Oil and Gas Terms Beginning with “S” — Page 6

A short piece of brass or steel that is used to retain sliding components in a fixed position until sufficient force is applied to break the pin. Once the pin is sheared, the components can then move to operate or… Read more →

A blowout preventer (BOP) closing element fitted with hardened tool steel blades designed to cut the drillpipe when the BOP is closed. A shear ram is normally used as a last resort to regain pressure control of a well… Read more →

The velocity gradient measured across the diameter of a fluid-flow channel, be it a pipe, annulus or other shape. Shear rate is the rate of change of velocity at which one layer of fluid passes over an adjacent layer.… Read more →

The bar or rod from which shear pins are cut for use in downhole slickline tools. Shear stock is prepared from carefully monitored materials to precise dimensions to ensure predictable and repeatable performance of… Read more →

The amount of deformation by shearing, in which parallel lines slide past each other in differing amounts. The measurement is expressed as the tangent of the change in angle between lines that were initially… Read more →

Another term for gel strength in a fluid. Shear strength opposes the movement of mud, whether by pumping or movement of pipe in a wellbore. Excessive shear strength can develop after a mud has been quiescent in the hole… Read more →

A test procedure published by the API that specifies the use of a shearometer tube and a set of weights to measure the shear strength of a mud (lbf/100 ft2 or kPa). The typical use for this test is for evaluation of a… Read more →

The force per unit area required to sustain a constant rate of fluid movement. Mathematically, shear stress can be defined as: If a fluid is placed between two parallel plates spaced 1.0 cm apart, and a force of 1.0… Read more →

An item of pressure-control equipment often fitted to the wellhead during well-intervention operations on live wells. Most commonly associated with coiled tubing operations, the shear-seal BOP is a ram-type preventer… Read more →

A test procedure published by the API that specifies the use of a shearometer tube and a set of weights to measure the shear strength of a mud (lbf/100 ft2 or kPa). The typical use for this test is for evaluation of a… Read more →

A pulley. In oilfield usage, the term usually refers to either the pulleys permanently mounted on the top of the rig (the crown blocks), or the pulleys used for running wireline tools into the wellbore. In the case of… Read more →

A luster, brightness or radiance. A sheen appears as a spectrum of colors and is commonly caused by a thin film on a surface that diffracts light. A film of diesel oil on water has a multicolored luster and is an… Read more →

A test intended to indicate the presence of free oil when drilling fluid, drilled cuttings, deck drainage, well treatment fluids, completion and workover fluids, produced water or sand or excess cementslurry are… Read more →

Continental shelf, or the area at the edges of a continent from the shoreline to a depth of 200 m [660 ft], where the continental slope begins. The shelf is commonly a wide, flat area with a slight seaward slope. The… Read more →

A technique in nuclear magnetic resonance (NMR) logging based on the shift in the T2 distributions, or spectra, acquired with different echo spacings. The technique is usually used to detect gas or light oil. These… Read more →

A downhole tool used to adjust the position of sliding sleeves or similar production and completion equipment. Shifting tools are typically run on slickline, although they may be used with coiled tubing in deviated or… Read more →

(noun) A guide fitting attached to the bottom of a casing string, liner, or other tubular that facilitates running the string into the wellbore by providing a rounded or tapered profile to deflect past ledges, dog legs,… Read more →

The space between the float or guide shoe and the landing or float collar. The principal function of this space is to ensure that the shoe is surrounded in high-quality cement and that any contamination that may bypass… Read more →

To use a special acoustic device to determine the fluid level in a conduit or annular space. The principle of operation relies on accurately recording the time taken for a return echo to be bounced from the fluid in… Read more →

To perforate a wellbore in preparation for production. Read more →

An abbreviated recovery of pipe out of, and then the replacement of same back into the wellbore. Such a trip is normally limited to 10 or 20 stands of drillpipe. Since the short trip is drillpipe only (no bottomhole… Read more →

Multiply-reflected seismic energy with a shorter travel path than long-path multiples. Short-path multiples tend to come from shallow subsurface phenomena or highly cyclical sedimentation and arrive soon after, and… Read more →

The location of an explosive seismic source below the surface. Before acquisition of surface seismic data onshore using explosive sources such as dynamite, holes are drilled at shotpoints and dynamite is placed in the… Read more →

A surface detection technique to verify that perforating guns have fired. This technique typically employs sensors that detect vibration or hydraulic shock at surface, and is used with TCP operations. Read more →

One of a number of locations or stations at the surface of the Earth at which a seismicsource is activated. Read more →

A formationlayer above or below the layer being measured by a logging tool. The term is used in particular in resistivity logging to describe the layers above and below a reservoir. Some resistivity tools, such as… Read more →

A surface observation of hydrocarbons, usually observed as florescent liquid on cuttings when viewed with an ultraviolet or black light (oil show) or increased gas readings from the mud logger's gas-detection equipment… Read more →

The force per unit area exerted at the bottom of a wellbore when it is closed at either the Christmas tree or the BOP stack. The SIBP is generated by a combination of the hydrostatic pressure from the weight of the… Read more →

The force per unit area exerted at the bottom of a wellbore when it is closed at either the Christmas tree or the BOP stack. The SIBP is generated by a combination of the hydrostatic pressure from the weight of the… Read more →

The surface force per unit area exerted at the top of a wellbore when it is closed at either the Christmas tree or the BOP stack. The pressure may be from the formation or an external and intentional source. The SIP may… Read more →