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

A shut-in royalty in oil and gas law is a periodic payment made by the lessee (working interest operator) to the royalty owner under the terms of an oil and gas lease when a well that is capable of producing in paying… Read more →

A side pocket mandrel (SPM) in oil and gas production completions is a specially machined tubular joint installed as an integral part of the production tubing string that contains an offset cylindrical pocket (the side… Read more →

Side-scan sonar is an acoustic remote sensing system deployed in marine and lacustrine environments to produce high-resolution images of the seafloor or lake bed and its shallow subsurface, in which a towfish or… Read more →

Siderite in petroleum geology is the iron carbonate mineral FeCO3 (ferrous carbonate) that occurs as diagenetic cement, concretions, and replacement mineral in sandstone, mudstone, and carbonate reservoir and seal rocks… Read more →

A sideswipe is an out-of-plane reflection event that appears in a 2D seismic section even though the geological feature producing it lies kilometres to the side of the survey line, rather than directly beneath it. The… Read more →

A sidetrack is a secondary wellbore deliberately drilled away from an existing hole, departing from the original path at a chosen kickoff point to reach a different bottomhole target, bypass an obstruction, or replace a… Read more →

Sidewall in petroleum engineering describes a configuration, measurement, or sample associated with the lateral wall of the borehole rather than the borehole bottom or the fluid column, encompassing a range of tools and… Read more →

A sidewall core is a small-diameter cylindrical rock sample recovered from the borehole wall after the hole has been drilled, acquired via wireline-conveyed percussion or rotary coring tools to provide lithology,… Read more →

Sieve analysis is a laboratory method for determining the particle size distribution of granular materials — particularly proppant (frac sand or ceramic beads) used in hydraulic fracturing, formation sand produced from… Read more →

Sigma (symbol Σ, also written as sigma or capture cross section) is the thermal neutron capture cross section of a formation — a measure of the formation's ability to absorb thermal neutrons, expressed in capture units… Read more →

Signal, in seismic and geophysical work, is the portion of the recorded wavefield that carries desirable information about the subsurface, the reflection energy that tells an interpreter where geologic interfaces lie,… Read more →

Signal-to-noise ratio (SNR) in seismic exploration and petroleum well logging is the ratio of the amplitude of the desired signal (the primary reflection response from subsurface interfaces in seismic data, or the… Read more →

In geophysics, a signature is the distinguishing character of a waveform in a seismic event, defined by its shape, polarity, amplitude, frequency content, and phase. The most consequential signature is that of the… Read more →

Signature deconvolution is a seismic data processing technique that removes the effect of the seismic source wavelet (the signature of the seismic source, including the pressure pulse shape, any bubble pulses in marine… Read more →

[SiO2]A chemically resistant dioxide of silicon that occurs in crystalline (quartz), amorphous (opal) and cryptocrystalline (chert) forms. Read more →

A type of salt derived from silicic acid. Read more →

The silicate anion is the orthosilicate ion, SiO4 with a four-minus charge, the fundamental building block of silicate chemistry and the active species in silicate-based drilling fluids. It is generated by dissolving… Read more →

A silicate mineral is any member of the dominant rock-forming mineral group whose crystal structure is built from the silica tetrahedron, a single silicon ion bonded to four oxygen ions in a four-cornered pyramid with… Read more →

What Is Silicate Mud? Silicate mud is a water-based drilling fluid system that uses soluble potassium or sodium silicate (water glass) as an inhibitive additive to stabilise reactive shale formations and unconsolidated… Read more →

Silicic acid (chemical formula H4SiO4, also written Si(OH)4 or orthosilicic acid) is the monomeric dissolved form of silicon dioxide in water, representing the species in which silicon is dissolved in aqueous solution… Read more →

Siliciclastic sediment is sedimentary material composed predominantly of detrital (mechanically transported and deposited) fragments of silicate minerals and silicate rock fragments derived by weathering and erosion of… Read more →

A term used to describe particle whose size is between 2 and 74 micrometers (200 mesh). Read more →

A similar fold in structural geology is a fold geometry in which the layers maintain a constant thickness when measured parallel to the axial surface (the plane that bisects the fold through the hinge zones of all… Read more →

A simple multiple in seismic reflection data is a type of coherent seismic noise consisting of a seismic wave that has undergone exactly one additional reflection beyond the direct travel path before being recorded at… Read more →

Simulated annealing (SA) is a probabilistic optimization algorithm inspired by the physical process of annealing in metallurgy, in which a material is heated to a high temperature and then slowly cooled to minimize the… Read more →

Simultaneous operation (SIMOP), in oil and gas drilling, production, and facilities management, refers to the conduct of two or more potentially hazardous operations at the same time on the same facility, well site, or… Read more →

Sinc x is the function defined as sin(x) divided by x, a smoothly oscillating curve that equals one at the origin and decays in ever-smaller ripples as x moves away from zero, crossing the axis at every integer multiple… Read more →

The single-pass method in petroleum engineering refers to a production logging or completion diagnostic technique in which all required measurements — flow rate, phase holdup, temperature, pressure, and fluid… Read more →

Referring to a flow or other phenomenon with only one component, normally oil, water or gas. Read more →

The flow of a single-phase fluid, such as oil, water or gas, through porous media. Read more →