Oil and gas terminology · MLC-0103

Oil and gas terms: C (465)

C pumpA centrifugal pump of the kind used at a rig or well site to move large volumes of liquid at low pressure...
CableA long, insulated conductor or bundle of conductors used in seismic acquisition to transmit electrical...
Cable headA specialized connector that attaches a wireline cable to downhole logging tools or perforating guns. It...
Cable-tool drillingA drilling method that uses a heavy string of tools repeatedly lifted and dropped into the wellbore to crush...
CakeThe layer of solid particles deposited on the wall of a borehole as the liquid phase of the drilling fluid...
Cake thicknessThe measured depth of the filter cake that forms on the wellbore wall during drilling operations. This layer...
CalciteA common rock-forming mineral of calcium carbonate, CaCO3, that makes up limestone and, after...
Calcium bromideA salt used to formulate high-density, solids-free completion and workover fluids, particularly in situations...
Calcium carbonateA naturally occurring mineral, CaCO3, widely used as a bridging agent and weighting material in drilling...
Calcium carbonate plugA temporary barrier formed by injecting a slurry of calcium carbonate (CaCO3) into a wellbore to isolate a...
Calcium chlorideA salt, CaCl2, commonly used in drilling fluids as a source of calcium ions, for density control in brines...
Calcium contaminationThe presence of calcium ions in a drilling fluid, which can originate from drilling through calcium-bearing...
Calcium hydroxideA strong base, Ca(OH)2, known as hydrated lime, added to water-based mud to raise pH and supply calcium ions...
Calcium mudA type of water-based drilling fluid where calcium ions are intentionally maintained at a relatively high...
Calcium naphthenateA waxy, insoluble precipitate that can form in crude oil, particularly heavy crude, due to the reaction of...
Calcium oxideA chemical compound, CaO, also known as quicklime, used in drilling fluids primarily as a source of calcium...
Calcium sulfateA mineral, CaSO4, commonly found in formations as gypsum (hydrated) or anhydrite (anhydrous), which can...
Calcium testA laboratory procedure to determine the concentration of calcium ions in a drilling fluid. This test involves...
CalibrationThe process of adjusting a measurement tool or a model to conform to a known standard or a set of direct...
CalicheA hardened layer of calcium carbonate that forms in arid and semi-arid soils, typically near the surface...
Caliper logA well log that records the diameter of a borehole along its depth, providing information about the hole's...
CameraA downhole instrument equipped with a lens and imaging sensor used to capture visual images or video of the...
CapThe uppermost layer or part of a geological body, most often the caprock that forms over the crest of a salt...
Cap the wellTo install equipment on a wellhead to stop the flow of fluids, either in an emergency or as part of...
Capacitance logA production logging tool that measures the dielectric properties of fluids in the wellbore to determine the...
Capacitance meterA downhole logging tool that measures the dielectric constant of fluids in a wellbore, providing an...
Capacity factor (of a valve), Cv, KvA measure of a valve's flow capacity, representing the volume of water at a specific temperature that can...
Capillary numberA dimensionless ratio that compares viscous forces to capillary forces within a porous medium. It indicates...
Capillary pressure curveA plot showing the relationship between capillary pressure and wetting phase saturation in a rock sample...
Capillary suction time testA laboratory test that times how long the liquid from a sample takes to move a fixed distance through filter...
Capillary tube viscometerA device used to measure the viscosity of a fluid by observing the time it takes for a known volume of fluid...
CaprockAn impermeable or very low-permeability rock layer that overlies a porous and permeable reservoir rock...
Capsule gunA perforating gun in which each shaped charge is sealed in its own pressure-tight capsule, and the capsules...
Carbide lag testA procedure to determine the circulation time, or lag time, for drilling fluid and cuttings to travel from...
Carbon densityA measurement derived from specialized logging tools that indicates the concentration of carbon atoms within...
Carbon dioxideA colorless, odorless gas that can be encountered during drilling operations, either naturally occurring in...
Carbon dioxide corrosionThe degradation of metallic components in oil and gas production systems caused by the presence of dissolved...
CarbonateA sedimentary rock primarily composed of carbonate minerals, such as calcite or dolomite, formed from the...
Carbonate gamma rayA gamma ray log measurement interpreted in carbonate formations, where the relationship between radioactivity...
Carbonate ionA polyatomic anion, CO3^2-, present in drilling fluids, often resulting from the dissolution of carbonate...
Carbonate scaleA hard, mineral deposit, primarily calcium carbonate (CaCO3), that forms on the internal surfaces of...
Carbonate testAn analysis that measures the carbonate species in a water-based mud filtrate using the Garrett Gas Train...
Carboxymethyl hydroxyethylcelluloseA synthetic polymer derived from cellulose, used as a viscosifier and fluid loss control agent in water-based...
Carboxymethyl starchA chemically modified, water-soluble polymer derived from starch, used as a fluid-loss control additive in...
CarboxymethylcelluloseA cellulose derivative widely used as a fluid loss control agent and viscosifier in water-based drilling...
Carried working interestA working interest in an oil and gas property where one party, the carrying party, agrees to pay all or a...
Carrier fluidA fluid that transports solid particles, such as proppant in hydraulic fracturing or gravel in gravel...
Carrier gunA perforating gun system where shaped charges are loaded into a steel tube, or carrier, which is then lowered...
Carrying capacityThe ability of a drilling fluid to transport drilled solids, or cuttings, from the bottom of the wellbore to...
CarryoverThe undesirable entrainment of liquid droplets or solid particles from one processing stage into a subsequent...
CartridgeA self-contained, modular component of a logging tool string that houses specific electronic circuits...
Cased holeA wellbore that has been lined with steel pipe (casing) and cemented in place to prevent collapse, isolate...
CasingSteel pipe installed in a wellbore to prevent the hole from caving in, isolate different fluid-bearing...
Casing bowlA conical receptacle machined into the top of a casing head or spool, designed to receive and support the...
Casing centralizerA mechanical device secured around a joint of casing to keep it from touching the sides of the wellbore. By...
Casing collarA short, threaded steel connector used to join two lengths of casing pipe. It provides a strong, leak-proof...
Casing collar locator (CCL)A downhole logging tool that detects the magnetic anomalies caused by the steel collars connecting sections...
Casing collar logA record generated by a casing collar locator (CCL) tool, showing the precise depths of the casing collars...
Casing completionA well completion method where the production casing is run and cemented through the hydrocarbon reservoir...
Casing couplingA threaded sleeve used to connect individual joints of casing pipe, forming a continuous string. These...
Casing gradeA classification of casing pipe based on its material strength, specifically its minimum yield strength...
Casing gunA perforating gun designed to be run inside the well's production casing to create holes through the casing...
Casing hangerA device that supports the weight of a casing string and seals the annular space between the casing and the...
Casing hardwareThe set of mechanical devices and accessories installed on or run with a casing string during well...
Casing headA heavy-duty fitting installed at the top of the surface casing string, providing a means to suspend...
Casing inspection logA record of the physical condition of the steel casing in a wellbore, obtained by running specialized logging...
Casing jointA single length of casing pipe, typically ranging from 20 to 45 feet, that is connected to other joints to...
Casing patchA remedial tool or technique used to repair damaged or corroded sections of well casing, restoring its...
Casing pointThe target depth in a wellbore at which drilling is stopped to run and cement a string of casing. This depth...
Casing potential profileA measurement of the electrical potential along the length of a well's casing, used to detect corrosion. This...
Casing pressureThe pressure measured in the annular space between the production tubing and the production casing, or...
Casing reciprocationThe process of moving a casing string up and down within the wellbore while circulating fluids, typically...
Casing rollerA downhole tool designed to restore the circularity of collapsed or dented casing in a wellbore. It consists...
Casing scraperA downhole tool with blades or brushes, run inside the casing string to remove drilling mud, cement sheath...
Casing shoeA short, heavy-walled section of casing with a rounded or beveled bottom, attached to the first joint of...
Casing shoe testA pressure test performed after cementing a casing string to evaluate the integrity of the cement bond and...
Casing spoolA component of the wellhead assembly that provides a means to suspend a casing string and seal the annulus...
Casing stringA continuous length of casing pipe made up of multiple joints, run into the wellbore and cemented in place...
Casing swageA tapered, cone-shaped steel tool driven down through a collapsed, dented or out-of-round section of casing...
Casing testA pressure test performed on a casing string after it has been cemented in place to verify its mechanical...
Casing threadA helical ridge machined onto the ends of casing pipes, designed to connect individual casing joints...
Casing valveA device installed on the casing head or casing spool to control flow into or out of the casing annulus...
CasingheadA heavy-duty fitting installed at the top of the surface casing string, serving as the foundation for the...
Cat lineA rope or cable attached to a cathead, used for hoisting or pulling operations on the rig floor. It provides...
CataclasiteA cohesive, fine-grained fault rock formed by brittle deformation and comminution of pre-existing rocks...
CataclasticDescribing the process of rock deformation involving brittle fracturing and crushing of mineral grains...
CatagenesisThe second stage of organic matter maturation, following diagenesis, in which burial heat of roughly 60 to...
CatheadA rotating drum or spool on the drawworks of a drilling rig, used to provide power for pulling ropes and...
CathodeThe electrode in an electrochemical cell where reduction occurs, meaning it gains electrons. In the context...
Cathodic protectionA method of corrosion control that makes a metal structure the cathode of an electrochemical cell, thereby...
CationA positively charged ion, formed when an atom or molecule loses one or more electrons. In drilling fluids...
Cation exchange capacityThe total capacity of a rock, particularly shales and clays, to adsorb exchangeable cations per unit mass. It...
CationicRelating to a molecule or functional group that carries a net positive electrical charge. Cationic...
CatlineA general-purpose rope or wire line used on a drilling rig for lifting and moving equipment around the rig...
CatwalkA long, narrow platform located at ground level adjacent to the drilling rig, used for storing and preparing...
Caustic extraction testA laboratory test on a barite sample to find out whether it contains sulfide or carbonate minerals that...
Caustic potashThe common name for potassium hydroxide (KOH), a strong, alkaline chemical used in some water-based and...
Caustic sodaSodium hydroxide (NaOH), a strong base added to water-based drilling fluids to increase pH and neutralize...
Cave effectThe distortion of logging tool measurements caused by an enlarged borehole section, or 'cave,' which can lead...
CavingsRock fragments that fall from the sides of a borehole into the well, distinct from the cuttings generated by...
CavitationThe formation of vapor bubbles within a liquid due to a rapid drop in pressure, often caused by the passage...
CBMNatural gas, mainly methane, held by adsorption on the internal surfaces of coal and in its natural...
CDPCommon Depth Point, a technique used in seismic reflection processing where traces with a common reflection...
CECCation exchange capacity, a measure of the total number of exchangeable cations that a material, such as clay...
CellarA concrete-lined pit dug below the rig floor, providing space for the installation of blowout preventers...
Cellulosic polymerA type of polymer derived from cellulose, used as a viscosifier and fluid loss control agent in water-based...
CementA binding material that precipitates in the pore spaces of sedimentary rocks, reducing porosity and...
Cement acceleratorA chemical additive mixed with cement slurry to reduce its setting time and increase the rate of early...
Cement additiveA substance mixed with cement slurry to modify its properties for specific wellbore conditions. These...
Cement bond logAn acoustic well log that evaluates the quality of the cement bond between the casing and the formation, and...
Cement dispersantA chemical additive used in cement slurries to reduce their viscosity and improve their flow properties...
Cement evaluation logAn acoustic well log run after a casing cementing job to assess the quality of the cement sheath in the...
Cement extenderA material added to cement slurry to increase its volume while maintaining or improving its performance...
Cement headA specialized piece of surface equipment connected to the top of the casing string during cementing...
Cement plugA column of cement placed in a wellbore to isolate zones, abandon a section of the well, or provide a base...
Cement retainerA downhole tool run on tubing or drill pipe that is set in the casing to provide a temporary or permanent...
Cement retarderA chemical additive used to prolong the setting time of cement slurry, allowing more time for placement in...
Cement squeezeA remedial cementing technique where cement slurry is forced under pressure into a specific zone to seal off...
CementationThe diagenetic process by which dissolved minerals precipitate in the pore spaces of sediments, binding the...
Cementation exponentAn empirical parameter, denoted as 'm', used in Archie's equation to relate the formation resistivity factor...
CementerThe specialized service company, and its personnel, contracted to perform cementing operations on a well. The...
CementingThe process of pumping a cement slurry down a wellbore and into the annular space between the casing and the...
Cementing engineerA specialist responsible for designing, planning, and overseeing cementing operations in oil and gas wells...
Cementing plugA device, typically made of rubber or plastic, used during cementing operations to separate different fluids...
CentipoiseA unit of dynamic viscosity equal to one millipascal-second, or one hundredth of a poise. Fresh water at...
CentralizerA mechanical device attached to casing or tubing to keep it centered within the wellbore during cementing...
Centrifugal pumpA dynamic pump that uses a rotating impeller to accelerate fluid, converting rotational energy into kinetic...
CentrifugeA mechanical device used in solids control systems that separates fine drilled solids from drilling fluid by...
Cesium acetateA high-density, solids-free brine made from cesium acetate, used as a completion or workover fluid...
Cesium formateA salt of cesium and formic acid, employed to create high-density, solids-free brine drilling fluids. These...
Chain tongsA hand tool used to apply torque to tubular goods, such as drill pipe, casing, or tubing, during make-up or...
ChalkA fine-grained, porous limestone composed primarily of the microscopic calcite skeletons of marine plankton...
ChannelA geological feature representing the path of an ancient river or submarine current, characterized by...
Channel waveA seismic wave that propagates within a low-velocity layer, guided by the boundaries of that layer. These...
ChannelingThe undesirable flow of fluids, such as cement or drilling mud, through preferential pathways or voids behind...
CharacterThe distinctive waveform of a seismic reflection, determined by its amplitude, frequency, and phase. This...
Charged zoneA formation interval whose pressure has been raised above its normal level by fluid pumped or leaked into it...
Charpy testA standardized high strain-rate test that measures the energy a material absorbs during fracture, which...
ChatbotA software application designed to simulate human conversation through text or voice commands, providing...
Check valveA mechanical device that permits fluid or gas to flow in only one direction, preventing backflow in a...
Checkshot surveyA procedure for measuring the travel time of seismic energy from the surface to a known depth in a borehole...
ChelateTo form a stable, water-soluble complex with metal ions, typically calcium, magnesium, or iron, through a...
Chelating agentA chemical compound that forms stable, water-soluble complexes with metal ions, preventing them from...
ChelationThe chemical process where a chelating agent forms a stable, ring-like complex with a metal ion, effectively...
Chemical barrelA drum-sized vessel holding tens of gallons, kept at the mud pits, that doses a liquid chemical into the...
Chemical cutterA downhole tool that uses a highly corrosive chemical reaction to sever tubulars, such as tubing or drill...
Chemical diversionA technique used to temporarily block fluid flow into highly permeable zones within a reservoir, redirecting...
Chemical diverterA material pumped into a well during stimulation treatments to temporarily plug the most permeable zones or...
Chemical floodingAn enhanced oil recovery (EOR) method that involves injecting chemical solutions into a reservoir to improve...
Chemical injectionThe process of introducing specific chemical solutions into a reservoir to alter fluid properties or...
Chemical marker injectionA production logging technique for measuring fluid velocity and identifying flow paths by injecting a small...
Chemical neutron sourceA radioactive material, typically Americium-Beryllium (Am-Be) or Plutonium-Beryllium (Pu-Be), that...
Chemical oxygen demandA measure of the amount of oxygen required to chemically oxidize organic and inorganic matter in a water...
Chemical potentialA measure of the change in a system's free energy when a substance is added, expressed per mole of that...
Chemical washA fluid containing specific chemical additives, such as surfactants or solvents, pumped into the wellbore to...
Chenevert methodA practical test for water activity in which the relative humidity of the air sealed above a mud or shale...
ChertA hard, dense, cryptocrystalline sedimentary rock composed of microcrystalline quartz (silica). It forms...
ChertyDescribing a rock containing or composed of chert, a very hard, fine-grained sedimentary rock consisting of...
Chloride testA chemical analysis performed on drilling fluid to determine the concentration of chloride ions. High...
ChloriteA group of phyllosilicate minerals that form in metamorphic and diagenetic environments, characterized by...
ChokeA restriction in the flow path of a well, typically a valve with an adjustable orifice, used to control the...
Choke lineA high-pressure pipe running from a side outlet on the blowout preventer stack to the choke manifold. During...
Choke manifoldAn arrangement of high-pressure valves and chokes used to control the flow rate and pressure of fluids from...
CHOPSAn acronym for Cold Heavy Oil Production with Sand, a method used to produce highly viscous heavy oil from...
Christmas treeAn assembly of valves, spools, and fittings installed on the wellhead of a completed oil or gas well to...
Chromate saltA chemical compound containing the chromate ion, historically used as a corrosion inhibitor in drilling...
Chrome ligniteA modified lignite product treated with chromium compounds, used as a deflocculant and fluid loss control...
Chrome lignosulfonateA complex organic polymer derived from lignin and treated with chromium, widely used as a deflocculant and...
Chrome tubingA type of downhole tubular goods manufactured from steel alloys containing chromium, which provides enhanced...
Chrome-freeDescribing a drilling fluid formulation that does not contain chromium compounds, which are often used as...
Chromic saltA chemical compound containing chromium in a trivalent state, sometimes used in drilling fluids as a...
Chronostratigraphic chartA diagram that illustrates the relative and absolute ages of rock units, organizing them into a hierarchical...
ChronostratigraphyThe branch of stratigraphy that classifies rock bodies by the interval of geologic time in which they formed...
Churn flowA multiphase flow regime in vertical or inclined pipes characterized by an oscillating, intermittent flow of...
CIAn abbreviation for Color Index, a number representing the percentage of dark, ferromagnesian (mafic)...
Circle shootingA marine 3D acquisition technique in which the vessel follows a circular or spiral track centered on a...
CirculateTo pump fluid down the drill string, through the bit, and up the annulus to the surface. This process cools...
Circulate outTo remove unwanted fluids or gases from the wellbore by pumping drilling fluid down the drill string and up...
CirculationThe movement of drilling fluid from the surface pits down the drill string, out through the bit nozzles and...
Circulation deviceA downhole tool designed to divert or control the flow of fluids within the wellbore, often used during...
Circulation lossThe uncontrolled flow of drilling fluid from the wellbore into a permeable formation or fracture, rather than...
Circulation subA downhole tool run as part of a tubing string that allows fluid to be diverted from the tubing bore into the...
Circulation systemThe network of pumps, pipes, and tanks that moves drilling fluid from the mud pits, down the drill string...
Circulation timeThe duration required for drilling fluid to travel from the surface, down the drillstring, through the bit...
Circulation valveA downhole device installed in a tubing string that enables the controlled diversion of fluids between the...
Citric acidA weak organic acid, C6H8O7, used in water-based muds to lower pH and to remove calcium, which makes it a...
City gateThe point at which a local natural gas distribution company takes ownership and responsibility for natural...
Classical reservoir modelingThe conventional approach of describing a reservoir with two-dimensional maps of properties such as...
Clastic intrusionA body of sedimentary material that has been forced into pre-existing rock layers while still unconsolidated...
Clastic sedimentMaterial consisting of fragments, or clasts, of pre-existing rocks and minerals that have been transported...
ClathrateA solid compound in which molecules of one substance are trapped within the crystal lattice of another...
ClayA fine-grained natural earthy material composed primarily of hydrous aluminum phyllosilicates, with particle...
Clay extenderA drilling fluid additive, typically a long-chain polymer such as polyacrylamide, that enhances the viscosity...
Clay stabilizerA chemical additive used in drilling, completion, and stimulation fluids to prevent the swelling and...
Clay swellingThe expansion of clay minerals within a reservoir rock when they come into contact with certain fluids...
Clay-bound waterWater that is tightly adsorbed to the surfaces of clay minerals within a rock's pore system, held by strong...
Clay-water interactionThe complex physicochemical process that occurs when clay minerals in a drilling fluid or a formation are...
CleanDescribing a rock formation or reservoir interval that contains minimal or no clay or shale content. A clean...
Clean outThe process of removing sand, scale, fill, or other unwanted debris from the bottom of a wellbore to restore...
CleanoutThe operation of removing unwanted solids, such as sand, scale, or drilling debris, from the wellbore to...
CleanupThe process of removing drilling fluids, debris, and other foreign materials from the wellbore and...
Clear brineA solids-free aqueous solution of salts, such as sodium chloride, calcium chloride, or potassium formate...
Clear-water drillingA drilling technique that uses only water, or water with minimal additives, as the circulating fluid to...
ClevisA U-shaped fitting with aligned holes in its two arms, through which a pin or bolt passes to join a rod...
Close inTo stop production from a well by closing the surface valves on the christmas tree, halting the flow of...
Closed mud systemA drilling fluid management approach where no mud or drilled cuttings are discharged into the environment at...
Closed-chamber testingA drill stem test technique in which the flow period is run against a closed, fixed volume, normally the...
Closed-in wellA well that is temporarily shut off from producing, either at the surface wellhead or with a downhole valve...
Closing unitA hydraulic power system that provides the necessary pressure and volume to operate the blowout preventers...
ClosureThe vertical distance from the highest point of a structural trap to the lowest contour that completely...
Closure pressureThe pressure at which a hydraulic fracture closes after the pumping of fracturing fluid has ceased...
Cloud computingThe delivery of on-demand computing services, including servers, storage, databases, networking, software...
Cloud pointThe temperature at which a clear liquid, such as an oil or a surfactant solution, begins to appear cloudy due...
Cloud point glycolA type of glycol-based additive used in water-based drilling fluids that exhibits a cloud point, meaning it...
Cloud service provider (CSP)A third-party company that offers cloud computing services, such as infrastructure, platforms, or software...
ClusterA group of wells, geological features, or data points that are spatially close or share similar petrophysical...
Cluster analysisA statistical technique used to group a set of objects in such a way that objects in the same group, or...
CMCCarboxymethyl cellulose, a polymer derived from cellulose, functions as a viscosifier and fluid loss control...
CMC-Hi VisA high-viscosity grade of carboxymethylcellulose, a polymer additive used in water-based drilling fluids. It...
CMC-HVTA high-viscosity grade of technical-grade carboxymethylcellulose, where the letter T marks the less purified...
CMC-Lo VisA low-viscosity grade of carboxymethyl cellulose, primarily used in water-based drilling fluids for fluid...
CMC-LVTA low-viscosity grade of technical-grade carboxymethylcellulose, where the letter T marks the less purified...
CMHECCarboxymethyl hydroxyethyl cellulose, a modified cellulosic polymer used as a viscosifier and fluid loss...
CMPA common midpoint gather, which is a collection of seismic traces that share a common reflection point in the...
CMSA chemically modified starch, carboxymethyl starch, added to water-based muds to control filtration. It forms...
CO2 injectionAn enhanced oil recovery method in which carbon dioxide is injected into a reservoir. The gas dissolves in...
CoalAn organic sedimentary rock that forms from the accumulation and compaction of plant matter in an...
Coal gasificationA process that converts coal into a gaseous fuel, known as syngas, by reacting it with oxygen, steam, and...
Coal seam gasNatural gas, primarily methane, adsorbed within the matrix of coal seams. This gas is extracted by drilling...
Coalbed methaneMethane gas stored within coal seams, adsorbed onto the solid coal matrix. It is produced by drilling wells...
CoalesceTo merge or combine small droplets or particles into larger ones, a process that occurs in emulsions or...
CoalescenceThe process by which dispersed droplets or particles in an emulsion or suspension combine to form larger...
CoarseDescribing particles or grains that are relatively large in size, typically referring to solid additives or...
CoatingA protective layer applied to the surface of equipment, pipelines, or other structures to prevent corrosion...
Coating flawA defect or discontinuity in a protective coating applied to a metal surface, such as a pipeline or vessel...
CODThe Chemical Oxygen Demand (COD), a measure of the amount of oxygen required to chemically oxidize all...
CodingThe process of assigning specific values or classifications to intervals of a well log based on interpreted...
CogenerationThe simultaneous production of electricity and useful heat from a single fuel source, such as natural gas...
Cognitive computingA technological paradigm that simulates human thought processes, including reasoning, learning, and...
CoherenceA measure of the similarity or continuity of seismic waveforms across adjacent traces in a seismic dataset...
Coherence filteringA seismic processing technique that enhances coherent signals and suppresses incoherent noise by analyzing...
Coherence mapA seismic attribute display that highlights discontinuities and changes in seismic waveform similarity...
Coherence vector mapA map that shows how strongly the data of two wells correlate, with an arrow from one well toward the other...
CoherentDescribing seismic waves or events that exhibit a consistent phase relationship between different traces or...
Coherent detectionA signal processing method that uses a reference signal to extract a desired signal from noisy data, based on...
Coherent noiseUnwanted seismic energy that exhibits a predictable pattern or consistent waveform across multiple traces...
Coiled tubingA continuous, flexible steel or composite pipe spooled onto a large reel for deployment into oil and gas...
Coiled tubing completionA well completion method that uses continuous, reeled tubing as the production conduit or for intervention...
Coiled tubing connectorA mechanical device used to attach downhole tools or other tubulars to the end of a coiled tubing string...
Coiled tubing stringA continuous, flexible steel pipe spooled on a large reel, used for well intervention and workover operations...
Coiled tubing unitThe complete set of surface equipment required to run coiled tubing into a well, consisting of a reel...
CokeA solid, carbonaceous residue formed from the thermal decomposition of hydrocarbons, often found in refinery...
CokrigingA geostatistical interpolation technique that estimates the value of a primary variable at unsampled...
Cold heavy oil production with sandAn unconventional production method for highly viscous heavy oil reservoirs that involves intentionally...
Cold productionA method of producing heavy oil without applying heat to reduce its viscosity. This technique relies on...
Collapse pressureThe external pressure differential that causes a tubular component, such as casing or tubing, to deform...
CollarA short, heavy section of pipe with threaded connections, used to join two lengths of casing or tubing in a...
Collar locatorA downhole wireline tool that detects the magnetic signature of casing collars, which are the threaded...
Collar lockA mechanical device designed to secure a downhole tool or component within a casing or tubing string by...
Collar logThe recorded output from a casing collar locator tool, presented as a curve on a well log. This log shows...
CollectorOn a coiled tubing reel that carries an electrical cable inside the tubing, the rotating electrical connector...
CollisionThe convergence and suturing of two continental plates, a process that deforms rock layers and builds...
ColloidA substance consisting of particles dispersed throughout another substance, where the dispersed particles are...
ColloidalDescribing a substance dispersed in a continuous medium, forming a system where particles are larger than...
Colloidal solidsFinely divided solids in a drilling fluid, such as hydrated bentonite, that are about 1 nanometer to 1...
Colloidal suspensionA mixture in which finely divided particles, larger than molecules but not visible to the naked eye, are...
Combi BOPA coiled tubing blowout preventer in which each ram pair combines two functions, so two sets of rams do the...
Combination stringA casing, tubing, or drill string assembled from sections of pipe with different weights, grades of steel, or...
Come out of the holeTo withdraw the drill string from the wellbore, an operation also known as tripping out. This procedure is...
Command trailerA mobile unit that serves as the central control hub for hydraulic fracturing operations at a well site. It...
Commercial rateThe minimum sustained production rate of oil or gas from a well or field that is considered economically...
Commingled completionA well completion design where fluids from two or more distinct producing zones within the same wellbore are...
Commingled flowThe production of fluids from two or more distinct reservoir zones through a single wellbore and a common...
Common midpoint methodA seismic acquisition and processing technique where multiple source-receiver pairs are used to record...
Common offsetA seismic data gather consisting of traces that all have the same source-receiver distance, or offset. These...
Common receiverA collection of seismic traces that share the same receiver location but originate from different source...
Common receiver gatherA collection of seismic traces recorded by a single receiver from multiple source locations. This type of...
Common reflection pointThe point on a subsurface reflector where seismic energy from multiple source-receiver pairs reflects before...
Common sourceA method of acquiring seismic data where a single source location is used to generate seismic waves that are...
Common source gatherA collection of seismic traces recorded by all active receivers for a single seismic shot or source...
CommunitizationThe pooling of small or irregularly shaped tracts of land into a single drilling unit to allow for efficient...
CompactionThe process by which sediments are progressively compressed under the weight of overlying material, leading...
Compaction correctionAn empirical correction applied to porosity calculated from sonic transit times in formations that are not...
Company manThe designated representative of the oil and gas operating company at a wellsite, responsible for overseeing...
Company representativeAn individual appointed by the operating company to supervise and manage specific operations or projects on...
CompartmentA discrete volume within a reservoir that is hydraulically isolated from other parts of the field by sealing...
CompartmentalizationThe division of a reservoir into separate, hydraulically isolated volumes by geological barriers such as...
CompatibilityThe ability of different fluids, chemicals, or materials to coexist without adverse reactions that would...
Compatible scalesA set of scales used for plotting well log data, where the range of each curve is chosen to allow for clear...
Compensated density logA wireline measurement that determines formation bulk density by emitting gamma rays into the formation and...
CompetentDescribing a rock layer that is relatively strong and resistant to flow or deformation under stress...
Complete a wellTo prepare a drilled well for production or injection by installing the necessary downhole and surface...
CompletionThe process of preparing a well for production after drilling, which involves installing the necessary...
Completion fluidA specialized fluid used during the well completion phase to control formation pressures, clean the wellbore...
Completion quality (CQ)A measure of how readily a formation interval accepts an effective hydraulic fracture, based on rock...
Completion skinA dimensionless factor that quantifies the additional pressure drop caused by near-wellbore damage or...
Complex trace analysisA method of seismic data processing that involves transforming a real seismic trace into a complex trace...
Composite frac treeA specialized wellhead assembly used during hydraulic fracturing that integrates multiple valves and...
Composite streamA single production stream that carries several fluids at once, such as oil, gas and water. The individual...
Compositional fluid analysisA laboratory process that determines the precise chemical makeup of a reservoir fluid sample, identifying the...
CompressibilityThe fractional change in volume of a substance per unit change in pressure, indicating how much a material's...
Compression ratioThe ratio of the absolute discharge pressure to the absolute suction pressure for a compressor stage or unit...
Compressional waveA type of seismic wave where particle motion is parallel to the direction of wave propagation, causing...
Compression-set packerA type of downhole packer that is set by applying downward compressive force to expand an elastomeric element...
CompressorA machine that raises the pressure of a gas by forcing it into a smaller volume. Compressors are classified...
Compressor plantA facility containing one or more compressors designed to increase the pressure of natural gas for...
Compton scatteringAn inelastic scattering process where a photon interacts with an electron, resulting in a decrease in the...
Computed tomographyA non-destructive imaging technique that uses X-rays to create detailed cross-sectional images of a...
Computer visionA field of artificial intelligence that enables computers to interpret and understand visual information from...
ConcentricDescribing two or more tubulars or casings that are placed one inside the other, sharing the same central...
Concentric foldA type of fold in which the individual layers maintain a uniform thickness as they are bent, resulting in...
Conceptual modelA qualitative representation of the geological and fluid flow characteristics of a reservoir, based on...
ConcessionA contractual agreement between a host government and an oil company, granting the company the exclusive...
CondensateA low-density liquid hydrocarbon mixture, mainly pentanes and heavier, that exists as vapor in a gas...
Condensate liquidsHydrocarbon liquids that condense from a gas phase as pressure and temperature decrease during production...
Condensate ratioThe volume of condensate produced per unit volume of natural gas, expressed as barrels of condensate per...
Condensed sectionA thin, fine-grained marine stratigraphic interval characterized by an extremely low rate of sediment...
Condensing driveA miscible gas injection process in which a gas enriched with intermediate hydrocarbons, such as ethane...
Conditional simulationA geostatistical modeling technique that generates multiple equiprobable realizations of a reservoir...
ConductanceThe ability of a material to conduct electric current, defined as the reciprocal of its electrical...
Conductive invasionThe process where drilling fluid filtrate, which is more conductive than the formation water, displaces...
Conductive rock matrix modelA petrophysical model used to interpret resistivity logs in formations where the rock matrix itself exhibits...
ConductivityThe ability of a material to conduct an electric current, which is the reciprocal of resistivity. In...
Conductometric titrationAn analytical chemistry technique where the endpoint of a titration is determined by monitoring the...
Conductor pipeThe largest diameter and shortest string of casing, installed in the initial phase of drilling a well. It is...
ConformableDescribing rock layers that lie one above another in an unbroken sequence, deposited continuously without...
ConformityA geological relationship where successive rock layers are deposited one after another without any...
Conical projectionA type of map projection that transforms the spherical surface of the Earth onto a cone, which is then...
ConingThe upward movement of water or downward movement of gas into a producing wellbore, forming a cone shape in...
Connate waterWater trapped in the pore spaces of sedimentary rocks at the time of their deposition, which has remained in...
ConnectionThe process of adding a new stand of drillpipe or casing to the drill string as the well deepens. This...
Connection gasA small slug of formation gas that enters the well while a connection is made, because stopping the pumps...
ConsistencyA measure of a fluid's resistance to flow, often related to its viscosity and yield point. In drilling...
ConsistometerA laboratory instrument that measures the thickening time of a cement slurry under simulated downhole...
ConsolidatedDescribing sediments or rocks that have been compacted and cemented into a solid, coherent mass. This...
ConsolidationThe process by which loose, fine-grained sediments, such as clay or silt, decrease in volume and increase in...
Constant composition expansionA laboratory experiment performed on a reservoir fluid sample to determine its phase behavior at a constant...
Constant rateA condition in well testing where fluids are produced from or injected into a well at a steady, unchanging...
ContactA boundary surface between two different rock bodies or between two distinct stratigraphic units. Contacts...
Contact angleThe angle formed when a liquid droplet rests on a solid surface, measured through the liquid to the solid...
Contact timeThe duration that a fluid, such as a chemical wash or spacer, is in physical contact with a surface before...
ContaminantAn undesirable substance present in a fluid or system that can negatively impact performance, cause damage...
Contamination gasGas that reaches the gas detector from a man-made source rather than from the rock, for example vapor from...
Continental shelfThe submerged extension of a continent, forming a relatively shallow, gently sloping seabed that extends from...
Contingency planA prepared course of action designed to address potential problems or emergencies that could arise during...
Continuity equationA fundamental principle in fluid dynamics that expresses the conservation of mass within a flowing system...
Continuous gas liftAn artificial lift method where gas is continuously injected into the production tubing at a specific depth...
Continuous phaseThe fluid medium that surrounds and suspends the dispersed phase in an emulsion or suspension. In a...
Continuous reservoirA hydrocarbon accumulation that lacks a distinct gas-water or oil-water contact and is characterized by...
ContourA line on a map that connects points of equal elevation or equal value of a specific geological parameter...
Contour intervalThe vertical distance or difference in value between successive contour lines on a map. A smaller contour...
Contour mapA graphical representation of a three-dimensional surface on a two-dimensional plane, using lines to connect...
Contract depthThe total measured depth specified in the drilling contract to which a well is to be drilled. Reaching this...
Contrastive language-image pretraining (CLIP)A multimodal machine learning model, known as Contrastive Language-Image Pretraining, trained on a large...
Control lineA small-diameter hydraulic or electrical conduit run alongside the production tubing in a wellbore, used to...
Control valveA device that regulates the flow rate, pressure, or temperature of a fluid within a process system by...
Controlled time surveyA radioactive tracer survey in which a slug of tracer is ejected, for example at the bottom of the tubing...
ControllerAn instrument or system that monitors a process variable and adjusts an output to maintain that variable at a...
ConvectionThe transfer of heat through the movement of fluids, such as liquids or gases, driven by density differences...
Conventional mudA water-based drilling fluid formulated with bentonite clay, barite for density, and lignosulfonates or...
Conventional reservoirA subsurface rock formation where hydrocarbons have accumulated in porous and permeable rock, allowing them...
ConvergenceThe geological process where two or more tectonic plates move toward each other and collide. This movement...
ConvergentDescribing a type of plate boundary where two tectonic plates are moving towards each other. This interaction...
Converted waveA seismic wave that changes its mode of propagation, such as a P-wave (compressional wave) converting to an...
ConveyanceThe legal act of transferring ownership or an interest in real property, such as mineral rights or a...
ConvolutionA mathematical operation that combines two functions to produce a third function, expressing how the shape of...
Convolutional neural network (CNN)A class of deep neural networks specifically designed to process and analyze visual data, such as images and...
ConvolveTo perform the mathematical operation of convolution, which combines two functions to produce a third...
CopolymerA polymer derived from two or more dissimilar types of monomer molecules linked together in the same chain...
Copper carbonateA chemical compound, CuCO3, used as a scavenger in drilling fluids to remove hydrogen sulfide (H2S), a highly...
CoreA cylindrical sample of rock or sediment retrieved from the wellbore, typically 2 to 4 inches in diameter and...
Core analysisThe laboratory study of rock samples, called cores, recovered from a wellbore to determine their physical and...
Core gamma logA high-resolution measurement of natural gamma radiation emitted by a rock core, taken in a laboratory after...
Core imageA high-resolution visual representation of a rock core, obtained through photography or digital scanning...
Core plugA small, cylindrical sample of rock drilled from a larger whole core, typically 1 to 1.5 inches in diameter...
Core testingThe laboratory analysis of rock samples taken from a wellbore to determine reservoir characteristics. These...
CorefloodingA laboratory procedure in which fluids are injected through a cylindrical rock sample, or core, to simulate...
Coring fluidA specialized drilling fluid formulated to maximize the quality and minimize the contamination of a rock core...
Corkscrew holeA borehole that exhibits a helical or spiral shape along its length, rather than being straight. This...
Corrected gamma rayA gamma ray log measurement that has been adjusted to account for environmental effects and borehole...
Correcting pressure to a datumThe process of adjusting measured downhole pressures to a common reference depth, or datum, to account for...
CorrelateTo establish the equivalence of rock units or geologic events between separate locations, such as different...
CorrelationThe process of demonstrating equivalency between rock units or geologic events in separate areas, such as...
CorrelogramA graphical representation of the autocorrelation function, showing the correlation of a time series or...
CorrosionThe deterioration of metallic materials due to chemical or electrochemical reactions with their environment...
Corrosion controlThe implementation of strategies and techniques to mitigate or prevent the degradation of metallic equipment...
Corrosion couponA small, pre-weighed metal strip or disc exposed to the drilling fluid system to monitor the rate of...
Corrosion fatigueA type of material degradation where the combined effects of cyclic stress and a corrosive environment lead...
Corrosion inhibitorA chemical substance added to fluids to reduce or prevent the degradation of metallic materials due to...
Corrosion rateThe speed at which a material deteriorates due to chemical or electrochemical reactions with its environment...
Corrosion-resistant alloy (CRA)A metallic material, such as stainless steel or nickel-based alloys, specifically engineered to withstand...
CosolventAn organic compound added to a primary solvent system to increase the solubility of certain components or to...
Cost oilThe part of production in a production sharing contract that the contractor takes first to recover its...
CosurfactantAn alcohol or other amphiphilic substance added to a surfactant-oil-water system to improve the stability and...
Counterbalance weightA heavy mass, usually mounted on the cranks of a beam pumping unit and on the beam in older beam-balanced...
Counterbalance winchA hydraulic winch on a snubbing or hydraulic workover unit, used to pick up and lay down tubing joints and...
CouponA small, precisely manufactured piece of material, typically metal, used for testing purposes within a...
CPMGThe Carr-Purcell-Meiboom-Gill pulse sequence, a technique used in nuclear magnetic resonance (NMR) logging to...
CrackingA refining process that breaks down large, complex hydrocarbon molecules into smaller, lighter molecules...
CratonA large, stable, and ancient part of the continental lithosphere that has remained relatively undeformed for...
CreamingThe upward migration and accumulation of the dispersed phase in an emulsion, forming a concentrated layer at...
CrestThe highest point of a structural trap, such as an anticline or dome, where hydrocarbons accumulate due to...
CrestingThe localized upward movement of water or downward movement of gas into a producing wellbore, similar to...
CRGA common receiver gather: a set of seismic traces recorded at one receiver location from many different...
Critical angleThe angle of incidence at which a seismic wave traveling from a slower medium to a faster medium is refracted...
Critical dampingA condition in a vibrating system where the damping force is just sufficient to prevent oscillation, allowing...
Critical flow rateThe production rate at which a flow-related limit is reached in a well, with a meaning that depends on the...
Critical gas flow rateThe minimum velocity at which gas must flow in a wellbore to continuously remove produced liquids, preventing...
Critical momentThe point in geological time when all elements of a petroleum system (source, reservoir, seal, and trap) are...
Critical rateThe flow rate at which the flow of a fluid in a pipe or annulus changes from laminar to turbulent. Whether...
Critical reflectionA seismic reflection that occurs when the angle of incidence at an interface equals the critical angle. At...
Crooked holeA wellbore that deviates significantly from its intended trajectory, either vertically or horizontally, due...
Crop outTo be exposed at the Earth's surface, as when a rock layer, fault, or other geological feature intersects the...
Cross dipoleAn acoustic logging measurement that uses dipole transmitters and receivers oriented orthogonally to each...
Cross overA short tubular component, also called a crossover sub, used to connect two downhole items having different...
Cross sectionA two-dimensional diagram that illustrates the vertical arrangement of rock layers and geological structures...
CrosscorrelateTo measure the similarity between two time series as a function of the time lag applied to one of them. In...
CrosscorrelationA mathematical operation that quantifies the similarity between two signals as a function of the time offset...
Crosscorrelation flowmeterA downhole tool that measures fluid velocity by detecting the time delay of naturally occurring or induced...
CrossflowThe movement of fluids between different permeable zones within a wellbore, often occurring when the...
CrosslineA direction perpendicular to the primary acquisition direction of seismic data, often referred to as the...
CrosslinkerA chemical agent added to a polymer solution to create chemical bonds between individual polymer chains...
CrossoverA short tubular component, also called a crossover sub, used to connect two downhole items having different...
Crossover service toolA gravel-pack and frac-pack service tool that redirects slurry pumped down the work string through crossover...
CrossplotA two-dimensional graph that displays the relationship between two different reservoir properties or log...
Crossplot porosityA graphical technique used to determine porosity and lithology by plotting two different porosity-sensitive...
Cross-sectionalDescribing a view or analysis that cuts through a geological feature or subsurface volume, revealing its...
Crosswell electromagnetic tomographyA geophysical imaging technique that uses electromagnetic waves transmitted between wells to map subsurface...
Crosswell reflection tomographyA seismic imaging method that uses reflected seismic waves traveling between boreholes to create...
Crosswell seismic tomographyA geophysical imaging technique that uses seismic waves transmitted between boreholes to create...
Crosswell tomographyA geophysical imaging technique that uses seismic or electromagnetic waves transmitted between two or more...
Crown blockA stationary assembly of sheaves or pulleys located at the very top of the drilling rig's mast or derrick. It...
Crown valveA valve installed at the top of a Christmas tree or wellhead assembly, positioned above the master valve. It...
Crude oilA naturally occurring, unrefined petroleum product composed of hydrocarbon compounds and other organic...
Crushed zoneThe compacted, fractured layer of rock lining a perforation tunnel, where the shaped-charge jet and its shock...
CrustThe outermost solid layer of the Earth, composed of igneous, metamorphic, and sedimentary rocks, which varies...
Crustal magnetic fieldThe portion of the Earth's magnetic field that originates from magnetized rocks within the Earth's crust...
Crystallization temperatureThe temperature at which salt crystals first form as a completion or workover brine cools; it rises with salt...
CSGCoal Seam Gas, a form of natural gas, primarily methane, adsorbed within coal beds. It is extracted by...
CSSA thermal enhanced oil recovery method that involves injecting steam into a well for a period, allowing it to...
CTAn abbreviation for coiled tubing, a continuous, flexible steel or composite pipe spooled onto a large reel...
Cubic packingA theoretical arrangement of spherical grains in a sedimentary rock where each sphere is directly above and...
Cultural anomalyA feature in geophysical data, such as a magnetic or gravity survey, caused by man-made objects rather than...
Cultural noiseUnwanted signals in geophysical data that originate from human activities or man-made structures. This noise...
Cumulative productionThe total volume of oil, gas, or water produced from a well, field, or reservoir over a specified period...
CuringThe chemical process of hydration and hardening in cement after it has been placed in a wellbore. During this...
CurveA graphical representation of a measured parameter plotted against depth or time, forming the fundamental...
Curve fittingThe process of constructing a mathematical function that best approximates a series of data points. In...
Curve matchingA technique used to compare and align a measured geophysical curve with a theoretical or reference curve. In...
CushionA column of fluid, such as water, brine, or diesel, placed in the drill string before running a drillstem...
Cut and thread fishing techniqueA fishing method for freeing a wireline tool string that has stuck downhole. The cable is clamped and cut at...
Cut oilCrude oil that contains an emulsion of water and sediment in concentrations exceeding the acceptable limits...
Cut pointThe specific particle size at which a solids control device, such as a shale shaker or hydrocyclone...
CuttingsSmall pieces of rock generated by the drill bit as it penetrates the formation, carried to the surface by the...
Cuttings liftingThe process of transporting drilled rock fragments, known as cuttings, from the bottom of the wellbore to the...
CybersecurityThe practice of protecting computer systems, networks, and data from digital attacks, unauthorized access...
Cycle condensateLiquid hydrocarbon recovered at the surface from the wet gas of a gas-condensate reservoir under a gas...
Cycle gasNatural gas that has been processed to remove liquid hydrocarbons and is then reinjected into the reservoir...
Cycle skipAn error in phase picking on a seismic or acoustic log where the picked arrival time jumps by one or more...
Cycle timeThe total time required for a complete circulation of drilling fluid from the surface, down the drill string...
Cyclic steam injectionA thermal enhanced oil recovery technique where steam is injected into a well, allowed to soak in the...
Cycling plantA facility that processes natural gas to extract liquid hydrocarbons, such as natural gas liquids, while...
CyclothemA specific, repeating sequence of sedimentary rock layers that records a single cycle of marine transgression...
CylinderA component of a reciprocating pump or compressor that contains the piston and provides the chamber where...
Cylinder operatorA type of valve actuator that uses a piston or diaphragm within a cylinder to convert fluid pressure...

465 of 4,468 terms in Oil and gas terminology (MLC-0103). Request the full dataset.