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

Water drive is a natural reservoir energy mechanism in which oil or gas production is sustained primarily by the expansion of an aquifer (a connected body of water-saturated rock) that underlies or surrounds the… Read more →

A water flood is the most common method of secondary recovery in oil and gas operations, in which water is injected into the reservoir formation through specifically distributed injection wells to physically displace… Read more →

The water formation volume factor, written Bw and expressed in reservoir barrels per stock-tank barrel (rb/STB) or in cubic metres per cubic metre (rm3/sm3), is the ratio of the volume occupied by formation water plus… Read more →

A water gun in marine seismic acquisition is an implosive seismic source device that generates acoustic energy by creating a controlled underwater cavitation chamber (a region of very low pressure) and then allowing it… Read more →

A fluid with water or brine as droplets dispersed into an external phase of oil. Read more →

Water influx is the encroachment of water from an adjacent aquifer into a hydrocarbon-bearing reservoir as reservoir pressure declines during production — a natural drive mechanism in which the pressure drop caused by… Read more →

Jargon applied to a mud additive used to control fluid loss. Read more →

A water mud emulsifier is a surface-active chemical additive used in water-based drilling fluids (WBM) to create and stabilize an oil-in-water emulsion by dispersing oil droplets uniformly throughout the aqueous… Read more →

Water production in oil and gas operations refers to the flow of water from the reservoir or from other subsurface sources into the producing wellbore, where it is lifted to the surface along with oil and gas and must… Read more →

Water saturation (Sw) is the fraction of water in a given pore space of a reservoir rock — providing one of the foundational petrophysical parameters that drives reservoir engineering analysis including… Read more →

The water-to-cement ratio in oilwell cementing is the proportion of mix water to dry cement in a slurry, conventionally expressed as a percentage by weight of cement (BWOC), so a 44 percent ratio means 44 parts water… Read more →

The water, oil and solids test (also called the retort test) is a quantitative distillation analysis performed on a drilling fluid sample in which a measured volume of mud is heated in a sealed retort chamber to… Read more →

Water-alternating-gas (WAG) is an enhanced oil recovery (EOR) injection strategy in which slugs of water and gas (typically CO2, hydrocarbon gas, or nitrogen) are injected into a reservoir in alternating cycles rather… Read more →

A water-base drilling fluid (WBDF, also called water-base mud or WBM) is a drilling fluid system in which water (fresh water, brackish water, saturated salt water, or seawater) serves as the major liquid phase and as… Read more →

Water-bottom roll is a coherent seismic noise event in marine seismic data consisting of a pseudo-Rayleigh wave (also described as a Scholte wave) that propagates along the interface between the water column and the… Read more →

A water-cut meter is a device for determining the water holdup (the volumetric water fraction in flowing multiphase fluid) in a producing well by measuring the electrical capacitance or impedance of the fluid mixture —… Read more →

Water-filled resistivity (Ro) is the electrical resistivity measured in a rock sample whose pore space is fully saturated with formation water, with no hydrocarbon present, and it serves as the petrophysical baseline… Read more →

What Is a Water-Flow Log? A water-flow log is a production logging measurement that detects and quantifies the movement of water in or around the wellbore, most commonly using oxygen activation of the pulsed neutron… Read more →

A fluid with water or brine as droplets dispersed into an external phase of oil. Read more →

A water-mud emulsifier in drilling engineering is a surface-active chemical additive incorporated into oil-based drilling fluids (OBM) that stabilizes a water-in-oil emulsion by adsorbing at the oil-water interface and… Read more →

The water-to-cement ratio is the amount of mix water carried per unit of dry cement in a slurry, stated as a percentage by weight of cement (BWOC), where 44 percent describes 44 mass parts of water blended with 100 mass… Read more →

Water-wet refers to the wettability condition of a reservoir rock in which the rock surfaces (the mineral grain surfaces and pore walls) have a stronger affinity for water than for oil — meaning that water… Read more →

What Is Water-Oil Ratio? The water-oil ratio (WOR) is the volume of water produced per unit volume of oil produced from a well or field — typically expressed in stock tank barrels of water per stock tank barrel of oil… Read more →

Water drive is a natural reservoir energy mechanism in which oil or gas production is sustained primarily by the expansion of an aquifer (a connected body of water-saturated rock) that underlies or surrounds the… Read more →

What Is a Waterflood in Oil and Gas? A waterflood is a secondary oil recovery method in which water is injected into a reservoir through dedicated injection wells to maintain reservoir pressure and physically displace… Read more →

The first indication of increased crude-oil production as the result of a waterflooding project. Read more →

(noun) A secondary oil recovery method in which water is injected into a reservoir through dedicated injection wells to maintain reservoir pressure and physically displace oil toward producing wells. Waterflooding is… Read more →

What Is a Wave? A wave is a travelling disturbance that carries energy through a material or along a surface. The material moves locally, but the energy moves onward. USGS earthquake references describe P waves as… Read more →

A mathematical expression to represent wavedisplacement and wave velocity (V) as functions of space (x,y,z) and time (t). Read more →

The shape of a wave, typically shown as a graph of amplitude (or other quantity of interest) versus time. Read more →