Oil and Gas Terms Beginning with “S” — Page 9

A slow formation is a subsurface rock unit in which the shear wave velocity (Vs) is lower than the acoustic velocity of the borehole fluid (Vmud), preventing refracted shear wave arrivals from being recorded by standard… Read more →

A substance added at slow rate to the production fluid stream to prevent corrosion. Read more →

Slowing-down length (Ls) is a nuclear physics parameter that quantifies the mean spatial distance over which fast neutrons emitted by a logging source (such as americium-beryllium, AmBe, or californium-252) are slowed… Read more →

Slowing-down time (also called moderation time or thermalization time) is the elapsed time required for fast neutrons emitted from a neutron source to lose kinetic energy through successive elastic and inelastic… Read more →

Slowness-time coherence (STC) is a semblance-based processing algorithm applied to full waveform acoustic logging data to identify and extract compressional (P-wave) and shear (S-wave) wave slownesses (the reciprocal of… Read more →

Sludge in oilfield acid stimulation chemistry is a thick, viscous emulsion containing oil, water, sediment, and various residue products that forms because of the chemical incompatibility between certain native crude… Read more →

A slug in petroleum engineering refers to a discrete volume or bank of fluid injected into a well or pipeline as a defined unit — the term is used in multiple distinct technical contexts: in enhanced oil recovery (EOR),… Read more →

A type of flow in which surface equipment may be damaged by the sudden impact of a liquid slug in a phenomenon called water hammer. Read more →

Accumulation of a water, oil or condensate in a gas pipeline. These fluids need to be removed using a pig. Read more →

A chemical used to break emulsions to determine the total amount of sediment and water in the samples. Read more →

(noun) The plural of slurry. Fluid mixtures containing suspended solid particles, such as cement slurries (a blend of cement powder and water used for zonal isolation), fracturing slurries (fluid carrying proppant), or… Read more →

A slurry is a flowable mixture of finely divided solids suspended in a liquid carrier, engineered so the solid phase stays dispersed long enough to be pumped, placed, and then either set or circulated out. In the oil… Read more →

Slurry density is the mass per unit volume of a freshly mixed cement slurry, drilling fluid, or other solids-laden fluid mixture, expressed in pounds per gallon (ppg), pounds per cubic foot (pcf), or kilograms per cubic… Read more →

Slurry stability is the ability of a cement slurry to remain homogeneous from the moment it is mixed until it sets downhole, holding its solids in uniform suspension without the heavier particles settling to the bottom… Read more →

Slurry yield is the volume of cement slurry produced when one sack of dry cement is mixed with its design quantity of mixing water and any additives, and it is the parameter that converts a sack count into the cubic… Read more →

Small-pore water is water held in microporosity or other very small pores, and the term most often refers to the nuclear magnetic resonance (NMR) signal produced by that water, a signal that appears at very short… Read more →

Smectite is a group of 2:1 phyllosilicate clay minerals defined by a unit cell of two tetrahedral silica sheets sandwiching a central octahedral alumina or magnesia sheet, with a generalised formula often written as… Read more →

Smectite clay (also called montmorillonite or swelling clay) is a layer silicate clay mineral with a 2:1 crystal structure (two tetrahedral silica sheets sandwiching one octahedral alumina sheet) and a large negative… Read more →

A smile is a concave-upward, roughly semicircular event seen on migrated seismic data that, as the name suggests, has the upturned shape of a smile and is an artifact rather than a real geologic reflector. It is one of… Read more →

Snubbing in well intervention is the operation of forcing pipe, tubing, or other tubulars into a wellbore that is under pressure (a live well) using a specialized hydraulic snubbing unit that provides the downward… Read more →

What Is Snubbing? Snubbing is a well intervention technique that forces tubular pipe into a live, pressurized wellbore against wellbore pressure acting on the pipe cross-section, using a specialized hydraulic jack unit… Read more →

The snubbing basket is the elevated work platform at the top of a snubbing unit where the crew stands to run or retrieve tubulars and tool strings, and from which all of the unit's hydraulic functions are operated. It… Read more →

Snubbing force is the net upward force that must be overcome to force (snub) a drill string, work string, or coiled tubing into a wellbore that has sufficient pressure to push the pipe back out — specifically, the net… Read more →

A snubbing jack is the primary mechanical component of a snubbing unit that provides the controlled vertical stroke and force required to run or retrieve a work string (drill pipe, coiled tubing, or work string pipe)… Read more →

The soak phase is the middle stage of a three-step cyclic steam stimulation (CSS) treatment, also called the huff-and-puff thermal recovery process, applied to heavy oil and bitumen reservoirs that are too viscous to… Read more →

In oilfield chemistry, a soap is a class of organic salt compounds formed by the chemical reaction of an aliphatic carboxylic acid (typically a fatty acid with a long aliphatic hydrocarbon chain) with an inorganic base… Read more →

Sodium bicarbonate (NaHCO₃, also called baking soda or bicarbonate of soda) is an alkaline salt used in drilling fluid engineering as a chemical treatment to neutralize and remove excess calcium contamination from… Read more →

Sodium carbonate (Na2CO3) is an inorganic chemical compound — known in oilfield drilling vernacular as soda ash — used routinely to treat calcium ion contamination in freshwater and seawater drilling muds, with the… Read more →

Oilfield slang term for rope not made of steel, such as nylon, cotton, or especially standard manila hemp rope. Read more →

Soft rock is an informal but widely used term in the geosciences for sedimentary rocks, particularly when geologists want to draw a working distinction between the rocks that interest the petroleum industry and the… Read more →