Oil and Gas Terms Beginning with “S” — Page 4

A condition encountered during some gravel-pack operations whereby the treatment area cannot accept further pack sand and a sudden increase in treatment pressure occurs. Under ideal conditions, this should signify that… Read more →

To remove impurities, water, liquid hydrocarbons or traces of other gases by passing the gas flowstream through a scrubber, a device in which the gas is mixed with a suitable liquid that absorbs or washes out the… Read more →

A device to remove dirt, water, foreign matter, or undesired liquids that are part of the gas flowstream. Air can be used to absorb water; also an oil bath might be useful to remove dust, dirt or other liquids. A… Read more →

Oil recovered from a knockout or scrubber device. Read more →

A type of receiver that can be positioned on the seafloor to acquire seismic data. Read more →

A relatively impermeable rock, commonly shale, anhydrite or salt, that forms a barrier or cap above and around reservoir rock such that fluids cannot migrate beyond the reservoir. A seal is a critical component of a… Read more →

A system of seals arranged on the component that engages in a sealbore to isolate the production-tubing conduit from the annulus. The seal assembly is typically longer than the sealbore to enable some movement of the… Read more →

A profiled completion component designed to accept a mating component equipped with a seal assembly. Completions are designed with seal receptacles to enable the production string to be removed without removing the… Read more →

A polished bore designed to accept a seal assembly, such as may be used in a permanent production packer. Read more →

A type of production packer that incorporates a sealbore that accepts a seal assembly fitted to the bottom of the production tubing. The sealbore packer is often set on wireline to enable accurate depth correlation. For… Read more →

The geological barriers that isolate fluid compartments within reservoirs or that hydraulically isolate reservoirs from each other. The seals may contain fluids (for example shales) but have very low permeability. The… Read more →

(noun) A short, internally profiled section of tubing installed in a completion string that provides a machined bore for setting and sealing flow-control devices such as plugs, blanking tools, and check valves. Unlike a… Read more →

A water-base mud designed for offshore drilling whose make-up water is taken from the ocean. Sea water contains relatively low salinity, about 3 to 4 wt. % NaCl, but has a high hardness because of Mg+2 and Ca+2 ions.… Read more →

The movement of generated hydrocarbons into a reservoir after their expulsion, or primary migration, from a source rock. Read more →

The porosity created through alteration of rock, commonly by processes such as dolomitization, dissolution and fracturing. Read more →

The method used to sustain production levels at viable rates following a fall in flow rate as the efficiency of the primary production methods declines. Secondary production methods frequently involve an artificial-lift… Read more →

What Is Secondary Recovery? Secondary recovery is the second stage of oil production in which external energy — injected water or gas — is introduced into a reservoir to maintain pressure and displace oil that primary… Read more →

The term of an oil and gas lease in which the lease is held in force after expiration of the primary term. Production, operations, continuous drilling and/or shut-in royalty payments are often used to extend an oil and… Read more →

An indicator of the porosity that does not contribute to a sonic measurement of interval transit time. The transit time is little affected by vugs, fractures and other irregular events because the sonic wave finds a… Read more →

The unconsolidated grains of minerals, organic matter or preexisting rocks, that can be transported by water, ice or wind, and deposited. The processes by which sediment forms and is transported occur at or near the… Read more →

One of the three main classes of rock (igneous, metamorphic and sedimentary). Sedimentary rocks are formed at the Earth's surface through deposition of sediments derived from weathered rocks, biogenic activity or… Read more →

A depression in the crust of the Earth formed by plate tectonic activity in which sediments accumulate. Continued deposition can cause further depression or subsidence. Sedimentary basins, or simply basins, vary from… Read more →

The process of separation of the components of a cementslurry during which the solids settle. Sedimentation is one of the characterizations used to define slurry stability. Read more →

Pertaining to waves of elastic energy, such as that transmitted by P-waves and S-waves, in the frequency range of approximately 1 to 100 Hz. Seismic energy is studied by scientists to interpret the composition, fluid… Read more →

(noun) The process of analysing seismic data to extract geological information about subsurface structures, stratigraphy, and rock properties. Seismic interpretation involves identifying and mapping reflectors, faults,… Read more →

The comparison, simulation or representation of seismic data to define the limits of seismic resolution, assess the ambiguity of interpretation or make predictions. Generation of a synthetic seismogram from a well log… Read more →

Traces recorded from a single shotpoint. Numerous seismic records are displayed together in a single seismic section. Read more →

A display of seismic data along a line, such a 2D seismic profile or a profile extracted from a volume of 3D seismic data. A seismic section consists of numerous traces with location given along the x-axis and two-way… Read more →

The seismic data recorded for one channel. A seismic trace represents the response of the elastic wavefield to velocity and density contrasts across interfaces of layers of rock or sediments as energy travels from a… Read more →

A technique for acquiring a vertical seismicprofile that uses the noise of the drill bit as a source and receivers laid out along the ground or seabed; also called a drill-noise VSP. In deep water, the receiver arrays… Read more →