Oil and Gas Terms Beginning with “S” — Page 5

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

A device or system that records the ground oscillations that make upexplorationseismic data or earthquakes, sometimes used incorrectly as a synonym for geophone. A seismograph can include amplifiers, receivers and a… Read more →

The study of seismic or elastic waves, such as from earthquakes, explosions or other causes. Interpretation of the structure and composition of the Earth from artificially created seismic waves is a chief concern of… Read more →

A device that records seismic energy in the form of ground motion and transforms it to an electrical impulse. Read more →

The technique of selectively firing successive perforating guns arranged in a multiple gun assembly. This method is used when several intervals are to be perforated in one run and when the gun assembly must be relocated… Read more →

A type of landing nipple designed to be run in a series throughout the wellbore. Two basic types of selective nipple system may be encountered, a nipple series in which the nipple design or profile determines the… Read more →

A technique used to fire individual perforating guns when multiple guns have been run together in a single trip into the well. Selective firing is used to improve operational efficiency when several intervals are to be… Read more →

A wireline tool to set and retrieve selectively set downhole equipment such as plugs and similar flow-control devices. The selective running tool enables equipment to be set in a target nipple that may be one of a… Read more →

A quantitative measure of the coherence of seismic data from multiple channels that is equal to the energy of a stacked trace divided by the energy of all the traces that make up the stack. If data from all channels are… Read more →

What Is a Semisubmersible? A semisubmersible is a floating offshore drilling or production unit supported on large submerged pontoons connected to the main deck by a series of vertical columns and structural braces. The… Read more →

In matrixstimulation, a characteristic of rock that indicates the degree of reaction between the rock minerals and a given treating fluid. A formation is described as sensitive if a given stimulating fluid damages the… Read more →

What Is a Separator in Oil and Gas? A separator in oil and gas production is a pressure vessel that uses gravity, retention time, and often mechanical enhancement to split the well stream into its component phases: oil,… Read more →

The pressure required to force fluids to enter a separator. Read more →

The gas that remains after its separation from condensate. Read more →

A clay mineral with long, slender, needle-like structure, similar to attapulgite. It contains a mixture of fibrous and amorphous clay-like materials. API and ISO specifications exist for sepiolite used in drilling… Read more →

A group of relatively conformable strata that represents a cycle of deposition and is bounded by unconformities or correlative conformities. Sequences are the fundamental unit of interpretation in sequence stratigraphy.… Read more →

A surface that separates older sequences from younger ones, commonly an unconformity (indicating subaerial exposure), but in limited cases a correlative conformable surface. A sequence boundary is an erosional surface… Read more →

What Is Sequence Stratigraphy? Sequence stratigraphy interprets basin-filling sedimentary successions in a framework of eustasy, tectonic subsidence, and sediment supply, dividing the rock record into genetically… Read more →

A procedure for estimating the reservoir characteristics between data points. Based on the idea of iterating from a first guess and refining through reduction of errors, the procedure generally transforms the model to… Read more →

(noun) A chemical additive that forms stable, soluble complexes with dissolved metal ions (such as calcium, magnesium, and iron) in drilling fluids, completion fluids, or produced water, preventing those ions from… Read more →

A drilling mud filled open steel or earthen berm tank that is not stirred or circulated. By having mud slowly pass through such a container, most large drilling solids sink to the bottom, cleaning the mud somewhat. If… Read more →

The separation of mineral and/or royalty interest from fee-simple title. Severance of interests is usually accomplished by reservation in a deed or assignment or by conveyance in mineral or royalty deed, assignment or… Read more →

Generally, an area of the Earth from which waves do not emerge or cannot be recorded. In seismology, the term is used to more specifically describe regions of the subsurface where P-waves and S-waves are difficult to… Read more →

A fine-grained, impermeable, sedimentaryrock composed of clays and other minerals, usually with a high percentage of quartz. Shale is the most common, and certainly the most troublesome, rock type that must be drilled… Read more →

The average reading of the spontaneous potential (SP) log opposite the shale layers in a well. Opposite shales, the SP is relatively constant and changes only slowly with depth. This is the shale baseline. The log is… Read more →

Natural gas produced from shale formations. Read more →

The primary and probably most important device on the rig for removing drilled solids from the mud. This vibrating sieve is simple in concept, but a bit more complicated to use efficiently. A wire-cloth screen vibrates… Read more →

An explosive device that utilizes a cavity-effect explosive reaction to generate a high-pressure, high-velocity jet that creates a perforation tunnel. The shape of the explosive material and powdered metal lining… Read more →

A type of vertical seismicprofile in which the source is a shear-wave source rather than a compressional-wave source. Shear waves travel through the Earth at about half the speed of compressional waves and respond… Read more →

An elastic constant for the ratio of shearstress to shear strain. The shear modulus is one of the Lame constants. It can be expressed mathematically as follows: Read more →