S

S& W Probe
An instrument used in the detection of S&W (Sediment & Water).

S Wave
A body wave, in which the particle motion is perpendicular to the direction of propagation.

S&w
The preferred term for Basic Sediment and Water (BS and W). This is commonly used as a measure for treating performance of hydrocarbon liquids. The American Society for Testing and Materials (ASTM) Standard Test No. D96-82, entitled Water and Sediment in Crude Oils, is an accepted standard for this test.

S&w Automatic Monitor
An electronic device detecting and measuring sediment and water (S&W) in producing oil and pipeline condensate.

S-turn Borehole
SEE: S-Type Wellbore.

S-type Wellbore
A wellbore path drilled with a vertical segment, a deviated segment, and a return toward a vertical segement.

Sack
An oil field measure of quantity which is converted to volume using yield of cement per sack. A known number of sacks of cement will yield a known volume of slurry. Example: surface casing was cemented with 2000 sx of class H. 16.4#/gal. cement (sx is the industry accepted abbreviation for sacks). The yield for this cement is 1.06 cubic feet per sack.

Saddle
(1) A fitting made in parts to clamp onto a pipe for the purpose of stopping a leak or providing an outlet.(2) A welded fitting used to reinforce an opening in a pipeline.

Saddle Bearing
A bearing between the walking beam and the sampson post of a pump jack or pumping unit.

Safe
Conforms in every detail to a design which has been demonstrated to perform satisfactorily in the service intended.

Safety Device
An instrument or control used within the safety system.

Safety Factor
The ratio of the maximum permissible working load to the load causing failure.

Safety Hat
SEE: Hard Hat.

Safety Head
A pressure relieving safety device containing a frangible disc designed to break when pressure on one side exceeds a specified amount.

Safety Joint
A fishing tool accessory placed above the tool. If the tool is engaged and the fish cannot be pulled, the safety joint will permit disengagement.

Safety Latch
A latch provided in a hook or elevator to prevent these devices from opening and dropping the weight prematurely.

Safety Net
A netting section around the perimeter of the flight deck used for personnel safety, and is normally provided in lieu of a safety shelf where the flight deck alone provides ground cushion effect.

Safety Shelf
A section of solid construction around the perimeter of the flight deck used for safety of personnel, and may be included in the ground cushion area.

Safety System Flare Volume
The volume of flaring pilot of purge gas or fuel to test safety flare system.

Safety Valve
An automatic valve designed to close or open when an abnormal condition exists.

Safety Valve Lock
A device attached to or a part of the subsurface safety valve (SSSV) that holds the valve in place.

Safety Valve Working Pressure Measurement
The performance rating of a safety valve.

Sale Transfer Volume
The sale or transfer volume, in whole units, that has been allocated to each source listed.

Sales Agreement
An agreement between a purchaser/buyer and seller (e.g., producer, marketer, pipeline LDC) which defines the terms and conditions of a purchase/sale and title transfer of product quantities.

Sales Allocation
The process by which supply is assigned to purchasers in accordance with a given priority during periods when total sales requests exceed the sellers' total supply.

Sales Date
The month and year that minerals are bought or sold off a lease.

Sales Delivery Point Location
The point of delivery for sales.

Sales Volume
The volume of product sold or traded.

Salinity
The concentration of salt in water.

Salt
(1) Chemically, the term salt is also applied to any one of a class of similar compounds formed when the hydrogen of an acid is partly or wholly replaced by a metal or a metallic radical.(2) In drilling fluid terminology, the term salt is applied to Sodium Chloride, NaCl.

Salt Bath Heater
A direct fired heater employing molten salt as a heat transfer medium.

Salt Dome
A dome shaped mass of rock salt that is formed by the intrusion of rock salt into the overlying sediments.

Salt Dome Storage
Cavities created out of underground salt formations for the storage of petroleum products, toxic waste, or other materials.

Salt Measured Depth
The measured depth in the borehole to the salt dome.

Salt True Vertical Depth
The subsea depth at the point where the borehole penetrates the salt dome.

Salt Water Clay
SEE: Attapulgite Clay.

Salt Water Disposal
SEE: Product Disposition.

Salt Water Flow
An influx of salt water into the borehole from the surrounding rocks.

Salt Water Intrusion
The invasion of salt water into a body of fresh water, occurring in either surface or ground water bodies. When this invasion is caused by oceanic waters, it is called sea water intrusion.

Sample
Material (solid, liquid or gas) collected and cataloged for reference or examination.

Sample Bomb
A thick-walled container, usually steel, used to hold samples of oil or gas under pressure.

Sample Catcher
(1) A device for catching gas vapor and/or liquids from a process area or pipeline for compositional analysis.(2) A device for catching drilling fluids as they emerge from the wellbore for geological analysis.

Sample Count
Number of values in a series of sampled data.

Sample Date
The date that the sample was obtained.

Sample Interval
(1) Interval at which samples are taken. The increment is dependent on the units of the incrementing index; e.g., time; depth.(2) The interval between readings; i.e., the time between successive samples of a digital seismic trace or depth between measurements in a well log curve.

Sample Interval Base Depth
The deepest measured depth of a sampled interval.

Sample Interval Depth
SEE: Sample Interval Top Depth OR Sample Interval Base Depth.

Sample Interval Top Depth
The shallowest measured depth of a sample interval.

Sample Rate
The rate at which the cuttings of the rock formation broken up by the drill bit are brought to the surface.

Sample Recovery Temperature
The temperature of distillate at the initial boiling point and specified distillate recovery percentages.

Sample Source Code
An indicator of the special type of vessel from which the sample was taken; e.g., separator , tank, etc.

Sample Type Code
The type of sample collected; e.g., washed cuttings; cuttings; conventional core; diamond core; lithology cut; drilling fluid; formation fluid.

Sampler
A device attached to a flowline permitting automatic sampling of products flowing in the line.

Sampson Post
An upright timber near a cable tool well on which is balanced a walking beam. It is used only in cable tool drilling.

Sand
A clastic sedimentary particle with a diameter between 1/16 and 2 millimeters, based on the Wentworth Scale of Measurement.

Sand (api)
Solid particles in a drilling fluid that are too large to pass through a U.S.S. No. 200 screen (74 micron equivalent), as referenced in API RP 13B.

Sand Bottom True Vertical Depth
The subsea depth to the bottom of the sand horizon.

Sand Class
The classes of sand, based on size, using the Wentworth Scale of Measurement; e.g., fine; medium; coarse.

Sand Control
Any method by which large amounts of sand are prevented from entering the wellbore. Methods include: Gravel Pack; Screen Liner; and Sand Consolidation.

Sand Control Treatment
A workover done on a borehole to mitigate sand production. Includes gravel packs done after initial completion and plasticizing treatments.

Sand Control Type
The type of sand control treatment performed on a well completion; e.g., gravel pack; screen; reperf.

Sand Discharge Gate
SEE: Underflow Opening.

Sand Jet
A system of one or more perforated pipes, or nozzles, located near the bottom of emulsion treaters which is used periodically to clean out sediments by flushing with water.

Sand Pan
An inverted angle baffle or trough located above the sand (sediment) outlet connections to facilitate uniform sand or sediment removal. Notches in the troughs or pans increase the velocity of the water leaving the vessel to prevent bridging.

Sand Pump
(1) A cylinder with a plunger inside and a valve at the bottom, lowered into a wellbore from time to time to take out the accumulated slime resulting from the action of the drill on the rock. Also referred to as: Shell Pump; Sludger. (2) A pump for artificially lifting wells producing fluids containing sand.

Sand Screen Liner Gauge
The gauge, or measure, of the opening in the sand control screen.

Sand Top Measured Depth
The measured depth to the top of the sand.

Sand Top True Vertical Depth
The subsea depth to the top of a sand.

Sanded Up
Borehole or well completion clogged by sand entering it from the surrounding rocks.

Sandstone
A cemented or consolidated sedimentary rock composed of; e.g., quartz; feldspar. Sandstone is a common rock in which petroleum and water accumulate.

Saturated Btu
The heating value contained in a cubic foot of natural gas fully saturated with water.

Saturated Btu At Delivery Conditions
The number of British thermal units (BTUs) contained in a cubic foot of natural gas fully saturated with water under actual delivery pressure, temperature, and gravity conditions.

Saturated Btu At Test Conditions
The number of British thermal units (BTUs) contained in a cubic foot of natural gas fully saturated with water at a specified pressure base and 60 degrees Fahrenheit.

Saturated Liquid
A liquid which is in equilibrium with a vapor at the prevailing pressure and temperature.

Saturated Solution
A solution is saturated if it contains at a given temperature as much of a solute as it can retain.

Saturated Vapor
A vapor which is in equilibrium with a liquid at the prevailing pressure and temperature.

Saturation
The fraction or percentage of the pore volume occupied by a specific fluid; e.g., oil; gas; water.

Saturation Pressure Measurement
The pressure where gas begins to be released from solution in oil or liquid begins to condense out of gas.

Saturation Pressure Type
Type of saturation pressure at the given temperature for the fluid; e.g., bubble point; dew point.

Saturation Temperature
The temperature at which the given saturation pressure was measured.

Scab
An imperfection in the form of a shell or veneer, generally attached to the surface by sound metal. It usually has its origin in an ingot defect.

Scale
A deposit precipitated out of water through an oxidation or other chemical process onto surfaces in contact with the water.

Scale Treatment
The act of chemically removing an encrusted oxide film formed inside a casing string.

Scattered Energy
Energy that is reflected in a random fashion by small reflectors.

Scheduling
A process by which nominations are first consolidated by key point, by contract, and verified with upstream/downstream parties. If the verified capacity is greater than or equal to the total nominated quantities, all nominated quantities are scheduled. If verified capacity is less than nominated quantities, nominated quantities will be allocated according to scheduling priorities.

Schmidt Diagram
In dipmeter interpretation, a polar plot where the azimuth indicates dip or drift direction and the distance from the origin indicates the dip or drift magnitude.

Schrader Core Valve
SEE: Drill Core Valve.

Scour
Soil erosion from waves and current action.

Scraper
Any device that is used to remove deposits (as scale or paraffin) from tubing, casing, rods, or flow lines; e.g., line scraper; paraffin scraper.

Scraper Trap
A pipeline quick connection for inserting or removing a scraper, or pipeline pig. The pig is forced through the line for cleaning or testing for obstructions.

Scratcher
A device fastened to casing which removes the mud cake from the wall of the borehole to condition it for cementing. The scratcher is fashioned of stiff wire.

Screen
A machine with screening surface(s) used to classify materials by size. Sieve analysis.

Screen Analysis
Determination of the relative percentages of substances, passing through or retained on a sequence of screens of decreasing mesh size. Analysis may be by wet or dry methods. Also referred to as: Sieve Analysis.

Screen Cloth
A type of screening surface, woven in square, rectangular, or slotted openings.

Screen Cloth Protector
SEE: Support Rubber.

Screen Cloth Rectangular Opening
When referring to wire cloth, having elongated openings defined by single or multiple cross wires. The mesh count in one direction is different from that at right angles to that direction.

Screen Liner
A special perforated pipe or casing which has the perforations protected by screen, usually used in loosely consolidated sand formations.

Screen Liner Depth
The measured depth the top of the screen liner set in the wellbore.

Screen Section
A finished piece of screening surface complete with edge or other preparation.

Screen Surface Plugging
The wedging or jamming of openings in a screening surface by particles, preventing passage of undersize material.

Screening
A mechanical process which accomplishes a division of particles on the basis of size by their acceptance or rejection by a screening surface.

Screening Surface
The medium containing the apertures for passage of the undersize material.

Screw Conveyor
SEE: Conveyor.

Screw Thread
A ridge of uniform section in the form of a helix on the internal or external surface of the pipe. Also referred to as: Thread.

Scroll
SEE: Flute.

Scrubber
A vessel in which entrained liquids or solids are removed from a gas stream.

Seal
(1) A thin metal strip used to seal a valve in an open or closed position. Seals are used on tanks in a battery to prevent the undetected opening and closing of the tanks.(2) An air tight or water tight closure or fitting.(3) SEE: Reservoir Seal.

Seal Record Review Date
The date the Bureau of Land Management (BLM) reviewed the seal record(s).

Seal Section
A device used to seal off pressure and prevent leakage in wellheads, submersible pumps, etc.

Sealing Agent
Any of many materials added to drilling fluid or cements to restore circulation.

Sealing Bore
The polished section of conduit that receives a packing element.

Seam
A straightline longitudinal crack or opening extending radially inward from the original outside surface. The seamless tube making process generally imparts a spiral path to the seam, but this is not usually noticeable in the threaded area. Seams may be caused by ingot cracks, surface pits on ingots, subsurface blowholes, or poor heating practices.

Seamless Pipe
Wrought steel tubular product made without a welded seam. It is manufactured by hot working steel, or if necessary, by subsequently cold finishing the hot worked tubular product to produce the desired shape, dimensions, and properties. Cold drawn tubular products, without appropriate heat treatment, are not acceptable.

Search Coil
Small coil or coils mounted in a transducer shoe.

Search Interval
In dipmeter interpretation, a depth interval corresponding to anticipated maximum dips.

Search Probe
A small coil or coil assembly that is placed on or near the pipe surface for detecting flaws and defects.

Search Unit
A device incorporating one or more transducers.

Seat
The fixed portion of the valve against which the movable part of the valve seals when in the closed position.

Secant Method
SEE: Trapezoidal Method and Average Angle Method under Borehole Survey Calculation Method.

Second Level Supervisor
An employee whose primary function is the direct supervision of the First Level Supervisor(s).

Secondary Means Of Escape
Fixed stairways or fixed ladders of metal construction or portable flexible ladders, knotted man ropes, and other satisfactory devices.

Secondary Recovery
The extraction of hydrocarbons from a reservoir beyond what can be recovered by normal methods of flowing or pumping. The use of waterflooding, gas injection, etc.

Secondary Sort
The secondary value on which the data is sorted. If multiple sort keys are used, this value will change faster than the primary key, yet slower than all remaining keys.

Secondary Water Treatment
Waste water treatment, beyond the primary state, in which bacteria consume the organic parts of the wastes. This biochemical action is accomplished by use of trickling filters or tha activated sludge process. Effective secondary treatment removes virtually all floating and settleable solids and approximately 90% of both BOD5 and suspended solids. Customarily, disinfection by chlorination is the final stage of the secondary treatment process.

Section Identifier
An indicator of (1) a subdivision of a township and which can be identified as Federal section and resurvey tracts, dominion section, Texas block (including block, league or block and township), Carter section, city subdivision, and civil section. A section usually contains 640 acres (more or less) and it may be divided by survey into subsections, lots or tracts.(2) one of the 36 divisions of a township in congressional areas. In nonCongressional areas there are 25 divisions in a township; e.g., The Ca

Section Milling
The process by which a portion of pipe casing is actually removed by a cutting operation involving a mill.

Section Number
The number corresponding to sections within a township and range. Section 1 is in the NE and section 36 is in the SE corner of the Congressional township. Sections are generally 1 mile square.

Sediment And Water
The preferred term for Basic Sediment and Water (BS and W), which consists of impurities present in oil as it comes from the well. S and W content is commonly used as a measure for treating performance of hydrocarbon liquids. The American Society for Testing and Materials (ASTM) Standard Test No. D96-82, entitled Water and Sediment in Crude Oils, is an accepted standard for this test.

Sedimentary Rock
(1) A rock formed from the consolidation of loose sediment that has accumulated in layers. Includes clastic rock, which consists of mechanically formed fragments of pre-existing rock, which may or may not have been transported by water, wind, ice or gravity;(2) Chemical rock, formed by precipitation from solution; (3) Organic rock, consisting of remains or secretions of plants and animals.

Sedimentary Structure
SEE: Structure (Sedimentary).

Sedimentation
(1) In waste water treatment, the settling out of solids by gravity.(2) The process of accumulating, transporting and depositing matter or material by wind or water.

Sedimentology
The branch of geology dealing with the study of sedimentary rocks and of the processes by which they were formed. The description, classification, origin and interpretation of sediments.

Seepage
Water that flows through the soil.

Seismic
Generation, propagation, recording, processing, and interpretation of acoustic or elastic body waves through the earth. Seismic generally implies lower frequency waves than the logging term sonic. Seismic will generally be used as a modifier to indicate that the term it modifies is in some way associated with a seismic experiment.

Seismic Acquisition
Term used to identify seismic information acquired or generated, usually in a land or marine environment.

Seismic Acquisition Line
A spatially contiguous collection of single or multiple occurrences of utilization of seismic source, receivers, or platform, at stations whose location and identity may be specified.

Seismic Acquisition Record
A collection of seismic traces. Usually the collection of traces representing a common source. Also referred to as record or shot record.

Seismic Acquisition Set
The seismic data created in an area of interest for processing together, including associated positioning data. A seismic acquisition set may include surface and/or well data. Examples are: a 3D seismic data volume, a 2Dseismic line, a checkshot or Vertical Seismic Profile.

Seismic Acquisition Survey Environment
The type of field environment in which seismic data was acquired; e.g., marine; land; marsh.

Seismic Amplitude
The deflection of a seismic receiver from a rest state caused by a seismic event. This deflection is typically sensed electronically.

Seismic Array
A geometric pattern of similar receivers and/or sources, such as electrodes, geophones, or hydrophones. An array is generally designed to enhance the detectability of certain transient events, while suppressing other interfering events.

Seismic Array Receiver Distance
The distance between the receivers in the seismic receiver array.

Seismic Array Source Distance
The distance between the sources in the seismic source array.

Seismic Cable
In seismic, the assembly of electrical conductors used to connect geophones or hydrophones to a recording instrument. This term can also refer to the telemetry connecting recording stations to a recording instrument.

Seismic Channel
A logical input port to a recording instrument. The term has meaning only in connection with recording systems. For a given recording event, each channel is associated with a specific signal generating device; i.e., a geophone array at a specific location.

Seismic Contract
A contract under which seismic data was acquired.

Seismic Crew
The group working together to carry out a geophysical field project.

Seismic Cube
Data which is representable via a matrix. The "surface indexes" of this matrix must represent inline indexes and crossline indexes from bin nodes from a single binset through its association to bin nodes.

Seismic Data
The collection of seismic data that exists at a particular state of the processing. Processing that changes the data will normally create a new seismic data set. The fundamental characteristic of data in this collection is that it references seismic objects; e.g., source/receiver occurrences, bin nodes, stations, etc.

Seismic Datum Shift
A correction value to observed reflection times which, when applied, gives the arrival time as if sources and/or receivers had been located on the datum surface.

Seismic Detector
SEE: Seismic Receiver.

Seismic Device
A device that generates, detects, or communicates either seismic waves or electric signals which represent seismic waves.

Seismic Device Node
A node within the spread at which location is determinable indirectly by offset from network nodes. This is normally the case with seismic detectors: source arrays often have positioning sensors mounted within them.

Seismic Facies
A region containing seismic reflections whose characteristic elements, such as amplitude, abundance, continuity, frequency, and configuration, distinguish the region from adjacent regions.

Seismic Feature
An identifiable linear surfacial or regional feature within a seismic image of the Earth. Seismic features are given identifying names which serve to support correlation between different seismic data sets.

Seismic Grid
A set of intersecting 2D seismic lines. (This is not to be confused with the term grid which refers to a coordinate system.) SEE: Grid(3).

Seismic Line
(1) A linearly, ordered collection of bin nodes or stations to which one or more seismic traces is associated.(2) A collection of seismic traces representing data collected along a specified path. The term Seismic Line alone is not sufficient to represent the desired collection of data. In general, there will need to be qualifiers to more precisely define the collection of seismic data to be assigned to each surface location; e.g., Seismic acquisition Line; Seismic Binned Line.

Seismic Line Multifold Coverage Number
A number identifying the common depth point (CDP) multiplicity of coverage involving a seismic line; i.e., 24 fold coverage occurs when the same CDP is sampled at 24 offset distances.

Seismic Line Name
An alphanumeric value assigned to a seismic line to identify the line.

Seismic Line Number
A numeric value used to uniquely identify a seismic line within an acquisition program.

Seismic Line Projected Deviated Wellbore Path
Projection of a the wellbore path of a deviated well onto the plane of the seismic line.

Seismic Line Projected Well Surface Location
Projection of the well surface location on the seismic line.

Seismic Mistie
The difference in time or depth between two seismic picks which are part of the same seismic feature at a binset intersection.

Seismic Panel
A two dimensional array of values which is related to a seismic object; e.g., semblance as a function of time and velocity at a bin node.

Seismic Party
SEE: Seismic Crew.

Seismic Permit Application Date
The year, month and day of the Geological and Geophysical (G&G) Permit application.

Seismic Permit Issued Date
The year, month and day that a Geological and Geophysical (G&G) Permit was issued.

Seismic Permit Number
The unique identification assigned by a Regulatory Agency to a Geological and Geophysical (G&G) Permit application.

Seismic Pick
A point of interest on a seismic trace, characterized by a particular amplitude, phase, velocity, or some other feature. The pick is identified by the bin node at which it occurs, by the relationship to a seismic feature, and by the travel time at which the pick occurs. It is usually associated with the arrival of a seismic wavefront.

Seismic Position Network
A group of nodes with observations defined between these nodes. Most observations define a geometric relationship between two or more nodes. Networks may be processed according to specific, consistent sets of rules, to determine position at the various nodes.

Seismic Position Node
A reference point fixed on a device whose location may move and may be determined from time to time. One seismic position node may be associated with one or more devices. A seismic position node may be either a seismic device node or a position sensor node.

Seismic Process
Computer processes applied to seismic line data, including program names and generic process types. A process will create/change/remove either seismic data, information related to the data, or the relationships among these.

Seismic Processing History
A collection of comments and/or other information describing the process(es) applied to a collection of seismic data.

Seismic Profile
The series of measurements made from a single source point location into a recording spread. Additional shots from the same general source location into the same spread are considered part of the same profile. However, if the same spread is shot from a different source point location, it is a different profile, or if the same source point location is shot into a different spread, it is also a different profile.

Seismic Receiver
A device that transforms seismic energy into electrical voltage. Geophone receivers ordinarily respond to one (or more) component(s) of the displacement, velocity, or acceleration involved in the passage of the seismic wave. Previously referred to as Seismic Detector.

Seismic Receiver Group
An array of geophones deployed at a station which collectively feed a single seismograph channel.

Seismic Receiver Orientation
Orientation of the seismic receiver with respect to the line.

Seismic Recording Length
Total length of time of the recorded traces or waveforms.

Seismic Reflection
The energy or wave from a seismic source which has been reflected (returned) from an acoustic impedance contrast (reflector) or series of contrasts within the earth.

Seismic Reflection Time
The time required for a seismic wave to propagate from source to receiver, reflecting off a given horizon.

Seismic Reflector
A geologic interface across which an acoustic impedance contrast occurs which causes incident seismic energy to be reflected.

Seismic Refraction Survey
A program to map geologic structures using head waves. The objective is to determine the arrival times of head waves in order to map the depth to the refractors in which they traveled. Involves head waves; i.e., involves a travel path in a high velocity medium parallel to the bedding.

Seismic Sample Domain
The domain frequency value in which the data are sampled; e.g., time; depth.

Seismic Section
A graphical display of seismic traces that represent a cross section of the earth subsurface.

Seismic Source
SEE: Source.

Seismic Source Element
The individual device which generates seismic energy. Usually several of these are combined into a group or array.

Seismic Source Line
A spatially contiguous collection of single or multiple occurrences of utilization of a seismic source, at stations whose location and identity may be specified.

Seismic Source Orientation
Orientation of the seismic source with respect to the line.

Seismic Spread
A collection of receiver stations that are to receive a seismic signal. Each station has a receiver group that will record a single seismic trace. In marine surveys, the spread also includes the seismic sources.

Seismic Survey
(1) A program for mapping subsurface geologic structures by creating seismic waves and observing the arrival time of the waves reflected from acoustic impedance contrasts or refracted through high velocity members.(2) The acquisition of seismic data: (a) within a specified time period; (b) at a specific area; (c) tied to a specific prospect; and/or (d) having all accounting expenses tied to a common entity; i.e., a 3D seismic data volume or a collection of 2D seismic lines.

Seismic Survey Line
An ordered collection of surveyed stations.

Seismic Taper
A smoothly varying gain function applied to a trace to gradually reduce the amplitude. In filtering, it is used to avoid dependence on high frequencies to represent a signal adequately.

Seismic Tie Line
The intersection of seismic lines.

Seismic Trace
The third value on which data is sorted.

Seismic Uphole Time
The time for the first energy from a buried explosion to reach a receiver located at the surface above the source.

Seismic Velocity
(1) The propogation rate for a seismic wave without necessarily implying any direction.(2) A rock property that represents the speed at which an elastic wave would propagate in the rock.

Seismic Velocity Analysis
The process of calculation of subsurface seismic velocity distributions using observed reflection moveout times observed at various source to receiver distances.

Seismic Velocity Gather
A collection of seismic traces used to analyze seismic velocities for a given surface location

Seismograph
A device which records vibrations in the earth, detected by geophones.

Seismograph Channel
A single series of interconnected devices through which data can flow from source (not the seismic source, but the reciever groups) to the recording seismograph.

Selector Control
A device used to control the flow of liquids or gases from one stream to another.

Selectrograph
Chart used to select the minimum required length of nonmagnetic drill collars.

Self Potential
SEE: Spontaneous Potential.

Seller
The party who has contractual signatory authority and warranty of title to sell product services, the product, or its by-products as a commodity. The seller may have legal authority to sell as agent for or on the behalf of other owners.

Seller Name
The name of the person, firm, company, or corporation who has entered into a contract or agreement to purchase petroleum products or buy petroleum products.

Selling Arrangement Code
An indicator of the type of sales contract under which the petroleum product is marketed.

Selling Arrangement Number
The number identifying the selling arrangement of the product.

Sensing Probe
Wireline instrument used in connection with Electronic Yaw Equipment.

Sensitive Reservoir
A reservoir in which ultimate recovery is decreased by high reservoir production rates. A high reservoir production rate is one which exceeds the Maximum Efficient Rate (MER).

Sensitivity
The ability to detect small differences or discontinuities.

Sensitivity Percentage
A ratio of the smallest flaw detectable divided by the wall thickness of the pipe being examined.

Sensor
Any device which monitors operating conditions to detect abnormal or unusual condition and transmit a signal/alarm to perform a specified function or notify designated operating personnel.

Sensor Calibration
The additive computed minus observed (C-O) and scale computed divided by observed (C/O) correction factors to be applied to (NOT which have been applied to) "raw" measurements.

Sensor Calibration Addition
The additive corrected minus observed (C-O) part of a sensor calibration,

Sensor Calibration Scale Factor
The multiplicative part corrected divided by observed (C/O) of the sensor calibration.

Separate Or Special Allowable Order Number
The number of an order or permit by the regulatory agency authorizing a well to produce at a separate or special permitted production rate, as an exception to the general rules and regulations regarding such rates.

Separation
A physical process where gas in solution (associated gas) is removed from crude oil through reduction of pressure.

Separator
(1) An item of production equipment used to separate free liquid components of the well production stream from gaseous elements. Separation is accompished principally by gravity, the heavier liquids falling to the bottom and the gas rising to the top.(2) A process vessel employed to separate liquids of distinctly different physical properties which result in layering or vapor phasing.

Separator Cone
SEE: Hydrocyclone.

Separator Gas Oil Ratio
The ratio of separator gas rate to separator oil (or condensate) rate, expressed as cubic feet of separator gas per barrel of separator oil (or condensate).

Separator Gas Oil Relative Volume Factor
The volume of separator oil at separator conditions of pressure and temperature divided by the volume of stock tank oil at stock tank conditions.

Separator Liquid Gravity Measurement
The density of the liquid as it exists at atmospheric conditions in a separator.

Separator Pressure Measurement
The pressure maintained in a separator during operation.

Separator Temperature
The operating temperature of the separator.

Separators Count
The number (count) of separators on a facility.

Sequence Stratigraphy
The branch of Stratigraphy dealing with rock sequences; i.e., rock relationships within a chronostratigraphic framework of repetitive, genetically related strata bounded by surfaces of erosion or nondeposition, or their correlative conformities.

Sequential Discriminator
An indicator that distinguishes items in a sequence; e.g., last, second, first, initial, final.

Sequestration
The formation of a stable, soluble complex by combining a metallic ion, such as calcium, magnesium, or iron, with a suitable agent thereby modifying the action of the ion. Representative sequestering agents are ethelenediamine tetraacetic acid (EDTA) or its sodium salts, pyrophosphates, tripolyphosphates, and citrates.

Serial Register
An index to filings made under a particular offering for lease or other type of application which is maintained in District Land Offices of the Bureau of Land Management, Regional Offices of the Minerals Management Service, and other agencies of the Department of the Interior, as appropriate.

Serial Register Approval Hour
The clock time (hour) a lease assignment was approved and documented to the serial register.

Serial Register Approval Minute
The clock time (minute) a lease assignment was approved and documented to the serial register.

Serialization
Assignment of a unique code, as required, to maintain proper records.

Service Settlement Type
Indicates whether the associated service is a charge (cost) or a credit (income) to the company, or is income to the party performing the service with no direct financial effect on the company.

Service Unit
An organization unit that provides services which aid in maximizing assets, profitability or meeting strategic objectives.

Service Well
A well drilled or completed for the purpose of supporting production in an existing field; e.g., injection wells, disposal wells, or wells for producing nonhydrocarbon materials.

Serviceability Limit State
Function of design variables which defines a condition at which a member no longer satisfies functional requirements, although it is still capable of carrying additional loads before reaching an ultimate limit state.

Set Casing
The well activity of installing of casing in a wellbore.

Setdown
The increase in Tension Leg Platform (TLP) draft with offset due to tendon system restraint.

Setting Off Course
A method of setting the direction of the borehole axis in anticipation of the drill bit walking. Also referred to as: Lead Angle.

Settle
(1) To sink gradually to the bottom.(2) To become clear by a deposit of sediment or scum.(3) To become compact by sinking.

Settleable Solids
Bits of debris and fine matter heavy enough to settle out of waste water.

Settled Production
Production at a regular rate of flow over a substantial period when the decline rate is slow as distinguished from the period of flush production.

Settlement Amount
The total monetary amount paid to adjust settlement values.

Settlement Option Notice
The number of days of prior notice required by the seller to effect settlement options.

Settlement Option Type
The options permitted the seller other than monetary payments for a component product; e.g., in kind; right to purchase.

Settlement Quantity Increment Percentage
Percentage used in adjusting settlement values based on the quantity of gas received.

Settler
SEE: Gunbarrel.

Settling Pit
A tank or open pit where well cuttings and coarse solids settle out of the drilling fluid before the drilling fluid is returned to circulation.

Settling Velocity
The velocity at which a particle of particular size, type, specific gravity, and concentration will settle in a fluid of a particular specific gravity and viscosity.

Severance Tax Amount
Production tax on the removal (or severing) of minerals from the ground based on a price per thousand cubic feet (MCF) of gas or barrel of oil or on a percentage of the value. Generally levied by the state or sovereign Indian Nation.

Sewage Treatment System
A system used to treat accumulated amounts of raw liquids or waste matter.

Sh Wave
Shear (S-) wave which has a horizontal component of motion only.

Shackle Rod System
A method of pumping several wells on one lease by means of small rods, or shackle rods, extending from the wells to a central pumping house, and connected to the wells in such a way as to carry the power of the central pump to each well.

Shadow
A region in a body that cannot be reached by ultrasonic energy traveling in a given direction because of the geometry of the body or a discontinuity in it.

Shaft
An elongated slender cylindrical form or vertical opening of uniform and limited cross section.

Shake Out
To spin a sample of oil at high speed to determine its BS&W content.

Shake Out Test
SEE: Shake Out.

Shale
A fine grained sedimentary rock composed of silt and clay sized particles.

Shale Density
The density of a representative shale sample taken from the cuttings, measured using a shale density kit.

Shale Shaker
A vibrating screen used to remove cuttings from the drilling fluid as it returns to the surface from the wellbore bottomhole.

Shallow Flaw
A discontinuity which has little depth in proportion to wall thickness and does not exceed critical flaw size of the appropriate specifications.

Shape
Sedimentology: The spatial or geometric form of the particles in a sediment or sedimentary rock, described in terms of sphericity and roundness. Also referred to as: Particle Shape; Grain Shape. Described as rounded, subrounded, subangular, angular.

Sharp Crest
The top intersection of the sides when the thread flanks are extended.

Shaved Thread
A specific condition of improper thread form exhibiting an excessive narrowness of thread width. Also referred to as: Thin Thread.

Shear
An action, resulting from applied forces, which causes or tends to cause two contiguous parts of a body to slide relative to each other in a direction parallel to their plane of contact. Also referred to as: Shearing Stress.

Shear Lag
Shear effects on beams which cause a nonuniform distribution of longitudinal bending stresses across the flange.

Shear Rate
The rate at which an action, resulting from applied forces, causes or tends to cause two adjacent parts of a body to slide relatively to each other in a direction parallel to their plane of contact.

Shear Ridge
First year ridge formed primarily by relative motion of two ice sheets in the direction parallel to their common boundary, called a slip page line. Composed of groundup ice chips, water soaked and refrozen.

Shear Strength
A measure of shear value. The minimum shearing stress that will produce permanent deformation.

Shear Wave
SEE: S Wave.

Shearometer
A device used as an alternative method for measuring gel strengths.

Sheath
Protective casing or covering. Cement sheath is the protective covering around the casing within a wellbore.

Sheave
(1) A wheel with a grooved circumference over which a rope or a v-belt is turned, either for the transmission of power for hoisting or hauling.(2) Any grooved wheel or pulley.

Sheet Ice
A region of relatively undisturbed, smooth first year ice that grows continuously throughout the winter season.

Shell
A horizontal vessel which contains the coil, firetube and heater bath.

Shell Panel
That portion of a shell which is bounded by two adjacent rings in the longitudinal direction and two adjacent stringers in the circumferential direction.

Shield
A layer or mass of material used to reduce the passage of ionizing radiation.

Shift
Refers to a time (or depth) shift on a seismic trace. The movement of the seismic samples either earlier (up) or later (down) in time (depth).

Shipboard Cable
Cable constructed in accordance with Institute of Electrical and Electronic Engineers (IEEE) Std. 45.

Shipper
The party who contracts with a transporter to move a product over the transporter's system.

Shock Absorber
Any of several devices for absorbing the energy of sudden impulses or shocks in machinery or structures;e.g., springs of automobiles.

Shoe
SEE: Detector Shoe.

Shoe Joint
The distance between the casing shoe and the float collar, which is usually made up of one or two joints of casing, and is located at the bottom of the casing string.

Shoot
Pass a short time pulse of high current through a conductor.

Shooting
The discharge of nitroglycerin at the wellbore bottomhole shatter the reservoir rock and increase production.

Shooting Nipple Assembly
A fabricated length of pipe equipped with a wireline blowout preventer and packoff installed above the blowout preventer stack to accommodate removal of logging or perforating tools and for protection against unexpected pressure while performing through casing wireline operations.

Shore Base Facility
An onshore support facility that during drilling, development, maintenance, and producing operations provide such services to the joint property as receiving and transshipment point for supplies, materials, and equipment; debarkation point for drilling and production personnel and services; communication, scheduling, and dispatching center; other associated functions benefiting the joint property.

Short Hook Up
Assembly composed of gauge bit, a near bit gauge stabilizer, and one or more drill collars. Used to build angle after an initial kick off.

Short Natural Gas Position
The circumstance when a company consumes more natural gas in its operations than it produces.

Short String
In a wellbore with multiple well completions, the short string is the tubing string for the shallower well completion.

Shot
The measurement taken or the survey reading taken as a picture or as a punched hole on a chart.

Shot Feeder
A small pot through which liquid (usually chemicals) can be injected into a system under pressure.

Shot Field
Residual magnetic field induced by a short impulse of magnetizing current. Often it is generated using a battery or capacitor discharge magnetizer.

Shot Gather
The collection of recorded events from a seismic source (or array), received by a spread of receivers.

Shot Record
SEE: Seismic Acquisition Record.

Shot Type Code
Indicates the type of instrument used to conduct the directional survey.

Shotpoint
The seismic energy source location. General alias for station, although a station may exist without any seismic source being assigned to it.

Shoulder
A condition where an excess of metal appears adjacent to the last thread in one or more places around the circumference. Usually an excessive amount of black threads appear opposite the shouldered area. Also referred to as: Hooked Threads.

Show
A trace or indication of oil or gas in a core, cuttings, or circulating drilling fluid, or interpreted from electrical or geophysical logs run in a wellbore.

Show Fluid Type
The type of product represented by the show; e.g., oil; gas; coal.

Show Source
Indicates source of the show data; e.g., log; drillstem test; cuttings.

Show Type
The type of hydrocarbon show; e.g., drilling fluid sensor; fluorescence or jeep; bleeding; condensate stain; gas odor.

Shrinkage
(1) The reduction in volume of a gas stream due to removal of hydrocarbon products, hydrogen sulfide, or carbon dioxide.(2) The unaccounted loss of products from storage tanks.(3) Loss in crude volume from reservoir when gas is evolved from solution.

Shrinkage Bearer
Indicates whether shrinkage is borne by buyer, seller or processor.

Shrinkage Factor
The oil volume divided by the change in oil volume from reservoir conditions to atmospheric pressure. These measurements are all made at reservoir temperature.

Shut- In Bottomhole Pressure Measurement
A shut- in pressure measurement recorded for a specified depth.

Shut- In Casing Pressure Measurement
The pressure measurement recorded for the space between the surface casing and the producing casing during a well test shut- in phase.

Shut- In Casing Temperature
The shut- in temperature that has been recorded for a gas well.

Shut- In Depth
The depth of the well completion at the time it was shut-in.

Shut- In Formation Pressure Measurement
SEE: Static Reservoir Pressure.

Shut- In Payment Amount
The amount of shut- in payment due a given payee prior to the addition of any bank service charge or alien tax adjustment for that payment.

Shut- In Payment Type
An indicator of the status of the lease; e.g., pay; pay immediately; hold; not applicable.

Shut- In Royalty
Payment to royalty owners under the terms of a mineral lease which allows the lessee to defer production from a well capable of producing in paying quantities but shut-in for lack of a market or marketing facilities. This type of royalty or some form of rental is usually required to prevent termination of the lease.

Shut- In Static Column Wellhead Pressure Factor
The calculation factor resulting from subtracating the static column wellhead pressure squared from the shut- in wellhead pressure squared.

Shut- In Time Interval
A time interval between two shut-in pressure measurements within a well test shut- in phase.

Shut- In Tubing Pressure Measurement
A shut- in pressure measurement recorded for the tubing during a well test shut-in phase.

Shut- In Tubing Temperature
The temperature inside the tubing on a shut- in well.

Shut- In Well Count
The total number of oil and gas wells in a shut-in, nonproducing, status at a specified level during a specified time period. (Normally at a lease or field level.)

Shut- In Wellhead Pressure Measurement
A shut- in pressure measurement recorded at the wellhead.

Shut- In Wellhead Pressure Squared Factor
The square root of the absolute wellhead shut- in pressure, divided by 1000.

Shut Off
The successful exclusion of flow of any unwanted fluid from the wellbore through the use of packers, cement, mud, plastic, etc.

Shut Off Base Depth
The deepest depth of the interval being shut off.

Shut Off Top Depth
The shallowest depth of the interval being shut off.

Shut Off Type Code
An indicator of the method used to shut off open borehole or perforated intervals at the time the well is completed; e.g., bridge plug; cased off; squeezed; straddle packer.

Shut-in
The condition of shutting off flow of fluids to or from the reservoir.

Shut-in Date
The date a well is shut-in.

Shut-in Flag
An indicator that a well is shut-in.

Shutdown Valve
An automatically operated valve used for isolating a process component or process system. Commonly abbrevaited as: SDV.

Si Unit Of Measure
A unit of measure based on the International System of Units (SI) as described in The International System of Units (SI), NBS Special Publication 330, U.S. Dept. of Commerce, National Bureau of Standards, Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. (1981) (Order by SD Catalogue number: C13.10:330/3.) Some measurement quantities are added to the SI defined set to deal with measurement quantities used by the petroleum industry but not defined by SI.

Side Door Mandrel
SEE: Gas Lift Mandrel.

Side Draw
The removal of a product from some point between the top and the bottom of a vessel.

Side Irons
The housing and supports for the bearings of a walking beam.

Side Pocket Mandrel
SEE: Gas Lift Mandrel.

Side Tension
Tensioning of a screening surface across the direction of material flow.

Sidetrack
A wellbore segment extending from a wellbore intersection along a wellbore path to a different wellbore bottomhole from any previously existing wellbore bottomholes.

Sidetrack Date
The date on which sidetrack operation begin.

Sidetracking
The well activity of drilling a new wellbore segment from a wellbore intersection to a new wellbore bottomhole or target.

Sidetracking Pocket
An enlargement of one side of the borehole made to facilitate changing the direction of the borehole axis. The borehole enlargement is usually accomplished by use of jetting action.

Sidewall Core Sample Taken Flag
An indicator of whether a core or rock sample was taken from the wall of an existing borehole by shooting a hollow projectile or by mechanically extracting a sample.

Sidewall Coring Tool
A percussion type device; i.e., gun which can be attached to the well logging cable to obtain a sidewall core.

Sidewall Neutron Log
A well log consisting of an epithermal neutron log made with the neutron source and detector mounted in a skid which is pressed against the borehole wall to minimize borehole effects.

Sieve
SEE: Testing Sieve.

Sieve Analysis
A statement by particle size and percentages of the amount of material in various particle size groupings.

Signal
(1) A response of electronic nondestructive testing (NDT) equipment to a pipe imperfection or defect.(2) That which carries desired information.

Signal To Noise Ratio
The ratio of the amplitude (power) or the desired energy (signal) to the amplitude (power) of the unwanted energy (noise). Abbreviated as S/N.

Signature Log
A display of the acoustic wave train in the amplitude time mode wherein the amplitudes of the different acoustic wave forms are shown as a function of time.

Silencer
A cylindrical vessel constructed with baffles, ports, and acoustical grids to muffle exhaust noise.

Silica Flour
A fine powder manufactured by grinding sand to a particle size in the range of about 0.074 mm to 0.044 mm. It is added to cementing formulations to prevent cement strength deterioration in high temperature installations within the wellbore.

Silica Gel
A porous substance consisting of SiO3. Used on occasion as a dehydrating agent in air or gas drilling where small amount of water is encountered.

Silica Sand
A high purity graded sand of a particle size in the range of about 0.210 mm to 0.088 mm. It is used in cementing formulations where a high density slurry with strength deterioration protection from high temperatures is required.

Silicate
A compound whose crystal structure contains SiO4 tetrahedra, either isolated or joined through one or more of the oxygen atoms to form groups, chains, sheets or 3-dimensional structures with metallic elements.

Silt
(1) A clastic sedimentary particle with a diameter between 1/256 and 1/16 millimeter, based on the Wentworth Scale of Measurement.(2) Materials that exhibit little or no swelling whose particle size generally falls between 2 microns and 74 microns (200 mesh).

Silt Class
The class of silt, based on size using the Wentworth Scale of Measurement.

Simpson's Rule Method
A borehole survey calculation method which uses the measured angle values to recreate the wellbore path using Simpson's rule for numeric integration, which approximates a path by passing a parabola through three points.

Simultaneous Lke
A like-kind-exchange (LKE) that happens the same day.

Single
One joint of drill pipe.

Single Shot Survey
A measurement of the inclination and direction of the borehole axis at one position with one recording.

Sinistral Fault
SEE: Left Lateral Strike Slip Fault.

Sinker Bar
A heavy weight or metal bar run with a wireline tool to add weight to the string so that the tool will readily sink into the wellbore.

Sinking
A method of controlling oil spills that employs an agent to entrap oil droplets and sink them to the bottom of the body of water. The oil and sinking agent are eventually biologically degraded.

Sintered Carbide
Most commonly, iron, chromium, or tungsten carbides bonded together with nickel or cobalt.

Sintering
Property that indicates the degree of bonding of ice blocks as a function of contact pressure, temperature, and time where the voids are either air or snow.

Sise
Surplus, idle and sub-optimal equipment.

Skelp
The rolled steel sheet used in the making of pipe with one longitudinal weld.

Skew
In seismic recording, the time difference accounting for the slight variance in time (for a given sample) between channels.

Skew Angle
(1) In ultrasonic testing, the angle by which the beam deviates right or left relative to its normal path in front of the transducer, due to curvature effects.(2) The angular offset of the axis cone from the geometric center of a roller cone drill bit.

Skid
(1) A prefabricated base for an equipment assembly. Skid mounted equipment is usually readily movable.(2) Also, to move equipment from one location to another without disassembly.

Skimmer Tank
A produced water processing tank designed to skim oil from the surface of the water.

Skimmer Unit
A device propelled over water that sucks or skims the hydrocarbon into a collector.

Skimming
The removal of lighter components while leaving the heavier components behind.

Skimming Pit
A pit into which oil and water is placed, the oil later being skimmed from the surface.

Skin
A radial zone of reduced permeability in the rocks surrounding the borehole resulting from damage due to drilling, completion and/or production practices.

Skip Distance
In ultrasonic testing, the surface distance required for an angle beam to traverse the metal thickness, be reflected from the far side, and return to the original surface.

Slacking Off
The releasing of tension either on casing, drill pipe, or tubing at the wellhead.

Slag Inclusion
Nonmetallic solid material entrapped in the weld deposit or between weld metal and base metal.

Slant Hole
SEE: Slant Type Directional Wellbore.

Slant Hole Rig
SEE: Slant Rig.

Slant Rig
Drilling rig specifically designed to drilling a slant type direction wellbore. The mast is slanted and special pipe handling equipment is needed.

Slant Type Directional Wellbore
(1) Usually refers to a wellbore path having a vertical wellbore segment, an angle build wellbore segment, and an angled but straight wellbore segment, which continues to total depth. (2) Used to define a wellbore path that is nonvertical at its wellbore origin. Also referred to as a Slant Hole.

Slenderness Ratio
The ratio of the effective length of a member to the radius of gyration of the member.

Slewing
SEE: Swing.

Slice
An isotime or isodepth horizontal section through a 3D data volume; e.g., time slice; horizon slice.

Slick Line
SEE: Solid Wire Line.

Sliding Scale Royalty
A royalty varying in accordance with the amount of production; i.e., a 1/8th royalty if the production is 100 barrels per day or less, and 3/16th royalty if the production is greater than 100 barrels per day. Difficult problems of interpretation of the sliding scale royalty clause arise when governmental regulations on a unitization agreement limit production on the amount of oil allocated to a particular tract.

Sliding Sleeve Nipple
A special device placed in a string of tubing which can be operated by a wireline tool to open or close orifices (openings) to permit circulation between the tubing and annulus. It may also be used to open or shut off production from well completions.

Sling
(1) A flat, wide piece of material used for moving material with a type of hoist, crane, etc.(2) A wire rope loop for use in lifting heavy equipment.

Slip
A wedge shaped piece of metal with teeth or other gripping elements used to prevent pipe from slipping down into the wellbore or for otherwise holding the pipe in place. Rotary slips fit around the drill pipe and wedge against the master bushing to support the pipe. Power slips are pneumatically or hydraulically actuated devices operated by the driller at this station and which dispenses with the manual handling of slips when making a connection. Packers and other downhole equipment are secured in positi

Slip Ram Preventer
A ram blowout preventer with pipe slips that, when engaged, prevent movement of the pipe but does not control flow.

Slip Stream
A stream which is removed from the main process stream for purposes of sampling, alternate processing, etc.

Slip Tube
A device for gauging tank cars, trucks, or storage tanks which are under pressure and cannot be opened to atmosphere.

Slip Velocity
The difference between the annular velocity of the drilling fluid and the rate at which cuttings are carried by the drilling fluid.

Sliver
An extremely thin elongated piece of metal that has been rolled into the surface of the parent metal to which it is attached usually by only one end.

Slope
On a shale shaker, the angle with the horizontal made by the first or top deck screen section(s). Must be specified as uphill or downhill.

Slope Angle Measurement
The angle deviation from the vertical of the horizontal.

Sloughing
SEE: Caving.

Slow Sand Filter
A very large filtering unit containing sand. The fluid flows through the sand bed very slowly because of the large bed size. Generally, these filters are too large to be economically practical.

Sludge
A deposit formed in one place which may be deposited in another place; e.g., low flow rate areas; tanks; vessels; bends in lines.

Sludge Conditioner
A surface active agent for maintaining sludge in a flocculent condition to facilitate its removal from the system.

Slug
Any relatively large mass of concentrated liquid, normally in a gas stream.

Slug Catcher
A coded horizontal or vertical vessel associated with a pipeline system downstream of a pig receiver to catch pipeline condensate in vapor pipelines.

Slug Flow
SEE: Heading.

Slug The Pipe
Before hoisting drill pipe, it is desirable to pump into the top section of it a quantity of heavy mud (a slug) which will cause the level of the fluid in the pipe to fall. Thus, when a stand of pipe is unscrewed, the drilling fluid will have been evacuated from it. This prevents crew members and the rig floor from becoming covered with the drilling fluid.

Slurry
A mixture and/or suspension of solid particles in one or more liquids.

Slurry Density
SEE: Cement Slurry Density.

Slurry Volume
SEE: Cement Slurry Volume.

Slurry Weight
SEE: Cement Slurry Density.

Slush Bucket
A hollow cylinder used to draw sludge from the bottom of the well.

Slush Pit
SEE: Settling Pit.

Small Fracture Count
The number of fractures in a depth interval that are less than 10cm in length.

Smooth Ice
Any area of sea ice that has not been noticeably affected by ice deformation mechanisms. Also referred to as: Sheet Ice.

Snatch Block
A block that can be opened up for putting a line over the roller or sheave.

Snubbing
Pulling or running pipe under pressure through a resilient sealing element where special equipment is used to apply external force to push the pipe into the wellbore or to control the pipe movement out of the wellbore.

Soap
The sodium or potassium salt of a high molecular weight fatty acid. When containing some metal other than sodium or potassium, they are called metallic soaps. Soaps are commonly used in drilling fluids to improve lubrication, emulsification, sample size, defoaming, etc.

Socket
A device fastened to the end of a rope by means of which the rope may be attached to its load. Also referred to as: Rope Socket.

Soda Ash
SEE: Sodium Carbonate.

Sodium
One of the alkali metal elements with a valence of 1 and an atomic weight of about 23. Numerous sodium compounds are used as additives to drilling fluids.

Sodium Bichromate
SEE: Sodium Dichromate.

Sodium Carbonate
A material used extensively for treating out various types of calcium contamination. It is commonly called soda ash. When sodium carbonate is added to a fluid, it increases the pH of the fluid by hydrolysis. Sodium carbonate can be added to salt (NaCl) water to increase the density of the fluid phase.

Sodium Carboxymethylcellulose
An organic material used to control filtration, suspend weighting material, and build viscosity in drilling fluids. Used in conjunction with bentonite where low solids drilling fluids are desired. Commonly abbreviated as: CMC.

Sodium Chromate
An inorganic water soluble chromium compound useful as an inhibitor of iron corrosion caused by oxygen.

Sodium Dichromate
Sodium chromate in acid systems. A corrosion inhibitor. Its chemical formula is Na2Cr207. Also referred to as: Sodium Bichromate.

Sodium Hydroxide
Commonly referred to as caustic or caustic soda. A chemical used primarily to impart a higher pH.

Sodium Nitrite
An inorganic water soluble chemical useful as an inhibitor of iron corrosion caused by oxygen.

Sodium Polyacrylate
A synthetic high molecular weight polymer of acrylonitrile used primarily as a fluid loss control agent.

Soft Line
A fiber rope.

Sol
A general term for colloidal dispersions, as distinguished from true solutions.

Solid Component
A substance with unique and distinct characteristics that normally occurs as a solid. This does not include chemical components. Examples of solid components are: walnut shells, frac sand, ball sealers, etc.

Solid Organic Matter
Organic matter in solid form, such as kerogen.

Solid Wire Line
A special wire line of very strong steel, usually 0.066 to 0.092 inch in diameter. Also referred to as: Slick Line.

Solids
All particles of matter in the drilling fluid; e.g., drilled formation cuttings; barite.

Solids Concentration
The total amount of solids in a drilling fluid as determined by distillation includes both the dissolved and the suspended or undissolved solids. The suspended solids content may be a combination of high and low specific gravity solids and native or commercial solids. Examples of dissolved solids are the soluble salts of sodium, calcium, and magnesium. Suspended solids make up the wall cake; dissolved solids remain in the filtrate.

Solids Control Equipment Item
An equipment item designed to separate out and discharge unwanted drilled solids and contaminants from a drilling fluid system. The mechanism by which this can be achieved can be split into four categories; screen separation, settling, forced centrifugal settling, and degassing.

Solids Discharge
That stream from a liquid solids separator containing a higher percentage of solids than does the feed.

Solids Discharge Capacity
The maximum rate at which a liquid solids separator can discharge solids without overloading.

Solids Free Fluid
A well operations fluid which depends on dissolved salts for its density, rather than suspended inert solids. They are typically used where the use of solids could lead to downhole formation damage or clog up perforations. Their use therefore is mainly for completion/workover activities. The type of salt used determines the maximum densities possible.

Solids Removal Screen
Screens used in solids removal equipment.

Solubility
(1) The quality of being soluble.(2) Capability of being dissolved in a fluid.

Soluble Oil
A compound which may possess corrosion inhibition properties, is dispersible in water, and is soluble in oil.

Solute
A substance which is dissolved in another.

Solution
A mixture of two or more components that form a homogeneous single phase; e.g., solids dissolved in liquid; liquid in liquid; gas in liquid.

Solution Gas
Gas dissolved under pressure in oil in a reservoir. Also referred to as casinghead gas; dissolved gas.

Solution Gas Drive
A natural drive mechanism where an oil reservoir derives its energy for production from the expansion of the natural gas in solution in the oil.

Solution Gas Oil Ratio
The ratio of gas to oil initially dissolved in the reservoir crude oil.

Solvent
Liquid used to dissolve a substance.

Sonde
Any instrument package containing both transmitting and receiving devices that can be lowered into the wellbore.

Sonic
Pertaining to acoustic or P waves in fluids. Sometimes includes other wave modes and hence becomes synonomous with seismic and elastic.

Sonic Log
An acoustic log of the travel time (interval transit time) of the compression wave over a unit distance; and hence, a record of the reciprocal of the compressional wave velocity. Used to measure porosity.

Sorption
Includes both adsorption and absorption. Sorption is basic to many processes used to remove gaseous and particulate pollutants from an emission and to clean up oil spills.

Sort
An arrangement of data by ordered key values or the process of making such an arrangement. Sort order is a description of which keys vary most slowly. The terms prime, secondary, tertiary, etc. are used to define the keys that vary most slowly, second most slowly, etc.

Sorting
Sedimentology: The spread or range of the particle size distribution within a clastic rock sample.

Sounder
A device used to determine the fluid level in a wellbore.

Soundness
A measure of the expansive properties of a cement as determined by the Autoclave Expansion Test given in ASTM C 151.

Sour Crude Oil
An oil containing free sulphur or other sulphur compounds whose total sulphur content is in excess of one percent. Also referred to as: Sour Crude.

Sour Environment
Fluids containing water as a liquid and hydrogen sulfide are considered sour environments and may cause sulfide stress cracking of susceptible materials. This phenomenon is affected by complex interactions of parameters including: (1) metal chemical composition, strength, heat treatment, and microstructure;(2) pH; (3) hydrogen sulfide concentration and total pressure;(4) total tensile strength;(5) temperature;(6) time. The user shall determine the environmental conditions in which the metal

Sour Gas
Natural gas containing chemical impurities, notably hydrogen sulfide (H2S) or other sulfur compounds. Gas is generally considered to be sour if it contains 10 or more grains of H2S or 200 or more grains of total sulfur per mcf. Also referred to as acid gas.

Sour Liquid
A liquid containing mercaptans or hydrogen sulfide. It is also known as "doctor sour" indicating mercaptan contamination.

Source
(1) A device (or array of devices) that releases energy for generating seismic waves, e.g., Vibroseis; Dynamite; Air gun. (2) Also, a natural energy source, such as an earthquake.

Source Orientation
The orientation of the seismic source. The orientation may be given as a textual description (Vertical; Horizontal Inline; Horizontal Crossline) or as a pair of angles.

Source Payor Name
The company originally reporting the sales.

Source Potential Generated
The results of an analysis to determine the potential volume of petroleum generation capacity of a source rock sample.

Source Profile
SEE: Seismic Profile.

Source Rock
Rocks rich in organic material and having the potential to generate hydrocarbons.

Souring
SEE: Fermentation.

Sp
SEE: Spontaneous Potential.

Space
SEE: Location.

Spacing
Aerial distribution of well locations producing from the same reservoir.

Spacing Order Assigned Date
The date a spacing order is assigned.

Spacing Pattern
The pattern by which wells are drilled; e.g., 5-spot, 10-spot, etc. if applicable.

Spacing Unit
A unit formed of one or more parcels of land to comply with spacing requirements and/or integration orders of state or other governmental regulatory bodies, or to conform to operating patterns established by operators in the absence of formal spacing rules. A spacing unit is normally of a size attributable to one well for drainage purposes. Spacing units are generally formed for development wells in a proven field and not for exploratory purposes.

Spacing Unit Order Number
The number assigned by a regulatory agency to a spacing unit.

Spacing Unit Orientation Type Code
An indicator of the type of the geographical positioning of the spacing unit; e.g. Stand Up 80 Acreas, Lay Down 80 Acreas.

Spacing Unit Size
The acreage size of the spacing unit.

Spaghetti
Very small tubing or pipe.

Spalling
Flaking off in small chips.

Spark Arrestor
A device placed on the exhaust of the stack to prevent sparks from being emitted to the outside atmosphere. It normally consists of a metallic wire screen attached across the top diameter of the stack.

Spe
Society of Petroleum Engineers of AIME.

Spear
A fishing tool which goes inside lost pipe in a wellbore to obtain a friction grip and permit recovery. It is the male counterpart of an overshot.

Special Process
Operations which convert or affect material properties.

Special Service
Those operations utilizing specialized equipment and personnel to perform work processes to support well drilling and servicing operations.

Species
The biological species classification of a living thing or fossil.

Specific Acoustic Impedance
A property of a material which is the product of its density and its elastic (or acoustic) wave velocity. A change in impedance will cause a reflection or refraction of the wave, and the magnitude of the change determines the strength of the reflection.

Specific Gravity Measurement
The ratio of the mass of a given volume of a substance at a given temperature and pressure to the mass of an equal volume of a standard substance at the same temperature and pressure. For vapors, the standard substance is air (dry and free of carbon dioxide) and for liquids, the standard substance is water.

Specific Heat
The number of calories required to raise 1 g of a substance 1 deg Centigrade. The specific heat of a drilling fluid gives an indication of the fluid's ability to keep the bit cool for a given circulation rate.

Speed
(1) Distance traveled per unit of time.(2) The frequency at which a vibrating screen operates, usually expressed in RPM or CPM.(3) The bowl rpm of a decanting centrifuge.(4) The rotor rpm of a perforated cylinder centrifuge.

Sphericity
Particle sphericity is a measure of how close a sand particle or grain approaches the shape of a sphere.

Spheroid
Mathematical surface to which coordinates are referenced. Defined by an ellipsoid of revolution which is revolved about its minor axis and which approximates to the earth's surface, devoid of topographic undulations. Examples: Clarke-1866; GRS-80; International-1924.

Spheroid Name
Reference spheroid and year on which the latitude and longitude are based; e.g., Clarke-1866.

Spheroidized Carbides
Iron carbides in steel present as tiny round spheres.

Spider
A solid steel casting designed to hold slips for the purpose of gripping and holding the tubing or casing while connecting another joint to the string. A device to hold a suspended string of casing in a wellbore.

Spinner
A type of downhole flowmeter consisting of an impeller, inside a protective cage, which is caused to rotate by the motion of borehole fluid past the blades. A survey is made by moving the tool against the flow of fluid, with the flow, or maintained stationary in the borehole. Its primary use is in monophasic flow streams.

Spinning Chain
A rope or chain coiled around a joint of casing or pipe and drawn around the cathead used in making up or unscrewing a joint of drill pipe or casing during the period that the pipe turns easily.

Spiral Drill Collar
A drill collar which has spiraled grooves milled around its outer body. This reduces the contact area between drill collar and drilled hole, and reduces the probability of getting stuck.

Spiral Weld Pipe
Pipe having a helical seam produced by automatic submerged arc welding.

Splash Zone
(1) (ENGINEERING): The part of the structure subjected to periodic wetting and drying due to tides, waves, and spray.(2) (GEOLOGY): The shoreline area that is affected by the splashing of seawater from breaking waves.

Split Deck
SEE: Divided Deck.

Split Stream Gas Plant Number
The number assigned to identify a second plant that processes gas from a split stream well.

Splitter
A distillation column in which two components of similar molecular weights are separated.

Spoil
Waste dirt or rock that has been removed from its original location.

Spoke
For a horizontal well, a spoke is a secondary wellbore segment off a lateral.

Spontaneous Potential
The difference of potential (DC voltage) between a movable electrode in the borehole and a distant reference electrode usually at the surface. Used to infer permeability and fresh water. Commonly abbreviated as: SP.

Spool
A short section of pipe with flanged ends, used in Christmas Tree assemblies to separate and support the various valves in the stack. Spools act as spacers for the valves in the blowout preventer.

Spool Head
A casinghead located between the starting head and tubing head used for hanging additional strings of casing.

Spot Location
SEE: Quarter-Quarter Spot.

Spot Month
The month closest to present in which futures contracts are currently trading.

Spot Oil
To place oil at a selected depth in a well in order to lubricate stuck pipe, clean the formation, or to prepare for acidizing, Hydrafrac treating, etc.

Spot Sale
Short term sale of gas to an end user, Local Distribution Company (LDC), or pipeline for which the duration varies.

Spotting
The technique of placing a quantity of fluid (oil, water, acid, cement, etc.) at a desired position in the wellbore in order to lubricate stuck pipe, clean the borehole wall, or to prepare for acidizing, hydrafracing, treating, etc.

Spray Discharge
The characteristic underflow of certain hydrocyclones discharging to the atmosphere and not overloaded with separate solids.

Spread
In the marine survey context, spread includes the seismic energy sources, the receivers and their containing streamers, and all positon sensors therein. In land surveys, the spread is the arrangement of seismic receivers in relation to the source point.

Spreader
A device or system designed to distribute incoming emulsion as uniformly as practical through the cross section of the vertical or horizontal shell.

Spring Loaded Valve
A gas lift valve which uses a spring to provide the closing force for the valve.

Springing
The high frequency vertical vibration of the Tension Leg Platform (TLP) spring mass system excited by cyclic loading at or near the TLP pitch or heave resonant periods. Also referred to as Ringing.

Spud Contractor Name
The name of the contractor spudding the well.

Spud Date
The day when the drilling bit penetrates the surface utilizing a drilling rig capable of drilling the well to the authorized total depth.

Spud Time
The actual time (hours and minutes) when the drilling bit penetrates the surface utilizing a drilling rig capable of drilling the well to the authorized depth.

Spudding In
The very beginning of drilling operations of a new well.

Square Drill Collar
A drill collar which has a square external profile, with the four corners chain fered.

Squealer
A noise maker attached to the end of an exhaust pipe.

Squeeze Additive Name
The brand name or generic name of the cement squeezing additive, which is combined with the cement to modify properties or characteristics.

Squeeze Additive Volume
The volume of squeeze additive.

Squeeze Job
Usually a secondary cementing job where cement is pumped into the rocks below the casing or through perforations to shut off of unwanted fluids.

Squeeze Job Date
The date the squeeze job well activity was performed.

Squeeze Material Density
The density of the cement slurry used in the squeeze job.

Squeeze Material Displacement Pressure Measurement
The average pressure attained when displacing the squeeze material into the formation.

Squeeze Material Displacement Rate
The average rate attained when displacing the squeeze material into the formation.

Squeeze Material Trade Name
The trade name of the squeezing material used in the squeeze job.

Squeeze Material Volume
The volume of the squeezing material actually mixed; may not all be used in the squeezing process.

Sscsv
SEE: Subsurface Controlled Safety Valve.

Sssv
SEE: Subsurface Safety Valve.

Sssv Assembly
A subsurface safety valve (SSSV) and safety valve lock. This term shall include only the SSSV when referring to tubing retrievable type SSSVs.

Sssv Equipment
The subsurface safety valve (SSSV), safety valve lock and safety valve landing nipple and related downhole accessories.

Sssv System
The downhole components, including the subsurface safety valve (SSSV), safety valve lock, landing nipple, flow couplings and any required control components.

Ssv Usv Actuator
The device which causes the surface safety valve/underwater safety valve (SSV/USV) valve to open when power is supplied and to automatically close when power is lost or released.

Ssv Usv Valve
The portion of the surface safety valve/underwater safety valve (SSV/USV) which contains the production fluid stream and shuts off flow when closed.

Stabbing
The act of guiding the end of a joint of pipe as it enters the coupling of another joint.

Stabbing Board
A temporary platform erected in the derrick at an elevation of 20 to 40 feet above the derrick floor. The derrickman or other crew member works on this board while casing is being run in a well.

Stability Meter
An instrument to measure the breakdown voltage of invert emulsions.

Stabilization
Continuous operation to a time when conditions remain at a constant level, or to a time when fluctuating conditions follow a definite repetitive sequence.

Stabilized
A well test is considered stabilized when, in the case of a flowing well, the flow rate through a given size of choke remains constant, or, in the case of a pumping well, when the fluid column within the wellbore remains constant in height.

Stabilizer
An item of equipment with a bladed section which is of a larger diameter than its own body, or is itself a bladed section which can be attached to another drillstem component. Typically the diameter of the stablized section will be the same (or under gauge by a prescribed amount) as that of the borehole in which it is to be placed. These components can be installed within a drillstem for a variety of reasons, some of which are: minimize the contact area between the drillstem and the borehole; centralize

Stabilizer Receiver
SEE: Stabilizer Unit.

Stabilizer Type
(1) Rotating Blade: Stabilizer with the largest outside diameter sections composed of narrow blades extending from the stabilizer body; e.g., welded blade; replaceable blade; integral blade.(2) Nonrotating Blade: stabilizer used to center drillstem in the borehole without reaming the borehole. Stabilizer ribs, usually of rubber, will not wear out rapidly since rotation occurs between the sleeve and a mandrel.(3) Full body, Spiral grooved: Full gauge long stabilizer with sets of spiral grooves cut

Stabilizer Unit
A multi-stage pressure vessel to selectively control liquid composition.

Stack
(1) Engineering: A vertical pipe on the exhaust end of the firetube which exhausts the products of combustion and creates draft through the firetube.(2) Seismic: The process of adding together a set of traces to produce a single trace.

Stack Datum
An arbitrary surface to which seismic data is related (shifted) prior to stacking. The stack datum corresponds to zero time on a trace.

Stack Downdraft Diverter
A device attached to the top of the stack designed to reduce the effects of wind currents on the burner system.

Stack Flame Arrestor
A device placed on the exhaust of the stack to prevent propagation of flame from inside the firetube to the outside atmosphere. It normally consists of a corrugated aluminum or stainless steel cell mounted in a metal housing which attaches to the top of the stack.

Stack Rain Shield
A device attached to the top of the stack to prevent rain from falling directly into the stack. It may also serve as a stack downdraft diverter.

Stacking A Rig
Storing a drilling rig upon completion of a job when the rig is to be withdrawn from operation for a period of time.

Stage
A period or step in a process whereby one or more batches of a given fluid or slurry are pumped at different time intervals or displaced to different depth intervals within a wellbore.

Stage Separation
An operation whereby produced fluids are separated into component liquids and gases by passing consecutively through two or more separator. The operating pressure of each succeeding separator is lower than the one preceding it.

Stage Step In Squeezing Process
The identifier of the individual cementing stage within the squeeze job. A stage is defined as a period or step in the cementing process whereby one or more cement batches are pumped at different depth intervals within the wellbore path.

Stainless Steel
(1) Nonmagnetic (austenitic): An alloy of over 16 percent chromium, over 7 percent nickel, and iron. Manganese can be used to partially replace nickel.(2) Magnetic (ferritic): An alloy of over 11 percent chromium and iron.

Stake
To accurately stake a surveyed location, such as a drill site.

Stand
(1) Two or more joints of pipe, either tubing or drillstem, screwed together. (2) A frame on which something is placed for support.

Stand Of Pipe
SEE: Stand.

Stand-off Shooting Distance
The distance from the perforating gun to the interior casing surface.

Standard Conditions
A combination of pressure and temperature used as a base for comparison of gas, fluid, or vapor quantities. Usually, a temperature of 60 degrees Fahrenheit and a pressure of 14.7 pounds per square inch absolute (psia).

Standard Deviation
A statistical measure of dispersion of sample observation values.

Standard Pressure
The pressure value that is determined by state or Federal regulatory agencies.

Standard Temperature
Typically 60 degrees Fahrenheit or its equivalent.

Standing Fluid Level
Stable level of drilling fluid in a wellbore.

Standing Valve
A stationary valve at the lower end of the working barrel of a sucker rod pump.

Standing Wave
A wave in which the energy flux is zero at all points. Such waves in elastic bodies result from the interaction of similar trains of waves running in the opposite direction and are usually due to reflected waves meeting those which are advancing.

Standing Wire Rope
A supporting nonoperating wire rope which maintains a constant distance between the points of attachment to the two components connected by the wire rope.

Standoff
(1) In well logging, the distance separating a sonde from the wall of the borehole.(2) A device for producing this separation.

Standpipe
A rig pipe, which is a part of the drilling fluid circulating system, extending up into the derrick to a height suitable for attaching the rotary hose.

Starch
A group of carbohydrates occurring in many plant cells. Starch is specially processed (pregelatinized) for use in drilling fluids to reduce filtration rate and occasionally to increase the viscosity.

Start Ing Test Time
The start time in hours, minutes of the test.

Starter
A device used to begin the rotation of an engine until it reaches a speed at which it will run on its own. (May be electrical, pneumatic or gas.)

Starting Fluid Level
A distance measured from a permanent datum point down to the top of any liquid in the wellbore prior to swabbing.

Starting Head
SEE: Casinghead.

Starting Tract Number
The starting tract number assigned by the Minerals Management Service (MMS) at the time of an OCS lease offering to identify a leasable component as a single bidding entity in a particular lease offering. An OCS tract may be comprised of one block or of portions of several blocks as long as the total acreage in one entity does not exceed 5,760 acres.

State Assigned County Code
State assigned Department of Revenue county codes for Kansas and state assigned Department of Conservation parish codes for Louisiana.

State Code
A code that uniquely identifies each state of the United States, and on the Outer Continental Shelf (OCS) areas, as defined in API Bulletin D12A, as amended.

State Name
The alpha name of each state.

State Pressure Base
The official gas pressure base to be used when reporting gas volumes to the state. The state pressure bases are monitored by the Interstate Oil Compact Commission.

State Royalty Exempt Amount
The monetary amount exempt from taxation that relates to a state royalty exemption.

State Seaward Boundary
The seaward boundary of the Submerged Lands Act Grant to a coastal state. The boundary is generally located three nautical miles from the baseline, but in the case of the gulf coasts of Florida and Texas, it is located approximately nine nautical miles from the baseline. See Submerged Lands Act, 43USC 1301-1325.

State Standard Volume
A volume of gas determined in accordance with measurement standards prescibed by state regulations.

Static
Opposite of dynamic; non-flowing.

Static Column Wellhead Pressure Factor
The square of the Static Column Wellhead Pressure, divided by 1000.

Static Column Wellhead Pressure Measurement
This term corresponds to a flowing wellhead pressure, adjusted for the pressure differential required to overcome frictional resistance to the flow of gas in a particular flow string. Determined by a series of equations and used in the calculation of the potential or deliverability of a well.

Static Correction
A correction (shift) applied to seismic data to compensate for the effects of variations in elevation, weathering layer thickness, weathering velocity, or reference to a datum.

Static Fluid Level
(1) The depth to which reservoir fluids will rise when the producing conduit is open to atmospheric pressure.(2) The level to which fluid rises within the wellbore when the wellbore is shut in.

Static Pressure Measurement
The pressure measurement recorded on a static fluid.

Static Pressure Type Code
An intdicator of the type of pressure integrity test performedi during drilling in completion or production operations. Examples include Blowout Preventer (BOP), casingshoe integrity.

Static Reservoir Pressure
The reservoir pressure measurement recorded in a small test chamber before reservoir fluids are allowed to flow in quantity in a subsequent well test phase.

Static Reservoir Temperature
The reservoir temperature measurement recorded in a small test chamber before reservoir fluids are allowed to flow in quantity in a subsequent well test phase.

Statics
The process of determining time shifts to be applied to seismic data to compensate for the effects of variations in elevation, weathering thicknesses, weathering inhomogeneities, or reference to a datum. A static shift is characterized by an equal time shift's begin applied to every sample on a trace, in contrast to dynamic shifts (NMO) in which different sample points receive different time shifts.

Statics Correction
Corrections applied to seismic data to eliminate the effects of variations in elevation, weathering thickness, or weathering velocity.

Station
A surface position in a seismic survey at which may be located a geophone group or a source device. Stations are mapped to absolute ground positions via the survey data.

Stave
Side section of a tank.

Steady State Phase Flow
An equation of flow in which the streamlines are invariant with flow.

Steam Chest
The steam end of a steam operated reciprocating pump.

Steam Injection
Steam injected into a formation to maintain or restore reservoir pressure to enhance ultimate recovery of hydrocarbons.

Steam Injection Volume
Volume of steam injected into the well completion.

Steam Rig
A rotary drilling rig with steam boilers and steam driven equipment.

Steam Trace
To install a steam line alongside another line or against a vessel under common insulation to prevent low temperature in the line or vessel.

Steamer
A vessel in which articles are subjected to steam.

Stearate
Salt of stearic acid, which is a saturated, 18 carbon fatty acid. Certain compounds, such as aluminum stearate, calcium stearate, zinc stearate, have been used in drilling fluids for one or more of the following purposes: defoamer; lubrication; air drilling in which a small amount of water is encountered, etc.

Steel
An alloy of iron and carbon having two main constituents iron and iron carbide.

Steering Readout
Directional instrument indication of the drilling tool alignment taken while drilling.

Step
A specific condition of improper thread form that exhibits an abrupt machining deviation above or below the normal thread profile.

Step Deck
A series of screening surfaces, each located in progressively lower parallel planes along the vibrating screen.

Step Out Well
SEE: Extension Well.

Stepwalk
A short platform at the end of a stairway to provide access to specific areas.

Stick Plot
A presentation of dipmeter results where the wellbore is represented by a line according to the projection of the wellbore onto a vertical plane, and the components of dip in this plane are indicated by short line segments.

Stiff Hookup
(1) A well stabilized, rigid bottomhole assembly to maintain inclination and direction of the borehole axis.(2) Opposite to limber hookup.

Stiff Leg
A type of derrick or crane.

Stiffened Panel
Structural component comprising one or two sets of equally spaced uniform stiffeners of equal cross section supporting a thin plate. If there is only one set of stiffeners the panel is uniaxially stiffened, and if there are two the panel is orthogonally stiffened.

Stiffener
Straight and slender thin walled member of uniform cross section containing at least one plane of symmetry, which serves as a stiffening element for a flat plate structure.

Stiffness
Quality or state of being rigid, resistance to bending under stresses within the elastic limit.

Stile
Steps made of walking up and over a fence or other obstruction.

Still
(1) A fractionator in which recoverable hydrocarbons are removed from rich oil. Open steam rather than reboiler vapor is usually used in the stripping section. Sometimes used synonymously for regenerator, as in amine still. (2) The vertical column in a Lean Oil Process (LOP) where upward flowing vapors remove, or strip, specific components from downward flowing liquids. It has the highest reboil temperature feed to remove heavier hydrocarbons.

Stimulation
Any process undertaken to enlarge the old channel or create new ones in the reservoir rock.

Stitching
Variation in the properties of the weld occurring at short regular intervals along the weld line due to repetitive variation in welding heat. The variation in properties gives rise to a regular pattern of light and dark areas visible only when the weld is broken in the weld line.

Sto
SEE: Stock Tank Oil.

Stock Tank
A storage tank for treated crude oil.

Stock Tank Gas Oil Ratio
The ratio of separator gas rate to stock tank oil rate, expressed as cubic feet of separator gas per barrel of stock tank oil.

Stock Tank Liquid Color Type
The color of the liquid within the stock tank.

Stock Tank Liquid Gravity Measurement

Stock Tank Liquid Gravity Measurement
The density of the liquid as it exists at atmospheric conditions in a storage tank.

Stock Tank Oil
The saleable oil contained in a storage vessel as oil production from a well or lease and stored until sold to purchaser.

Stopcocking
The practice of alternately closing and opening a stopcock placed in the tubing near the connection to the flow line to release accumulations of oil and gas under pressure from a well completion.

Storage Medium
The means used for storage of bulk data. Types of storage media include: tape, disk, and CD-ROM.

Storage Type Code
The indicator for whether sales are conducted on a facility.

Stormer Viscometer
A rotational shear viscometer used for measuring the viscosity and gel strength of drilling fluids. This instrument has been largely superseded by the direct indicating viscometer.

Straddle Packer
Two packers set above and below a presumed pay zone, thereby isolating it from the rest of the wellbore. Used in drillstem tests.

Straddle Plant
A gas plant constructed near a transmission company pipeline downstream from the fields where the gas is produced. The gas is sold at the lease/field to the transmission company. The producer and/or plant owner(s) retain processing rights and reimburse the transmission company for the plant volume reduction (PVR), volume and quality, either in cash or in additional gas deliveries. Also referred to as: On line Plants.

Straight Beam
A vibrating pulse wave train traveling normal to the test surface.

Straight Hole Downhole Motor
A downhole motor designed to drill straight ahead. Usually a straight hole motor is longer, larger and provides more torque than does a directional downhole motor.

Straight Hole Turbodrill
SEE: Straight Hole Downhole Motor; Turbodrill.

Straight In Directional Hole
A wellbore path with a build and a straight locked in wellbore segment. There is no drop off wellbore segment.

Straight Mechanical Drive
Internal combustion engines connected to leads by clutches which can be slipped a moderate amount.

Straight Wellbore
Wellbore drilled with the intention to proceed in a nonchanging direction.

Strap
(1) To calibrate a tank.(2) To measure the drill pipe while pulling out of the wellbore. Used to determine driller's measured depth.

Strata
The layering of sedimentary rocks, visibly separated by surfaces.

Stratification
The natural layering or lamination usually characteristic of sediments and sedimentary rocks.

Stratigraphic Classification
An arbitrary but systematic arrangement, zonation or partioning of the sequence of rock strata into units with reference to any or all of the many different characteristics, properties or attributes which the strata may have. The American Code of Stratigraphic Nomenclature is an example of a formal stratigraphic classification.

Stratigraphic Correlation
Correlation of indicators of stratigraphy from multiple sources, such as wells, outcrops or seismic.

Stratigraphic Thickness
The thickness of the stratigraphic unit measured perpendicular to the bedding planes.

Stratigraphic Trap
A stratigraphic trap is one having a geometrical configuration of reservoir rock and reservoir seal determined by variation rock characteristics. Such variation in porosity and permeability can be caused by; e.g., stratigraphic or facies variation; variation in rock diagenesis.

Stratigraphic Unit
A stratum or body of adjacent strata recognized as a unit in the classification of a rock sequence with respect to some specified characteristics.

Stratigraphic Unit Name
The name of a stratigraphic unit.

Stratigraphic Well
A well drilled to obtain information pertaining to a specific geologic condition. Such wells are drilled usually without any intention of completing them for hydrocarbon production; e.g., C.O.S.T. wells.

Stratigraphy
The branch of geology dealing with the relationships of rock strata. Stratigraphy includes interpretation of succession and age relationships of rock strata, as well as their internal composition.

Stream Trace
The trace of a stream bed either on the surface or in a rock.

Streamer
A marine cable incorporating pressure hydrophones, designed for continuous towing through water.

Streaming Potential
The electrokinetic portion of the spontaneous potential (SP) electric log curve which can be significantly influenced by the characteristics of the filtrate and drilling fluid cake of the drilling fluid that was used to drill the wellbore.

Streamline Flow
SEE: Laminar Flow.

Strength Retrogression
The decline with age of strength of the hardened cement slurry. This may occur at temperatures above a critical temperature.

Stress
The load per unit area.

Stress Corrosion Cracking
The cracking which results from a combination or corrosion and stress when certain susceptible materials are exposed to specific corrosive media.

Stress Relief
Controlled heating of material to a predetermined temperature for the purpose of reducing any residual stresses after welding.

Stress Relieved
The residual stresses are significantly reduced by post weld heat treatment.

Stress Reversal
Change in stress from tension to compression, or vice versa.

Stretch Mill Indentation
Localized thinning of the pipe body wall usually located on the inside surface.

Strike
The direction of the line of intersection of a surface with the horizontal; e.g., a bedding or fault surface. Strike direction is a horizontal line perpendicular to dip direction.

Strike Plate
Extra piece of metal to protect the bottom of a tank from plumb bob at end of gauger's tape.

Strike Price Amount
The contingency price at which a specific risk management right or option can be exercised. A mechanism for granting authority and setting price limits on transactions.

Strike Slip Fault
A fault in which the movement of the fault blocks is parallel to the fault's strike.

String
The entire length of casing, tubing, sucker rods, or drill pipe run into a wellbore.

String Reamer
Reamer placed within the drillstem assembly to increase the diameter of any keyseat through which it passes; used to remove doglegs and keyseats and to straighten the borehole axis.

String Shot
An explosive method to back off stuck pipe utilizing primacord.

String Stabilizer
Stabilizer placed anywhere in the drillstem assembly above the near bit stabilizer.

Stringer Stiffened
A member with longitudinal stiffeners.

Strip A Well
To pull sucker rods and tubing from a wellbore at the same time.

Strip Chart
In lieu of the circular chart for recording gas flow through an orifice meter, strip charts are sometimes used.

Strip Log
A well log, often presented in colors and symbols, of the lithologies encountered while drilling, indicating shows and well tests.

Stripper
(1) SEE: Stripper Well.(2) The vertical column in a Lean Oil Process (LOP) upstream of a still with one reboil feed which strips methanes and ethanes from the rich oil.

Stripper Gas
Production from a well completion which produces gas at a rate not exceeding 60 mcf per day over 90 days.

Stripper Oil
Oil produced by a well completion efficiently producing less than ten barrels per day.

Stripper Well
A low capacity well or one having a small productivity and approaching its economic limit of operation. The term is specifically defined in statutes of some states and may vary from state to state. Also referred to as: Marginal Well.

Stripping
Pulling or running pipe under pressure through a resilient sealing element.

Stroke
The distance between the extremities of motion; i.e., the diameter of a circular motion.

Structural Competence
The ability of the machine and its components to withstand the stresses imposed by applied loads.

Structural Geology
The branch of geology dealing with the general disposition, attitude, arrangement or relative positions of rock masses of a region, consequent upon deformational processes, such as faulting, folding and intrusion.

Structural Steel Pipe
A cylindrical tubular member formed from plate steel with longitudinal and circumferential butt welded seams and having a uniform wall thickness.

Structural Trap
A structural trap is one having an upper boundary that has been made concave, as viewed from below, by local rock deformations, such as folding or faulting, or both, of the reservoir rock.

Structure
(1) Sedimentary: Large to medium scale features in a sedimentary rock formed in the sediments: (A) during deposition, such as graded bedding, ripple marks and cross stratification; (B) after deposition and before consolidation; e.g., loading and dewatering deformations; (C) biogenic structures, such as bioturbation and trace fossils. (2) Tectonics: The geometrical configuration, attitude, arrangement or relative positions of rock masses of a region, resulting from regional deformation processes; e.g.,

Structure Identification Number
A unique number assigned to a specific structure within a complex.

Stuck Pipe
Drill pipe, collars, casing, tubing or other downhole equipment that have inadvertently become unmovable in the borehole.

Stuck Point Depth
A distance measured from a permanent datum point to the top of a tool or piece of junk which is unable to be removed. Can also be where the top of cement is holding pipe to the wellbore.

Studded Connection
A connection in which thread anchored studs are screwed into tapped holes.

Studded Flange Connection
A flanged end and outlet connection in which thread anchored studs screwed into tapped holes replace the holes for bolt studs.

Stuffing Box
(1) A packing gland.(2) A chamber or box to hold packing material around a moving pump rod, valve stem or wireline to prevent the escape of gas or liquid.

Su
SEE: Service Unit.

Sub
Short threaded pieces used to adapt parts of the drilling string which cannot otherwise be screwed together because of difference in thread size or design.

Sub Cellar Deck
A deck located below the cellar deck. Decks below the cellar deck will be designated as Sub Cellar Deck A, Sub Cellar Deck B, etc.

Sub-optimal Equipment
Equipment not meeting required or anticipated operating demands.

Subject To Plant Size Flag
An indicator of whether or not a gas settlement should be adjusted for the processing plant size.

Submarine Casing Hanger
The device inside the submarine housing to support the casing or tubing string.

Submarine Christmas Tree
The production tree of valves installed on a submarine wellhead.

Submarine Manifold
The subsea well template may incorporate a subsea manifold when wells are completed with subsea trees. Here, production fluid is conveyed from the trees via pipes on the template to a subsea manifold at the base of a production riser. Production fluid may be commingled at the manifold if the number of subsea wells exceeds the number of production risers available.

Submarine Well Template
A structural frame which provides location and anchor points for the subsea wellheads, riser systems, and guidance systems.

Submarine Wellhead System
Describes the general characteristics of the equipment installed on the bottom of the sea to hold the casing, the blowout preventer (BOP) stack, and guide the drilling assembly.

Submerged Arc Welded Pipe
Pipe having one longitudinal seam formed by automatic submerged arc welding.

Submerged Lands Act
The Federal act which declares that the subsoil and seabed of the Outer Continental Shelf (OCS) are subject to the jurisdiction and control of the United States. The Act authorizes the Secretary of the Interior to lease such lands for certain purposes. Refered to as 43USC 1301-1325.

Submerged Zone
The part of the structure below the splash zone.

Submersibile Pump Protector
The device that shields the electric motor preventing damage from downhole fluids.

Subprocess
A series of actions that complete a primary activity of one or more of the steps in a process.

Subsea Depth
The depth measured below sea level; i.e., sea level is the reference datum. The depth axis is vertical, and positive downward.

Subsea Diverter
A piping manifold positioned at the top of the drilling riser to divert formation gas and liquid to an acceptable discharge point, preventing flow to working areas.

Substructure
The foundation on which the derrick and engines sit. Contains space for storage and well control equipment.

Subsurface Controlled Safety Valve
Commonly abbreviated SSCSV. Subsurface controlled subsurface safety valve, a subsurface safety valve (SSSV) actuated by the pressure characteristics within the wellbore. These devices are usually actuated by differential pressure through the SSCSV (Velocity Type) or by tubing pressure at the SSCSV (High or Low Tubing Pressure Types).

Subsurface Discontinuity
Any discontinuity that does not open onto the surface (either ID or OD). Also referred to as: Subsurface Imperfection.

Subsurface Equipment
Equipment put into a wellbore to perform an operation below the wellhead.

Subsurface Lease Parcel
A specific tract of the Earth defined by areal extent and depth interval.

Subsurface Safety Valve
A device installed in the production tubing in a wellbore below the wellhead and designed to prevent uncontrolled flow when actuated. These devices can be installed and retrieved by wireline (wireline retrievable) and pump down methods or be an integral part of the tubing string (tubing retrievable). Commonly abbreviated: SSSV.

Subweathering
A layer immediately below the weathering layer. In a physical sense, the weather/subweathering interface often corresponds to the water table.

Success
The outcome of drilling a well from which the owners elect to produce hydrocarbons.

Successful Efforts Accounting Method
An accounting method under which costs incurred in searching for, acquiring, and developing oil and gas reserves should be capitalized if they result directly in reserves. All other costs are expensed.

Successor To An Existing Contract
Under the Natural Gas Policy Act (NGPA), 1978, as amended, any contract other than a rollover contract entered into on or after November 9, 1978 for the first sale of natural gas which was previously subject to an existing contract.

Sucker Rod
A metallic rod with screw connection at the ends providing a means for connecting with other rods forming a series or a string of rods used to extend down in a wellbore to the working parts of a pump and to actuate same.

Sucker Rod Hanger
A device used in the upper part of a derrick from which to suspend stands of sucker rods when they are pulled from the wellbore.

Suggestive Trademark
A trademark or service mark that suggests or hints at, but does not describe, qualities or characteristics of a product or service.

Sulfide Stress Cracking
The stress corrosion cracking of high strength steels which results when the corrosive media contains hydrogen sulfide (H2S).

Sulfide Stress Cracking Service
Process streams which contain water or brine and hydrogen sulfide (H2S) in concentrations high enough to induce stress corrosion cracking of susceptible materials.

Sulfite Test
A test for determining the concentration of sulfite in water.

Sulfur Dioxide
A toxic gas, which may be produced from the oxidation of hydrogen sulfide bearing fluids in operations such as gas flaring or well ignition. This gas is slightly heavier than air. Inhalation at certain concentrations can lead to injury or death.

Sulfur Dioxide Percentage
The MOL percentage of sulfur dioxide in a flared or burned gas stream.

Sulfur Plant
A plant which removes hydrogen sulfide from the gas and produces sulfur.

Sun Resistant
Ability to withstand exposure to direct sunlight as defined by UL Std. 62, Safety Standard for Flexible Cord and Fixture Wire.

Sundry Notice Approval Date
The date the sundry notice is approved by regulatory agency.

Sundry Notice Received Date
The date the sundry notice is received from the operator.

Sundry Notice Type Code
The indicator for the type of Sundry Notice received.

Supercompressibility Factor
A deviation of natural gas from Boyle's and Charles' Laws for ideal gas. Natural gas is not an ideal gas in that it is a mixture of several gases. As the pressure increases, the volume of space that a given weight of natural gas would occupy becomes increasingly less than the volume calculated by application of Boyle's and Charles' Laws.

Superheater
That portion of a boiler in which the temperature of the steam is raised above the saturation temperature.

Superposition
The order in which rocks are placed or accumulated in beds one above another, such that successively younger layers are deposited on lower and older layers.

Supersaturation
A solution containing a higher concentration of a solute in a solvent than would normally correspond to its solubility at a given temperature.

Supplemental Mailing Address
Additional information (other than name, street, city, state, zip code) required for a mailing location.

Supplier
Any individual or organization who furnishes materials, products, or services to another individual or organization.

Support Bar
Member of the screening surface support frame that forms the crown