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

A description of the contents of a digital record. Read more →

Vertical displacement efficiency (EI) in a reservoir displacement process is the ratio of the cumulative vertical height of the pay zone that has been contacted by the injection fluid to the total vertical pay zone… Read more →

Vertical lift is the true vertical distance between any two points in a wellbore, regardless of how far apart they are when measured along the actual path of the hole. In a straight vertical well, vertical lift equals… Read more →

Vertical resistivity (Rv) is the resistivity of a formation measured by current flowing in a vertical plane (parallel to the vertical axis, perpendicular to the bedding planes in horizontally bedded formations) —… Read more →

What Is Vertical Resolution in Well Logging? Vertical resolution is the minimum bed thickness that a logging tool can detect and characterise as a distinct layer parallel to the tool axis. A tool with a vertical… Read more →

Vertical response in well logging describes the spatial resolution capability of a measurement tool, defined as the minimum bed thickness that can be accurately resolved and the vertical extent over which the tool's… Read more →

What Is a Vertical Seismic Profile? A vertical seismic profile (VSP) is a borehole seismic acquisition technique that deploys downhole geophone arrays inside a wellbore to record seismic energy generated by a surface… Read more →

A vertical separator is a pressure vessel mounted with its cylindrical axis perpendicular to the ground, used to split a raw production stream into its constituent phases of oil, gas and water before the products move… Read more →

A method to convey or reserve oil, gas, or mineral rights in a defined portion of land such as the Northwest Quarter of a tract. Read more →

A supertanker with a capacity between 100,000 and 500,000 deadweight tons. The term is commonly abbreviated as VLCC. Read more →

Bubble-shaped cavities in volcanicrock formed by expansion of gas dissolved in the precursor magma. Read more →

A type of porosity resulting from the presence of vesicles, or gas bubbles, in igneous rock. Read more →

A vibrator is an adjustable mechanical seismic source that delivers controlled vibratory energy into the ground to acquire reflection seismic data , and it is the dominant land source across the Western Canadian… Read more →

What Is Vibratory Seismic Data? Vibratory seismic data is land seismic reflection data acquired using Vibroseis trucks as the energy source, where hydraulic vibrators sweep a controlled frequency range (typically 8 to… Read more →

VAMA (vinyl acetate-maleic anhydride copolymer) is a synthetic organic polymer used as a filtration control additive and viscosifier in water-based drilling fluids, formed by the free-radical copolymerization of vinyl… Read more →

A vinyl polymer in drilling fluid chemistry is a synthetic polymer formed by chain-growth polymerization of vinyl monomers — molecules containing the vinyl group (CH2=CH-) — with polyvinyl alcohol (PVA), polyvinyl… Read more →

The original, undisturbed pressure of a reservoir prior to fluid production. Read more →

(noun) An abbreviation for viscosity, the measure of a fluid's internal resistance to flow under an applied shear stress. In drilling and production operations, viscosity is a critical property of drilling fluids,… Read more →

Viscosity is the fundamental physical property of a fluid that quantifies its internal resistance to flow — defined as the ratio of shear stress (the force per unit area applied tangentially to a fluid layer) to shear… Read more →

Viscous force is the resistance to flow exhibited by a fluid as it deforms under shear or extensional stress — proportional to the rate at which the fluid velocity is changing in space (the velocity gradient or strain… Read more →

(noun) Crude oil with high viscosity and low API gravity that resists flow under normal reservoir or surface conditions, typically requiring thermal stimulation, diluent blending, or specialised artificial lift to… Read more →

Vitrinite is a maceral group — a microscopically distinct organic constituent of coal and fine-grained sedimentary rocks derived from the woody tissues of land plants (cellulose, lignin, and humic substances from plant… Read more →

Vitrinite reflectance (Ro%) is a thermal maturity indicator measured as the mean percentage of incident white light reflected from vitrinite maceral particles in a polished rock sample immersed in oil under… Read more →

A surface feature of the Earth that allows magma, ash and gas to erupt. The vent can be a fissure or a conical structure. Read more →

Volumetric cross section (denoted U) is a quantitative parameter in nuclear well logging characterizing the cross-section of a formation material to photoelectric absorption of low-energy gamma rays, expressed in barns… Read more →

(noun) The ratio of the actual volume of fluid displaced per pump stroke to the theoretical displacement volume of the pump cylinder, expressed as a percentage. In sucker rod pumping systems, volumetric efficiency is… Read more →

A cavity, void or large pore in a rock that is commonly lined with mineral precipitates. Read more →

Vugular porosity is pore space made up of vugs, which are cavities, holes, or openings within a rock that are typically larger than the individual grains or crystals surrounding them and are formed by the dissolution of… Read more →