Oil and Gas Terms Beginning with “S” — Page 12

To place the male threads of a piece of the drillstring, such as a joint of drillpipe, into the mating female threads, prior to making up tight. Read more →

To guide and engage components that are designed to couple, such as a seal assembly in a sealborepacker. Read more →

A valve that is connected to the work string in the event that the well starts to flow when running or retrieving the string. A stabbing valve generally is kept on the rig floor as a contingency against unexpected well… Read more →

A state that a producing well reaches when the flow rate and well pressure are apparently constant for a reasonable period of time, such as a few hours or a day or more. The actual time period is rather arbitrary and… Read more →

A term describing a flowing well when its rate of production through a given choke size remains constant, or in the case of a pumping well, when the fluid column within the well remains constant in height. Read more →

A gas well producing at a constant rate in which wellheadpressure changes no more than a small amount as a function of time. The actual amount of change permitted in a given time period to allow a well to be designated… Read more →

The geometric profile around a correctly placed perforation. With the removal of perforating debris and the crushed zone by flushing or stimulation treatment, the exposed formation forms an arch that is capable of… Read more →

To sum traces to improve the signal-to-noise ratio, reduce noise and improve seismic data quality. Traces from different shot records with a common reflection point, such as common midpoint (CMP) data, are stacked to… Read more →

The distance-time relationship determined from analysis of normal moveout (NMO) measurements from common depth point gathers of seismic data. The stacking velocity is used to correct the arrival times of events in the… Read more →

An operation in which the well stream is passed through two or more separators that are arranged in series. The first separator is called first-stage separator, the second separator is called second-stage separator and… Read more →

An operation in which numerous reservoir intervals are hydraulically stimulated in succession. Staged hydraulic fracturing operations are commonly performed from horizontal wellbores placed in shale gas reservoirs.… Read more →

Two or three single joints of drillpipe or drill collars that remain screwed together during tripping operations. Most modern medium- to deep-capacity drilling rigs handle three-joint stands, called "trebles" or… Read more →

A rigid metal conduit that provides the high-pressure pathway for drilling mud to travel approximately one-third of the way up the derrick, where it connects to a flexible high-pressure hose (kelly hose). Many large… Read more →

A type of batch-treating technique used in corrosion control. The batch of corrosion inhibitor is displaced through the annulus to the bottom of the well. Once the inhibitor is at the bottom, it is circulated up the… Read more →

In a subsurface sucker-rod pump, a valve that permits flow up the tubing to fill the pump-barrel chamber while preventing downward flow. Read more →

A piece of material designed to hold a logging tool a certain distance away from the borehole wall. It is usually made of hard rubber and consists of four to six fins of the desired length. Read more →

A rigid metal conduit that provides the high-pressure pathway for drilling mud to travel approximately one-third of the way up the derrick, where it connects to a flexible high-pressure hose (kelly hose). Many large… Read more →

A drilling-mud additive used to control fluid loss in water muds ranging from freshwater to saturated-salt to high-pH lime muds. Starches have thermal stability to about 250°F [121°C]. They are subject to bacterial… Read more →

A mud test in which the mud sample is not agitated. This test is usually performed at a selected high temperature. Typically, the mud sample is sealed in a mud-aging cell and placed in an oven for a given period of time… Read more →

Often called statics, a bulk shift of a seismic trace in time during seismic processing. A common static correction is the weathering correction, which compensates for a layer of low seismic velocity material near the… Read more →

A filtration process in which the slurry being filtered remains static. Filter cake continues to grow thicker as filtration continues. Under static conditions, no cake erosion occurs. In theory, the filtrate volume… Read more →

The level to which fluid rises in a well when the well is shut in. The hydrostatic head of this fluid is equal to the well bottomhole pressure. Read more →

The pressure measured in a well after the well has been closed in for a period of time, often after 24 or 72 hours. When a reservoir is first discovered, the static pressure equals the initial pressure. After production… Read more →

The ideal spontaneous potential (SP) that would be observed opposite a permeablebed if the SP currents were prevented from flowing and any shaliness in the bed were ignored. The static spontaneous potential (SSP) is… Read more →

A mud test in which the mud sample is not agitated. This test is usually performed at a selected high temperature. Typically, the mud sample is sealed in a mud-aging cell and placed in an oven for a given period of time… Read more →

A form of homogeneity in a single characteristic. Local stationarity occurs when two or more adjacent, locally homogeneous samples yield similar values of the property of interest. Read more →

The slip set on a snubbing unit located at the base of the jack. Two sets of stationary slips are available, one set for pipe-heavy conditions and another for pipe-light conditions. Read more →

The stationary slip set on a snubbing unit used when operating under light-pipe conditions. Under these conditions, the wellheadpressure is sufficient to eject the tubing string from the wellbore. Therefore, the slips… Read more →

A branch of mathematics that attempts to bring some understanding in the analysis of quantitative measurements. This science deals with the collection, analysis and interpretation of numerical data, often using… Read more →

A system that has reached equilibrium for the measurement or phenomenon concerned. In the case of permeability measurements on core samples, a steady state is reached when the flow rate, the upstream and the downstream… Read more →