Oil and Gas Terms Beginning with “S” — Page 16

A well shut in at the surface, rather than downhole. Most transient well tests are conducted in this manner for convenience. Read more →

Surface free energy that exists between a liquid and air. Surface tension can be observed as a curved meniscus in a small tube of the liquid. This energy barrier prevents a liquid (such as water) from spontaneously… Read more →

A wave that propagates at the interface between two media as opposed to through a medium. A surface wave can travel at the interface between the Earth and air, or the Earth and water. Love waves and Rayleigh waves are… Read more →

A downhole safety valve that is operated from surface facilities through a control line strapped to the external surface of the production tubing. Two basic types of SCSSV are common: wireline retrievable, whereby the… Read more →

A chemical that preferentially adsorbs at an interface, lowering the surface tension or interfacial tension between fluids or between a fluid and a solid. This term encompasses a multitude of materials that function as… Read more →

An enhanced oil recovery process in which a small amount of surfactant is added to an aqueous fluid injected to sweep the reservoir. The presence of surfactant reduces the interfacial tension between the oil and water… Read more →

An enhanced oil recovery process in which alternating slugs of a surfactant solution and gas are injected into a reservoir. The injected surfactant and gas mix and generate foam that reduces the gas mobility, especially… Read more →

A vessel placed in a flowline through which liquids or gases are flowed to neutralize sudden pressure surges. Read more →

A formationlayer above or below the layer being measured by a logging tool. The term is used in particular to describe the adjacent layers above or below a horizontal well. In a vertical well, the term shoulder bed is… Read more →

To record a measurement versus depth or time, or both, of one or more physical quantities in or around a well. In early years, the term was used more often than log. Read more →

Dispersed particles in a slurry that can be separated by filtration and are not dissolved. In the water, oil and solids test (retort test), the retort solids are divided into two types, dissolved and suspended solids.… Read more →

To unload liquids from the production tubing to initiate flow from the reservoir. A swabbing tool string incorporates a weighted bar and swab cup assembly that are run in the wellbore on heavy wireline. When the… Read more →

The topmost valve on a Christmas tree that provides vertical access to the wellbore. Read more →

A threaded adapter used to connect a circulating line to a casing or tubing string. A casing or tubing swage generally is required as a contingency option to enable any obstruction or fill to be circulated clear during… Read more →

A downhole tool, generally run on slickline, that is used to open collapsed or damaged tubing. Configured with a tapered profile, the swaging tool acts as a circular wedge to force the tubing wall out as it is driven… Read more →

A wetland depositional environment in which water is present either permanently or intermittently and in which trees and large woody plants can grow but peat does not form. Swamps can contain considerable quantities of… Read more →

A measure of the effectiveness of an enhanced oil recovery process that depends on the volume of the reservoir contacted by the injected fluid. The volumetric sweep efficiency is an overall result that depends on the… Read more →

A relatively small volume of viscous fluid, typically a carrier gel, that is circulated to sweep, or remove, debris or residual fluids from the circulation system. Read more →

Pertaining to crude oil or natural gas lacking appreciable amounts of sulfur or sulfur compounds. Read more →

The corrosion caused by contact with carbon dioxide [CO2] dissolved in water.In gas condensate wells, sweet corrosion takes the form of deep pitting inside the tubing walls. The pitting is produced only at depths where… Read more →

Crude oil containing low levels of sulfur compounds, especially hydrogen sulfide [H2S]. The facilities and equipment to handle sweet crude are significantly simpler than those required for other potentially corrosive… Read more →

Oil containing small amounts of hydrogen sulfide and carbon dioxide. Read more →

Natural gas that contains small amounts of hydrogen sulfide and carbon dioxide. Read more →

Colloquial expression for a target location or area within a play or a reservoir that represents the best production or potential production. Geoscientists and engineers attempt to mapsweet spots enable wellbores to be… Read more →

A process used to remove hydrogen sulfide [H2S] and carbon dioxide [CO2] from a gas stream. These components are removed because they can form acidic solutions when they contact water, which will cause corrosion… Read more →

An isolation device that relies on elastomers to expand and form an annular seal when immersed in certain wellbore fluids. The elastomers used in these packers are either oil- or water-sensitive. Their expansion rates… Read more →

A mechanical device that suspends the weight of the drillstring. It is designed to allow rotation of the drillstring beneath it conveying high volumes of high-pressuredrilling mud between the rig's circulation system… Read more →

The slang abbreviation for synthetic. The term can be confusing to the uninitiated, so its use is avoided. Read more →

Basin- or trough-shaped fold in rock in which rock layers are downwardly convex. The youngest rock layers form the core of the fold and outward from the core progressively older rocks occur. Synclines typically do not… Read more →

Any of a number of fluids (liquids) manufactured from starting products of known composition and purity. Popular fluid types include several olefin oligomers of ethylene. Esters made from vegetable fatty acid and… Read more →