Oil and Gas Terms Beginning with “S” — Page 15

A submersible drilling rig (also called a submersible or conventional submersible) is an offshore drilling unit designed for shallow-water operations — typically water depths of 6 to 35 meters — in which the lower hull… Read more →

In petroleum exploration, subsalt refers to geological structures, reservoir intervals, or formations located beneath a body of evaporitic salt (salt diapir, allochthonous salt canopy, or salt sheet) whose high acoustic… Read more →

A well in which the wellhead, Christmas tree and production-control equipment is located on the seabed. Read more →

Subsidence, in geology and petroleum engineering, is the downward displacement or sinking of the earth's surface or subsurface rock due to natural geological processes or human-induced activities, occurring at rates… Read more →

Any pressure measured in a well below the surface. Read more →

A subsurface safety valve (SSSV), also called a downhole safety valve (DHSV) or simply a safety valve, is a downhole pressure-controlled device installed in the production tubing of an oil or gas well — typically 100 to… Read more →

A subsurface surface-controlled safety valve (SSCSV), also abbreviated SSCSV or tubing-retrievable surface-controlled subsurface safety valve (TRSCSSV), is a downhole wellbore safety device installed in the production… Read more →

A sucker rod is a solid steel rod (typically 25 feet (7.62 meters) in length, threaded at both ends with API-standardized couplings) that forms the mechanical link in the rod string connecting the surface pumping unit's… Read more →

(noun) A positive displacement downhole pump, driven by a surface beam pumping unit through a string of sucker rods, consisting of a standing valve at the bottom, a travelling valve on the plunger, and a close-fitting… Read more →

The suction pit (also called the suction tank or active pit) is the drilling fluid compartment at the lowest end of the surface mud circulation system from which the rig's mud pumps draw fluid to circulate down the… Read more →

What Are Sulfate-Reducing Bacteria (SRB)? Sulfate-reducing bacteria (SRB) are anaerobic microorganisms that use sulfate (SO₄²⁻) as a terminal electron acceptor in their metabolism, reducing it to hydrogen sulfide (H₂S)… Read more →

The ability of set cement to resist deterioration in the presence of sulfate ions. Read more →

A cement in which the amount of tricalcium aluminate is controlled as specified by API Specification 10A. Read more →

What Are Sulfate-Reducing Bacteria (SRB)? Sulfate-reducing bacteria (SRB) are anaerobic microorganisms that use sulfate (SO₄²⁻) as a terminal electron acceptor in their metabolism, reducing it to hydrogen sulfide (H₂S)… Read more →

A cement in which the amount of tricalcium aluminate is controlled as specified by API Specification 10A. Read more →

What Is a Sulfide in Oil and Gas? In oil and gas operations, sulfide refers primarily to hydrogen sulfide (H2S), a toxic and corrosive gas present in sour crude oil, sour gas, and formation water, as well as to the iron… Read more →

A sulfide scavenger is a chemical additive introduced into drilling fluids, completion fluids, or production fluids to irreversibly react with and remove hydrogen sulfide (H2S), bisulfide ions (HS-), and polysulfide… Read more →

Sulfonated asphalt (also called sulfonated gilsonite, sulfonated bitumen, or NAS, sodium asphalt sulfonate) is a chemically modified bituminous material used as a multifunctional additive in water-based drilling fluids,… Read more →

Sulfonated polystyrene-maleic anhydride copolymer (SSMA) is a synthetic anionic polymer used as a deflocculant and filtration control additive in high-temperature, high-pressure (HTHP) water-based drilling fluids, where… Read more →

Light crude oil containing sulfur compounds such as hydrogen sulfide. Read more →

The summation of fluids method is a petrophysical technique for calculating the total porosity of a formation from wireline well logs by algebraically summing the measured apparent porosities from two or more… Read more →

Superficial velocity (also called Darcy velocity or specific discharge) is the volumetric flow rate of a fluid divided by the total cross-sectional area of the conduit through which it flows, without correction for the… Read more →

What Is Superposition in Well Testing? Superposition is a mathematical principle applied in pressure transient analysis (PTA) that allows the pressure response of a reservoir to multiple wells or multiple rate changes… Read more →

A mathematical computation that accounts for production from multiple wells. Image wells are used to model the effect of impermeable barriers. Read more →

Superposition in time (also called the superposition principle or time superposition) is the mathematical technique used in pressure transient analysis to account for the complete production history of a well before and… Read more →

In offshore operations, any barge, boat or ship that brings materials and personnel to and from the rigsite. Read more →

In seismic acquisition and processing, the attenuation of amplitudes to reduce the effects of noise or to prevent overload from the high energy of first breaks. Read more →

Surface casing is the large-diameter, relatively low-pressure pipe string set in the shallowest competent formations of a wellbore to protect fresh-water aquifers from contamination by drilling fluids, formation fluids,… Read more →

A surface interest is the ownership right to occupy and use the surface of a parcel of land, distinct from the mineral interest beneath it. In most of the Western Canadian Sedimentary Basin, the surface estate and the… Read more →

Surface pressure is the pressure measured at or near the wellhead of an oil or gas well, generally just below the master valve or wing valve and above the choke manifold, and it serves as the primary real-time indicator… Read more →