Oil and gas terminology · MLC-0103

Oil and gas terms: A (255)

• AThe tortuosity or lithology factor in Archie's equation, which relates formation resistivity to porosity and...
• Abandonment costsThe expenses incurred to permanently decommission an oil or gas well or facility at the end of its productive...
• Abnormal pressureSubsurface formation fluid pressure that deviates significantly from the normal hydrostatic pressure...
• Abrasion testA laboratory test that rates how abrasive a drilling fluid weighting material, such as barite or hematite, is...
• Abrasive jettingA well intervention technique that uses a high-velocity stream of fluid mixed with abrasive particles to cut...
• Absolute ageThe numerical age of a rock, fossil, or geological event, expressed in years. This age is determined using...
• Absolute filterA filter designed to remove all particles larger than a specified micron rating, providing a high degree of...
• Absolute open flow potentialThe maximum theoretical rate at which a gas well could produce if the bottomhole flowing pressure were...
• Absolute permeabilityA measure of the ability of a porous medium to transmit a single fluid when the medium is 100% saturated with...
• Absolute pressureThe total pressure exerted on a surface, measured relative to a perfect vacuum (zero pressure). It is...
• Absolute volumeThe actual volume occupied by the solid particles of a substance, excluding any void spaces or pores. It is...
• Absorbing boundary conditionsA set of mathematical constraints applied at the edges of a computational grid during numerical modeling of...
• AbsorptanceThe fraction of incident electromagnetic radiation or acoustic energy that is absorbed by a material or...
• AbsorptionThe process by which the energy of a propagating wave, such as a seismic wave, is diminished as it passes...
• Absorption bandA range of frequencies within the electromagnetic spectrum where a substance absorbs radiation more strongly...
• Absorption oilA lean liquid hydrocarbon used in an absorption process to remove heavier hydrocarbon components from a...
• AbyssThe deepest parts of the ocean floor, typically found at depths greater than 3,000 meters (10,000 feet)...
• AbyssalRelating to the deep ocean environment at depths between 3,000 and 6,000 meters (approximately 10,000 to...
• AcceleratorA cement additive that shortens the thickening and setting time of a slurry so it develops strength sooner...
• Accelerator sourceA device used in pulsed neutron logging tools that generates high-energy neutrons by accelerating charged...
• AccelerometerA sensor that measures acceleration, which is the rate of change of velocity, typically in units of meters...
• AccommodationThe space available for sediment to accumulate, governed by the combined effects of sea-level change and...
• AccretionThe buildup of sticky, partly hydrated cuttings and clay on the bit, drill collars, stabilizers, and other...
• AccumulationA body of hydrocarbons, either oil or natural gas, trapped in a reservoir rock beneath the Earth's surface...
• AccumulatorA device that stores hydraulic energy under pressure, used in drilling and production operations to provide a...
• AccuracyThe degree to which a measured value from a logging tool or laboratory test conforms to the true value of the...
• Acetic acidA weak organic acid used in well stimulation treatments, particularly in carbonate reservoirs, to dissolve...
• AcidA chemical solution, typically hydrochloric acid or hydrofluoric acid, used in drilling and completion...
• Acid effectThe influence of acidic drilling fluids or formation fluids on the response of certain logging tools...
• Acid fracA stimulation treatment that combines hydraulic fracturing with acidizing to enhance hydrocarbon production...
• Acid gasA mixture of hydrogen sulfide (H₂S) and carbon dioxide (CO₂) removed from a sour natural gas or refinery gas...
• Acid inhibitorA chemical additive used in acidizing treatments to reduce the corrosive attack of the acid on downhole...
• Acid jobA well stimulation treatment involving the injection of acid into a reservoir to dissolve rock and enlarge...
• Acid numberA measure of the amount of potassium hydroxide, expressed in milligrams, required to neutralize the acidic...
• Acid stimulationA well treatment technique involving the injection of acid into a reservoir to dissolve formation minerals...
• Acid tankA specialized storage vessel designed to safely hold and transport corrosive acid solutions used in well...
• Acid washA well intervention technique involving the injection of a relatively small volume of acid into the wellbore...
• AcidityThe measure of hydrogen ion concentration in a drilling fluid, indicating its position on the pH scale. High...
• AcidizeTo treat a wellbore or reservoir formation with acid to dissolve soluble materials, enlarge pore spaces, and...
• AcidizingA well stimulation technique that involves injecting an acid solution into a reservoir to dissolve soluble...
• AcousticRelating to sound waves and their propagation through a medium, particularly in the context of seismic and...
• Acoustic couplerA device that converts electrical signals into sound waves and vice versa, allowing data transmission over a...
• Acoustic emissionThe generation of transient elastic waves produced by a sudden release of energy within a material undergoing...
• Acoustic impedanceA physical property of a material that describes its resistance to the propagation of sound waves. It is...
• Acoustic impedance sectionA seismic display derived from seismic reflection data, showing variations in acoustic impedance within the...
• Acoustic logA well log that measures the travel time of an acoustic wave through the formation adjacent to the borehole...
• Acoustic modeA specific pattern of elastic wave propagation within a medium, characterized by its frequency, wavelength...
• Acoustic positioningA method of determining the precise location of underwater objects or vessels using sound waves. Transponders...
• Acoustic transducerA device that converts electrical energy into acoustic energy, and vice versa, used in acoustic logging...
• Acoustic transparencyThe property of a material or medium that allows acoustic waves to pass through it with minimal attenuation...
• Acoustic traveltimeThe time required for a sound wave to travel a specific distance through a medium, also known as transit...
• Acoustic velocityThe speed at which an acoustic wave propagates through a medium, determined by the medium's elastic...
• Acoustic velocity logA well log that measures the travel time of a sound wave through the formation adjacent to the borehole...
• Acoustic waveA propagation of energy through a medium as a mechanical vibration, which can be detected by sensors. These...
• AcquisitionThe process of recording geophysical data in the field, particularly for a seismic survey. This operation...
• Acquisition logA set of wireline or logging-while-drilling measurements recorded during the first pass through a newly...
• Acrylamide acrylate polymerA copolymer of acrylamide and acrylate, usually sold as partially hydrolyzed polyacrylamide (PHPA), added to...
• Acrylamide polymerA synthetic, water-soluble polymer used as a drilling fluid additive to control viscosity and reduce fluid...
• Acrylamido-methyl-propane sulfonate polymerA synthetic copolymer used as a high-temperature fluid loss control agent and rheology modifier in...
• Acrylate polymerA synthetic polymer used as a deflocculant or thinner in water-based drilling fluids, particularly in...
• Activation logA well logging technique that measures the induced radioactivity in formation minerals after neutron...
• Active marginA continental margin that coincides with a tectonic plate boundary, characterized by frequent earthquakes and...
• Active sulfideSoluble sulfide ions present in a drilling fluid, originating from formation influxes of hydrogen sulfide...
• Activity of aqueous solutionsA thermodynamic measure of the effective concentration of water in an aqueous drilling fluid, influencing the...
• Acyclic compoundAn organic chemical compound characterized by an open-chain molecular structure, meaning its carbon atoms are...
• Adapter spoolA short, flanged pipe section used to connect two pieces of equipment with different flange sizes, pressure...
• AdditivityA property where the total value of a characteristic for a composite system is the sum of the values for its...
• Adhesion tensionThe difference between the interfacial tension of a solid-liquid system and the interfacial tension of a...
• Adjacent bedA rock layer situated above or below the zone of interest in a wellbore. These beds can influence log...
• Adjustable chokeA device with a variable orifice that controls the flow rate and pressure of fluids in a wellbore or...
• Adjusted flow timeAn equivalent flow duration, used in pressure buildup analysis, calculated as the volume produced since the...
• Adsorbed gasNatural gas, primarily methane, that is held on the internal surfaces of organic matter and clay minerals...
• AdsorptionA surface phenomenon where molecules of a gas or liquid adhere to the surface of a solid adsorbent material...
• Advective transport modelingA simulation technique that calculates the movement of fluids or dissolved substances through a porous medium...
• Adversarial attackA malicious input designed to deceive a machine learning model, causing it to misclassify data or make...
• AeolianRelating to geological processes driven by wind, including the erosion, transport, and deposition of...
• AeolotropyThe property of a rock exhibiting different values for a physical property when measured in different...
• Aerated layerA near-surface layer of unconsolidated soil, sand, or weathered rock containing air in its pore spaces...
• AerobicRelating to an environment, organism, or process that requires the presence of free oxygen. In drilling...
• Aeromagnetic surveyA geophysical survey conducted from an aircraft to measure variations in the Earth's magnetic field. A...
• AfterflowThe continued flow of fluids into the wellbore from the reservoir after the wellhead valves have been closed...
• AGCA processing function, Automatic Gain Control, that adjusts the amplitude of seismic traces to compensate for...
• AGC time constantThe parameter that defines the time window or averaging period over which the Automatic Gain Control (AGC)...
• Agentic aiArtificial intelligence systems designed to act autonomously, making decisions and executing tasks to achieve...
• Agent-to-agent (a2a)A type of interaction where two or more autonomous software agents communicate and exchange information...
• AgglomerationThe process where small particles in a drilling fluid clump together to form larger masses. This can occur...
• AggradationThe process of building up land surface elevation through the deposition of sediment. This occurs when the...
• AggradationalDescribing a sedimentary process where the rate of sediment accumulation is greater than the rate of...
• AggregateA group or cluster of particles in a fluid, most often clay platelets stacked face to face in a water-based...
• AggregationThe clustering of clay platelets into compact face-to-face stacks in a water-based mud, driven by divalent...
• Ai acceleratorSpecialized hardware designed to speed up the processing of artificial intelligence workloads, particularly...
• Ai agentAn autonomous software entity that uses sensors or data inputs to perceive its environment and acts upon that...
• Ai ethicsA field of study concerned with the moral principles and values that should guide the design, development...
• Air drillA drilling method that uses compressed air or another gas as the circulating medium to remove cuttings from...
• Air drillingA drilling method that uses compressed air or other gases as the circulating medium instead of drilling mud...
• Air gunA seismic energy source used in marine geophysical surveys that generates a powerful acoustic pulse by...
• Air shootingA land seismic acquisition technique where the energy source is discharged in the air just above the Earth's...
• Air waveA seismic wave that travels through the air from the source to the receiver, rather than through the ground...
• Air-cut mudDrilling fluid that has become contaminated with entrained air or gas, reducing its density and hydrostatic...
• Alford rotationA technique applied to multi-component seismic data, particularly shear-wave data, to determine the fast and...
• AlgorithmA finite set of well-defined, unambiguous instructions or rules for solving a problem or performing a...
• Algorithmic biasSystematic and repeatable errors in a computer system that create unfair outcomes, such as favoring one group...
• Alias filterAn electronic filter applied to a seismic signal before it is digitized to remove frequencies higher than the...
• AliasingThe misrepresentation of a high-frequency signal as a lower-frequency signal when the sampling rate is...
• AlidadeA sighting device used in conjunction with a plane table for topographic mapping and geological surveying. It...
• Aliphatic compoundAn organic compound whose carbon skeleton is not aromatic, either an open chain, straight or branched, or a...
• AlkalineDescribing a substance, particularly a drilling fluid, with a pH value greater than 7.0, indicating a basic...
• Alkaline floodingAn enhanced oil recovery method that involves injecting an alkaline solution, such as sodium hydroxide...
• Alkaline-surfactant-polymer floodingAn enhanced oil recovery (EOR) method that injects a solution containing alkali, surfactant, and polymer into...
• AlkalinityA measure of the capacity of a drilling fluid to neutralize acids, expressed as the concentration of hydroxyl...
• Alkalinity testA standard chemical titration procedure performed on drilling fluid filtrate to quantify its alkaline...
• AllochthonA large mass of rock that has been transported from its original place of formation, often over a...
• AllochthonousDescribing rock masses, sediments, or organisms that originated in a location other than where they are...
• AllogenicDescribing constituents within a rock that originated from outside the depositional basin and were...
• AlluvialDescribing sediments or landforms created by flowing water, such as rivers and streams. Alluvial deposits...
• AlluviumUnconsolidated sediment deposited by flowing water, including rivers, streams, and floods. It comprises a...
• All-welded constructionA method of fabricating equipment, such as pipeline ball valves or pressure vessels, where the body...
• Alpha processingA signal processing technique applied to array induction logging data to correct for environmental effects...
• Altered zoneA region of rock around a wellbore where the original petrophysical properties have been changed by drilling...
• AlumA group of hydrated double sulfates of aluminum, such as aluminum potassium sulfate, used as a flocculant or...
• Aluminum activation logA nuclear logging tool that measures the concentration of aluminum in a formation by bombarding it with...
• Ambient temperatureThe temperature of the surrounding environment at a given location, which influences the performance and...
• AmidesOrganic compounds derived from ammonia or amines, where a carbonyl group is attached to a nitrogen atom. In...
• AminesOrganic compounds derived from ammonia by replacing one or more hydrogens with carbon groups, used in...
• AmplitudeThe maximum displacement or distance moved by a point on a vibrating body or wave measured from its...
• Amplitude anomalyAn unusually strong or weak seismic reflection amplitude that deviates from the expected background response...
• Amplitude distortionThe alteration of the amplitude of a seismic signal as it passes through the earth or a recording system...
• Amplitude variation with offsetThe change in the amplitude of a seismic reflection as a function of the distance between the seismic source...
• Amplitude variation with offset and azimuthThe change in seismic reflection amplitude as a function of both the source-receiver offset and the azimuth...
• AMPSA copolymer built from the sulfonated monomer 2-acrylamido-2-methylpropane sulfonic acid, usually with...
• AnaerobicDescribing an environment or process that occurs in the absence of free oxygen. In geology, anaerobic...
• AnalogA geological formation or reservoir that shares similar characteristics, such as depositional environment...
• Angle of approachThe angle at which a seismic ray path arrives at a detector or an interface, measured with respect to the...
• Angle of incidenceThe angle between an incoming seismic ray and the normal to the reflecting or refracting interface. According...
• Angle valveA type of globe valve where the inlet and outlet ports are oriented at a 90-degree angle to each other. This...
• Angular dispersionThe variation in the direction of wave propagation as it travels through a medium. This phenomenon occurs...
• Angular unconformityA type of unconformity where younger sedimentary layers are deposited on top of older, tilted or folded...
• AnhydriteA common evaporite mineral composed of anhydrous calcium sulfate (CaSO4). It forms when gypsum loses its...
• Aniline point testA laboratory procedure to determine the aniline point of a drilling fluid, which is the minimum temperature...
• AnionAn atom or molecule that has gained one or more electrons, resulting in a net negative electrical charge. In...
• AnionicDescribing a chemical compound that carries a net negative electrical charge when dissolved in a solution...
• AnisotropicDescribing a material whose physical properties, such as seismic velocity, vary with the direction of...
• Anisotropic formationA subsurface rock layer in which a physical property, such as permeability or elastic modulus, has a...
• AnisotropyThe property of a material, such as a rock formation, having different values for a physical property when...
• AnnubarA type of differential pressure flow sensor used to measure the flow rate of gases, liquids, and steam in...
• Annular BOPA large valve within the blowout preventer (BOP) stack designed to seal the annular space between the drill...
• Annular flowA flow regime in multiphase pipelines where a liquid film coats the inner wall of the pipe, and gas flows as...
• Annular gas flowThe uncontrolled movement of gas up the annular space between casing strings or between the casing and the...
• Annular pressureThe fluid pressure within any of the annular spaces in a well, such as the space between the production...
• Annular productionThe flow of hydrocarbons or other fluids to the surface through the annular space between the production...
• Annular spaceThe space between two concentric pipes or between a pipe and the wall of a wellbore. This void is often...
• Annular velocityThe speed at which drilling fluid moves through the annulus, the space between the drill string and the...
• AnnuliThe plural form of annulus, referring to multiple annular spaces within a wellbore. These spaces exist...
• AnnulusThe space between two concentric objects, such as between a pipe and the wellbore wall or between two strings...
• AnodeThe electrode of an electrochemical cell at which oxidation occurs and metal is lost, so corrosion on a drill...
• AnomalousDescribing a deviation from the expected or normal geological pattern or measurement. An anomaly in...
• AnomalyA deviation from the expected or average value of a geological or geophysical parameter, which may indicate a...
• AnoxicDescribing an environment completely devoid of dissolved oxygen, often found in deep water bodies or...
• Antialias filterA low-pass filter applied to analog signals before digital conversion to prevent aliasing, which is the...
• AnticlinalRelating to an anticline, which is an upward-arching fold in rock layers where the oldest strata are in the...
• Anticlinal trapA geological structure where hydrocarbons accumulate in the crest of an anticline, which is an upward-arching...
• AnticlineAn upward-arching fold in rock strata, resembling an arch or dome, where the oldest rocks are found in the...
• AntifoamA chemical additive used in drilling fluids to prevent or break down foam formation, which can interfere with...
• Antifoam agentA chemical substance added to drilling fluids to suppress the formation of foam or to destabilize existing...
• AntisqueezeA drilling fluid additive designed to prevent or mitigate the swelling of clay minerals in shales, which can...
• Antithetic faultA normal fault that dips in the opposite direction to the main fault or regional dip, forming a graben or...
• Antiwhirl bitA type of drill bit designed with an asymmetric cutting structure to prevent bit whirl, an undesirable...
• AOFThe maximum theoretical rate at which a gas well could produce if the bottomhole flowing pressure were...
• AOFPThe maximum theoretical rate at which a gas well could produce if the bottomhole flowing pressure were...
• ApertureThe spatial extent or area over which seismic data are collected or processed to form an image. In seismic...
• APIThe American Petroleum Institute, a national trade association representing all segments of the oil and...
• API cementCement formulations that conform to the specifications and testing standards established by the American...
• API fluid-loss testA standardized laboratory procedure to measure the filtration rate of a drilling fluid under specific...
• API gravityA measure of the density of petroleum liquids relative to water, expressed in degrees on the American...
• API Recommended Practice 10B: Recommended Practice for Testing Well CementsA standard from the American Petroleum Institute (API) that provides procedures for testing well cements and...
• API Spec 6D: Specification for Pipeline ValvesAn American Petroleum Institute standard that defines the design, manufacturing, testing, and documentation...
• API unitA unit of the American Petroleum Institute for gamma ray and neutron logs, defined by calibration in the API...
• API waterThe amount of mixing water that API Specification 10A prescribes for each class of cement when it is tested...
• Apparent anisotropyThe observed directional dependence of seismic wave velocity that does not necessarily reflect the true...
• Apparent dipThe angle that a geological surface, such as a bedding plane or fault, makes with a horizontal plane when...
• Apparent matrixThe properties of a rock matrix as inferred from well log measurements, which can differ from the properties...
• Apparent velocityThe velocity at which a seismic wave appears to travel along a surface or interface, as measured by...
• Apparent viscosityA measure of a drilling fluid's resistance to flow under specific shear rate conditions, calculated by...
• Apparent wavelengthThe observed wavelength of a seismic wave as it propagates along a surface or through a medium, which may...
• Application programming interface (API)A set of rules, protocols, and tools that specifies how different software components should interact, acting...
• Applied-potential methodA geophysical technique used to map subsurface resistivity variations by injecting an electric current into...
• AppraisalThe process of evaluating the size, characteristics, and commercial viability of a discovered oil or gas...
• AquiferA subsurface layer of permeable rock, such as sandstone or fractured limestone, or unconsolidated materials...
• Archie equationA fundamental empirical relationship that links the electrical resistivity of a clean, water-saturated...
• Archie rockA reservoir rock that exhibits electrical properties consistent with the assumptions of the Archie equation...
• Area open to flowThe total cross-sectional area of all perforation tunnels connecting a wellbore to a reservoir formation...
• Areal displacement efficiencyThe effectiveness of a fluid injection process in displacing oil from a reservoir rock within a specific...
• Areal sweep efficiencyThe fraction of the reservoir area contacted by an injected fluid during a displacement process, such as...
• ArenaceousDescribing a sedimentary rock, sediment, or mineral deposit that is sand-sized or composed primarily of sand...
• ArgillaceousDescribing a rock or sediment that is composed predominantly of clay-sized particles, which are smaller than...
• Arithmetic meanA statistical measure of central tendency calculated by summing a set of values and dividing by the number of...
• ArmorThe protective outer sheath of a wireline logging cable, consisting of two or more layers of high-strength...
• Aromatic content testA laboratory procedure to determine the concentration of aromatic hydrocarbons, such as benzene and toluene...
• Aromatic hydrocarbonAn organic compound containing one or more benzene rings, characterized by a stable cyclic structure with...
• ArrayA group of seismic sources or receivers arranged in a specific geometric pattern to record or generate...
• Array inductionA type of induction logging tool that employs multiple transmitter-receiver coil spacings to measure...
• Array laterologA resistivity logging tool that employs multiple current electrodes and guard electrodes to focus the...
• Array propagation resistivityA measurement technique that uses multiple transmitter-receiver antennas to determine formation resistivity...
• Array sonicA well logging tool equipped with multiple acoustic transmitters and receivers to measure the travel time of...
• ArrivalThe detection of a seismic wave at a receiver, marking the onset of a distinct seismic event. This can be a...
• Arrival timeThe elapsed time for a seismic wave to travel from its source to a specific geophone or hydrophone in a...
• Artificial general intelligence (AGI)A theoretical form of artificial intelligence that can understand, learn, and apply intelligence to any...
• Artificial intelligenceThe application of computational algorithms and machine learning techniques to analyze vast quantities of...
• Artificial liftAny method used to increase the flow of hydrocarbons from a well when natural reservoir pressure is...
• Artificial superintelligence (ASI)A hypothetical intelligence that is significantly more intelligent than the best human brains in virtually...
• As-delivered BTUThe heat content of a fuel, measured in British Thermal Units (BTU), at the point of delivery to a consumer...
• ASMEAn abbreviation for the American Society of Mechanical Engineers, an organization that develops codes and...
• ASP floodingA chemical enhanced oil recovery method involving the sequential or simultaneous injection of an alkali, a...
• AsphaltA black, sticky, highly viscous form of petroleum, also known as bitumen, composed primarily of heavy...
• Asphaltene onset concentrationThe specific concentration of a precipitating agent, or a specific pressure and temperature condition, at...
• Asphaltene onset pressureThe pressure at which asphaltenes begin to precipitate from crude oil as reservoir pressure declines or gas...
• Asphaltene precipitationThe process by which asphaltene molecules, which are heavy, polar components of crude oil, aggregate and...
• AsphaltenesHeavy, polar molecular components of crude oil that are soluble in aromatic solvents but insoluble in...
• Asphaltic crudeA type of crude oil containing a high concentration of asphaltenes, which are large, complex hydrocarbon...
• Asphaltic mud additiveA finely ground asphalt material added to drilling fluids, primarily oil-based muds, to improve filtration...
• AssignmentA legal document that transfers ownership of an oil and gas lease, a working interest, or a royalty interest...
• AsthenosphereThe ductile, semi-fluid layer of the Earth's upper mantle, located beneath the lithosphere, extending from...
• ASTMAn international standards organization, originally the American Society for Testing and Materials, that...
• Atmospheric corrosionThe degradation of exposed metal such as wellheads, Christmas trees and surface piping through reaction with...
• AttapulgiteA type of clay mineral, also known as palygorskite, used as a viscosifier in saltwater drilling fluids where...
• AttenuateTo reduce the amplitude or intensity of a seismic wave as it propagates through the Earth. This reduction...
• AttenuationThe reduction in amplitude and energy of a seismic wave as it travels through the subsurface. This phenomenon...
• Attenuation resistivityA formation resistivity measurement derived from the attenuation, or reduction in amplitude, of an...
• AttitudeThe orientation of a planar geological feature, such as a bedding plane, fault, or joint, in...
• AttributeA quantitative measurement derived from seismic data that highlights specific characteristics of the...
• Audio measurementThe technique of using acoustic sensors to detect and analyze sounds generated by fluid flow within a...
• AulacogenA failed rift arm that extends inland from a triple junction, where continental rifting has occurred. These...
• AuthigenicDescribing minerals or other constituents that formed in place within a sedimentary rock or sediment after...
• Authority for expenditureA detailed estimate of the costs associated with a proposed oil and gas operation, such as drilling a well...
• Authorization for expenditure (AFE)A formal document outlining the estimated costs for a specific oil and gas project, such as drilling...
• AutochthonA mass of rock that remains in its original place of formation relative to the underlying basement, even if...
• AutocorrelationA mathematical operation that compares a signal with a time-shifted version of itself, revealing repeating...
• Automatic gain controlA processing step that automatically adjusts the amplitude of seismic traces to balance weak and strong...
• AutotrackTo automatically follow and pick a seismic horizon or feature across a seismic volume using computer...
• AutotrackingThe automated process of identifying and following a seismic horizon or geological feature throughout a...
• AVAn abbreviation for apparent viscosity, a rheological property of drilling fluids. It represents the...
• AVAAn abbreviation for Amplitude Variation with Angle, which describes the change in the amplitude of a seismic...
• AVAZAn abbreviation for Amplitude Variation with Azimuth, which describes the change in seismic reflection...
• Average reservoir pressureThe representative pressure of the reservoir at a given time, reflecting the overall energy state of the...
• Average velocityThe total distance traveled by a seismic wave divided by its total traveltime from the source to a reflector...
• AVOAn abbreviation for Amplitude Variation with Offset, which describes the change in the amplitude of a seismic...
• AVOAZAn abbreviation for Amplitude Variation with Offset and Azimuth, which describes the change in seismic...
• Axial loadingThe force applied along the longitudinal axis of a tubular component, such as casing or tubing, either in...
• Axial surfaceAn imaginary plane that connects the hinge lines of successive folded layers within a single fold. It divides...
• Axis of rotational symmetryA line about which a three-dimensional object or a two-dimensional shape can be rotated by some angle, less...
• AzimuthThe horizontal angle measured clockwise from a true north reference line to a specific direction or line. In...
• AzimuthalDescribing a measurement or property that varies with direction around the circumference of the wellbore...
• Azimuthal densityA formation density measurement that is recorded in sectors around the circumference of the borehole, rather...
• Azimuthal laterologA resistivity logging tool that measures the electrical resistance of rock formations in different directions...
• Azimuthal resolutionThe ability of a logging tool to distinguish between features or properties that vary around the...

255 of 4,469 terms in Oil and gas terminology (MLC-0103). Request the full dataset.