Oil and Gas Terms Beginning with “F” — Page 7

Any fluid that occurs in the pores of a rock. Strata containing different fluids, such as various saturations of oil, gas and water, may be encountered in the process of drilling an oil or gas well. Fluids found in the… Read more →

Pressure above which injection of fluids will cause the rockformation to fracture hydraulically. Read more →

The pressure within the reservoirrock. The formation pressure value can be further categorized as relating to flowing well or shut-in conditions. Read more →

What Is Formation Water? Formation water occupies the pore spaces of a reservoir rock as naturally occurring brine, representing the connate water that saturated the formation before and after hydrocarbon migration. Its… Read more →

An organic acid [HCOOH] used in oil- and gas-well stimulation treatments. Formic acid has an advantage over HCl in that formic acid is easier to inhibit against pipe corrosion at temperatures as high as 400°F [204°C].… Read more →

The technique of determining what a given sensor would measure in a given formation and environment by applying a set of theoretical equations for the sensor response. Forward modeling is used to determine the general… Read more →

A laboratory test to determine the phase envelope between lean gas and oil by equilibrating a gas sample several times with fresh samples of oil. In a forward-contact test, light and intermediate components are stripped… Read more →

The practice of taking a model and calculating what the observed values should be, such as predicting the gravityanomaly around a saltdome using a gravity model or predicting the traveltime of a seismicwave from a… Read more →

Preserved remnants of plants or animals, such as skeletons, shells, casts or molds, tracks or borings, and feces. Read more →

Four-component (4C) borehole or marineseismic data are typically acquired using three orthogonally-oriented geophones and a hydrophone within an ocean-bottom sensor (deployed in node-type systems as well as cables).… Read more →

Three-dimensional (3D) seismic data acquired at different times over the same area to assess changes in a producing hydrocarbonreservoir with time. Changes may be observed in fluid location and saturation, pressure and… Read more →

Collective term for the personnel required to run a successful hydraulic fracturing operation. Members of the frac crew prepare the equipment on the wellsite prior to the operation, mix and pump the necessary chemicals… Read more →

The primary fluid used in hydraulic fracturing operations. Several chemical additives generally will be added to the frac gel to form a treatment fluid specifically designed for the anticipated wellbore, reservoir and… Read more →

The pressure gradient, generally stated in psi/ft [kPa/m], at which a specific formation interval breaks down and accepts fluid. Determining the frac gradient is a key requirement in designing and analyzing a hydraulic… Read more →

A specialized perforating-gun system that contains shaped charges loaded at 0°, 60°, 120°, or 180° phase angles to provide a casingentrance hole of approximately 0.5 in. [1.3 cm], which is intended to be large enough… Read more →

A high-pressure, high-volume pump used in hydraulic fracturing treatments. Read more →

A high-pressure isolation valve fitted to the top of the wellhead on a well that is about to be hydraulically fractured. The frac valve can be closed to isolate the treating equipment from the wellbore. Read more →

A special mathematical geometry with properties that reproduce a pattern over a range of scales. They can contain some variations so that the patterns do not perfectly repeat. This geometry claims to represent many… Read more →

Analysis of a geometrical system using fractal mathematics. This analysis is sometimes used in geostatistics to describe depositional systems and other geological phenomena. Read more →

Networks that are described using the mathematics of fractals. These are useful for describing certain types of fracture systems. Read more →

A well-stimulation operation in which acid, usually hydrochloric [HCl], is injected into a carbonateformation at a pressure above the formation-fracturing pressure. Flowing acid tends to etch the fracture faces in a… Read more →

Product of fracturepermeability times fracture width for a finite-conductivity fracture. Read more →

What Is Fracture Gradient? The fracture gradient is the minimum wellbore pressure — expressed as an equivalent fluid density gradient (psi/ft or lb/gal EMW) — required to initiate or propagate a hydraulic fracture in a… Read more →

Radial distance from the wellbore to the outer tip of a fracture penetrated by the well or propagated from the well by hydraulic fracturing. Read more →

Patterns in multiple fractures that intersect with each other. Fractures are formed when rock is stressed or strained, as by the forces associated with plate-tectonic activity. When multiple fractures are propagated,… Read more →

That portion of a dual-porosity reservoirs permeability that is associated with the secondary porosity created by open, natural fractures. In many of these reservoirs, fracture permeability can be the major controlling… Read more →

A type of secondary porosity produced by the tectonic fracturing of rock. Fractures themselves typically do not have much volume, but by joining preexisting pores, they enhance permeability significantly. In exceedingly… Read more →

Analysis of a well that passes through a natural fracture or that has been hydraulically fractured. The fracture is treated as a slab of high permeability that is an effective extension of the actual wellbore. Flow is… Read more →

A fluid injected into a well as part of a stimulation operation. Fracturing fluids for shale reservoirs usually contain water, proppant, and a small amount of nonaqueous fluids designed to reduce friction pressure while… Read more →

(noun) The downhole pressure at which a formation rock fractures and a hydraulic fracture initiates and propagates. Fracturing pressure is a function of the in-situ stress state, rock tensile strength, pore pressure,… Read more →