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

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

In a displacement process, the ratio of the cumulative height of the vertical sections of the pay zone that are contacted by injection fluid to the total vertical pay zone height. Vertical displacement efficiency (EI)… Read more →

The vertical distance between two points in a horizontal or deviated wellbore. Any calculations relating to wellbore pressure or downhole pump performance will be based on the vertical lift rather than the distance… Read more →

The resistivity of a formation measured by flowing current in a vertical plane. In anisotropic formations, the horizontal and vertical resistivities are different. In a vertical well, wirelineinduction logs and… 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 →

The response of a logging measurement as a function of distance parallel to the tool axis. The word vertical implies a vertical well, but the term is used at other wellbore deviations.Vertical responses are determined… 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 vessel with its cylindrical axes perpendicular to the ground that is used to separate oil, gas and water from the production stream. The vessel can be a two-phase or three-phase separator. 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 →

An adjustable mechanical source that delivers vibratory seismic energy to the Earth for acquisition of seismic data. Mounted on large trucks, vibrators are commonly used for acquisition of onshore seismic data. Read more →

Seismic data whose energy source is a truck-mounted device called a vibrator that uses a vibrating plate to generate waves of seismic energy; also known as Vibroseis data (Vibroseis is a mark of Conoco). The frequency… Read more →

A copolymer of vinyl acetate (ethylenic polymer) and anhydrous maleic acid (a di-hydroxy acid). The vinyl acetate polymer component is usually high molecular weight. As such, with polar groups on the structure, it is… Read more →

A class of polymers constructed with the monomer ethylene, H2C=CH2, with hydrogen replaced by various chemical groups. Among the many vinyl-based polymers and copolymers are acrylates, methacrylates, acrylamides,… 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 →

A property of fluids and slurries that indicates their resistance to flow, defined as the ratio of shearstress to shear rate. Viscosity can be expressed mathematically as follows: Poise is the unit for viscosity,… Read more →

A measure of a fluid's resistance to flow. Viscous forces in a fluid are proportional to the rate at which the fluid velocity is changing in space; the proportionality constant is the viscosity. For Newtonian liquids… 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 →

A type of woody kerogen that is relatively uniform in composition. Since vitrinite changes predictably and consistently upon heating, its reflectance is a useful measurement of source rock maturity. Strictly speaking,… Read more →

A measure of the thermal maturity of organic matter. This analytical method was developed to rank the maturity of coals and is now used in other rocks to determine whether they have generated hydrocarbons or could be… 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 →

The cross section of a material to photoelectric absorption, in barns/cm3. The volumetric cross section, U, is from the product of the photoelectric factor, PEF or Pe , and the electron density. In practice, U is… 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 →

Pore space consisting of cavities or vugs. Vugular porosity can occur in rocks prone to dissolution, such as limestone, in which case it is secondary porosity. Read more →