Oil and Gas Terms Beginning with “S” — Page 8

A technique for acquiring deviation information from a borehole on a slickline. In high-angle wells, a multishot technique is usually used instead. Read more →

A single-tank composite sample is a representative liquid mixture created by combining individual samples drawn from the upper, middle, and lower sections of a single oilfield storage tank, blended in proportion to the… Read more →

Sinistral (from the Latin sinistra, meaning left) describes a strike-slip or left-lateral fault in which an observer standing on either side of the fault and looking across it sees the opposite block moving to the left;… Read more →

Sintered, in the context of petroleum engineering and downhole equipment, refers to a material or component produced by sintering — the process of compacting and bonding a powdered solid material (metal, ceramic, or… Read more →

A property or characteristic that has the form of a sine wave. Read more →

Sized calcium carbonate (also called calcium carbonate bridging agent or CaCO3 bridging material) is a chemically soluble, acid-dissolvable mineral additive incorporated into completion fluids, drill-in fluids, and… Read more →

Sized salt is sodium chloride (NaCl) solid particles that have been processed to provide a specified minimum and maximum range of particle sizes and that may also have a specified distribution of sizes within that range… Read more →

Skewness is a measure of the degree to which a probability distribution departs from the bilateral symmetry of a normal distribution, describing whether the data lean to one side with a longer tail on the other. A… Read more →

To skid in offshore drilling operations is to slide a drilling rig laterally across the deck of a fixed platform or jack-up rig from one well slot position to another, using hydraulic cylinders pushing against… Read more →

What Is Skin Factor in Oil and Gas? The skin factor (or simply skin , symbol S) is a dimensionless number that quantifies the deviation of a well's actual productivity from its theoretical productivity in an undamaged… Read more →

Skin depth is the characteristic distance over which an electromagnetic (EM) wave loses strength as it propagates into a conductive medium, formally the depth at which the field amplitude decays to 1/e, roughly 37… Read more →

Skin effect is a dimensionless parameter (S) in well test analysis that quantifies the additional pressure drop near the wellbore relative to what would be expected for an ideal undamaged well: a positive skin indicates… Read more →

What Is Skin Factor? The skin factor (S or S_skin) is a dimensionless number that quantifies the additional pressure drop in the near-wellbore region compared to ideal, undamaged radial flow through an infinite… Read more →

A specially designed drilling rig capable of drilling directional wells. Read more →

A slant stack is a seismic-processing operation that sums, or stacks, seismic traces after shifting each one in time by an amount proportional to its source-to-receiver offset. The result transforms data from the… Read more →

Slickline is a single-strand, solid wire used to run and retrieve tools and flow-control equipment in producing oil and gas wells without killing the well or removing the production tubing, distinguishing it from… Read more →

In directional drilling, a slide is a drilling mode in which the drill string is held stationary and not rotated from surface while the downhole motor (mud motor or positive-displacement motor) turns the bit using the… Read more →

A sliding sleeve (also called a sliding sleeve valve, production sleeve, or ported sleeve) is a completion device installed in the production tubing string that provides a controllable flow path between the inside of… Read more →

What Is a Slim Hole Well? A slim hole well is a borehole drilled with a reduced diameter profile throughout some or all of its depth, typically using bit sizes of 6 inches or smaller compared to the 8.5-12.25 inch bits… Read more →

What Is a Slim Tube Test? A slim tube test is a laboratory procedure used to determine the minimum miscibility pressure (MMP) of a gas injection enhanced oil recovery scheme by displacing reservoir crude oil through a… Read more →

Slime-forming bacteria are facultative microorganisms, able to live with or without oxygen, that secrete extracellular polymeric substances to build dense mats of slime, or biofilm, across any wetted surface in an… Read more →

Slime-forming bacteria are facultative oilfield microorganisms, equally able to grow with or without oxygen, that produce thick mats of high-density slime, a biofilm of extracellular polymeric substances, across the… Read more →

What Is a Slimhole Well? A slimhole well is a wellbore drilled with a reduced-diameter borehole profile, characteristically using bit sizes below 6 inches in the producing section, enabling significant reductions in rig… Read more →

Slip is the phenomenon in multiphase flow where one phase travels faster than another, sliding past it along the pipe or tubing. When gas and liquid flow together up a wellbore or along a flowline, buoyancy and… Read more →

Slip and cut in drilling engineering is the maintenance procedure for the drilling line (wire rope that connects the traveling block, hook, and swivel assembly to the draw-works drum) in which a predetermined length of… Read more →

A slip joint is a completion component designed to accommodate axial movement of the production tubing string while maintaining a continuous hydraulic seal between a sliding inner mandrel and an outer housing, allowing… Read more →

A slip lock is a mechanical locking device used in wellbore completion and well control equipment to prevent the unintentional movement or withdrawal of slips (the wedge-shaped gripping elements that grip casing or pipe… Read more →

Slip velocity in multiphase flow through pipes and wellbores is the difference between the average in-situ velocities of two or more fluid phases flowing simultaneously through the same conduit, arising because the… Read more →

Slip and cut is the drilling rig maintenance procedure in which a measured length of drilling line (the wire rope connecting the draw-works drum to the traveling block assembly through the crown block sheaves) is… Read more →

Slips are the toothed, wedge-shaped gripping device that suspends a drillstring in the wellbore whenever the rig is not actively lifting it with the hook. Functionally, slips are a set of three or more hardened steel… Read more →