Oil and Gas Terms Beginning with “S” — Page 11

The distribution of gamma ray energies, or the number of gamma rays as a function of gamma ray energy. Read more →

The apparent loss of intensity of a gravitational or magnetic field with distance. Spherical divergence decreases energy with the square of the distance. Read more →

Spherical flow is a flow geometry in which reservoir fluids converge toward a point (or, in the partial penetration case, a hemispherical surface) from all directions in three-dimensional space, in contrast to radial… Read more →

What Is Spherical Focusing? Spherical focusing is an electrode arrangement used in wireline resistivity logging tools to focus electrical current into a spherical shell pattern around the measuring electrode,… Read more →

A spherical harmonic is a mathematical function defined on the surface of a sphere that is a solution to Laplace's equation (the partial differential equation nabla^2 f = 0) when expressed in spherical coordinates (r,… Read more →

A spherical separator is a pressure vessel with a spherical or near-spherical shell geometry used for the separation of oil, gas, and water phases in petroleum production facilities, designed to handle slug flow… Read more →

A spherical wave is an elastic disturbance that radiates outward in every direction from a point source, forming a continuously expanding spherical wavefront whose surface area grows in proportion to the square of the… Read more →

The spill point of a petroleum trap is the lowest structural elevation of the trap's closure — the point at which hydrocarbons would begin to migrate out of the trap laterally if the trap were filled to that depth — and… Read more →

A spin flowmeter (also called a spinner flowmeter or production logging spinner) is a downhole instrument run on wireline or coiled tubing inside a producing or injecting well that measures local fluid velocity by… Read more →

A spine and ribs plot in formation evaluation is a graphical quality-control and mudcake correction tool used with two-detector compensated density logs, displaying the long-spacing detector count rate on one axis… Read more →

What Is a Spinner Flowmeter? A spinner flowmeter is a downhole production logging tool that measures in-situ fluid velocity inside a wellbore by counting the rotational speed of an impeller or vane assembly. As wellbore… Read more →

Spinner reversal is the change in direction of rotation that occurs when a spinner flowmeter logging tool is moving through a wellbore in the same direction as the fluid flow but at a higher velocity than the fluid — at… Read more →

What Is a Spinning Chain? A spinning chain is a length of ordinary steel link chain used by the drilling crew to rapidly spin new pipe joints into a standing drillstring connection, wrapped around the lower tool joint… Read more →

A spinning drop tensiometer is a laboratory instrument that measures ultra-low interfacial tension (IFT) between two immiscible liquids by injecting a small drop of the less-dense fluid into a horizontal tube filled… Read more →

A spline in petroleum engineering and geoscience computing is a mathematical interpolation procedure that fits a smooth continuous curve through or near a set of discrete data points, where the curve is constructed as a… Read more →

What Is Spontaneous Potential? The spontaneous potential (SP) log measures the natural electrochemical voltage, in millivolts, generated between a moving borehole electrode and a fixed surface reference electrode as the… Read more →

A spooler in oil and gas operations is a surface equipment system designed to wind, store, and deploy a continuous length of coiled tubing, wireline, flexible pipe, umbilical cable, or other flexible linear material… Read more →

In the oil and gas industry, "spot" has multiple context-dependent meanings that all relate to the concept of immediate availability or precise location: in crude oil and natural gas trading, a spot transaction (or spot… Read more →

A sample of liquid or sediments obtained at a specific depth inside a tank using a thief or a bottle. Spot samples are analyzed to determine the gravity of the oil and BS&W content of the fluid in the tank. Read more →

A spotting fluid is a specially formulated liquid pumped into the wellbore and displaced to the depth of a stuck drill string or bottom hole assembly, where it penetrates the differential pressure filter cake holding… Read more →

In seismic acquisition, a spread (also called a receiver spread or geophone spread) is the geometrical arrangement of the geophone groups (or hydrophone groups in marine surveys) that are active and recording during the… Read more →

Spreading loss (also called geometrical spreading or geometrical divergence) is the reduction in seismic wave amplitude that occurs as the wavefront expands outward from the source and its energy is distributed over an… Read more →

What Is a Spud? A spud marks the moment drilling begins on a new well, the first rotation of the drill bit breaking ground at the surface or seafloor. Operators report the spud date to regulators including the AER in… Read more →

Spud mud is the initial drilling fluid used when first drilling a well (spudding in), typically a simple, low-cost, low-density fluid such as freshwater, seawater, or a lightly treated bentonite-water mixture that is… Read more →

Spurt loss is the instantaneous volume of liquid (the "spurt") that passes through a filter medium during the brief initial period before deposition of a competent and controlling filter cake — providing the early-time… Read more →

A square log (also called a blocked log or step log) is a digitized representation of a wireline well log in which the continuously varying measurement is averaged and displayed as a series of discrete, constant-value… Read more →

What Is Squeeze Cementing? Squeeze cementing forces cement slurry under pressure through perforations, channels, or voids in an existing wellbore to restore or establish zonal isolation between formations. Operators… Read more →

A squeeze manifold is a specialized surface equipment arrangement — a piping and valve assembly installed at the wellhead — that enables controlled high-pressure pumping of treatment fluids (cement, chemical scale… Read more →

A squeeze packer is a specialized type of retrievable packer specifically designed for use in cement squeeze operations — providing the temporary wellbore isolation that allows controlled cement slurry placement at a… Read more →

Squeeze pressure in well cementing and oil and gas production operations is the maximum hydraulic pressure applied at the wellhead or at a specific downhole tool (squeeze packer, bridge plug, or drillstring) during a… Read more →