Technical
Thesaurus oil & gas
Sacrificial anode
A ring or slab of metal
placed on a key part of an underwater structure in order to protect it from
corrosion; the sea water attacks the anode rather than the structure.
Safety belt
A safety harness used by
the derrick man when working on the monkeyboard.
Sales in place
Estimate of Security
Exchange Commission (USA) reserve sold while in the ground, to another party.
Salt column
A column of salt which has
broken through overlying formations.
Salt dome
A dome of salt that has
broken through overlying formations.
Salt dome trap
A trap produced by an
impervious salt dome.
Salt gel
See attapulgite.
Salt pillow
A mass of salt that has
risen up under overlying formations, causing them to bulge upwards, but which
has not actually broken through.
Salt pillow trap
A form of anticlinal trap
produced by a pillow of salt forcing the overlying rocks upwards into a dome.
Samples
1. The well cuttings
obtained at designated footage intervals during drilling. From an examination
of these cuttings, the geologist determines the type of rock and formations
being drilled and estimates oil and gas content. 2. Small quantities of well
fluids obtained for analysis.
Sampling
The process of obtaining a
small quantity of material which is as representative as possible of the total
volume.
Sand
An abrasive material
composed of small quartz grains formed from the disintegration of pre-existing
rocks. Sand consists of particles less than two millimetres and greater than
1/16 of a millimetre in diameter.
Sand line
A wireline (cable) used on
a drilling rig to raise and lower the bailer or sand pump in the well bore.
Logging devices and other light-weight equipment are also lowered into the hole
on the sand line.
Sanded up
A well clogged by sand that
has drifted and washed into the well bore , from the producing formation by the
action of the formation fluid.
Sandstone
A type of rock composed
primarily of quartz grains.
Satellite link
A communications system whereby
a signal is passed between two points via an Earth satellite.
Satellite navigation
A positioning method using
satellites.
Saturated hydrocarbon
A hydrocarbon with no
unsaturated carbon-to-carbon bonds in its molecule.
Saturation diving
A technique whereby divers
work and live under high pressure for long periods instead of undergoing
decompression after every job.
SBL
Short baseline. Generally
used to define medium range acoustic positioning systems.
Scratcher
A device fastened to the
outside of casing that removes the mud cake from the wall of the hole to
condition the hole for cementing. By rotating or moving the casing string up
and down as it is being run into the hole, the scratcher, formed of stiff wire,
removes the cake so that the cement can bond solidly to the formation.
Scrubbing
Purification of a gas or
liquid by washing it in a tower.
Sea floor housekeeping
The procedure whereby an
oil company carries out regular inspections of the sea-bed to detect (and
subsequently recover) any potentially harmful debris.
Sea level datum
A determination of mean sea
level that has been adopted as a standard datum of heights although it may
differ from a later determination over a longer period of time.
Seal
An impermeable rock
overlaying an oil or gas reservoir which prevents the migration of fluids from
the reservoirs. Also referred to as cap rock.
Sealant polymer
A polymer added to drilling
mud in order to make a porous formation impermeable.
Sealed bid auction
An auction in which the
competing parties submit confidential bids by a specified date; sometimes known
as a blind auction.
Secondary cementing
Any cementing operation
after the primary cementing operation. Secondary cementing includes a plug-back
job, in which a plug of cement is positioned at a specific point in the well
and allowed to set. Wells are plugged to shut off bottom water or to reduce the
depth of the well for other reasons. See primary cementing and squeeze
cementing.
Secondary migration
Long globules of oil are
forced through pore spaces in the rock by the force of moving water. It is
usually forced upwards being lighter than water until it emerges at the surface
or is trapped under a cap rock to form an accumulation of oil or gas.
Secondary recovery
Recovery of oil and gas
from a reservoir by artificially maintaining or enhancing the reservoir
pressure by injecting gas, water or other substances into the reservoir block.
Sector
An area of the continental
shelf in which the mineral rights belong to one particular State.
Sector scan sonar
A horizontal aperture sonar
used to detect obstructions ahead of the vessel by mechanical or electronic
scanning in the horizontal plane.
Sedimentary basin
An area in which thick
layers of sedimentary rocks have been laid down over a long period of time.
Sedimentary rocks
Rocks laid down by the
accumulation of sediments at the bottom of a sea, lake, river, or swamp.
Sediments
Loose material that is laid
down at the bottom of a sea, lake, river, or swamp.
Seismic
An acoustic method using a
source and multichannel recording to compile sections or profiles under the
earth or sea-bed; one of the main geophysical methods on land and sea; (e.g.
high resolution, 3D, VSP, refraction).
Seismic exploration
An exploration technique
involving the use of seismic methods. See seismic survey.
Seismic reflection
The study of the shallower
internal structure of the earth by generating acoustic waves and registering
their reflection from subsurface layers.
Seismic survey
A technique for determining
the detailed structure of the rocks underlying a particular area by passing
acoustic shock waves into the strata and detecting and measuring the reflected
signals.
Seismograph
A device that detects
reflections of vibrations in the earth, used in prospecting for probable
oil-bearing structures. Vibrations are created by discharging explosives in
shallow boreholes, by striking the surface with a heavy blow, or by generating
low-frequency sound waves. The type and velocity of the vibrations as recorded
by the seismograph indicate the general characteristics of the section of earth
through which the vibrations pass.
Self-sufficiency
The situation that arises
when oil companies operating within a given nation's boundaries produce enough
oil or gas to meet the nation's domestic needs.
Semi-submersible drilling rig
A floating, offshore
drilling structure that has hulls submerged in the water but not resting on the
sea floor. Living quarters, storage space, and so forth are assembled on the deck.
Semi-submersible rigs are either self- propelled or towed to a drilling site
and either anchored or dynamically positioned over the site, or both.
Semi-submersibles are more stable than drillships and are used extensively to
drill wildcat wells in rough waters such as the
Sensible heat
The amount of heat required
to raise or lower the temperature of a substance without a change of state
occurring.
Separation plant
See processing plant.
Separators
Processing equipment which
splits the wellhead fluid into separate oil, water and gas streams.
Set casing
To run and cement casing at
a certain depth in the well bore. Sometimes, the term set pipe is used when
referring to setting casing.
Settling pit
The mud pit onto which mud
flows and in which heavy solids are allowed to settle out. Often auxiliary
equipment (as desanders) must be installed to speed this process.
Severe tropical cyclone
A tropical cyclone with
winds exceeding 63 knots (storm force). Also known as typhoon or hurricane.
Shaker
Shortened form of shale
shaker. See shale shaker.
Shaker pit
The mud pit adjacent to the
shale shaker, usually the first pit into which the mud flows after returning
from the hole.
Shale
A fine-grained sedimentary
rock composed of consolidated silt and clay or mud. Shale is the most
frequently occurring sedimentary rock.
Shale shaker
A vibrating or rotating
screen which removes the coarse drill cuttings ii: from the drilling mud prior
to its recirculation.
Shaped charge
A relatively small
container of high explosive that is loaded into a perforating gun. Upon
detonation, the charge releases a small, high-velocity stream of particles (a
jet) that penetrates the casing, cement, and formation. See gun perforator.
Shear ram
The components in a blowout
preventer that cut, or shear, through drill 1 pipe and form a seal against well
pressure. Shear rams are used in mobile offshore drilling operations to provide
a quick method of moving the rig away from the hole when there is no time to
trip the drill stem out of the hole.
Sheave
(Pronounced
"shiv") A grooved pulley.
Shims
Thin sheets of metal used
to adjust the fit of a bearing or to level a unit of equipment on its
foundation. For fitting a bearing, a number of very thin (.001 to .30-inch)
shims are put between the two halves of the bearing (between the box and cap).
Shims are added or removed until the bearing fits properly on the journal.
Ship's aft draught
The depth measured from the
sea level to the deepest submerged rear/stern part of a ship.
Ship's articles
The agreement between the
master and his crew, giving details of conditions and terms.
Ship's forward draught:
The depth measured from the
sea level to the deepest submerged forward part of a ship.
Ship's list
The degree of
inclination/lean measured along the width of the ship with reference to the
vertical, in balancing a vessel.
Ship's trim
The degree of inclination
measured along the length of the ship with reference to the sea level, in
balancing a vessel.
Shock sub
A joint in the drilling
string located above the bit to absorb and prevent any vibrations from
affecting the drill bit (same functions as a shock absorber).
Shot
A small explosion used to
produce shock waves during a seismic survey.
Show
An indication of oil or gas
from an exploratory well.
Shut-down
To stop work temporarily or
to stop a machine or operation.
Shut-in bottomhole pressure
The pressure at the bottom
of a well when the surface valves on the well are completely closed. The
pressure is caused by fluids that exist in the formation at the bottom of the
well.
Shuttle helicopter
A small helicopter used to
transfer regular personnel between the various structures on a large offshore
field.
Shuttle Tanker
An oil tanker which makes
regular round trips between a producing field and an onshore terminal or
refinery.
Side door elevators
Casing or tubing elevators
with a hinged latch that opens on one side to permit it to be fastened around
the pipe and secured for hoisting.
Sidetrack drilling
A remedial operation which
results in the creation of a new section of well bore for the purpose of
detouring around "junk", redrilling a lost hole or straightening key
seats and crooked holes. Also called sidetracking.
Sidewall coring
A coring technique in which
core samples are obtained from a zone that has already been drilled. A hollow
bullet is fired into the formation wall to capture the core and then retrieved
on a flexible steel cable. This method is especially useful in soft rock areas.
Sidewell cores
Cylindrical sections of
rock or sediments obtained by shooting hollow cylinders of steel into the wall
of the well bore and subsequently recovering them together with their contents.
Sight glass (gauge glass)
A glass pipe connected
vertically to the side of a tank for measuring liquid levels.
Significant facility
Group of equipment that
have a significant role on a platform/plant to facilitate functioning (e.g.,
train, rig, test separator, etc.).
Silt
Materials that exhibit
little or no swelling whose particle size generally falls between 2 microns and
API sand size, or 74 microns (200-mesh).
Simple interest
Interest calculated on the
basis of the principal (sum originally borrowed) only.
Single
A joint of drill pipe. Compare
double, thribble, and fourble.
Single buoy mooring (SBM)
See exposed location single
buoy mooring.
Single point mooring (SPM)
See exposed location single
buoy mooring.
Site survey
Mandatory sea-bed and
subsurface investigation of proposed offshore drilling locations. It usually
involves an analogue survey (bathymetry, sonar imagery and shallow profiling),
a high resolution seismic survey (mainly for gas hazard identification) and
often a simple coring/sampling programme.
Skid mounted
Refers to a pumping unit or
other oil field equipment that has no permanent or fixed foundation but is
welded or bolted to metal runners or timber skids. Skid-mounted units are
usually readily movable by pulling as a sled or by hoisting onto a truck.
Skidding the rig
Moving a rig from the
location of a lost or completed hole preparatory to starting a new hole with
little or no dismantling of equipment.
Skimmer
An anti-pollution device
rather like a large vacuum cleaner which sucks oil from the surface of the sea.
Slack off
To lower a load or ease up
on a line.
Slick
See oil slick.
Slick line
A solid steel wire used for
wireless operations; also called piano wire. See wireline.
Slim hole drilling
A slim hole will be defined
as a well in which 90 per cent or more of the length has an open hole diameter
of seven inches (
Sling
A wire loop for use in
lifting heavy equipment.
Slip joint
A special sleeve-Iike
section of pipe run in the drill string to absorb the vertical motion of a
floating drilling platform caused by wave action.
Slippage
Occurrence in two-phase
flow when the heavier phase (liquid) is by passed by the lighter phase (gas).
Slips
Steel wedges which are
forced into the tapered opening of the drilling table to hold the free end of
the drill pipe in place.
Slips
Stell wedges which are
forced into the tapered opening of the drilling table to hold the free end of
the drill pipe in place.
Sloughing
The partial or complete
collapse of the walls of a hole resulting from incompetence, unconsolidated
formations, high angle or repose, and wetting along internal bedding planes.
Slurry
A plastic mixture of cement
and water that is pumped into a well to harden; there it supports the casing
and provides a seal in the well bore to prevent migration of underground
fluids.
Slush pumps
See mud pumps.
Smectite
See bentonite.
Snubbing
The procedure of running
pipe or casing into the well while the well is exerting pressure on the surface
equipment.
SOLAS
The Safety Of Life At Sea
convention is governed by the International Maritime Organisation (IMO) and
deals with all safety equipment requirements for ships at sea.
Soluble
Capable of being dissolved,
usually in water, unless another solvent is specified.
Solution gas drive
A primary recovery process
in which oil is driven out of a reservoir by the natural pressure exerted by
the dissolved gas.
Sonar
A technique whereby
underwater objects are located by bouncing sound waves off them and detecting
the reflected signals; also used to measure pipe wall thickness.
Sonic logging
The recording of the time
required for a sound wave to travel a specific distance through a formation.
Difference in observed travel times is largely caused by variations in
porosities of the medium, an important determination. The sonic log, which may
be run simultaneously with a spontaneous potential log or a gamma-ray log, is
useful for correlation and often is used in conjunction with other logging
services for substantiation of porosities. It is run in an uncased hole.
Sound velocity
The rate of motion at which
sound energy moves through a medium. The velocity of sound in sea water is a function
of temperature, salinity, and the changes in pressure associated with changes
in depth. An increase in any of these factors tends to increase the velocity.
Sour gas
Natural or associated gas
with a high sulphur content.
Source
Device generating acoustic
impulses, namely profiling or seismic system components like bombers or
airings.
Source rock
The rock in which oil or
natural gas originates.
Sourcrude
Crude oil with a high
sulphur content.
Spar
A floating on-field storage
tank into which oil flows from a production platform prior to being transferred
to a tanker for shipping ashore.
Sparger
A sprinkler device. Usually
applies to devices for distributing gases or air in liquids.
Sparkler
A medium to high energy
acoustic profiling source; towed subsurface or deep; data is recorded in
analogue or digital mode; penetration: tens to hundreds of metres; now
generally falling into disuse.
SPE
Society of Petroleum
Engineers
Spear
A fishing tool used to
retrieve pipe lost in a well. The spear is lowered down the hole and into the
lost pipe, and when weight, torque, or both are applied to the string to which
the spear is attached, the slips in the spear expand and tightly grip the
inside of the wall of the lost pipe. Then the string, spear, and lost pipe are
pulled to the surface. See fishing tool.
Speciality chemical
A chemical made in a
relatively small quantity for a particular application.
Specific gravity
The ratio of the density of
a substance at a particular temperature to the density of water at four degrees
C.
Speed made good
The actual velocity of the
ship along a course measured in relation to the ocean bottom or the fixed
objects ashore.
Speed of propagation
The speed with which waves
of energy travel through or along a medium other than a specially constructed
path.
Speed of sound
The speed of propagation of
sound waves.
Sphere
A spherical device inserted
in a pipeline for the purpose of sweeping the line clean of water, liquid
hydrocarbons, rust or other foreign matter. See pig.
Spheroid
An ellipsoid, a figure
resembling a sphere. In geodesy this term is frequently used to mean Reference
Spheroid, being the shape of the Earth defined by a Datum.
Spider
The hinged, latching device
attached to the elevators (the hoisting arms that lift pipe and casing in the
derrick). Elevator-spider is a unit, and is attached to the travelling-block
hook for hoisting pipe, casing and tubing out of the hole and lowering in. The
spider is manually locked around a length of tubing just below the tool joint.
Some advanced types of elevator spiders are air operated.
Spillage
An accidental release of
oil, or another liquid.
Spin up
To screw one stand of drill
pipe or tubing rapidly into another with a spinning chain. After making up the
joint in this manner, the heavy pipe tongs are applied to make the joint tight.
Spinning cathead
A spooling attachment on
the make up cathead to permit use of a spinning chain to spin up or make up
drill pipe. See spinning chain.
Spinning chain
A Y -shaped chain used to
spin up (tighten) one joint of drill pipe into another. In use, one end of the
chain is attached to the tongs, another end to the spinning cathead , and the
third end is free. The free end is wrapped around the tool joint, and the cathead
pulls the chain off the joint, causing the joint to spin (turn) rapidly and
tighten up. After the chain is pulled off the joint, the tongs are secured in
the same spot, and the continued pull on the chain (and thus on the tongs) by
the cathead makes up the joint to final tightness.
Spinning line
A wire rope or chain that
is wrapped round a section of pipe and used to screw (or spin up) the section
into another section.
Spinning tong
An air operated power tong
used to spin up pipe.
Splash zone
The area where waves of
ocean or lake strike the support members of offshore platforms and production
installations; the water line. The splash zone is particularly subject to
corrosion because of the action of both (salt) water and air.
Spud
To begin drilling; to start
the hole.
Spudding in
The process of starting to
drill a well by making a hole in the sea-bed using a large diameter bit.
Spur line
A small diameter underwater
pipeline connecting a production or drilling platform to a terminal platform,
on-field storage facility, or main pipeline to the shore.
Squeeze
An operation whereby cement
is injected under pressure between the casing and the well bore at a particular
depth.
Squeeze cementing
The forcing of cement
slurry by pressure to specified points in a well to cause seals at the points
of squeeze. It is a secondary cementing method that is used to isolate a
producing formation, seal off water, repair casing leaks, and so forth. See
cementing.
SSB (USBL)
Super Short Baseline.
Generally used to define very short range acoustic positioning systems.
Stab
To guide the end of a pipe
into a coupling or tool joint when making up a connection. See coupling and
tool joint.
Stabbing
Inserting the threaded end
of a pipe or rod into the coupling at the end of another pipe or rod.
Stabbing board
A retractable platform in
the upper part of the derrick on which the derrick man stands in order to align
two sections of pipe which are to be joined.
Stabiliser
A tower designed to
separate the high vapour pressure of gasoline products during the refining
process.
Stabiliser placement
The distance above the
drilling bit at which the stabiliser is located on the drilling column.
Stabiliser sleeve
A bushing the size of the
borehole inserted in the drill column to help maintain a vertical hole, to hold
the bit on course.
Stabiliser tower
A fractionating column used
to lower the vapour pressure of gasoline products during the refining process.
Stack
A method fundamental to
seismic in which adjacent traces or channels are added to enhance signal and
reduce noise.
Stake a well
To locate precisely on the
surface of the ground the point at which a well is to be drilled. After
exploration techniques have revealed the possibility of the existence of a
subsurface, hydrocarbon-bearing formation, a certified and registered land
surveyor drives a stake into the ground to mark the spot where the well is to
be drilled.
Stand
The connected points of
pipe racked in the derrick or mast when making a trip.
Stand of pipe
A length of drill pipe,
tubing or other pipe consisting of one or more sections that is stood, racked
or hung in a derrick during drilling operations.
Stand pipe
The rigid pipe that
conducts the drilling mud up the derrick into the rotary hose.
Stand-by boat
A boat (often a converted
fishing boat) which maintains permanent station near an offshore structure in
order to provide support facilities in an emergency.
Static electricity
The accumulation of an
electric charge caused by friction on materials which are, bad conductors of
electricity. If the charge builds up to a sufficient value, it may cause a
spark which constitutes a hazard in the vicinity of flammable or explosive
vapours.
Station (tide)
A place where tidal
observations are obtained. It is a primary tide station when continuous
observations are available for a sufficient number of years to determine the
characteristic tide features for the locality. A secondary tide station is
operated during a short period of time to obtain data for specific purpose.
STCW CODE 1978 AS AMENDED 1995
Commonly know as the STCW9S
code, this is the International Maritime Organisations Standard for Training
Certification and Watchkeeping. All maritime personnel who fall under the
jurisdiction of AM SA and Marine Orders must be qualified to this standard by
February 2002.
Steam trap
A device which permits the
discharge of water arising from condensed steam from pipelines, heat
exchangers, etc, without a loss of steam.
Steel jacket
The steel lattice structure
used to support an offshore steel platform.
Steel platform
See jacket platform.
Step out well
A well drilled beyond the
proven limits of a field to investigate a possible extension to that field;
sometimes called an out step well.
Stills
A still is an image
captured using an underwater camera and stored on film until processed.
Stimulation
Any process undertaken to
enlarge old channels or create new ones in the producing formation of a well
(e.g., acidising or formation fracturing). See acidise.
Stinger
The boom used to lower an
underwater pipeline onto the sea-bed from a lay barge.
Stock
See inventory.
Storm force winds
Winds of Beaufort force 12
or above (> 63 knots).
Strata
Successive layers of
sediments or sedimentary rock; singular.
Stratification
The natural layering or
lamination characteristic of sediments and sedimentary rocks.
Stratigraphic trap
A trap formed at the time
the sediments containing it were actually laid down rather than by subsequent
tectonic processes.
Streamer (cable)
The underwater acoustic
receiver for seismic methods, towed subsurface behind the vessel; hundreds of
metres or kilometres long, it is a major hardware investment, high resolution
or 2D vessels tow, 3D vessels tow two or more.
String
The entire length of
casing, tubing, or drill pipe run into a hole; the casing string. Compare drill
string and drill stem.
String up
To thread the drilling line
through the sheaves of the crown block and travelling block. One end of the
line is secured to the hoisting drum and the other to the derrick substructure.
See sheave.
Structural trap
A trap produced by the
distortion of once horizontal strata by some tectonic process(es).
Structure Name
The name of a particular
instance of a structure type is a Structure Name. Subtructures and Components
attached to this structure are stored in the Hierarchical Tree. e.g. West
Kingfish is an Oil and Gas production Jacket in the Bass Straits. Its Structure
Type is Jacket and its Structure Name is West Kingfish.
StructureType
Inspection Manager can
record data for a variety of Structures and Sub- structures. Within Inspection
Manager Eventing Module "Structure Type" refers to the specific class
of structure being inspected. Tasks may be assigned to any item under the Structure
Type entry in the tree. e.g. Jackets, Concrete Gravity Structures, Monopod's
and Pipelines are all Structure Types.
Stuck pipe
Drill pipe, drill collars,
casing or tubing that has inadvertently become immobile in the hole. It may
occur when drilling is in progress, when casing is being run in the hole, or
when the drill pipe is being hoisted.
Styrene
An important ethylene-based
monomer used in a wide variety of petrochemical processes, e.g. the manufacture
of polystyrene and synthetic rubber.
Sub-basin
A synclinal structure
contained within a basin. A basin may contain one or more sub-basins.
Sublimate
A solid obtained by the
condensation of vapour without passing through the liquid state.
Submersible drilling rig
An offshore drilling structure
with several compartments that are flooded to cause the structure to submerge
and rest on the sea floor. Most submersible rigs are used only in shallow
waters.
Subsea completion
The process of installing a
subsea, or ocean floor, wellhead.
Subsea wellhead
A wellhead installed on the
sea floor and controlled remotely from a platform, or floating production
facility, or from land.
Substructure
The support frame of an
offshore platform on which the derrick, engines, quarters, helicopter pad,
cranes, etc., are installed.
Sub-structures/Components
The structure to be
inspected may be much defined in as much detail as required. Any item under the
Structure Name in the hierarchical tree may be either a Sub-structure or a
Component of the Structure.
Sucker rod
Steel rod which, together
with other rods, will form a string that connects the pump inside a well's
tubing downhole to the pumping jack on the surface.
Suction pit
The mud pit from which mud
is picked up by the suction of the mud pumps; also called a sump pit and mud
suction pit.
Sulpholane
A cyclic aliphatic compound
containing sulphur that is used as a selective solvent for the separation of
aromatic and aliphatic compounds.
Sulpholene
A cyclic addition compound
of butadiene and sulphur dioxide which can be hydrogenated to produce
sulpholane.
An element that is present
in some crude oil and natural gas as an impurity in the form of its various
compounds.
Sump
A shallow pipe, well or
tank used to hold superfluous liquids or slurries.
Supply base
An onshore base from which
supply boats operate.
Supply boat
A specially designed vessel
to ferry supplies, material and equipment to and from offshore structures.
Support vessel
A specially designed vessel
that provides a range of safety and support facilities on an offshore field.
Surface casing
See surface pipe.
Surface pipe
The first string of casing
(after the conductor pipe) that is set in a well, varying in length from a few
hundred to several thousand feet. Compare conductor pipe.
Surge
A sudden change in flow,
liquid level, temperature or pressure, etc. in a pipeline or vessel.
Suspend
To leave a productive well
safely closed in for a prolonged period. Often done after the drilling phase
but before the completion and christmas tree are installed, until more wells
are available for completion.
Swab valve
The top valve in the
christmas tree, through which wireline work is carried out.
Swabbing
Inward fluid flow caused by
pulling equipment out of a fluid-filled bore hole.
Swage
A heavy, steel tool,
tapered at one end, used to force open casing that has collapsed downhole in a
well.
Swage nipple
An adaptor; a short pipe
fitting, a nipple, that is a different size on each end, e.g. two inch to three
inch; two inch to four inch.
Sweet crude
Crude oil with a low
sulphur content.
Swivel
The rotating coupling which
connects the rotary hose to the drill string.
Syncline
A tectonic structure in
which strata are folded so as to form a dip or bowl (i.e. concave on top).
Synthetic natural gas (SNG)
Gas manufactured from coal
or oil that has the same basic chemical composition and burning characteristics
as natural gas.
Synthetic rubber
Rubber that is manufactured
from petrochemicals rather than obtained naturally from rubber trees.
System of
sounding lines
The predetermined lines
that the survey vessel is to follow for the best development of the depth
contours in an area.