away due to the action of the drill bit's teeth, which are screened out of the liquid mud system at the shale shakers.

Cuttings, Drill Cuttings

Cuttings are small pieces of rock that break away due to the action of the drill bit's teeth, which are screened out of the liquid mud system at the shale shakers.

Cuttings, Drill Cuttings, Ditch Cuttings

Small pieces of rock that break away due to the action of the drill bit's teeth, screened out of the liquid mud system at the shale shakers. Sometimes termed drill cuttings or ditch cuttings.

Cycle

In alternating current, one complete change in voltage from zero to maximum positive, back to zero, to maximum negative, and back to zero. In quality control, a pattern of instability on a control chart formed when data points alternate above and below the process centerline.

Cycle Skipping

An error in sonic logging that occurs when both detectors are not activated by the same peak or trough of the returning wave train, causing one to be activated by the next cycle instead. It is easily identified because the time difference equals the time interval between successive pulse cycles.

Cyclic Reforming

A type of catalytic reforming in which a "swing reactor" regenerates a portion of the catalyst while the other reactors continue to operate.

Cyclization

A reforming reaction in which a paraffin is converted to a naphthene.

Cyclone

A cone-shaped vessel that uses centrifugal force to separate solid particles (such as catalyst) from air, gas, or other gases. Also called a cyclone separator.

Cyclone separator

A cone-shaped vessel that uses centrifugal force to remove contaminants from a gas or vapor stream.

Cyclonic Passage

A device which creates a swirling flow of the fluids.

Cycloparaffin

See Naphthene.

Cylinder

A comparatively small, heavy, bottle-shaped vessel used to store compressed gases.

Cylinder Clearance

The space that exists in the head end or crank end of the cylinder. Increasing or decreasing this space adjusts the volume of gas the cylinder can handle.

Cylindrical rotor

A type of rotor commonly used with AC generators when high speeds of rotation and large amounts of power are needed; its cylindrical construction allows it to be affected less than a salient-pole rotor by centrifugal force and other stresses involved at high speeds.

calcareous

Calcareous refers to something (in this case a shell) that is formed from or contains a high proportion of calcium carbonate, in the form of calcite or aragonite.

caliche

Caliche (also known as calcrete, hardpan, or duricrust) refers to a sedimentary rock formed in arid and semi-arid regions when calcium carbonate precipitates out of solution cementing soil, sand, gravel, or other loose sediments together.

carbonate sediments

Carbonate sediments are formed in shallow, warm oceans either by direct precipitation out of seawater or by the biological extraction of calcium carbonate from seawater to form skeletal material. The sediment is, therefore, composed of varying sizes and shapes of particles that are mixed together, creating a variety of textures. This sediment may be bound together by encrusting organisms or deposited loosely and subject to transport by ocean currents.

carbonates

Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals.

cased borehole

A cased hole is a wellbore that has been lined with cemented steel.

channels

A channel is a device that carries data from the receivers to a recorder. In land work, this is typically a string or group of receivers that are connected to a cable which transmits the seismic data to a recorder. In marine work, the channels are built into the streamers, which are connected to the recorder in the vessel. In some modern, wireless systems, individual receiver units either record the data within the unit for later retrieval or they wirelessly transmit the data to a recorder.

chronometers

Chronometer refers to any method or tool used to accurately measure the age of a rock or fossil; essentially acting as a "timekeeper" for geological events.

chronostratigraphic

Chronostratigraphy is the study of the age and relative time relationships of rock strata in Earth's history with the goal of reconstructing past events (by correlating the ages of rocks around the world) to determine the depositional environments in which rocks were deposited.

clast

A clast is a fragment of rock or mineral that breaks off from an existing rock through physical weathering. Clasts have a wide size range, from less than a micron to the size of an apartment building.

clastic rock formations

Clastic rocks are composed of fragments (clasts) of pre-existing minerals and rock. These clasts break off existing rocks and minerals and, through forces of nature (erosion, wind, rain, etc.) form new rocks.

clasts

A clast is a fragment of rock or mineral debris that has been broken off of a larger rock through physical weathering.

clean sand

Clean sand refers to sandstone with a minimal amount of silt and clay matrix, meaning the sand grains are primarily composed of quartz with very little other material mixed in; essentially a "pure" sandstone.

clearance volume

The volume remaining in the cylinder when the piston is at the end of its stroke.

co-rendering

Co-rendering is an interpretation aid that assigns different attributes to display parameters, such as hue, intensity and saturation, so that they all contribute to the final color display.

confining pressure

Confining pressure, also known as lithostatic pressure or hydrostatic pressure, is the uniform pressure exerted on a rock in the subsurface. Confining pressure has equal pressure on all sides.

conjugate pairs

Faults of the same type that are formed during the same deformation episode. These occur in two symmetrical sets with parallel strikes, opposite dips and opposite or reciprocal sense of movement to each other.

consolidation

Consolidation is the process by which the volume of soil or sediment decreases, and its density increases in response to a compressive stress or increasing load.

contour line

A contour line is a curve along which the elevation or depth has a constant value, so that the curve joins points of equal value. For example, 300 m above sea level.

counterion

Counterions are the mobile ions found in ion exchange polymers and colloids. A counterion can be either an anion or a cation, depending on whether it carries a negative or positive charge, respectively. Consequently, a counterion to an anion will be a cation and a counterion to a cation will be an anion.

coupons

Small, specially designed metallic or non-metallic test specimens or samples that are placed on the external surface of a pipeline to assess the rate and severity of corrosion.

crevasse subdeltas

Crevasse subdeltas develop on modern river-dominated delta plains and consist of relatively large receiving bays that have depths of 32-49 ft (10-15 m). These may be affected by the interaction of river currents and marine processes. The process by which these are formed is referred to as “bay filling”. Crevasses form as a result of the movement and shear stress that is generated when two semi-rigid pieces above a plastic substrate have different rates of movement.

cross-section

The effective area within which a neutron must pass to interact with an atomic nucleus

cryptocrystalline

Cryptocrystalline is a rock texture in which the individual crystals are too small to be seen with the naked eye or even with a standard optical microscope. The crystals are so tiny that they can only be identified using advanced techniques like X-ray diffraction.

culture

Culture refers to any physical items specific to the prospect area that are important to know when planning the exploration program, for processing and interpreting the data. This could include pipelines, roads, lease areas, known shorelines, faults, etcetera.

cut bank

A cut bank, also known as a river cliff or river-cut cliff, is the outside bank of a curve in a water channel that is continually undergoing erosion. Cut banks are found in abundance along mature or meandering streams.