Oil and gas terminology · MLC-0103

Oil and gas terms: H (157)

• H2SAn abbreviation for hydrogen sulfide, a highly toxic and corrosive gas often found in oil and gas reservoirs...
• HadeThe angle of inclination of a fault plane measured from the vertical. It is the complement of the dip angle...
• HaematiteA naturally occurring iron oxide mineral (Fe2O3) used as a high-density weighting agent in drilling fluids to...
• HaliteThe mineralogical name for rock salt, composed of sodium chloride (NaCl). It is a common evaporite mineral...
• HallucinationThe generation of factually incorrect, nonsensical, or fabricated information by an AI model, which is...
• Hammer unionA high-pressure, threaded connection used to join two pipes or hoses quickly and securely without the need...
• HangoffTo suspend a string of pipe or tubing from a hanger in the wellhead, transferring its weight from the...
• Hard rockGeological formations characterized by high compressive strength and low porosity, making them difficult to...
• Hard waterWater containing a high concentration of dissolved multivalent cations, primarily calcium and magnesium ions...
• HardbandingThe process of applying a wear-resistant alloy material to the exterior surface of drill pipe tool joints and...
• HardfacingA metallurgical process that applies a wear-resistant material to the surface of a component, extending its...
• HardgroundA lithified seafloor surface that has been exposed to marine currents and biological activity, resulting in...
• Hardness ionA multivalent cation, primarily calcium (Ca2+) or magnesium (Mg2+), present in water that can negatively...
• Harmonic distortionThe introduction of unwanted frequencies that are integer multiples of the fundamental frequency into a...
• HatchAn access opening on a storage tank, vessel, or other equipment, typically fitted with a cover, that allows...
• HBPHeld By Production, a legal status of an oil and gas lease that remains in effect as long as hydrocarbons are...
• HClHydrochloric acid, a strong mineral acid used in oil and gas operations for matrix acidizing and fracture...
• HE starchA modified starch, typically hydroxyethyl starch, used as a filtration control additive in water-based...
• HeadThe height of a column of fluid that corresponds to a given pressure, expressed as a length such as feet or...
• Head waveA seismic wave that travels along an interface between two layers with different velocities, refracting...
• HeaderThe portion of a digital seismic trace record containing ancillary information about the data that follows...
• Header boxA distribution chamber at the inlet of a shale shaker that receives drilling fluid returning from the...
• HeaterA piece of equipment used to raise the temperature of crude oil, natural gas, or other fluids in production...
• Heater treaterA vessel used at a production facility to separate an oil and water emulsion by applying heat to accelerate...
• Heavy metalA metallic element with a high atomic weight and density, such as lead, mercury, cadmium, or zinc, that can...
• Heavy oilCrude oil with high density and viscosity that does not flow easily under normal reservoir conditions. Its...
• Heavy pipeA condition, in snubbing and other live-well work, in which the weight of the string in the hole is greater...
• Heavyweight drillpipeA type of drillpipe with thicker walls and longer tool joints than standard drillpipe, providing increased...
• HECHydroxyethyl cellulose, a non-ionic cellulose derivative used as a viscosifier and fluid loss control agent...
• HectoriteA naturally occurring smectite clay mineral, similar to bentonite, used as a viscosifier and suspending agent...
• Held by productionA legal status of an oil and gas lease that extends its term beyond the primary period as long as...
• HematiteA naturally occurring iron oxide mineral (Fe2O3) used as a high-density weighting agent in drilling fluids to...
• Herschel-Bulkley fluidA non-Newtonian fluid model that exhibits both a yield stress and shear-thinning behavior. It begins to flow...
• HertzThe standard unit of frequency, representing one cycle per second, used to measure the rate of oscillation or...
• Hesitation squeezeA cementing technique used to repair casing leaks or isolate zones by injecting cement into the affected area...
• HeterogeneityThe condition of having spatially variable properties within a rock formation or reservoir, such as...
• HeterogeneousDescribing a material or system that exhibits variations in its properties or composition from one point to...
• Heterogeneous formationA subsurface rock layer whose physical properties, such as permeability, porosity, and mineralogy, change...
• HFAn abbreviation for hydrofluoric acid, a highly corrosive acid used in well stimulation treatments to...
• HGSAn abbreviation for high-gravity solids, the dense weighting materials added to a drilling fluid to raise its...
• HHPAn abbreviation for hydraulic horsepower, the power available from the drilling fluid flow rate and pressure...
• HiatalRelating to a hiatus, which is a break or gap in the geologic record where a rock unit is absent due to a...
• HiatusA break or gap in the geological record, representing a period during which no deposition occurred or during...
• Hierarchical cluster analysisA statistical method that builds a hierarchy of clusters by iteratively merging or splitting groups of data...
• High explosiveA chemical compound that detonates rapidly, producing a powerful shock wave and a large volume of gas, used...
• High performance computing (HPC)The application of aggregated computing power to solve complex scientific and engineering problems far more...
• High pressure squeezeA cementing operation where cement is injected into a formation or perforations at pressures exceeding the...
• High shot density gunA hollow carrier perforating gun built to carry many shaped charges per foot, so a short interval receives a...
• High-gravity solidsDense solid particles added to a drilling fluid to raise its density, chiefly barite (barium sulfate...
• High-pressure air injectionAn enhanced oil recovery method that injects air into a deep, high-pressure reservoir that typically holds...
• High-pressure, high-temperatureDescribing subsurface environments characterized by reservoir pressures exceeding 10,000 psi and temperatures...
• High-pressure, high-temperature filtration testA laboratory procedure to measure the fluid loss and filter cake properties of a drilling fluid under...
• High-pressure, high-temperature viscometerA laboratory instrument designed to measure the rheological properties of drilling fluids, such as viscosity...
• High-pressure manifoldAn assembly of pipes, valves, and gauges designed to control and distribute high-pressure fluids, such as...
• High-side toolfaceThe angle between a directional tool's toolface and the high side of the hole, measured clockwise when...
• High-specific-gravity solidsSolid particles of high density, with a specific gravity far above that of clays and drilled rock (about...
• Highstand systems tractThe set of sedimentary deposits that accumulates during the late stage of a sea-level rise, when the rate of...
• High-temperature completionsCompletion equipment and designs for wells with high downhole temperature, such as steam-injected heavy oil...
• History matchingThe process of adjusting a reservoir simulation model to reproduce past production and pressure data from a...
• HLB numberThe Hydrophilic-Lipophilic Balance number, a value from 0 to 20 that indicates the degree to which a...
• HodogramA plot that displays the particle motion of a seismic wave in two or three dimensions over time. It shows the...
• HoldupThe fraction of the cross-sectional area of a pipe or wellbore occupied by a specific fluid phase, such as...
• Holdup depthThe depth in a wellbore at which a tool or piece of equipment being run into the hole encounters an...
• Holdup imageA visual representation of the distribution of different fluid phases across the wellbore cross-section...
• Holdup logA production logging tool measurement that determines the proportion of each fluid phase (oil, gas, water)...
• Holdup meterA downhole production logging instrument designed to measure the volumetric fraction of each fluid phase...
• Hole cleaningThe process of removing drilled cuttings from the wellbore and transporting them to the surface using the...
• Hollow carrier gunA perforating gun system where shaped charges are loaded inside a reusable steel tube, or carrier, which...
• HomogeneityThe uniformity of physical properties throughout a rock volume, such as a reservoir. A perfectly homogeneous...
• HomogeneousDescribing a rock formation or reservoir with uniform physical properties, such as porosity, permeability...
• Homogeneous formationA rock layer or reservoir where the physical properties, such as porosity, permeability, and mineralogy, are...
• HookA large, heavy-duty lifting device suspended from the traveling block on a drilling rig, used to support the...
• Hook loadThe total weight suspended from the drilling rig's hook, including the drill string, drill collars, and any...
• Hookwall packerA retrievable service packer, with the RTTS design as the common example, that is run on tubing, rotated to...
• HopperA funnel-shaped piece of equipment used to add powdered or granular materials, such as bentonite or barite...
• HorizonA specific stratigraphic level or boundary within a rock sequence that serves as a marker for geological...
• Horizon sliceA 2D map displaying a seismic attribute extracted along a single interpreted horizon within a 3D seismic...
• Horizontal drillingA drilling technique where the wellbore deviates from the vertical and extends horizontally within a...
• Horizontal resistivityThe electrical resistivity of a formation measured parallel to the bedding planes, denoted as Rh. In...
• Horizontal separatorA cylindrical vessel oriented horizontally, used to separate oil, gas, and water from a produced fluid...
• Horizontal severanceThe division of mineral rights at a specific depth or geological formation, allowing different parties to own...
• Horizontal transverse isotropyA form of seismic anisotropy in which the medium has a horizontal axis of symmetry, so properties are the...
• Horizontal treeA tree configuration, mostly used subsea, in which the tubing hanger lands inside the tree body and the...
• Horner slopeThe slope of the straight-line portion of a pressure buildup plot, where bottomhole pressure is plotted...
• HorstAn uplifted block of crustal rock bounded on at least two sides by normal faults, forming a topographic high...
• Hostile environmentA set of well conditions severe enough to damage metal parts, rubber seals, mud chemicals, electronics and...
• Hot limeCalcium oxide (CaO), a highly reactive chemical used in drilling fluids to treat carbon dioxide contamination...
• Hot oilerA specialized service truck equipped with a heater and pump designed to circulate hot oil or other heated...
• Hot oilingA well intervention technique that involves circulating heated crude oil or other hot fluids down the...
• Hot tappingThe process of creating a new connection to an existing pipeline or vessel while it remains in service under...
• Hot waterfloodingAn enhanced oil recovery method where heated water is injected into a reservoir to displace and mobilize...
• Hough transformA feature extraction algorithm used in image analysis to find instances of objects with a certain shape by a...
• HousingThe protective outer casing of a downhole logging tool, designed to shield the internal electronics and...
• HP starchHydroxypropyl starch, a modified natural polymer used as a fluid loss control additive and viscosifier in...
• HPHTA classification for wells whose downhole pressure and temperature exceed normal equipment limits, so they...
• HPHT filtration testA laboratory procedure that measures the filtration characteristics of a drilling fluid under simulated...
• HPUA hydraulic power unit, which is a self-contained system that supplies pressurized fluid to operate hydraulic...
• HSEA framework of policies, procedures, and regulations focused on protecting the workforce, the public, and the...
• HTISeismic anisotropy with a horizontal symmetry axis, as produced by a set of parallel vertical fractures whose...
• Huff and puffA cyclic injection process used in enhanced oil recovery, particularly for heavy oil, where a solvent or...
• Human-in-the-loop (HITL)A system design that integrates human interaction into a machine learning cycle, where people review...
• Humble formulaAn empirical equation that relates formation factor to porosity in clean, water-bearing sandstones. It...
• Humic acidA complex organic compound formed from the decomposition of plant and animal matter, used as a deflocculant...
• HumidityThe amount of water vapor present in the air, expressed as a percentage of the maximum amount the air can...
• Humidity meterAn instrument used to measure the amount of water vapor in the air, also known as a hygrometer. This device...
• HumpingA pressure anomaly in a buildup test in which the recorded pressure rises above the level it will finally...
• HWDPAn abbreviation for heavy-weight drill pipe, a type of tubular with thicker walls than standard drill pipe...
• Hybrid cloudA computing environment that combines a private cloud with one or more public cloud services, allowing data...
• Hybrid scaleA track scale on a log that is partly linear and partly nonlinear, so a single trace can cover both small and...
• HydrateA crystalline solid compound formed when water molecules encapsulate gas molecules, typically methane, under...
• HydrationThe chemical process where water molecules combine with a substance, often leading to the formation of new...
• Hydraulic bypassA mechanism within a downhole tool that allows fluid to flow around a restricted section or through an...
• Hydraulic cementA powdered material that, when mixed with water, forms a slurry that hardens and sets due to chemical...
• Hydraulic centralizerA centralizer fitted to a coiled tubing or wireline tool string that is engaged by raising fluid pressure...
• Hydraulic disconnectA safety device incorporated into a coiled tubing or wireline bottomhole assembly that allows for remote...
• Hydraulic fracture monitoringThe use of geophysical and pressure-based methods to measure the geometry and growth of fractures created...
• Hydraulic fracturingA well stimulation technique that involves injecting high-pressure fluid into a wellbore to create or enlarge...
• Hydraulic headThe total mechanical energy per unit weight of fluid at a given point, representing the sum of elevation...
• Hydraulic horsepowerThe power available from the drilling fluid flow rate and pressure at a specific point in the circulating...
• Hydraulic packerA downhole tool that creates a seal between the tubing and the casing by using hydraulic pressure to expand...
• Hydraulic power packA self-contained unit that generates and supplies hydraulic fluid under pressure to operate hydraulic tools...
• Hydraulic power unitA self-contained system that generates and controls hydraulic power to operate machinery and actuators. It...
• Hydraulic pumpingAn artificial lift method that uses a power fluid, typically crude oil or water, to drive a downhole pump...
• Hydraulic release toolA downhole component that disconnects from a packer or other tool by applying hydraulic pressure from the...
• Hydraulic setDescribing a downhole tool, such as a packer or bridge plug, that is activated and secured in place by...
• HydrocarbonAn organic compound composed solely of hydrogen and carbon atoms, forming the primary constituents of...
• Hydrocarbon indicatorA seismic attribute or combination of attributes that suggests the presence of hydrocarbons in the...
• Hydrocarbon kitchenA geological region where organic-rich source rocks have reached sufficient temperature and pressure...
• Hydrochloric acidA strong mineral acid, HCl, used in oil and gas operations for acidizing treatments to dissolve carbonate...
• HydrocycloneA mechanical device used in drilling fluid solids control systems to separate solid particles from the liquid...
• HydrocycloningA mechanical separation process that uses centrifugal force to remove solids from drilling fluid. The fluid...
• Hydrofluoric acidA highly corrosive acid used in sandstone acidizing treatments to dissolve silicate minerals like clays and...
• Hydrofluoric-hydrochloric acidA mixture of hydrofluoric acid (HF) and hydrochloric acid (HCl) used in matrix acidizing treatments...
• Hydrogen blisteringA form of hydrogen-induced damage in steel, where atomic hydrogen diffuses into the metal and recombines to...
• Hydrogen embrittlementA reduction in the ductility and load-bearing capacity of a metal caused by the absorption of atomic...
• Hydrogen indexA measure of the concentration of hydrogen atoms per unit volume in a formation, relative to the...
• Hydrogen probeA device used to detect and measure the concentration of atomic hydrogen in steel components, particularly in...
• Hydrogen sulfideA highly toxic and corrosive gas, chemical formula H2S, that can be encountered in oil and gas reservoirs. It...
• Hydrogen-induced failuresMaterial failures in steel components resulting from the presence and diffusion of hydrogen atoms within the...
• HydrolysisA chemical reaction in which water reacts with a compound, breaking it down into two or more new compounds...
• HydrometerA device used to measure the density or specific gravity of drilling fluids. It consists of a weighted...
• Hydrophile-lipophile balance numberA dimensionless value on a scale indicating the degree to which a surfactant is water-soluble (hydrophilic)...
• HydrophilicDescribing a substance that has an affinity for water and tends to dissolve in, mix with, or be wetted by...
• HydrophobicDescribing a substance that repels water and tends not to mix with or be wetted by water. In drilling fluids...
• HydrophoneA transducer that converts underwater acoustic pressure waves into electrical signals. In marine seismic...
• Hydrostatic bailerA specialized bailing tool that uses the hydrostatic pressure of the wellbore fluid to create a differential...
• Hydrostatic headThe pressure exerted by a column of fluid at rest, resulting from the force of gravity. It is calculated as...
• Hydrostatic pressureThe pressure exerted by a fluid at rest due to the force of gravity, acting equally in all directions at a...
• HydrothermalRelating to the action of hot water, especially in the formation and alteration of minerals and rocks...
• Hydrothermal alterationThe process where hot, chemically active fluids circulate through rocks, causing changes in their mineralogy...
• Hydroxyethyl starchA modified natural polymer used as a fluid-loss control agent in certain water-based drilling and completion...
• HydroxyethylcelluloseA nonionic, water-soluble polymer used as a viscosifier and fluid-loss additive in drilling, completion, and...
• Hydroxypropyl starchA modified starch polymer used as a viscosifier and fluid loss control agent in water-based drilling fluids...
• HygrometerAn instrument used to measure the humidity or moisture content of the air or other gases. In drilling...
• HygroscopicDescribing a substance that readily attracts and holds water molecules from the surrounding atmosphere...
• HyperparametersConfiguration variables that are external to a machine learning model and whose values cannot be estimated...
• HyperscalerA provider of cloud computing services with massive infrastructure and the ability to scale resources on...

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