Oil and Gas Terms Beginning with “S” — Page 2

The ability of fluid to move through a rock, as measured by the reduction in amplitude or increase in slowness of the acoustic Stoneley wave generated in the borehole. The velocity and amplitude of the Stoneley wave are… Read more →

A type of large-amplitude interface, or surface, wave generated by a sonic tool in a borehole. Stoneley waves can propagate along a solid-fluid interface, such as along the walls of a fluid-filled borehole and are the… Read more →

An assembly of heavy beams used as the foundation on which the derrick or mast and usually the drawworks sit. Read more →

Abbreviation for water saturation. Read more →

The dimensionless ratio of the weight of a material to that of the same volume of water. Most common minerals have specific gravities between 2 and 7. Read more →

An environment of coastal sedimentation characterized by arid or semiarid conditions above the level of high tide and by the absence of vegetation. Evaporites, eolian deposits and tidal-flood deposits are common in… Read more →

A unit of measure for portland cement. In the United States, a sack refers the amount of cement that occupies a bulk volume of 1.0 ft3. For most portland cement, including API classes of cement, a sack weighs 94 pounds.… Read more →

A mechanical device attached to tool strings or flush surface tubulars as they are assembled or disassembled. The safety clamp prevents the tool string from being dropped downhole accidentally if the slips or elevators… Read more →

A blank gun section or spacer installed between the top perforating-gun assembly and firing head in a TCP operation. The safety spacer serves to position the gun assembly a safe distance below the rig floor during… Read more →

Settling of particles in the annulus of a well, which can occur when the mud is static or being circulated. Because of the combination of secondary flow and gravitational forces, weighting materials can settle (sag) in… Read more →

The product formed by neutralization of an acid and a base. The term is more specifically applied to sodium chloride. Neutralization is an important reaction in many aspects of mud control and treatment. Read more →

What Is a Salt Dome? A salt dome is a diapir (an intrusive geological body formed by buoyant rise of less-dense material) composed of halite (rock salt) and associated evaporite minerals that has pierced upward through… Read more →

A temporary plugging agent comprising graded granules of salt that form a physical or hydraulic barrier. The different grain sizes are prepared as a slurry for placement, then allowed to settle into a plug. The… Read more →

A type of refraction survey to help define a salt-sediment interface near a wellbore. The source is typically placed directly above the top of a salt dome and the receivers are placed at a number of locations within the… Read more →

A type of reflectionsurvey to help define a salt-sediment interface near a wellbore. Read more →

An influx of formation water, usually salty and sometimes hard, into the mud in the wellbore. Saltwater flows contaminate freshwater or seawater muds, making it expensive, difficult and time-consuming to regain the mud… Read more →

A water mud containing varying amounts of dissolved sodium chloride, NaCl, as a major component. Undissolved salt may also be present in saturated salt muds to increase density beyond 10 lbm/gal or to act as a bridging… Read more →

The number of data points or measurements per unit of time or distance. Read more →

The distance or time between data points or measurements. Read more →

The number of measurements per unit of time, or the inverse of the sample interval. Read more →

The error introduced by the sampling process caused by making measurements on only a limited portion of a formation. Read more →

The depth or time between successive measurements by a sensor. For measurements-while-drilling (MWD) logs, the sampling interval is most commonly a time. For wireline measurements, it is most commonly a depth. Read more →

A generic term used to describe small formation particles known as fines that may be produced with the reservoir fluid. Sand production generally is undesirable and, if severe, may require some remedial action to… Read more →

A swabbing device used to clean up sand that has accumulated in the wellbore. Because sands abrasiveness is detrimental to the normal operation of production equipment, its production should be minimized. A sand bailer… Read more →

The process of removing sand or similar fill from a wellbore. Many wells produce sand that may accumulate and restrict production if not removed from the wellbore by the production fluid. Coiled tubing and snubbing… Read more →

A means of controlling the undesirable production of sand from weak sandstone formations. Sand consolidation chemically binds the grains of sand that make up the formationmatrix while maintaining sufficient permeability… Read more →

What Is Sand Control in Oil and Gas? Sand control encompasses the completion and production engineering techniques used to prevent unconsolidated or weakly consolidated formation sand from being produced with reservoir… Read more →

A long cable, installed on most drilling and workover rigs, used when swabbing or bailing in the production tubing or wellbore tubulars. The sand line is typically stored and operated on a winch drum that is part of the… Read more →

The migration of formationsand caused by the flow of reservoir fluids. The production of sand is generally undesirable since it can restrict productivity, erodecompletion components, impede wellbore access, interfere… Read more →

A test to determine the volume percent of solids in a mud that are retained on 200-mesh screen. A glass, sand-content tube with a tapered lower end and a 200-mesh screen are used in the test. The test measures percent… Read more →