Discover the IHRDC Energy Glossary_beta

sabkha

An Arabic word for flat, salt-encrusted areas that are subject to periodic flooding and evaporation. Sabkhas are supratidal, forming along arid coastlines, characterized by evaporite-carbonate deposits with some siliciclastics and the accumulation of aeolian clays, evaporites, and salts.

sacrificial anode

A method of cathodic protection.

saddle bearing

A bearing located on top of the sampson post. The saddle bearing supports the walking beam and allows it to pivot.

safety belt

A belt securing a driver or passenger to their seat as a precaution against injury in a crash.

safety data sheet (SDS)

A 16-section document that contains information on the specific hazards of a chemical, its health effects and treatment, clean-up instructions, and other information.

safety fuse plugs

A device on a compressed as cylinder that releases gas in the event of a fire to prevent an explosion.

safety glasses

Glasses, usually with side shields, that meet the minimum recognized standards for impact resistance.

safety head

The flanges and fittings used to hold a rupture disc; another name for rupture disk assemblies.

safety interlock system

A security fence, security key, and switch that serve to isolate a capacitor bank.

safety relief valve

A valve that can be used as either a safety valve or a relief valve, depending on the application.

safety switch

Usually, a knife-type switch that is manually operated by means of a handle and linkage.

safety valve

An automatic pressure relief device that pops open quickly to relieve excess pressure in a system containing steam or gas, venting to the atmosphere. Commonly used in gas and steam systems.

sag ponds

A body of fresh water collected in the lowest parts of a depression formed between two sides of an active strike-slip, transtensional or normal fault zone.

salient-pole rotor

A type of rotor, primarily used in low-speed applications, that has windings wrapped around metal pole pieces.

saline

Having some dissolved salt content.

salinity

The saltiness, or dissolved salt content, of water.

salinity, saline

Salinity is the saltiness, or dissolved salt content, of water.

salt cavern storage

A storage facility that cycles gas in and out of underground caverns leached, brined or mined in either bedded salt or a salt dome.

sample

A small representative quantity of gas or liquid obtained for analysis.

sample analysis

The procedure which measures the components, contaminants and/or BTU value of a natural gas or liquid stream.

sample cylinder

A pressure device with which natural gas and liquid samples are collected; typically made of stainless steel.

sample point

The raw data from an analog to digital converter used to calculate waveform points.

sampler

A device on the LACT unit which collects and maintains a sample of the liquid passing through the unit.

Sampson post

The structure that supports the beam.

sandface

The physical interface between the formation and the wellbore.

sandstone

A clastic sedimentary rock (also called arenite) composed of sand-sized minerals and rock grains, most commonly quartz and/or feldspar.

sandstone line for spontaneous potential

The sandstone line on a Spontaneous Potential (SP) curve is established by the position of the SP curve opposite clean, permeable formations.

sandstone, sand

Sandstone, or arenite, is a clastic sedimentary rock composed of sand-sized minerals and rock grains. Most sandstone is composed of quartz and/or feldspar.

sandstone, sand, siliciclastic

A clastic sedimentary rock (also called arenite) composed of sand-sized minerals and rock grains, most commonly quartz and/or feldspar.

sandstone, sand, siliciclastic, silica

Sandstone, or arenite, is a clastic sedimentary rock composed of sand-sized minerals and rock grains. Most sandstone is composed of quartz and/or feldspar. Often, in the oil industry, the terms sandstone and sand are incorrectly used interchangeably.

saprolite

Saprolite is a soft, earthy, and thoroughly decomposed rock, often rich in clay, that is formed in situ by the chemical weathering of igneous, metamorphic, or sedimentary rocks that retains some of the original rock's structures.

saturated air

Air that is holding its maximum amount of water vapor.

saturated gas

A gas stream which contains the maximum water vapor at its operating conditions.

saturated molecule

A molecule whose structure is such that no additional atoms may be added to it.

saturated solution

A solution containing as much solute as it can dissolve at a given temperature and pressure.

saturating transformer

A device in a pilot wire relay that limits the voltage output that is impressed on the pilot wires in a pilot wire relaying system.

saturation

A state in which an increase in the input signal to an amplifier causes no further increase in output; the output is at or near the supply voltage.

saturation exponent (n)

The exponent n in the relation of water saturation (Sw) to resistivity index (I) where I = Sw⁻ⁿ. It expresses the effect on resistivity of desaturating a rock sample, or replacing water with a non-conductive fluid.

saturation temperature

The temperature at which water will boil at a given pressure.

save

The process of uploading a project from a PLC to a PC or to an EEPROM.

sawtooth and triangle waves

Waves that result from circuits designed to control voltages linearly, such as the horizontal sweep of an analog oscilloscope. The transitions between voltage levels of these waves change at a constant rate. These transitions are called ramps.

SC connector

A type of optic cable connector that snaps straight into equipment.

SCADA system

Supervisory Control and Data Acquisition system that collects data on process or production, and issues automated control decisions to local equipment controllers.

scaffold

An elevated work platform for personnel and materials.

scale

A deposit or coating formed on the surface of metal, rock, or other material due to precipitation from chemical reactions or changes in pressure, temperature, or solution composition. Can build up on the insides of water tubes, pipes, and equipment, interfering with heat transfer and restricting flow. Also, the ratio between the size of an object on a drawing and its actual size.

scale inhibitors

Chemicals added to cooling water to protect equipment from scale formation.

scan cycle

The three-step process that a PLC uses to perform its job: scan the inputs, perform the program logic, and set the outputs.

scanning electron microscope (SEM)

A scanning electron microscope is a type of electron microscope that produces images of a rock sample by scanning it with a focused beam of electrons. The electrons interact with atoms in the rock, producing various signals that can be detected and that contain information about the rock's composition.

schematic

A schematic is a diagram that represents the elements of a system using abstract, graphic symbols rather than realistic pictures.

schematic diagram

A drawing that uses symbols to show the electrical connections and functions of a specific circuit arrangement, with components shown in their proper electrical locations. Also called an elementary diagram.

scientific notation

The expression of a quantity as a decimal number times a power of ten.

scintillation counter

A scintillation counter is a device for detecting and recording scintillations, especially in order to measure ionizing radiation.

scintillation detector

Scintillation detectors use crystals that emit light when gamma rays interact with the atoms in the crystals. The intensity of the light produced is proportional to the energy deposited in the crystal by the gamma ray.

Scottish qualifications authority (SQA)

The national accreditation and awarding body for Scotland. Its purpose is to help people fulfill their potential and maintain standards across Scottish education. SQA engages with learners, schools, colleges and training providers across Scotland, the rest of the UK and internationally, to develop, maintain, and improve a framework of qualifications, and to set and maintain standards for many other awarding bodies and accredited qualifications.

Scottish vocational qualification (SVQ)

SVQs are work-based qualifications that work as a guarantee that someone can do their job well and to the national standards for their sector. Qualifications in the oil and gas sector include, among others, Instrument and Control Technicians, Electrical Technicians, Mechanical Technicians, Control Room Operators.

scour and fill

Scour and fill refers to a structure that has been eroded by water flow and has then been filled with coarse sediment over time.

SCR

Silicon-Controlled Rectifier. A silicon device with four PNPN layers having an input control terminal (gate), an output terminal (anode), and a terminal common to both (cathode). A high-speed, solid-state switch used in variable speed drives and for lighting/heating control.

scraper rings

Rings on the piston rod which remove lubricants.

screen

An air cleaning device to prevent large contaminants from entering a system. Also, a device installed upstream of a pump or compressor to keep solid material from entering the suction.

screen out

A condition that occurs when the solid proppant carried out in fracture treatment fluid creates a bridge across the perforations or similar restriction flow area.

screw

A threaded fastener with a nail-shaped or rod-shaped body and a slotted or recessed head. A screw is designed to be inserted into material by rotating, and is used for fastening pieces of solid material together.

screw pump

A rotary positive displacement pump that uses one or more screws to move fluid.

scrubber

A device or vessel that uses absorption, spray, or other methods to remove impurities and contaminants from a gas, vapor, or exhaust stream. In amine treatment, a component that removes amine solution carried by sweetened gas.

sea floor

This effect can also occur in fresh water bodies, but for consistency, we have chosen to use the term 'sea floor' in this section.

seal

A layered lithological unit capable of impeding hydrocarbon movement, typically thick, laterally continuous, ductile rock with high capillary entry pressure. Also, any device for eliminating or controlling fluid flow between areas.

seal gas

Dry, clean, higher pressure gas supplied between labyrinth seals of the expander-compressor to prevent process gas from reaching the bearings or lubrication system.

seal, sealing fault

A seal is a layered lithological unit capable of impeding hydrocarbon movement. Effective seals for hydrocarbon accumulations are typically thick, laterally continuous, ductile rocks with high capillary entry pressures. Faults can be seals.

search

A software troubleshooting tool that allows you to find specific instructions in a program.

search angle

Search angle defines how far up and down the hole the computer matching process seeks a correlation and, depending on the hole size, reflects the analyst's initial estimate of the highest expected dip.

seasoning new wireline logging cable

Seasoning is the process of balancing cable torque in a new wireline logging cable.

seat

A stationary part of a valve onto which a disc or other flow control component presses to stop flow through the valve.

secondary burn

See Proof burn.

secondary coil

The coil in a transformer in which an EMF is induced.

secondary element

Part of a meter station, consisting of the meter piping, meter manifold, recording devices, and associated measurement equipment such as static pressure recorders, density meters, and samplers.

secondary loop

The inner, or slave, control loop in a cascade control system that controls its variable according to a set point provided by the primary loop.

secondary porosity

Porosity created after deposition and burial through alteration of rock by mechanical processes (compaction, deformation, fracturing) and geochemical processes (dissolution, dolomitization, precipitation, volume reductions by mineralogical changes).

secondary porosity index

The secondary porosity index is an indicator of the porosity that does not contribute to a sonic measurement of interval transit time. The transit time is little affected by vugs, fractures and other irregular events because the sonic wave finds a faster path around them. Spherical pores such as oomolds also have less effect on travel time than oblate pores. Thus, when the sonic porosity is less than some measurement of the total porosity, the difference can be attributed to the presence of post-depositional, or secondary, porosity.

secondary recovery

Secondary recovery technique refers to any method for removing oil from a reservoir after all natural recovery methods have been exhausted.

secondary supervisor

Supervisors may assign an employee's competency role to another user with Supervisor permissions in order to have that person - called a secondary supervisor - complete all or part of the supervisor assessment. One example might be where the secondary supervisor is a subject matter expert in a safety critical competency. The primary supervisor will need to review and submit any assessment completed by a secondary supervisor. Although the secondary supervisor will mark an assessment complete when finished, it will not be finalized until the primary supervisor submits it.

secondary winding

The winding of a transformer into which voltage is induced and to which a load is connected.

section

A subdivision of a part in the NEC.

section drawing

A cutaway drawing that shows the inside of a building or an object.

sectionalizer

Operates when a line is "dead" due to the operation of a reclosing relay or circuit breaker in order to isolate a section of line while allowing the remainder of the circuit to remain energized.

sedimentology

The study of sediments such as sand, silt, and clay, and the processes that result in their formation, transport, deposition, and diagenesis.

seeding

Adding crystals to a solution to cause new crystals to form around them.

seif dune

A seif dune is a long, narrow sand dune or chain of dunes, generally oriented in a direction parallel to the prevailing wind.

seismic data

Seismic data is comprised of sound (seismic) wave recordings of Earth's subsurface that are obtained in seismic surveys. Seismic waves are generated by specialized equipment that reflects off subsurface rock layers which are then are captured by recording equipment. The data are processed and interpreted to provide a "picture" of the subsurface geology in either 2D (single slice) or 3D (volume) formats, depending on the survey design.

seismic data (3D and 2D)

3D seismic data is a set of numerous, closely spaced seismic lines that provide a high spatially sampled measure of the subsurface reflectivity. 2D seismic data is a group of 2D seismic lines acquired individually, as opposed to the multiple, closely spaced lines acquired together in 3D seismic data.

seismic survey

Technique for determining the structure of underground rock formations by sending energy waves or sound waves into the earth and recording the time it takes for waves to reflect back to the surface. Three-dimensional (3D) seismic surveys provide enhanced subsurface images for selecting well locations.

select carcinogen

Any substance which meets one of the following criteria: (i) It is regulated by OSHA as a carcinogen; or (ii) It is listed under the category, "known to be carcinogens," in the Annual Report on Carcinogens published by the National Toxicology Program (NTP) (latest edition); or (iii) It is listed under Group 1 ("carcinogenic to humans") by the International Agency for Research on Cancer Monographs (IARC) (latest editions); or (iv) It is listed in either Group 2A or 2B by IARC or under the category, "reasonably anticipated to be carcinogens" by NTP, and causes statistically significant tumor incidence in experimental animals in accordance with any of the following criteria: (A) After inhalation exposure of 6-7 hours per day, 5 days per week, for a significant portion of a lifetime to dosages of less than 10 mg/(3); (B) After repeated skin application of less than 300 (mg/kg of body weight) per week; or (C) After oral dosages of less than 50 mg/kg of body weight per day.

selective azeotropic solvents

Solvents that form azeotropes with only certain types of compounds.

selective control

A control system in which the numbers of controlled and manipulated variables are unequal; a method of sharing variables.

selective coordination

The process of isolating a faulted circuit from the rest of an electrical system by the proper selection of overcurrent protective devices within the system.

selectivity

The differing degrees of attraction that different ions have to resin bead sites. Also, the ability of a catalyst to select certain hydrocarbon components for reaction.

selector

A control device that selects one input from two or more inputs on the basis of comparative magnitude; for example, a high selector or low selector.

self-assessment or employee assessment (EA)

An employee uses CMS Online software to indicate his competency level for each Competency Unit by checking the box next to the skills that he can perform.

self-contained breathing apparatus

An air-supplied respirator that provides clean air from tanks for breathing. Also referred to as an SCBA.

self-contained breathing apparatus (SCBA)

Personal protective equipment that supplies users with breathable air from a compressed air tank that is typically worn on the user's back.

self-cooled power transformer

A power transformer that is cooled by the natural circulation of oil and air.

self-cooled/forced-air cooled power transformer

A power transformer that is cooled by the natural circulation of oil and the forced circulation of air.

self-induction

A type of induction that occurs within a single conductor; it occurs when a change in the electromagnetic field around a conductor induces a voltage in that conductor.

semi-open impeller

An impeller that has a shroud on only one side of the vanes.

semiregenerative reforming

A type of catalytic reforming in which the catalyst is regenerated inside the reactors while the unit is shut down.

sensible heat

Heat that is transferred during a temperature change.

sensible heat transfer

A heat transfer process that causes a measurable change in temperature rather than a phase change.

sensing device

A device that responds to the condition of a process variable.

sensitive volume

The region from which an NMR signal will preferentially be acquired because of strong magnetic field inhomogeneity elsewhere.

sensitivity

The difference between the MON and RON of a given gasoline. Gasoline with high sensitivity is more affected by changes in engine operating conditions than is gasoline with low sensitivity.

sensitizer

A chemical that causes an allergic reaction in normal tissue after repeated exposure to the chemical.

sensor

A transducer whose purpose is to sense or detect some characteristic of its environment.

separately excited

A DC motor in which the armature windings and the field windings are not energized by the same source.

separator

A vessel that allows gas to separate from liquids, or in which different components settle out according to their different densities. Also called a settling tank, accumulator, or receiver.

sequence filter

A device in a pilot wire relay that converts three-phase current inputs into a single-phase voltage output.

sequence valve

A pressure control valve that senses pressure changes to control the sequence of operation of two separate components.

sequencing

A discrete control function that allows events to take place only in a particular order.

sequencing chart

A chart that shows the positions of a motor controller's components during various stages of controller operation.

serial connection

A connection between racks or devices where data is transmitted one bit at a time. The physical medium is usually coaxial cable or a shielded twisted pair.

serial troubleshooting

A method of troubleshooting in which each component in a circuit or process is tested in sequence until the source of the problem is located.

sericite

Sericite is a fine-grained fibrous variety of muscovite, mainly found in schist.

series

A DC motor in which the armature windings and the field windings are wired in series and energized by the same source.

series circuit

A circuit that has only one path for current flow, with components connected end to end.

series motor

A DC motor in which the field coils are connected in series with the armature.

series reactor

Substation equipment used to limit rapid changes in current flow.

series regulator

A regulator that is in series with the load.

series-parallel circuit

A circuit that has both series and parallel current paths, with some components connected in series and some in parallel.

servo system

A system that employs proportional valves along with a system of feedback in a closed loop configuration.

set point

The desired limit or particular value at which a control loop attempts to maintain a process variable.

set rod

A rod that can be screwed in to disconnect limit switch gearing from motor operator gearing.

setpoint

The point at which a process loop should stabilize, typically established by supervisory controllers. Also, the commanded speed at which a variable speed drive is set to run.

settling

The third stage of clarification, in which floc settles to the bottom of a settling basin, leaving clarified water at the top.

settling time

The time required for an output voltage to settle within a specified error band of the final value after a step change at the input (also known as total response time). Also, the time it takes for water to separate from oil.

severity

A measure of how much a hydrocarbon molecule is cracked during the cat cracking process.

shackle

A U-shaped connector with a removable pin used to connect or couple rope or chain to other pieces of rigging equipment. Sometimes called a clevis.

shading

The short-circuiting of a portion of an electromagnet by metal rings or coils in a protective relay.

shaft voltage

The difference in voltage potential between the shaft of a motor and ground. Shaft voltages can cause lubricant failure and bearing failure, and they can affect the stability of motor flux fields during the operation of a variable speed drive.

shale

A fine-grained, fissile, detrital sedimentary rock formed by consolidation of clay- and silt-sized particles into thin, relatively impermeable layers. Certain shale formations (such as the Eagle Ford and Barnett) contain large amounts of oil and natural gas.

shale baseline

The shale baseline is 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.

shale gas

Natural gas that is found trapped within shale formations.

shale oil

Shale oil is oil that is found trapped within shale formations.

shale shaker

A shale shaker is a piece of equipment that is part of the solids-control equipment on a drilling rig. It has mesh grills used for separating the drill cuttings from the circulating drilling mud.

shale shakers

Components of drilling equipment (mesh grills) used as the first phase of solids control on a drilling rig, separating drill cuttings from the circulating drilling mud.

shale shavers

Shale shakers are mesh grills used for separating the drill, or ditch, cuttings from the circulating drilling mud.

shale swelling

Shale swelling is caused by clay (one of the major components of shale) absorbing water, usually from drilling fluid.

shale volume, volume of shale, Vsh

Shale volume (Vsh) is the volumetric percentage of shale within a formation, or in a specific interval of a formation.

shale, shaly

Shale is a fine-grained, fissile, detrital sedimentary rock formed by consolidation of clay- and silt-sized particles into thin, relatively impermeable layers.

shear fracture

A shear fracture refers to the breakage and/or disintegration of a rock formation due to the application of a strain force on its surface.

shear strength

Shear strength is the strength of a material against the type of yield or structural failure when the material fails in shear.

shear velocity

Shear velocity is the velocity of shear waves.

shear wave

A shear wave (S wave) is an elastic body wave in which particles oscillate perpendicular to the direction in which the wave propagates. Shear waves travel more slowly than compressional waves (P waves) and cannot travel through fluids because fluids do not support shear. Interpretation of S waves can allow determination of rock properties such as fracture density and orientation, Poisson's ratio, and rock type by cross-plotting P wave and S wave velocities and by other techniques.

sheathed capacitance probe

A singular capacitance probe that uses a tubular metal shell and a metal inner rod as the two plates of the "capacitor."

sheave

A grooved wheel or pulley used for changing a rope's direction of travel.

sheave, sheave wheel

A sheave is a pulley used for running wireline tools into the wellbore. During wireline operations, two sheaves are temporarily hung in the derrick, and the wireline is run from the logging truck through the sheaves and then down to the logging tool in the wellbore.

shelf couplers

Devices located at the ends of a tank car and used to connect the car to other cars in a train.

shell

The part of a fire tube boiler that holds the water necessary to produce steam.

shell and tube heat exchanger

A heat exchanger that consists of a shell, tubes, tube sheets, and heads that function together in the heat exchange process between two fluids.

shell side

The area within the shell and outside pf the tubes of a shell and tube heat exchanger.

shell-side fluid

The fluid flowing through the shell and around the outside of the tubes in a shell and tube heat exchanger.

shielded metal arc welding

A method of arc welding that uses short, coated electrodes to provide metal for the weld and material to create the gas shield. Also called stick welding.

shipping papers

Documentation that must accompany a hazardous materials shipment; shipping papers (sometimes referred to as manifests, invoices, or bills of lading) detail the type of hazardous material being shipped and any safety concerns presented by that material.

shock

A condition caused by a sudden change in operating conditions that tends to severely disrupt a biological treatment process.

shooters

A shooter is a position on the field seismic crew whose primary responsibility is to detonate explosive charges, in coordination with the Observer.

short

A condition of maximum current flow and minimum resistance in an electrical circuit; an accidental low-resistance current path.

short circuit

A connection accidentally established in an electrical circuit when an unintended path of very low resistance is created, causing current to reach its maximum value.

short-circuit output current

The maximum continuous output current available from the amplifier with the output shorted to ground, to either supply, or to a specified point. Sometimes a low value series resistor is specified.

short-term exposure limit (STEL)

The maximum amount of a substance to which a worker can be exposed for up to fifteen minutes.

shoulder tendinitis

Inflammation of the tendons of the shoulder. Also called rotator cuff syndrome, it can result from working overhead with heavy objects.

show

A show is a surface observation of hydrocarbons, which usually appears 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 (gas show).

shrink

A temporary drop in boiler drum level caused by changes in steam flow.

shroud

A metal plate or covering over the vanes of an impeller or over a compressor component, providing support and protection.

shunt

A DC motor in which the armature windings and the field windings are wired in parallel and energized by the same source.

shunt motor

A DC motor in which the field coils and the armature are connected in parallel.

shunt reactor

Equipment used to improve power factor by offsetting excessive demand for capacitive power.

shunt regulator

A regulator that is in parallel with the load.

shunt resistor

The component in an ammeter that causes most of the current being measured to bypass the display circuitry; also called a meter shunt.

shut in

To close off a well so that it stops producing.

shutter ridges

A ridge which has moved along a fault line, blocking or diverting drainage.

side door overshot

The side door overshot is a fishing tool that is used to retrieve logging sondes that are stuck in a borehole. The advantage of this method is that it does not require the wireline to be cut. This tool is attached to drill pipe and lowered downhole.

sidelobes

Sidelobes are additional components of the main source signature pulse that are usually noise and detract from the main signal.

sidereal

Sidereal: The time it takes for the Earth to complete one rotation about its axis, with respect to the “fixed” stars.

sidestream stripper

A small tower, with trays inside, that uses steam to remove light ends from the LCD fraction from the main fractionator.

sidetrack

A secondary wellbore that deviates from the original wellbore. Intentional sidetracks might bypass an unusable section of the original wellbore or explore a nearby geological feature.

sidewall core (percussion sidewall core and rotary sidewall core)

A sidewall core is taken from the side of the borehole, using either percussion or a mechanical drilling process (rotary sidewall cores).

sidewall core (percussion sidewall cores and rotary sidewall cores)

A core taken from the side of the borehole using either a percussion tool (firing hollow bullets) or a mechanical drilling process (rotary sidewall cores).

sidewall cores

A sidewall core is a small cylindrical core of rock, of maximum length 3 in. and maximum diameter 1 in., taken from the side of the open borehole using a logging tool run on wireline. Sidewall cores can be acquired using either percussion or mechanical drilling methods.

siemen

Standard international unit of measurement for conductivity. Usually expressed in readouts as micro siemens, S.

sight glass

A device located on the outside of a vessel or separator used for monitoring and checking liquid levels inside.

sightglass

A transparent vertical tube attached to a tank that fills to the same level as the liquid in the tank, allowing operators to see the level in the tank.

sigma

Sigma is the macroscopic cross section for the absorption of thermal neutrons, or capture cross section, of a volume of matter, measured in capture units.

signal

Electronic information sent from one device or element to another.

signal common

Similar to electrical ground. In op amp circuits with bipolar supply voltages. signal common is a point that is electrically common to the supply voltages and to the input and output voltages; usually zero volts.

signature bonus

Cash consideration paid to a landowner or mineral owner upon the execution of an oil and gas Exploration Agreement.

signed number

A number that is marked as either positive or negative.

silicates, silica

A silicate is a compound containing an anionic silicon compound. The great majority of silicates are oxides.

siliciclastic

Siliciclastic is containing silica.

siliciclastic sediment

Siliciclastic sediments are silica-based, non-carbonaceous sediments that are broken from pre-existing rocks, transported elsewhere, and redeposited before forming another rock.

silicon controlled rectifier (SCR)

A unidirectional electronic device that has three P-N junctions. The point at which the device can conduct can be controlled by applying a potential to its gate. SCR's are often used as rectifiers when the value of DC output must be regulated.

silo

A relatively large and narrow, vertical, cylindrical vessel that usually has a closed, dome-shaped top.

siltstone

A sedimentary rock with a grain size in the silt range, finer than sandstone and coarser than claystone.

siltstone, silt

A sedimentary rock with a grain size in the silt range, finer than sandstone and coarser than claystone.

siltstone, silt, silty

Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystone.

silver oxide

A film that forms on the surfaces of silver contacts; a good conductor of electricity.

simplex

Optical cable containing one fiber.

simplex piston pump

A piston pump that contains one piston.

simplex pump

A reciprocating pump that contains a single piston, plunger, or similar device.

simulation [evidence]

The employee performs a task in a simulated or training environment. Simulation is used when the employee is unlikely, within a reasonable time frame, to have the opportunity to demonstrate competence at the workplace. Any simulation will have to mirror real activities and must be stated in the assessment plan.

simulation [learning resource]

Simulation-based training uses simulated environments and scenarios to prepare learners for real-life situations. The learner can practice in a safe, controlled setting before facing actual challenges in the workplace. They are more motivated and engaged, leading to better long-term retention of skill and knowledge.

sine curve

A sine curve is a curve representing periodic oscillations of constant amplitude as given by a sine function.

sine wave

The output voltage waveform produced by a typical AC generator.

single

A single is one section of drill pipe, 30 ft (9.1m) in length.

single blade damper

A type of damper that has only one blade. Also known as a butterfly damper.

single line diagram

A drawing that shows all of the circuits of a system as single lines.

single loop

A closed process control loop in which a single process variable is controlled by a single analog or digital controller.

single loop control

A type of process control in which one process loop is controlled by a single controller.

single phasing

The loss of voltage on one of three phases of a three-phase circuit.

single shot

A signal measured by an oscilloscope that occurs only once.

single sweep

A trigger mode for displaying one screen full of a signal and then stopping.

single-acting compressor

A compressor which compresses gas on only the forward stroke.

single-acting pump

A reciprocating pump that operates by admitting fluid on one part of the reciprocating movement and discharging fluid on the other part.

single-barrel, offset tongue connector

A mechanical connector that is used for terminating a single conductor. The offset tongue allows the terminal and the conductor to he relatively flat against a surface.

single-conductor cable

A cable that consists of one large stranded conductor.

single-duct ventilation system

A system that has one supply air duct and one return air duct.

single-leg sling

A length of wire rope, chain, or synthetic material with some type of fitting or connector at each end.

single-mode fiber

Fibers with a central core of about 9 microns. Commonly used either for very high data transmission speed or long distance Wide Area Networks.

single-pass condenser

A type of condenser in which circulating water flows through the condenser only once.

single-pass heat exchanger

A heat exchanger in which each fluid passes through only once.

single-phase generator

A generator that has one stator winding and produces one output voltage.

single-point level detection

A system of level measurement that monitors levels at critical points; when a liquid reaches a predetermined level, the system initiates an alarm or a corrective action.

single-shot reclosing

A reclosing relay that recloses a circuit breaker only once, usually instantaneously.

single-strand conductor

A conductor that consists of a single wire.

sinking

An electrical connection with the field device connected to the power source. In sinking I/O modules, the common side connects to ground and the field device connects to the power source and the module.

sinking connection

A type of electrical connection. Sinking input or output modules have their common side connected to ground. The field device has one side connected to the power source and the other to the I/O module's terminal.

sinusoid

Another term for a sine curve.

sinusoidal oscillator

An oscillator that produces a sine wave signal.

sites

Charged locations on resin beads that attract and hold ions.

sixteen-bit word

A digital expression of 16 bits; for example, 0100 0111 0100 0111.

sizer

A device used to determine the proper size of respirator for an individual to wear.

skill-based information

Information that requires hands-on experience to practice and learn; usually taught more effectively through OJT than in a classroom.

skilled application (competency level 3)

Able to analyze and explain task in depth including impact on operations, key operating parameters and other related systems & processes / Able to troubleshoot / Can identify abnormal situations / Able to work independently / Applies procedures consistently and understands concepts / Shares and transfers information, best practices, and lessons learned / Mentors and coaches less experienced employees.

skills-based information

Information that requires hands-on experience to practice and learn; usually taught more effectively through OJT than in a classroom.

skin damage, factor

The most commonly used measure of formation damage in a well is the skin factor, S. The skin factor is a dimensionless pressure drop caused by a flow restriction in the near-wellbore region.

skin factor

A dimensionless number representing the degree of formation damage caused by drilling.

skin factor, skin

The skin factor (s) is a dimensionless number representing the degree of formation “damage”, or “improvement”, each of which can be the result of a number of different causes. Formation damage is assigned a positive number; formation improvement is assigned a negative number.

slack water

A short period in a body of tidal water when the water is completely unstressed and there is no movement either way in the tidal stream. This period occurs before the direction of the tidal stream reverses.

slew rate

The rate of change in the output voltage with respect to time for a step change at the input.

slickensides

Smoothly polished rock surfaces caused by frictional movement between rocks along both sides of a fault or fracture.

slickline

A thin, non-electric cable used for the selective placement and retrieval of wellbore hardware, such as plugs, gauges, and valves located in sidepocket mandrels.

sliding vane pump

A rotary pump that uses vanes that slide in and out of a rotor to move fluid.

slimhole

An inexact term describing a borehole, and its associated casing program, that is significantly smaller than a standard approach, commonly a wellbore with a diameter less than 6 inches.

slimhole logging tool

A slimhole logging tool is one capable of being run in small borehole diameters, sometimes as small as 3 7/8 inches in diameter.

sling

A length of wire rope, chain, or synthetic material used to secure a lifting device to a load, often serving as the connecting link between them.

sling psychrometer

A device that is commonly used for spot-checking humidity measurements.

slip

The difference in speed between the stator's magnetic field and the rotor in an AC motor, often expressed as a percentage.

slip blind

A circular metal plate installed in a line to prohibit flow. Normally the blind has a "Tee" handle to facilitate the identification, installation, and removal of the blind.

slip rings

Metallic rings used on some AC generators either to transfer the output voltage to brushes that are connected to an external circuit or to carry excitation current from the exciter to the field of the AC generator.

slip-on flange

A flange with a socket-type hub that slips over the end of a piece of pipe and is welded to the pipe.

slip-type micrometer

An outside micrometer with a slip device to keep excess pressure from being applied from the tool to the object being measured.

slop drain

The drain from the area that collects leakoff from a pump's stuffing box.

slop tank

See Recovery tank.

slope

On a graph or an oscilloscope screen, the ratio of a vertical distance to a horizontal distance.

slotted liners

Slotted (or pre-perforated) liner completions are by far the most common completion run in horizontal wells. The primary purpose of the slotted liner is preventing hole collapse in formations that may tend to cave in after being drilled, or as the formation pressure depletes.

slowness

Slowness is the reciprocal of velocity.

sludge

Suspended solids that have settled and formed a thick mixture; a thick concentration of suspended solids in cooling towers, wastewater, or other systems.

sludge handling

Treating sludge to reduce its volume and prepare it for safe disposal.

slumping

A condition in which a loss of aeration causes the catalyst to become less fluid and back up in a cat cracker.

slurry

A mixture of liquid and solids flowing together.

small volume prover

A precise volume checking device which can prove flow meters with fewer pulses.

smart device

A process control field device with an internal microprocessor that can store data, instructions. etc. A fully digital device can transmit process data to and receive configuration data from controllers or a DCS.

smart pigging

Smart or “intelligent” pigs inspect the pipeline with sensors and record the data for later analysis.

smectite

A group of clay phyllosilicate minerals with a relatively open, three-layer 2:1 (TOT) structure, including dioctahedral smectites (such as montmorillonite and nontronite) and trioctahedral smectites (such as saponite). They mainly consist of montmorillonite but can contain secondary minerals such as quartz and calcite.

snowballing

A condition in which coke deposits on the catalyst build up on previous deposits; caused by insufficient combustion.

soak

The time specified to keep a process variable at a designated set point during a ramp startup.

social life cycle analysis (S-LCA)

A methodology for assessing internalities and externalities of the production of goods and services based on social and socioeconomic indicators.

socket

A type of end fitting that is used to attach a wire rope to other rigging equipment.

sodium chloride (NaCl) equivalent

The sodium chloride (NaCl) equivalent is correctly calculated using the following formula: Sodium (mg) \( \small \times \) 2.54 ÷ 1,000 = Salt content (g).

sodium hydroxide (NaOH)

A dilute alkali solution that s used to treat products that contain relatively small amount of H₂S: Also known as caustic soda.

soft solder

A fusible alloy that consists primarily of tin and lead.

software

Programs composed of coded instructions that determine the functions of a computer, including screen display, operating environment, and various specific tasks such as word processing, database management, etc.

solder connectors

Connectors that require soldering when they are insulted.

soldering

A welding application that uses lead-tin or silver solder as a filler and bonding material.

solderless connectors

Connectors that do not require soldering when they are installed. They include compression connectors and mechanical connectors.

solenoid

An on/off type of electric device, usually a coil of conducting wire, that uses an electromagnetic field to move metallic objects or operate valves. Also called a solenoid actuator.

solid bed leaching

A leaching system in which a sol vent flows through a fixed bed of solid particles.

solid-state circuit element

A relay element in which inputs are electronically processed through circuits to produce an output signal.

solid-state relay

A relay that consists of electronic circuits instead of moving electrical and mechanical parts.

solute

The substance that is dissolved in a solution.

solution

In chemistry, one or more substances evenly dispersed throughout another substance (a homogeneous mixture) not easily separated by mechanical means. In geology, refers to the process where substances (such as carbonate sediments) form out of or dissolve into liquid, typically a brine solution, playing a crucial role in sediment transport and deposition.

solution gas

Natural gas that is dissolved in crude oil in the reservoir at prevailing reservoir conditions of temperature and pressure. Also called entrained gas.

solution voids

Solution voids are spaces within a rock where some rock material has dissolved.

solvent

A substance that can dissolve another substance; usually the component making up the greater amount of a solution. Also, an ingredient added to a mixture to reduce attraction between molecules of close-boiling components and increase the difference in their volatilities.

sonde, logging sonde

The section of a logging tool that contains the measurement sensors, distinct from the cartridge that contains the electronics and power supplies.

sonic

Sonic, alternatively termed acoustic, is the branch of physics concerned with the properties of sound.

sonic log, acoustic log

A display of the travel time of acoustic (compressional) waves versus depth in a well. Sonic tools emit a sound wave that travels from the source to the formation and back to a receiver.

sonic monopole transducers

Sonic monopole (axisymmetric) transducers generate omnidirectional sonic, or acoustic, waves.

sonic velocity, acoustic velocity

Sonic, or acoustic velocity, is the velocity of a sonic, or acoustic, wave in a medium.

sootblower

A device that uses steam or compressed air to blow ash or slag off boiler tubes.

sootblowing

A method of controlling steam temperature by using sootblowers to remove soot from boiler tubes.

sorbed gas

Gas accumulated on the surface of a grain of reservoir rock or organic particles in a shale reservoir.

sorting

The range of sedimentary grain sizes that occur in sediment or sedimentary rocks.

sound

Any pressure variation that the human ear can detect.

sound waves

A series of pressure vibrations that travel through a medium such as air or water.

sour crude

Generally, a crude oil whose sulfur content is greater than 1%.

sour gas

Natural gas containing significant amounts of acid gases (hydrogen sulfide and/or carbon dioxide).

source

The primary source that provides the power that is converted to electricity through chemical, mechanical, or other means. Energy sources include coal, petroleum and petroleum products, gas, water, uranium, wind, sunlight, geothermal, and other sources.

source rock

Source rock is a rock capable of generating petroleum. Source rocks are usually shales, sometimes limestones.

source sampling

The process of using manual measurement methods to determine the emissions from a potential air pollution source.

source unit (source)

In a nuclear radiation system for level measurement or control, the part that contains the radioactive source and shielding; mounted externally on a container.

sourcing

An electrical connection with the field device connected to ground/common. In sourcing I/O modules, the common side connects to the power source and the field device connects to ground/common and the module.

sourcing connection

A type of electrical connection. Sourcing input or output modules have their common side connected to the power source. The field device has one side connected to ground/common and the other to the I/O modules terminal.

south pole

The southernmost point of the Earth's axis.

space management

A defensive driving technique that involves always keeping an appropriate amount of space around a vehicle to the front, to the sides and to the rear. It also involves staying out of an area where you can be in an accident as a result of someone else's sudden move or mistake.

spacer

A metal disk similar in appearance to a slip blind, except that the spacer is not solid and thus permits flow through the line.

spacing

The distance between wells producing from the same reservoir. Spacing is often expressed in terms of acres (e.g. 80-acre spacing) and is often established by regulatory agencies.

spade terminal

A crimp-on terminal that has a forked tongue. Also called a fork terminal.

sparker seismic surveys

A seismic survey in which the energy source is an electrical discharge. The discharge occurs between two electrodes that are submerged in salt water. The heat generated by the discharge vaporizes the water, which then condenses to create an implosion.

spec plate

A plate that lists a tank truck's design specifications and Department of Transportation (DOT) classification.

special core analysis

Special core analysis, often abbreviated to SCAL, is a laboratory procedure for conducting flow experiments on core plugs taken from a petroleum reservoir. Special core analysis is distinguished from "routine or conventional core analysis" by adding more experiments, including measurements of two phase flow properties, determining relative permeability and capillary pressure.

special core analysis (SCAL)

A set of laboratory procedures for conducting flow experiments on core plugs, distinguished from routine core analysis by adding measurements of two-phase flow properties, including determining relative permeability and capillary pressure.

specific gravity

The ratio of the weight (or density) of a fixed volume of a substance to the weight (or density) of an equal volume of water, indicating whether a liquid is more or less dense than water.

specific gravity test

A test that determines the density of a liquid compared to the density of water at a standard temperature.

specific permeability, absolute permeability

The permeability when a single fluid, or phase, is present in the rock. Often referred to as absolute permeability.

specification sheets

Written requirements issued by architects and engineers to establish general conditions, standards, and detailed instructions to use with the blueprints; also referred to as specs.

spectacle blind

A combination blind and spacer formed from the same piece of metal. A spectacle blind has the shape of a figure "8". One end is solid and prohibits flow when inserted in the line; the other end is open and permits flow when inserted in the line.

spectral fitting analysis technique

In the spectral fitting analysis technique, the elemental signature of elements is matched for the entire spectra.

spectral gamma ray

Spectral gamma ray logs measure the amounts of potassium, thorium and uranium naturally emitted by rocks, which offers several advantages. They can help with clay typing. Variations of the relative amounts of potassium, thorium, and uranium are associated with specific shale minerals.

spectroscopy

The study of the interaction between matter and radiated energy. Used in pulsed neutron logging to measure the spectrum of gamma rays emitted by a formation bombarded by high-energy neutrons. Also, an analytical technique based on the interaction of electromagnetic radiation with matter.

speed range

The relationship between the maximum and minimum speeds at which a drive is designed to operate. The range is typically expressed as a ratio, such as 25:1, indicating the drive can operate from normal speed to 1/25 of normal speed.

spent catalyst

Catalyst with coke deposits resulting from the cracking process.

sphere

A ball-shaped tank that rests on legs elevating it off the ground. A type of high-pressure above ground storage tank.

spherical flow regime

A spherical flow regime is a flow regime that occurs when the predominant flow pattern is toward a point.

spheroid

A flat-bottomed, pumpkin-shaped spherical pressure tank that rests on the ground or on a concrete pad, braced by a series of supports around the base. Generally used as a low-pressure tank.

spiculed

Spiculed, or spiculitic, refers to rocks composed of sponge spicules, which are needle-like structures that form the skeletal support of sponges. These rocks are often found in sedimentary environments where sponges thrived.

spill box

A containment device provided to catch leaks at sampling points, piping connections, valves, and on barges.

spill dam

A component located around the manway cover on a tank truck, designed to hold any spilled product until it can be recovered through a drain hose.

spin echo

A spin echo is the refocusing of spin magnetization by a pulse of resonant electromagnetic radiation.

spinal column (spine)

The interlocking bones running from the skull to the hips that support the upper body and protect the spinal cord from injury.

spinal discs

Shock-absorbing cushions that separate the vertebrae of the spine and help bear the weight of the upper body.

spine and ribs plot

The spine and ribs plot is, for a two detector density tool, the plot of long-spacing versus short-spacing count rates for different formation densities, mud cake densities and mud cake thicknesses. The plot takes its name from the spine, which is the locus of points with no mud cake, and the ribs, which show the effect of mud cake at certain fixed formation densities. The plot illustrates graphically that for a given formation density there is only one rib for all normal mud cake densities and thicknesses. Thus, although there are three unknowns, it is possible to make a correction using two measurements.

spiral-wound gasket

A metallic gasket made from a continuous strip of corrugated metal with filler cushion and wound spirally from inside to outside. The gasket has a metal ring on its inner and outer rims.

splice

A connection made to join two conductors together.

splines

Equally spaced ridges on the surface of a component that allow the component to engage another component.

split-bolt connector

A mechanical connector in which two conductors are positioned on top of each other in the split, and a nut on the connector is tightened to secure the connection.

split-spread

Split spread is an acquisition method of reflection surveying in which the source point is at (or perpendicularly offset from) the center of the geophone spread. This is also called a straddle-spread.

split-spread method

Fold is the number of sets of subsurface seismic reflections that have the same common midpoint.

splitter

A device used for sampling solid materials traveling through conveyor systems.

sponge coke

Coke with a sponge-like appearance that is produced in a coking unit.

sponge coring

Sponge coring is a sponge sleeve modification to a conventional core barrel. This sponge sleeve or liner modification of the inner core barrel is made of a tough porous polyurethane sponge which is preferentially oil wet. The sponge absorbs any oil preferentially oil wet. The sponge absorbs any oil which bleeds from the core.

spontaneous combustion

The self-ignition of a flammable or combustible material through chemical reaction of its elements, without an external source of ignition.

spontaneous potential, SP

Spontaneous potential is the ideal spontaneous potential (SP) that would be observed opposite a shaly, permeable bed if the SP currents were prevented from flowing. In the middle of a thick, permeable bed whose resistivity is not too high, the SP reads close to the pseudostatic spontaneous potential (PSP). In other conditions, however, the SP may be significantly less than the PSP.

spot cylinder

A sample collected at a particular location for one specific time.

spotting

Positioning a tank truck, tank car, or barge at a location such as a loading rack or dock.

spray tower

A scrubber that contains no packing; liquid is sprayed into the tower in the form of fine droplets that contact a rising gas or vapor stream and remove contaminants from it.

spread length

The spread length is the distance from the first shotpoint to the end of the last active receiver group.

spreader beam

A device that is sometimes used to change the rigging configuration for a large load from an angled lift to a straight, vertical lift.

spud

To start the well drilling process by removing rock, dirt and other sedimentary material with the drill bit.

spud, well spud

Spudding in or to spud a well means to begin drilling operations. The drill string, consisting of a drill bit, drill collars, drill pipe, and kelly, is assembled and lowered into the conductor pipe.

spurt loss

The instantaneous volume (spurt) of drilling mud that passes through a filter medium prior to the deposition of a competent and controlling filter mud cake.

square

A four-sided shape with four 90° angles and four equal sides. Also, the result of multiplying any number by itself.

square root

A factor of a number that, when multiplied by itself (squared), produces the given number.

square root component

A control device in which the output is the square root of the input.

square wave

A common wave shape consisting of repeating square pulses.

squirrel cage rotor

A rotor made of conducting bars that are shorted together by end rings.

ST connector

A type of optic cable connector that is connected to equipment with a turn.

stab-in reboiler

A type of internal reboiler.

stability

A chemical's resistance to change or disintegration.

stability triangle

The imaginary geometric figure formed by connecting the three support points of a forklift (at the two front wheels and the center of the rear axle at the steering pivot point). The center of gravity must remain within this triangle to prevent tipping.

stabilized cat-cracked gasoline

Cat-cracked gasoline from which the lighter components have been removed.

stabilizer

In drilling, a piece of downhole equipment in the BHA that mechanically stabilizes the assembly in the borehole to avoid unintentional sidetracking, vibrations, and ensure hole quality. In refining, a distillation tower used to separate light components to control a product's initial boiling point.

stabilizer, drilling stabilizer

A drilling stabilizer is a piece of downhole equipment used in the bottom hole assembly (BHA) of a drill string. It mechanically stabilizes the BHA in the borehole to avoid unintentional sidetracking and vibrations, which helps ensure the quality of the hole being drilled.

stable state

A condition in multivibrator circuits in which one of the two amplifier stages is conducting and the other stage is not conducting.

stack damper

A device inside the stack that is adjusted to increase or decrease the amount of air and gas flow through a furnace.

stage gate, stage gate process

A stage gate process is a project management technique in which the development of an exploration and production asset is divided into stages, separated by gates.

staggered stop

A defensive driving technique that involves stopping at least five or six feet behind the pavement markings when you stop in the lane closest to the center one. This protects your vehicle from large vehicles or others that may make short left turns.

stakeholder

Any person or organization that is actively involved in the project, whose interests may be positively or negatively impacted by the project or who may exert influence over the project.

standard

A single piece of metal precisely machined to a specific size.

standard competency models

standard deviation

The standard deviation is a statistic that measures the dispersion of a dataset relative to its mean and is calculated as the square root of the variance.

standard threshold shift

The deviation, in decibels, of a measured hearing threshold level from one previously established.

standardization meetings

Assessors hold standardization meetings to identify any discrepancies between assessors in their judgment of candidates' evidence and allow adjustments to be made to remedy them. As well as reducing subjectivity among assessors, they help to improve the consistency of judgments and allows internal verifiers to identify and disseminate good practice. Standardization meetings should take place throughout the assessment process and records of these meetings, including any feedback to assessors, should be kept as evidence of internal verification activity.

standby attendant

A person who remains outside a storage tank during cleaning and maintenance work to monitor the workers who are inside the tank and tank conditions and notify rescue personnel when necessary.

standing valve

The valve in a rod pump closest to the bottom of the pump. It is in the part of the pump that does not move up and down.

standpipe

A vertical pipe connected to a pressurized water supply system that is used to secure a uniform pressure.

star

A type of network topology in which all of the cables are routed to a central point, where they connect to a hub.

star formation

A grounding scheme in which grounds for multiple controllers are each wired directly to a grounding bus.

static dissipative materials

Static dissipative materials have an electrical resistance between insulated and conductive materials.

static mixer

A blending device with fixed blades, contained in a blend header or meter tube upstream of a sample probe, that causes mixing of the fluid stream.

static postures

A type of awkward posture in which the same posture or position is held throughout an exertion. Static postures put increased loads or forces on the muscles and tendons, which contributes to fatigue. Examples of static postures include gripping tools that cannot be put down, holding the arms out or up to perform tasks, or standing in one place for prolonged periods.

static pressure

The force exerted by a fluid confined within a tank, pipe, or duct as measured by a gauge. In HVAC, the pressure of air at rest inside a duct.

static reservoir model

A computer model of a reservoir created by geologists and geophysicists that provides a static description of the reservoir prior to production, used for improving resource estimation and making field development decisions.

static reservoir modelling, static reservoir model

Static reservoir modelling is those reservoir modelling activities up to the point when a simulation model is ready to simulate the flow of fluids.

static SP, static spontaneous potential, SSP

The static spontaneous potential (SSP) is the ideal spontaneous potential that would be observed opposite a permeable bed if the SP currents were prevented from flowing and any shaliness in the bed were ignored. The SSP is equal to the electrochemical potential.

statics

Statics involves the correction for near surface velocity variations using surface velocity modeling and refraction analysis. This process uses the first arrival times of refracted seismic energy to compute near surface velocities and layer thicknesses.

statics problems

Statics problems can include variations in elevation, near-surface low-velocity-layer (weathering) thickness, weathering velocity, and/or reference to a datum.

stationary

Not moving.

stationary field generator

A type of AC generator in which direct current is fed to the stator and the output voltage from the generator is taken from the rotor through slip rings and brushes.

statistical process control (SPC)

A technique of using statistical methods to help identify and eliminate problems in some industrial processes.

stator

The fixed, or non-moving, part of a motor or AC generator.

steady state conditions

Operating conditions in which a boiler operates at a constant load and consistently produces a designated steam output with little or no fluctuation.

steady-state conditions

Conditions in a system that remain constant over a period of time.

steam chest

A collection area designed to distribute steam to the turbine control valves.

steam cycle

In a power plant, the fluid flow path from the boiler, through the turbine, through the condenser, and back to the boiler.

steam ejectors

Devices used to pull uncondensed vapor from the top of a vacuum tower or from a condenser.

steam jet

A device that uses the flow of steam to move another fluid, such as air.

steam jet air ejector

A device that can be used to establish a vacuum and remove non-condensable gases from a condenser.

steam traps

Devices located at low points in steam lines where condensate naturally collects. Designed to remove water from steam lines without allowing steam to escape.

steam-assisted gravity drainage (SAGD)

A process used to recover bitumen that is too deep to mine. A pair of horizontal wells is drilled from a central well pad. In a plant nearby, steam generators heat water and transform it into steam. The steam then travels through above-ground pipelines to the wells. It enters the ground via the steam injection well and heats the bitumen to a temperature at which it can flow by gravity into the producing well. The resulting bitumen and condensed steam emulsion is then piped from the producing well to the plant, where it is separated and treated. The water is recycled for generating new steam.

steam/water cycle

The flow paths of steam and water through the various steam systems within a power plant.

steepest descent

Steepest descent is a special case of gradient descent where the step length is chosen to minimize the objective function value.

stem

The part of a valve that connects the handwheel to the disc and moves the disc to control flow.

stem nut

A sleeve with threads inside and splines outside that transmits the motion of a drive sleeve to a valve stem.

step distance, step length

Step distance, or step length, defines the depth increment to be used between successive rounds of correlations. This is often set to half the correlation interval, giving a 50% overlap.

step input

A sudden change in the value of a process variable.

step signal

Signals such as steps and pulses that only occur once are called single-shot or transient signals. The step indicates a sudden change in voltage, such as what you would see if you turned on a power switch.

step-down transformer

A transformer that decreases or reduces voltage as it induces voltage from its primary winding to its secondary winding.

step-out drilling

This process of drilling involves moving outward from the initial wildcat well to define the limits of the reservoir.

step-up transformer

A transformer that increases voltage as it induces voltage from its primary winding to its secondary winding.

step-up transformers

A transformer in which the output voltage is greater than the input voltage.

stepladder

A self-supporting ladder consisting of two elements hinged at the top.

stereogram

A two-dimensional, circular representation of a sphere giving a three-dimensional representation of a solid object or surface, in which lines of longitude and latitude form a coordinate system (a net) on which projections of great and small circles occupy the equatorial plane.

stereonet

A graphical tool representing the hemisphere of a globe, used for the presentation, analysis, and interpretation of three-dimensional directional data such as planes and lines.

stiction

The effect of excessive static friction. Stiction causes analog actuators and actuated equipment to move in jets even when the input control signal is smoothly increasing or decreasing.

stimulation, well stimulation

A stimulation is any treatment performed to restore, or enhance, the productivity of a well. Stimulation treatments fall into two main categories, hydraulic fracturing treatments and matrix treatments.

stock tank oil initially in place, STOIIP

STOIIP is the abbreviation for Stock Tank Oil Initially in Place.

STOIIP

The abbreviation for Stock Tank Oil Initially In Place.

stoker

A type of combustion equipment that is designed to supply solid fuel, such as coal or wood, to a boiler.

Stoneley velocity

Stoneley velocity is the velocity of Stoneley waves.

Stoneley wave

A high-amplitude boundary wave, or interface wave, that typically propagates along a solid-solid interface.

storage tank

A tank used to store a finished product ready for distribution, or to hold treated oil before transfer by a LACT unit.

stoss

Stoss refers to the side of a landform that receives, or has received, the thrust of a flow.

straddle stacker

A type of forklift that conserves space by straddling the load.

straight angle

A180 angle.

straight ladder

A non-adjustable ladder of a fixed length.

straight run

A material that has been separated, but has not undergone any chemical changes.

straight run gasoline

A gasoline feed from the crude unit that is sent to the gasoline blending area.

straight-run asphalts

Semi-solid to solid products that remain after the lighter petroleum distillates and the heavier, oily distillates have been removed. Also called asphalt cements.

straight-tube heat exchanger

A type of shell and tube heat exchanger that has straight tubes that extend from a tube sheet at one end of the heat exchanger to a tube sheet at the other end.

straightening vane

A bundle of tubes inserted in the meter tube upstream of the meter¬ing device to eliminate turbulence.

straightening vanes

Plates in a separator which reduce or eliminate gas turbulence.

strain

A normalized measure of deformation representing the displacement between particles in a body relative to a reference length.

strainer

A device or vessel used to remove solid particles from a fluid stream, such as in a LACT unit or upstream of a metering device.

stranded conductor

A conductor that consists of a group of wires that are usually twisted together and not insulated from each other.

strapping

Measuring the dimensions of a lease tank to accurately determine the volume of oil at any measured depth.

strapping a tank

Following a standard method for measuring a tank to determine its exact volumetric capacity.

stratabound fracture

A stratabound fracture is a fracture that terminates at geological strata.

stratification

Stratification ordinarily describes the layering that occurs in sedimentary rocks. Stratification, or bedding layers, are greater than one centimeter in thickness. Laminations are less than one centimeter thick.

stratigraphic

Stratigraphy is the study of the history, composition, relative ages and distribution of rock strata.

stratigraphic correlation

Stratigraphic correlation is the demonstration of the equivalency of stratigraphic units, normally involving a correlation of geological events between nearby wells displayed on a cross-section.

stratigraphic traps

A type of geologic trap, created by changes in rock lithologic characteristics, such as porosity or permeability.

stratigraphic units

Stratigraphic units are a sequence of rock beds, a specific rock type or group of rock types that can be traced over a fairly broad region.

stratigraphy

The study of the history, composition, relative ages, and distribution of rock strata.

stratigraphy, stratigraphic

Stratigraphy is the study of the history, composition, relative ages and distribution of rock strata.

stratum

A stratum is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either bedding surfaces or bedding planes.

stress

A physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other; the result of applied forces.

strike

Strike is the direction of a line formed by the intersection of a fault, bed, or other planar feature with a horizontal plane.

strike direction

A geological feature's strike is the azimuth of an imagined horizontal line across the plane.

strike slip, strike slip fault

A strike slip fault is a fault in which rock strata are displaced mainly in a horizontal direction, parallel to the line of the fault.

strikers

Movable blocks on the front of a torque switch; used to adjust the amount of torque that the switch responds to.

string shots

A set of sources, either downhole or at the surface, that are repeated a number of times to help establish velocity models for a play.

stringer

A stringer is a very thin rock layer; typically this is comprised of sandstone.

strip chart

A chart made on a long strip of paper that can be used to show operating conditions over a period of time.

stripper

In electrical work, a tool used to remove insulation from a conductor. In processing, a vessel that uses hot vapor to separate lighter, more volatile components from heavier ones. In catalytic cracking, a device that uses steam to remove hydrocarbon vapors from spent catalyst. In amine treatment, a component where acid gases are removed from rich amine.

stripper (still)

A vertical pressure vessel where rich amine and steam are brought together to remove acid gases from the amine solution.

stripper tower

A distillation tower that separates light components from a feed, but does not produce a liquid overhead product.

stripping gas

Warm gas percolated through glycol being regenerated to help remove water not removed by the distillation process, enabling purification of glycol to nearly 100%.

stripping steam

Steam that is added to the bottom of a distillation tower in order to vaporize the light ends in the liquid.

stroke

In pumping, one complete rotation of the crankshaft. In compressors, the movement of the piston from one end of the cylinder to the other.

structural formula

A representation of the number, kinds, and arrangement of atoms in a molecule.

structural reconstruction, restoration or palinspastic restoration

Structural reconstruction, or palinspastic restoration, is a technique used to progressively undeform a geological section in an attempt to validate the interpretation used to build the section.

structural shale

Structural shale is a particular type of shale distribution in which the shale exists as grains within a rock framework, in contrast to dispersed shale and laminar shale.

structural trend

A structural trend indicates the compass direction in which the longest axis of the structure is aligned.

structure, structural, tectonics

Tectonics is concerned with the processes which control the structure and properties of the Earth's crust, and its evolution through time.

structure, tectonics

Tectonics is concerned with the processes that control the structure and properties of the Earth's crust and its evolution through time.

stub-up

The part of a length of conduit that is bent in a different direction when a stub bend is made.

stuffing box

The area between a pump shaft and casing that contains packing material or a mechanical seal. In beam pumping, the surface connection that seals the production tubing with packing around the polished rod to restrict leakage.

subaerial

Subaerial relates to something that exists or occurs in the open air or on Earth's surface, rather than underwater or underground.

subcritical conditions

Conditions below the critical point of 705 degrees Fahrenheit and 3206 psi.

subject matter expert (SME)

submarine fan

A submarine fan is a cone-shaped accumulation of sediment found on the deep ocean floor. These are formed by turbidity currents and sediment gravity flows.

subroutine

A separate PLC program that runs when directed to by the main PLC program or by another subroutine.

subsidiary hazard

A hazard other than the most dangerous hazard posed by a material.

substation

A facility in which voltage is changed or transformed to accommodate one or more electrical distribution systems.

successions

The chronological layers of sedimentary rock that accumulate in an area over time, influenced by geological processes such as tectonics, sediment supply, and changes in sea level. In undisturbed sequences, newer units are typically above older units.

suction eye

The area at the center of an impeller where fluid is drawn into a pump.

suction line

A pipe that is used to discharge material from a tank.

suction pressure

The pressure at the suction port of a compressor.

suction valves

Valves which open to allow gas to enter the cylinder.

suite, logging suite

Several wireline logging runs acquired in succession within the same activity stage, such as at a casing point.

sulfides

A sulfide is a binary compound of sulfur with another element.

sulfidizing

A stage of catalyst regeneration in which sulfides are applied to the surface of the catalyst.

sulfur dioxide (SO₂)

A toxic gas that is produced when fuel products containing H₂S are burned.

sulfur oxides

The products formed when sulfur combines with oxygen. When released to the environment, they create a form of air pollution.

sulfuric acid

A type of catalyst that is commonly used in alkylation units.

summing amplifier

An op amp circuit whose output voltage is the sum of it input voltages. Where all of the input voltages are applied to the inverting terminal, the circuit is known as an inverting summing amplifier.

summing component

A control device in which the output is the sum of two or more inputs.

summing junction

A point on the inverting input terminal of an op amp circuit at which the potential will equal the potential at the reference junction.

supercharging

Increased sand face pressure caused by drilling fluid filtrate leak-off, resulting in excess pressure due to mud filtrate invasion in low-permeability formations.

supercritical boiler

A boiler that normally operates at conditions that are above the critical point, at which the density of water and the density of steam are the same.

supercritical conditions

Conditions above the critical point of 705 degrees Fahrenheit and 3206 psi.

superheated steam

Steam that has been heated above the saturation temperature.

superheater

A component that heats steam above the saturation temperature.

supersaturated solution

A solution that contains more dissolved solute than it should be able to hold at a given temperature and pressure.

supervisor

The person assigned to complete a Supervisor Assessment. This may be the employee's actual supervisor or manager, a team leader, a senior position holder, a third-party from a different business unit or another competent person.

supervisor assessment (SA)

A supervisor completes an online Assessment of each of his personnel based on long-term observation of job performance using CMS Online software.

supply current

The current into the VCC+/VDD+ or VCC-/VDD- terminal of the op-amp while it is operating.

supply current (shutdown)

The current into the VCC+/VDD+ or VCC-/VDD- terminal of the amplifier while it is turned off.

supply voltage

Bias voltage applied to the op amp power supply pin(s), usually specified as a ± value referenced to network ground.

support competencies

Competencies that identify the underlying basic knowledge, skills and experiences that an individual must have to undertake the Core Competencies to the required level. Included are those secondary and nonroutine competencies expected in defined job duties (competencies necessary to function effectively in a position, but the CUs would not be to the depth and detail of a Functional Core CU).

surface area

The amount of exposed surface between things. Usually expressed in square inches.

surface tension

The contractive tendency of the surface of a liquid that allows it to resist an external force, caused by the attraction of particles in the surface layer by the bulk of the liquid, which tends to minimize surface area. Surface tension applies to a single liquid surface, whereas interfacial tension applies to the interface of two immiscible liquids.

surface tension forces

A contractive tendency of the surface of a liquid that allows it to resist an external force.

surge device

In a differential relay, a device that blocks small amounts of fault current, but allows heavy amounts of fault current to flow through the relay's current coil.

surge suppressors

Electrical components typically applied to contactors, relays, and solenoids to prevent induced voltages from disturbing nearby drive components.

surge tank

A vessel or tank that provides the capacity for handling surges in the volume of flow between process units, or for storing dry glycol.

surging

The rapid flow of gas back and forth through a centrifugal compressor.

suspended solids

Dust and other solid particles that contaminate the water in a cooling tower.

suspended well

A suspended well is one which used to produce hydrocarbons from a reservoir and at which operations have ceased and will not resume for a period of time, often at least 30 days.

swash bar

Swash bars are built by wave-induced accumulations of sand in the distal portions of ebb deltas and move onshore.

sweep

One horizontal pass of an oscilloscope's electron beam from left to right across the screen.

sweep speed

For an analog oscilloscope, an indication of how fast the Dace can sweep across the screen, allowing you to see fine details. The fastest sweep speed of an oscilloscope is usually given in nanoseconds/div.

sweet crude

Generally, a crude oil whose sulfur content is less than 1%.

sweet gas

Natural gas containing little or no acid gases (hydrogen sulfide or CO2).

sweetening

The process of removing sour contaminants (acid gases or sulfur compounds) from natural gas to improve odor or color.

swell

A temporary rise in boiler drum level caused by changes in steam flow.

swing check valve

A check valve that has a hinged disc that swings open to allow fluid to flow through the valve.

switch

A device that can be opened or closed to start or stop current flow in a circuit.

switch rack

Equipment that routes electricity to pump slabs and pits; also called a motor control center.

switched feedback resistance amplifier

An inverting amplifier with two or more resistors in its feedback path that are switched into the feedback path by a switching device.

switchgear assembly

An assembly of circuit breakers and related components that are housed in a single enclosure.

switchyard

A facility that connects generators to transmission lines or connects transmission lines together.

swivel

A component that helps prevent wire rope from transferring its normal twisting motion to the load being lifted.

symbol

A name given to a device in a ladder diagram (synonym for alias, tag, or label). Also, a small picture used to represent a component in an electrical system.

synchronous inputs

Are normal data inputs J and K to a flip-flop that has effect on the outputs Q and Q-NOT only in step, or in sync, with the clock signal transitions.

synsedimentary

A fault or fold that forms or grows within a sediment during sedimentation.

synthetic seismogram

A direct one-dimensional model of acoustic energy traveling through the layers of the Earth, generated by calculating reflection coefficients from sonic and density logs and applying a wavelet. Usually generated to compare with actual seismic data and identify reflectors with known formations.

syphilis

A chronic infectious disease, caused by a bacteria, that affects the genitals, skin, mucous membranes, aorta, brain, liver, bones and nerves. It is usually transmitted during sexual intercourse, but often passed on to an unborn child.

system

A group of equipment that works together to process materials.

system identification number

A number assigned to the components in a process control system to identify the system to which the components belong.

system prefix

A prefix that identifies which plant system a component belongs to.