Oil and Gas Terms Beginning with “A” — Page 2

The absolute open flow potential (AOFP) is the maximum theoretical flow rate a gas well could produce if the flowing wellhead pressure were reduced to atmospheric pressure (zero gauge pressure), with no mechanical… Read more →

Absolute permeability is the permeability of a rock measured when it is completely saturated with a single, non-reactive fluid, usually brine or gas. It characterizes the rock's intrinsic ability to transmit fluid,… Read more →

Absolute pressure is the total pressure at a point in a fluid system, measured relative to a perfect vacuum (zero pressure). Absolute pressure equals gauge pressure plus local atmospheric pressure: P_abs = P_gauge +… Read more →

Absolute volume is the volume that a unit mass of a solid material occupies or displaces when added to a liquid, expressed as the ratio of a solid's volume to its mass. In the drilling fluids industry, absolute volume… Read more →

Absorbing boundary conditions (ABCs) are mathematical treatments applied at the edges of a finite computational domain in seismic wave simulation, designed to prevent artificial reflections from the boundaries of the… Read more →

Absorptance is the dimensionless ratio of the amount of electromagnetic radiation absorbed by a substance to the total amount of radiation incident upon it at a given wavelength or wavelength range. Absorptance ranges… Read more →

In petroleum engineering and natural gas processing, absorption refers to two related but distinct phenomena. In gas processing, absorption is the mass transfer process in which a component dissolved in a gas phase is… Read more →

An absorption band is a range of electromagnetic wavelengths (or frequencies) at which a specific substance absorbs radiation more strongly than at neighboring wavelengths, producing a dip in the transmitted or… Read more →

Absorption oil is a light liquid hydrocarbon, typically a naphtha or kerosene fraction with a boiling range of approximately 120 to 220°C, used in natural gas processing plants to absorb propane, butane, and heavier… Read more →

Abyssal refers to the depositional environment and associated sediments of the deepest parts of the ocean basins, generally at water depths greater than 2,000 metres and commonly below 4,000 metres. The abyssal… Read more →

In drilling operations, an accelerator is a downhole tool placed in the drill string above a jar tool to store additional mechanical energy that is released instantaneously when the jar fires, multiplying the impact… Read more →

An accelerometer is a sensor that measures linear acceleration along one or more defined axes. In petroleum drilling, accelerometers are the primary sensors inside measurement-while-drilling (MWD) survey tools, where… Read more →

Accommodation is a sequence stratigraphy term for the amount of space available for sediment to accumulate at or below base level. Base level is the surface to which erosion tends and below which deposition can occur;… Read more →

In drilling engineering, accretion is the build-up of partially hydrated drill cuttings on the surface of the bit, drill collars, stabilizers, or other bottomhole assembly (BHA) components. Reactive shale cuttings that… Read more →

A petroleum accumulation is a naturally occurring concentration of oil, gas, or both that has migrated from a source rock, moved through permeable rock, and become trapped in a subsurface location where it cannot escape… Read more →

In drilling and well control, an accumulator is a hydraulic pressure vessel that stores energy in the form of pre-charged nitrogen gas compressed by hydraulic fluid, providing the rapid closing force needed to shut in a… Read more →

Accuracy is the closeness of a measured value to the true or accepted reference value of the quantity being measured. In petroleum engineering, accuracy is a fundamental property of every measurement system, from the… Read more →

Acetic acid (CH₃COOH) is a weak organic acid used in oilfield operations primarily as a retarded acidizing agent, a scale dissolving chemical, and a pre-flush or post-flush fluid in acid stimulation programs. In its… Read more →

In petroleum engineering, acid refers to the class of reactive chemical solutions used to dissolve mineral damage, enhance connectivity between the wellbore and the reservoir, and stimulate production by creating new… Read more →

The acid effect is the change in a pulsed neutron capture log measurement that occurs when an acid treatment dissolves carbonate minerals in the near-wellbore region, creating new porosity and altering the hydrogen… Read more →

An acid frac, short for acid fracturing, is a hydraulic fracturing treatment performed in carbonate formations (limestones and dolomites) where acid is pumped into a hydraulic fracture to etch the fracture faces… Read more →

Acid gas refers to gas components that dissolve in water to form acidic solutions, principally hydrogen sulfide (H₂S) and carbon dioxide (CO₂). In the oil and gas industry, the term is used in two related contexts: to… Read more →

An acid inhibitor is a chemical additive included in oilfield acid treatment fluids to reduce the rate at which the acid corrodes steel tubulars, completion equipment, and downhole tools. Without an inhibitor,… Read more →

The acid number, formally the total acid number (TAN), is a standardized measurement of the concentration of acidic components in a crude oil or petroleum product, expressed in milligrams of potassium hydroxide (KOH)… Read more →

An acid tank is a rubber-lined or fiber-reinforced plastic (FRP) vessel used to transport concentrated acid (most commonly hydrochloric acid at 28 to 36% concentration) to wellsite locations for oilfield stimulation… Read more →

An acid wash is a wellbore treatment that pumps dilute acid into the perforations, perforation tunnels, or casing interior to dissolve mineral scale, carbonate cement, rust, and other deposits that restrict flow and… Read more →

Acidizing is the oilfield operation of pumping acid into a well to remove formation damage, dissolve minerals that restrict flow, or create new flow channels that improve the connection between the wellbore and the… Read more →

In geophysics and well logging, acoustic refers to the propagation of compressional waves (P-waves) through rock, fluid, or materials, and to the measurement tools and techniques that use these wave properties to… Read more →

Acoustic basement is the level in the Earth below which seismic reflection data cannot effectively image the rock, either because the underlying material lacks reflectivity (has no impedance contrasts between layers),… Read more →

In oilfield drilling and telemetry, an acoustic coupler is a device that converts between electrical or digital signals and acoustic (sound) waves transmitted through a physical medium, particularly through the steel… Read more →