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

Stoneley permeability is the effective permeability of a formation derived from analysis of the Stoneley wave recorded on a borehole acoustic log. When a Stoneley wave propagates past a permeable interval, the… Read more →

A Stoneley wave is a large-amplitude interface wave generated by a sonic logging tool within a fluid-filled borehole. It propagates along the boundary between the borehole fluid and the surrounding formation, traveling… Read more →

An assembly of heavy beams used as the foundation on which the derrick or mast and usually the drawworks sit. Read more →

Abbreviation for water saturation. Read more →

The dimensionless ratio of the weight of a material to that of the same volume of water. Most common minerals have specific gravities between 2 and 7. Read more →

A sabkha (from the Arabic for salt flat) is an arid to semi-arid coastal sedimentary environment lying just above normal high tide that is characterized by the absence of vegetation, intermittent marine flooding driven… Read more →

A sack in oil and gas well construction is a unit of measure and packaging for Portland cement used in cementing operations, defined in the United States as the quantity of cement that occupies a bulk volume of 1.0… Read more →

A safety clamp (also called a slip-type safety clamp, tubing safety clamp, or rod safety clamp) is a mechanical device temporarily attached to the outer diameter of a tubular string (production tubing, drill pipe,… Read more →

A safety spacer is a blank gun section or non-firing spacer assembly installed between the top perforating-gun assembly and the firing head in a tubing-conveyed perforating (TCP) operation — providing the operational… Read more →

Sag in drilling engineering refers to the gravitational settling of dense weighting materials (primarily barite, with specific gravity of 4.2, or ilmenite and hematite in high-density applications) out of suspension in… Read more →

The product formed by neutralization of an acid and a base. The term is more specifically applied to sodium chloride. Neutralization is an important reaction in many aspects of mud control and treatment. Read more →

What Is a Salt Dome? A salt dome is a diapir (an intrusive geological body formed by buoyant rise of less-dense material) composed of halite (rock salt) and associated evaporite minerals that has pierced upward through… Read more →

A salt plug is a body of mobile halite (rock salt, NaCl) that has intruded upward through overlying sedimentary strata by diapirism — the buoyancy-driven flow of low-density, ductile salt through denser overlying… Read more →

A salt proximity survey is a borehole geophysical measurement technique used to determine the distance and direction from a wellbore to a nearby salt body — typically a salt dome, salt wall, or allochthonous salt sheet… Read more →

A type of reflectionsurvey to help define a salt-sediment interface near a wellbore. Read more →

A saltwater flow is an operational drilling event in which formation water (typically saline and sometimes containing high concentrations of dissolved minerals creating "hard" water with high calcium and magnesium… Read more →

What Is Saltwater Mud? Saltwater mud is a water-based drilling fluid containing dissolved sodium chloride as a major continuous-phase component, ranging from seawater-diluted systems to fully saturated salt solutions,… Read more →

The number of data points or measurements per unit of time or distance. Read more →

The distance or time between data points or measurements. Read more →

The number of measurements per unit of time, or the inverse of the sample interval. Read more →

The error introduced by the sampling process caused by making measurements on only a limited portion of a formation. Read more →

The sampling interval is the spacing, in either depth or time, between successive measurements taken by a sensor as it records a log. It is one of the most consequential acquisition parameters in formation evaluation… Read more →

Sand in petroleum production refers to fine formation particles (also called fines) that are produced along with reservoir fluids (oil, gas, and water) when the mechanical strength of the formation rock around the… Read more →

A sand bailer is a downhole tool run on slickline that retrieves sand, debris, and fluid from the bottom of the wellbore or from a specific interval of the tubing string, typically used to clean out sand accumulation… Read more →

A sand cleanout is a well intervention operation that removes accumulated sand, proppant, scale, or other solid debris from the wellbore, perforations, and near-wellbore formation to restore production that has been… Read more →

Sand consolidation is a well completion and production engineering technique that chemically binds the individual sand grains of a weak or unconsolidated sandstone reservoir together in the near-wellbore region to… Read more →

What Is Sand Control in Oil and Gas? Sand control encompasses the completion and production engineering techniques used to prevent unconsolidated or weakly consolidated formation sand from being produced with reservoir… Read more →

A sand line in the petroleum drilling industry is a single-strand or multi-strand wire rope used in cable tool drilling operations (the historical percussion drilling method that preceded modern rotary drilling) to… Read more →

Sand production in oil and gas well operations refers to the migration and transport of formation sand grains or other unconsolidated or weakly consolidated reservoir rock particles from the producing formation into the… Read more →

A sand test is a field measurement that determines the volume percentage of sand-sized and coarser particles (greater than 74 microns in diameter, equivalent to particles retained on a 200-mesh API screen) in a drilling… Read more →