Glossary

second.

the configuration of pipe when it enters the water from a stinger of a lay barge in pipeline construction. The overbend is closest to the barge, and the sag bend is on the seafloor. Compare J curve. See sag bend.

a method of installing an offshore pipeline in which lengths of pipe are welded together horizontally and launched over the stern of the pipe-lay vessel over a long stinger while the vessel moves slowly forward. S-laying is typically employed in shallow to medium-depth waters. It avoids subjecting the pipeline to excessive stresses. See stinger. Compare J-lay.

in a top drive, the S-shaped pipe that incorporates a gooseneck to which the rotary hose is attached. It conducts drilling mud into the top drive from the rotary hose. See top drive.

sample tops; used in drilling reports.

sediment and water. API Committee on Petroleum Measurement prefers this abbreviation to the older “BS&W.”

a small device inserted in a pipeline to measure the amount of S&W in the liquid flowing through the line.

see playa.

a container for cement, bentonite, ilmenite, barite, caustic, and so forth. Sacks (bags) contain the following amounts: Cement 94 pounds (42.6 kilograms) (1 cubic foot) Bentonite 100 pounds (45.5 kilograms) Ilmenite 100 pounds Barite 100 pounds

1. in cathodic protection, anodes made from metals whose galvanic potentials render them anodic to steel in an electrolyte. They are used up, or sacrificed. 2. a positively charged electrode that prevents the electrical current in the water from corroding and deteriorating the structure.

see pipe saddle.

the center bearing on a conventional walking beam pumping unit. It is mounted on top of the samson post.

see clamp.

Safety Award for Excellence program.

a congressional act that provides for the protection of underground sources of drinking water by regulating drinking water systems and injection wells.

in crane operations, that portion of a wire rope’s nominal strength that can be applied either to move or sustain a load without damaging or breaking the rope. The safe working load of a rope is accurate only when the rope is new and the equipment is in good condition. Because most ropes on an installation quickly become used, the safe working load of a rope is also quickly reduced. For this reason, safe working load is seldom used to denote wire-rope strength. See nominal strength.

an MMS safety award program that recognizes private companies that protect the human and natural environment by avoiding accidents and pollution through adherence to safety and environmental regulations and guidelines.

a clamp placed very tightly around a drill collar that is suspended in the rotary table by drill collar slips. Should the slips fail, the clamp is too large to go through the opening in the rotary table and therefore prevents the drill collar string from falling into the hole. Also called drill collar clamp.

a means of gauging the adequacy of the strength of a mooring component. It is expressed as a factor or ratio of the ultimate breaking strength or design load (e.g., a safety factor means that the maximum load seen on a component in a particular condition is half the breaking strength of that component).

a measurement of load safety for wire rope obtained by using the following formula: Factor of safety = B/W where xxx. Also called design factor of wire rope.

instrumented systems to protect against overpressure; failure of the systems can result in the release of hazardous chemicals and/or cause unsafe working conditions.

an accessory to a fishing tool, placed above it. If the tool cannot be disengaged from the fish, the safety joint permits easy disengagement of the string of pipe above the safety joint. Thus, part of the safety joint and the tool attached to the fish remain in the hole and become part of the fish.

a latch provided on a hook to prevent an object suspended from the hook from accidentally slipping or falling out of it.

see trip margin.

international maritime rules established to set minimum safety standards for ships and mobile offshore drilling units under way or under tow.

the monkeyboard, or platform on a derrick or mast on which the derrickhand works while wearing a safety harness (attached to the mast or derrick) to prevent falling.

a device made up in a tubing string above a packer or other downhole tool that allows a crew on the surface to remove the tubing string should the packer or other tool get stuck.

see pop valve.

metal-toed shoes or boots with nonskid, corrosion-resistant soles worn by oilfield workers to minimize falls and injury to their feet.

a wireline device normally mounted near the monkeyboard to afford the derrickhand a means of quick exit to the surface in case of emergency. It is usually affixed to a wireline, one end of which is attached to the derrick or mast and the other end to the surface. To exit by the safety slide, the derrickhand grasps a handle on it and rides it down to the ground. Also called a Geronimo.

a designated time for management officials in a company to meet with frontline workers to discuss safety issues. Usually, it is not necessary to cease normal operations during a safety stand down.

1. an automatic valve that opens or closes when an abnormal condition occurs (e.g., a pressure relief valve on a separator that opens if the pressure exceeds the set point, or the shutdown valve at the wellhead that closes if the line pressure becomes too high or too low). 2. a control device (a valve) installed at the top of the drill stem, which, when closed, prevents flow out of the drill pipe if a kick occurs during tripping operations.

steel cable attached to the monkeyboard and anchored to the ground at some distance from the rig. It is used by the derrickhand to slide clear of danger in an emergency.

a five-step scale meteorologists use to rate the intensity of hurricanes. The scale has five categories, with category 1 being the least intense and category 5 being the most. Meteorologists use the scale to estimate potential property damage and flooding expected along the coast from a hurricane’s landfall. The hurricane’s wind speed determines its category. A category 1 hurricane has sustained wind speeds of from 74 to 95 miles per hour (mph), a category 2 from 96 to 110 mph, a category 3 from 111 to 130 mph, a category 4 from 131 to 155 mph, and a category 5 more than 155 mph. Herbert Saffir, a consulting engineer, and Bob Simpson, director of the National Hurricane Center, formulated the scale in 1969.

a temporarily unsupported span of pipe between the stinger and the seabed in marine pipe laying.

steam-assisted gravity drainage.

the distortion of the hull of a vessel when the middle is lower than either end because of excessively heavy or unbalanced loads. Compare hogging.

any line through which oil, gas, or products flow to a sales point.

see oil sales outlet.

see salt mud.

a measure of the amount of salt dissolved in a liquid.

a special nuclear well log that produces an estimate of the relative amounts of oil, gas, or salt water in a formation. This log is electronically adjusted to reflect gamma ray emissions resulting from the collision of neutrons with chlorine atoms in the formations.

single anchor leg mooring.

a compound that is formed (along with water) by the reaction of an acid with a base. A common salt (table salt) is sodium chloride, NaCl, derived by combining hydrochloric acid, HCl, with sodium hydroxide, NaOH. The result is sodium chloride and water, H2O. This process is written chemically as HCl + NaOH →  NaCl + H2O. Another salt is calcium sulfate, CaSO4, obtained when sulfuric acid, H2SO4, is combined with calcium hydroxide, Ca (OH)2.

a 55-gallon (208-litre) drum modified to salt-saturate the water going into circulation to prevent the dissolution of formation salt when building mud volume.

a phenomenon that sometimes occurs when a salt formation is drilled. Because some salt formations tend to behave somewhat as a liquid, they flow, or creep, into the borehole after it is drilled. Salt creep reduces the size of the borehole and must be taken into account.

a dome that is caused by an intrusion of rock salt into overlying sediments. A piercement salt dome is one that has been pushed up so that it penetrates the overlying sediments, leaving them truncated. The formations above the salt plug are usually arched so that they dip in all directions away from the center of the dome, thus frequently forming traps for petroleum accumulations.

1. a drilling mud in which the water has an appreciable amount of salt (usually sodium or calcium chloride) dissolved in it. Also called saltwater mud or saline drilling fluid. 2. a mud with a resistivity less than or equal to the formation water resistivity.

see plastic deformation.

a water that contains a large quantity of salt, i.e., brine.

a cementing slurry whose liquid phase contains sodium chloride.

see attapulgite.

the method and system for the disposal of salt water produced with crude oil. A typical system is composed of collection centers (in which salt water from several wells is gathered), a central treating plant (in which salt water is conditioned to remove scale- or corrosion-forming substances), and disposal wells (in which treated salt waste is injected into a suitable formation).

an influx of formation salt water into the wellbore.

see salt mud.

a tool with a sharp pointed end designed to slice into sand and a hollow cylinder to trap sand samples. The sample bailer is slammed into the bottom of the wellbore with enough impact to force sand into it.

in underbalanced drilling, a device installed in the blooey line to retrieve samples of the cuttings (dust) returning to the surface from the bottom of the hole.

the mixing required to prepare liquid samples taken from a pipeline or sample loop prior to sample transfer for analysis.

on a pipeline or loop, a device for governing the operation of the sample extracting mechanism in proportion to either time or flow.

device for extracting the sample grabs from the pipeline or from the sample loop.

the volume of liquid extracted from the pipe by a single actuation of the sample extractor. The sum of all grabs results in a sample.

the extraction, conditions, transferring, and transporting of a representative sample from a container to analytical glassware or centrifuge tubes.

a graphic representative model of the rock formations penetrated by drilling, prepared by the geologist from samples and cores.

a relatively small pipe that is a by-pass from the main pipeline. Liquid in the pipeline also flows through the loop, from which the liquid can be sampled.

drilling fluid formulated so that it will not alter the properties of the cuttings the fluid carries up the well.

the technique used to validate an automatic sampling system.

receptacle normally connected to a sampling draw-off connection or pipeline probe and used to receive the sample. When disconnected it may be used as a sample container.

a float moving vertically within a linearly tapered tube and exposing a variable area to the flow. Also called variable area flowmeter.

a device attached to a pipeline to permit continuous sampling of the oil, gas, or product flowing in the line.

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.

1. the taking of a representative sample of fluid from a tank or pipeline to measure its temperature, specific gravity, and S&W content. 2. the process of cutting a core or pieces of core for analysis.

1. the part of the surface equipment of a standard cable-tool drilling rig that supports the walking beam. 2. the member of a rod pumping unit that supports the walking beam.

1. an abrasive material composed of small quartz grains formed from the disintegration of preexisting rocks. Sand consists of particles less than 2 millimetres (0.078 inches) and greater than 1⁄16  millimetre (0.062 inches) in diameter. 2. sandstone.

a device used to remove sand from the wellbore. It sucks up sand by creating a partial vacuum and traps the sand by closing at the bottom.

any one of several methods by which the loose, unconsolidated grains of a producing formation are made to adhere to prevent a well from producing sand but permit it to produce oil and gas.

the insoluble abrasive solids contents of a drilling fluid rejected by a 200-mesh screen. Usually expressed as the percentage bulk volume of sand in a drilling fluid. This test is an elementary type in that the retained solids are not necessarily silica and may not be altogether abrasive. For additional information concerning the kinds of solids retained on the 200-mesh screen, more specific tests would be required. See mesh.

any method by which large amounts of sand in a sandy formation are prevented from entering the wellbore. Sand in the wellbore can cause plugging and premature wear of well equipment. See gravel pack, sand consolidation, screen liner.

a device that ejects sand at a very high velocity to cut casing being salvaged from a plugged and abandoned well.

on the drawworks, a spool for the sandline.

a column of sand that has entered and accumulated in the wellbore.

see lens.

to plug a well inadvertently with proppants during formation fracturing. Sanding out is usually the result of a slowed fracture-fluid velocity, or screening effect, which allows the proppants to become separated from the fluid instead of being carried away from the wellbore. Also called screening out.

a metal drum on a drilling rig or a workover unit around which the sandline is wound. On a drilling rig, it may be attached to the drawworks cat­shaft and may be used for coring or other wireline operations. When used on a drilling rig, it is sometimes called a coring reel.

see wire-wrapped screen.

a steel tank placed under the shale shaker into which mud falls after passing through the shale shaker. The shaker removes mainly cuttings from the mud so solids such as sand and other fine particles fall with the mud into the sand trap. Many of the solids fall out of the mud in the sand trap; those that do not settle out are removed with other specialized solids control mud treatment equipment such as desanders and desilters.

a map that shows the thickness of subsurface sands. See isopach map.

1. of a well, under restricted production because of sand accumulation in the wellbore. 2. impeded or hindered, especially because of sand accumulation.

method of fracturing subsurface rock formations by injecting fluid and sand under high pressure to increase permeability. Fractures are kept open by the grains of sand.

a phenomenon that occurs when sand and sediment settle out of oil being produced from a well and impedes or blocks the flow of produced fluids from the well.

a wireline used on drilling rigs and well-servicing rigs to operate a swab or bailer, to retrieve cores or to run logging devices. It is usually 9⁄16  of an inch (14 millimetres) in diameter and several thousand feet or metres long.

a special bit or mill run on a cable-tool drilling line, a well servicing rig, or the sandline of a rotary drilling rig to mill out tools or drill out downhole debris.

a sedimentary rock composed of individual mineral grains of rock fragments between 0.06 and 2 millimetres (0.002 and 0.079 inches) in diameter and cemented together by silica, calcite, iron oxide, and so forth. Sandstone is commonly porous and permeable and therefore a likely type of rock in which to find a petroleum reservoir.

a reservoir stimulation method the main purpose of which is to remove clay from the sandstone to better allow reservoir fluids to flow into the wellbore. Clay, either naturally occurring or put there by the clay in drilling mud when the well was drilled, can block the permeability of the sandstone and thus interfere with the flow of formation fluids into the well.

sodium acid pyrophosphate.

Superfund Amendments and Reauthorization Act of 1986. A series of regulations promulgated by the EPA for general industry after the Bhopal disaster in India, where thousands died as a result of the release of a toxic cloud from an insecticide factory. SARA requires oil and gas operators to (1) appoint an emergency coordinator, (2) submit a list or individual Material Safety Data Sheets for all hazardous chemicals present at a facility at or above 10,000 pounds or extremely hazardous substances at or above 500 pounds or the threshold planning quantity, (3) submit an annual inventory of hazardous chemicals or extremely hazardous substances reported on the Material Safety Data Sheets, (4) notify the State Emergency Response Commission (SERC) of the presence of an extremely hazardous substance at or above the threshold planning quantity, (5) report releases of any hazardous or extremely hazardous chemical that leaves the boundaries of the facility at or above the reporting quantity to the SERC and the Local Planning Committee.

saturated or saturation; used in drilling reports.

the chamber control where the LST monitors all aspects of the chamber complex. Commonly referred to as saturation control.

a system that is located some distance from a gas plant for which it performs a function. Examples are absorbers or compressors, in which gas is treated or compressed prior to reaching the plant.

usually a single well drilled offshore by a mobile offshore drilling unit to produce hydrocarbons from the outer fringes of a reservoir that cannot be produced by primary development wells drilled from a permanent drilling structure (such as a platform rig). Sometimes, several satellite wells will be drilled to exploit marginal reservoirs and avoid the enormous expense of erecting a platform.

a measure of heating value for natural gas that is fully saturated with water vapor under standard temperature, pressure, and gravity conditions. This is typically a laboratory condition to standardize the amount of water vapor in the gas at a convenient, albeit arbitrary, level. This standard of measure usually has little or nothing to do with the state in which the gas is actually delivered for first sales.

the number of Btus contained in a cubic foot of natural gas fully saturated with water under actual delivery pressure, temperature, and gravity conditions.

the number of Btus contained in a cubic foot of natural gas fully saturated with water at a specified pressure base and 60°F (15.5°C).

in magnetic circuits, the instant in the core of a coil whereby the flux density reaches a level beyond which little or no additional density can be achieved by further increases in magnetomotive force.

hydrocarbon compounds, e.g., in natural gas and natural gas liquids, in which all carbon valence bonds are filled with hydrogen atoms.

liquid that is at its boiling point or is in equilibrium with a vapor phase in its containing vessel.

mud that contains the maximum amount of salt that can be dissolved.

water that has all the salt dissolved in it that is possible at a given temperature.

a solution that contains at a given temperature as much of a solute as it can retain. At 68°F (20°C) it takes 126.5 pounds (57.38 kilograms) of salt to saturate 1 barrel (0.1592 cubic metres) of fresh water. See supersaturation.

steam that exists at a temperature corresponding to its absolute pressure. It may contain, or be free of, water particles.

vapor at its dew point.

1. a state of being filled or permeated to capacity. Sometimes used to mean the degree or percentage of saturation (e.g., the saturation of the pore space in a formation or the saturation of gas in a liquid, both in reality meaning the extent of saturation). 2. the condition of air when it contains the largest amount of water vapor it can possibly hold at a given temperature and pressure.

procedures in accordance with which a diver is continuously subjected to an ambient pressure greater than atmospheric pressure so that his body tissues and blood become saturated with the constituent elements of the breathing gas. Once the diver’s body becomes saturated, he can remain within a specified zone for an unlimited time without incurring any additional decompression obligation.

the point at which, at a certain temperature and pressure, no more solid material will dissolve in a liquid.

an expendable substitute device made up in the drill stem to absorb much of the wear between the frequently broken joints (such as between the kelly or top drive and the drill pipe). See kelly saver sub.

Supplemental Aviation Weather Reporting Station.

an electronic circuit that converts energy from a direct-current source to a periodically varying electric output; its waveform has the shape of a sawtooth.

an electronic device that creates, or generates, an output voltage that has a waveform in the shape of a sawtooth. Such a generator produces sweep voltage for cathode-ray tubes. See sweep voltage.

a unit for measuring the viscosity of lighter petroleum products and lubricating oils. See Saybolt viscometer.

an instrument used to measure the viscosity of fluids, consisting basically of a container with a hole or jet of a standard size in the bottom. The time required for the flow of a specific volume of fluid is recorded in seconds at three temperatures (100°F–37.8°C, 130°F–54.4°C, and 210°F–98.9°C). The time measurement unit is referred to as the Saybolt Second Universal (SSU).

static bottomhole temperature.

synthetic-based mud.

stratocumulus.

1. a mineral deposit (e.g., calcium carbonate) that precipitates out of water and adheres to the inside of pipes, heaters, and other equipment. 2. an ordered set of gauge marks together with their defining figures, words, or symbols with relation to which position of the index is observed when reading an instrument.

the line, actual or implied, that passes through the midpoints of the shortest marks on the scale.

the interval between any two successive scale marks of the scale.

the linear or curvilinear length measured along the scale base between the centers of the terminal scale marks.

a line or other mark on the scale of an indicating device corresponding to one or more defined values of the quantity measured.

the set of numbers marked on a scale that correspond either to the values of the quantity measured, defined by the scale marks, or that indicate only the numerical order of the scale marks.

1. the zone included between the scale marks that corresponds to the maximum and minimum values of the scale. 2. the difference between the maximum and minimum values of the scale.

a circular-shaped wire brush that is attached to a pneumatically, hydraulically, or electrically operated tool (such as a grinder) and that is used to remove rust or scale from pipe or other oilfield equipment.

an orifice meter chart with faint lines, intended to be read, or integrated, by a scanner machine.

(nautical) the dimensions of the structural members in the hull.

an extended cliff or steep slope, produced by erosion or faulting, that separates two level or gently sloping areas, i.e., an escarpment.

to remove exhaust gases from a cylinder by forcing compressed air in and exhaust gases out. Such removal takes place in all two-cycle diesel engines.

in two-strokes-per-cycle engines, a measure of the engine blower’s ability to remove exhaust gases from the engine cylinder after combustion.

positive-pressure self-contained breathing apparatus.

standard cubic feet.

standard cubic feet per day.

the employee responsible for establishing pipeline oil movements based on the coordination of all shipper requirements.

a drawing of an electric circuit that uses several standard symbols to represent electrical components and that shows the arrangement and connections of the conductors and the components in the circuit. Same as flow diagram.

a coarse-grained, foliated metamorphic rock that splits easily into layers. It is formed when shale under deep burial becomes slate and then, with more intense metamorphism, becomes schist.

(pronounced “slumber-jay”)one of the pioneer companies in electric well logging, named for the French scientist who first developed the method. Today, many companies provide logging services of all kinds.

see Schmitt trigger.

pulse generator capable of assuming either of two stable states (a bi­stable pulse generator) in which an output pulse of constant amplitude exists only as long as the input voltage exceeds a certain value. Also called a Schmitt circuit. See bistable.

see Schottky diode.

a diode formed by contact between a semiconductor layer and a metal coating. It is used as a special rectifier. Electrons or holes are emitted from the area where the semiconductor and metal coating contact each other (the p-n junction) and move to the metal coating. It provides very fast switching speeds. Also called a hot-carrier diode, Schottky barrier diode.

detects the light emitted when a gamma ray strikes a scintillator. Measures gamma rays emitted by a formation.

one of four types of detectors used since the inception of radiation logging. It converts tiny flashes of light produced by gamma rays as they expend themselves in certain crystals into electrical pulses. Pulse size depends on the amount of energy absorbed.

special material, either plastic or crystalline, that fluoresces when struck by a gamma ray.

the ratio of the total length of a mooring line (as on a mobile offshore drilling rig) to the depth of the water.

the NEPA process of identifying the scope and significance of important issues associated with a proposed federal action and identifying alternatives to that action through coordination and consultation with government (federal, state, and local), the public, and any interested individuals or organizations.

Shell Claus Off-Gas Treating process.

silicon-controlled rectifier.

an arrangement of silicon-controlled rectifiers into a common electrical bridge circuit.

any device that is used to remove deposits (such as scale or paraffin) from tubing, casing, rods, flow lines, or pipelines.

a specially designed piece of equipment that is installed in a pipeline to launch or receive a pipeline scraper.

a device that is fastened to the outside of casing to remove mud cake from the wall of a 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.

determination of the relative percentages of substances, e.g., the suspended solids in a drilling fluid that pass through or are retained on a sequence of screens of decreasing mesh size. Also called sieve analysis.

a pipe that is perforated and often arranged with a wire wrapping to act as a sieve to prevent or minimize the entry of sand particles into the wellbore. Also called a screen pipe. See wire-wrapped screen.

see sand out.

see wire-wrapped screen.

an instrument for measuring the sand content of drilling mud.

the tendency of proppants to separate from fracture fluid when the speed, or velocity, of the fluid is low.

see sand out.

on a ship or other floating vessel, the propeller located below the waterline and at the stern of the vessel that is driven by the vessel’s engines. The engines turn the screw, or, often, screws, which move the vessel through the water.

a packer in which the packing element is expanded by rotating the pipe. It is used when it is not desirable to put tubing weight on the packer.

to remove certain constituents of a gas by passing it through a scrubber in which the gas is intimately mixed with a suitable liquid that absorbs or washes out the constituent to be removed.

1. a vessel through which fluids are passed to remove dirt, other foreign matter, or an undesired component of the fluid. 2. a vessel with or without internal devices used to separate entrained liquids or solids from gas. It may be used to protect downstream rotating equipment or to recover valuable liquids from a gas or vapor originating upstream. 3. a unit that removes carbon dioxide from the diver’s breathing medium by chemical absorption.

oil that is recovered from a knockout (scrubber) vessel. Usually associated with a plant that requires compression. Gas is scrubbed prior to compression.

1. the purification of gas by treatment in a water or chemical wash. Scrubbing also removes the entrained water in the gas. 2. friction wear.

surface-controlled subsurface safety valve.

self-contained underwater breathing apparatus.

see fractus.

sand or sandstone; used in drilling reports.

a submersible decompression chamber.

shut down for orders; used in drilling reports.

Safe Drinking Water Act.

sandy; used in drilling reports.

suction embedment anchor.

an open-ended parachute-shaped device that creates drag but, because water flows through it, slows the speed of a body attached to it.

see advection fog.

any of several types of ice that form on the surface of the sea when the temperature drops below the seawater’s freezing point. Types of sea ice include fast ice, or coast ice, which is sea ice attached to the shore; pack ice, which is a solid concentration of ice that covers more than half of the visible sea surface; sheet ice, which is a smooth, thin layer of ice on the water’s surface; and brash, which are ice fragments that float on the sea’s surface. Sea ice also forms ice fields, which are large, flat expanses of ice on the sea’s surface. Similar to ice fields are floes, which are simply small ice fields.

see steam fog.

a relative term used to describe the condition of a large body of water, usually an ocean or a sea. Generally, sea states describe the height and intensity of the waves occurring at the time of the observation.

valve-controlled pipelines, fitted with pumps, which permit a vessel to take on seawater for ballasting into any of the vessel’s tanks.

the final testing of a ship or offshore drilling vessel before it is put to work.

see seafloor.

special diverter designed to handle shallow gas kicks that occur offshore. Unlike a normal diverter that the gas from the kick releases at the surface, an SBGD allows the gas to be released from the wellhead on the seafloor. Thus, the gas bypasses the rig. See diverter.

see temporary guide base.

the bottom of the ocean. Also called seabed.

apparatus that seals the annulus between each casing string, and isolates the previous casing from the higher wellbore pressures encountered at greater depths.

a smooth, polished bore in pipe or in a packer that is designed to provide a surface against which to make an effective seal.

a sealing member placed in the production tubing that is landed (placed) inside the packer’s seal bore.

a small chamber in a gas meter installation that traps water and prevents it from causing inaccurate measurement.

a smoothly finished steel tube with rubber or synthetic seal rings run on the bottom of the tubing string and seated in a permanent packer in order to make a pressure seal.

an extension with seals that is placed in the tubing string and that moves within a packer bore or a packer-bore extension.

a short tube attached to the packer seal bore that extends the length of the bore; used where excessive tubing expansion or contraction is anticipated.

a packer containing a seal bore to receive a tubing seal assembly.

the penetration of a drilling fluid into a potentially productive formation, thus restricting or preventing the formation from producing.

a wire-rope strand design commonly used as drilling line. It consists of a single, central wire around which are laid two additional layers of wire. The inner layer of wires are all the same diameter but are smaller in diameter than the central wire. The outer layer of wires are also all the same diameter but they are thicker in diameter than the inner wires. A typical Seale strand consists of 19 wires: 1 central wire, 9 inner wires, and 9 outer wires. Several strands are laid together to make the wire rope.

on a roller cone bit, a type of bearing that is not exposed to the drilling fluid in the wellbore. Instead, a synthetic rubber ring is placed between the outside of each cone and the shirttail of the bit where the cones reside. This seal prevents drilling fluid from entering the space between the cone and shirttail and thus the bearings, which lie inside the cones. Sealed bearing bits must also contain a built-in reservoir of grease since they are not lubricated by the drilling fluid.

any of various materials, such as mica flakes or walnut hulls, that cure lost circulation. See lost circulation, lost circulation materials.

a fault that contains material of low permeability, such as gouge.

drill pipe that is manufactured in one continuous piece. Most drill pipe is of seamless construction.

the point in the wellbore at which the bottom of the casing is set.

a special tube installed in a string of tubing, having machined contours to fit a matching wireline tool with locking pawls. It is used to hold a regulator, choke, or safety valve; to anchor a pump; or to permit installation of gas-lift valves. Also called a landing nipple. A smooth bore tubing nipple, having an inside diameter less than tubing, used to accept the seal assembly of a rod pump, as a stop for a plunger, as a safety stop for tubing swabs.

a special class of saltwater muds in which sea water is used as the fluid phase.

launched in 1979, an ultra large crude carrier (ULCC) that was the longest ship ever built. Her length was 1,509 ft and the width was 226 ft. Fully laden, the ship’s displacement was 724,239 tons. The Seawise Giant was later named the Happy Giant, Jahre Viking, and Knock Nevis as her ownership changed hands. In 1986, Iraqi warplanes attacked and sunk the ship in the Gulf of Hormuz. She was later salvaged and repaired. Currently, the tanker is moored off the coast of Qatar at the Al Shaheen oil field, where she is used as a floating storage and offloading unit.

see playa.

1. secant. 2. second. 3. section; used in drilling reports.

in a right triangle, the trigonometric function that is the ratio of the hypotenuse to the side adjacent to a given angle.

1. the fundamental unit of time in the metric system. 2. in some countries, the crew member who relieves the toolpusher, or rig manager, and is second in command.

vessel motions caused by both wave action and impacted by the stiffness of the mooring system.

see secondary winding.

a device that produces electricity from the chemical reaction of conductors of dissimilar metals through an electrolyte. In a secondary cell, the electrolyte is a liquid solution and the chemical reaction is reversible-that is, the secondary cell can be recharged. It is often called a wet cell. See dry cell, wet cell.

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.

in a riser connector, a way of routing hydraulic fluid to provide additional unlocking force that may be required to overcome high friction forces generated between the tapers on the cam ring and the locking dogs, or segments.

see remote control panel.

that part of an orifice meter installation that contains the recording elements, including the gauge lines, orifice meter chart, flow recorder, clock, static spring, etc.

a power line from the lease distribution point to electrical apparatus on the lease.

in a transformer, the reduction (loss) of electrical energy that occurs in the secondary winding of the transformer.

movement of hydrocarbons, subsequent to primary migration, through porous, permeable reservoir rock, by which oil and gas become concentrated in one locality.

porosity created in a formation after it has formed, because of dissolution or stress distortion taking place naturally, or because of treatment by acid or injection of coarse sand.

1. the use of water-flooding or gas injection to maintain formation pressure during primary production and to reduce the rate of decline of the original reservoir drive. 2. water-flooding of a depleted reservoir. 3. the first improved recovery method of any type applied to a reservoir to produce oil not recoverable by primary recovery methods. See pressure maintenance, primary recovery.

sediment that does not show up in an untreated sample of emulsion but that does appear as additional water in a sample treated with a slugging compound. Compare primary sediment.

a standard the value of which is fixed by direct or indirect comparison with a primary standard or by means of a reference-value standard. Compare primary standard, working standard.

the term, usually in a phrase like “so long thereafter as oil or gas is produced in paying quantities,” that extends a lease beyond its primary term. Compare primary term.

the use of blowout prevention equipment to control a kick. Compare primary well control.

in a transformer, the second of two windings (coils) in which electrical energy is induced by the magnetic energy in the primary winding. Compare primary winding.

the time in seconds that it takes 1 quart of drilling mud to flow out of a Marsh funnel. It is a measure of the mud’s viscosity. See also Marsh funnel.

1. a unit of land measurement in the rectangular survey system. Each 6-mile (9.7-kilometre) square, or township, is divided into 36 sections. A section usually is 1 square mile (2,590 square kilometres), or 640 acres (256 hectares). It may be larger or smaller, depending on its position in the township. 2. vertically arrayed data.

the process by which a portion of pipe, usually casing, is actually removed by cutting with a mill.

sediment; used in drilling reports.

1. the matter that settles to the bottom of a liquid; also called tank bottoms. 2. in geology, buried layers of sedimentary rocks.

a material coexisting with, yet foreign to, petroleum liquid and requiring a separate measurement for reasons that include sales accounting. This foreign material includes free water and sediment (dynamic measurement) and/or emulsified or suspended water and sediment (static measurement). The quantity of suspended material present is determined by a centrifuge or laboratory testing of a sample of petroleum liquid.

a sample obtained from the bottom of the tank to determine the amount of nonmerchantable material present.

the sediment in oil or other liquid that tends to adhere, or cling, to the side of a tank or vessel.

a rock composed of materials that were transported to their present position by wind or water. Sandstone, shale, and limestone are sedimentary rocks.

the process of deposition of layers of clastic particles or minerals that settle out of water, ice, or other transporting media.

the science dealing with the description, classification, and interpretation of sediments and sedimentary rock.

an undesirable particle or granule found in a paint or varnish.

the surface appearance of oil or gas that results naturally when a reservoir rock becomes exposed to the surface, thus allowing oil or gas to flow out of fissures in the rock.

Society of Exploration Geophysicists.

see gravity drainage.

seismograph; used in drilling reports.

of or relating to an earthquake or earth vibration, including those artificially induced.

see well velocity survey.

detailed information obtained from earth vibration produced naturally or artificially (as in geophysical prospecting).

a method of geophysical prospecting using the generation, reflection, refraction detection, and analysis of sound waves in the earth.

an agreement that permits seismic exploration of land for a specified price per acre. The company gathering seismic information can, by the terms of the agreement, eventually lease selected acreage, again for an agreed-upon price.

digital recording of the return to geophones of a shock wave emitted from the surface.

a cross section of a subsurface area, in which seismic reflections are gathered and recorded by a seismic survey. Computers process the survey data and generate the profile. See seismic survey.

see tsunami.

see record section.

an exploration method in which strong low-frequency sound waves are generated on the surface or in the water to find subsurface rock structures that may contain hydrocarbons. The sound waves travel through the layers of the earth’s crust; however, at formation boundaries some of the waves are reflected back to the surface where sensitive detectors pick them up. Reflections from shallow formations arrive at the surface sooner than reflections from deep formations, and since the reflections are recorded, a record of the depth and configuration of the various formations can be generated. Interpretation of the record can reveal possible hydrocarbon-bearing formations.

shock wave generated by an earthquake or explosion.

the record of an earth tremor by a seismograph.

a device that detects vibrations in the earth. It is used in studying the earth’s interior and 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 vibrating a heavy plate in contact with the ground. 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.

the study of earth vibrations.

an instrument that measures motions in the ground, including those generated by earthquakes, explosions, and sources such as devices that generate very low sound frequencies.

to bind the end of a wire rope with fine wire or a metal band to prevent it from unraveling.

a wrapping of wire around the end of a wire rope, the purpose of which is to prevent the strands of the wire rope from unwrapping.

a small-diameter wire-rope strand, usually made up of seven wires. It is used to seize large-diameter wire rope. See seizing.

a wire used to seize the end of wire rope. See seizing.

to set a downhole production tool by shearing shear screws or pins that the operator installed before the tool was run.

once the drawworks receives power from either the compound or electric motors, the type of transmission that allows the driller to select how the power is distributed (torque/speed combinations) to various components of the drawworks. The drawworks on both mechanical-drive and electric-drive rigs have a selective transmission.

a feature on some downhole production tools that allows the operator to select the setting depth of the tools.

a single receiver used with a remote transmission system to permit the use of one or more tank transmitters so that selective liquid level readings can be obtained by switching from one tank to another. Compare single-tank remote gauge.

a sampling device that is operated by streamflow or stream pressure.

see jackup drilling rig.

see jackup drilling rig.

a base on which the floor and mast of a drilling rig rests and which, after it is placed in the desired location, is raised into position as a single unit.

see spontaneous potential.

see spontaneous potential curve.

1. able to move or travel using a built-in power source, rather than requiring an external power source. 2. of or relating to a rig’s ability to move or travel with its own power source.

see carrier rig.

a type of electric AC motor used to transmit motion and position.

subsea electronic module.

1. short for semisubmersible drilling rig. 2. Short for semi-trailer. See semisubmersible drilling rig, semi-trailer.

a trailer without a front axle. Usually, a tractor, which is a powerful truck, supports and hauls the weight of the semi-trailer. Also called , semi-truck, semi-tractor trailer truck.

a welding technique in which the arc is maintained in a continuous stream of gas between an electrode and the pipe being welded. The semiautomatic welding apparatus consists of a spool of coiled wire that provides filler metal for the weld, a pair of driving rollers that guide the wire to the weld, a welding gun, and a supply of shielding gas. Each type of semiautomatic welding is usually identified by the type of shielding gas used; in CO2 wire welding, for example, carbon dioxide is the shielding gas.

a diving life-support system in which the gas is partially vented and the remainder is recycled, purified, and reoxygenated.

a solid (such as germanium or silicon) whose electrical conductivity lies between that of a conductor and that of an insulator. Semiconductor materials are used in the manufacture of diode rectifiers, transistors, and integrated circuits.

a tide having two high water levels and two low water levels per day.

a perforating gun that consists of a metallic strip on which encapsulated shaped charges are mounted. After the gun is fired, the strip is retrieved. See gun-perforate.

a substance that is neither liquid nor solid but that flows slowly as a liquid.

the ability to let small molecules pass or flow through.

a state in which a specially designed floating drilling rig (a semisubmersible) floats just below the water’s surface.

see semisubmersible drilling rig.

a floating offshore drilling unit that has pontoons and columns that, when flooded, cause the unit to submerge to a predetermined depth. Living quarters, storage space, and so forth are assembled on the deck. Semisubmersible rigs are self-propelled or towed to a drilling site and anchored or dynamically positioned over the site, or both. In shallow water, some semisubmersibles can be ballasted to rest on the seabed. Semisubmersibles are more stable than drill ships and ship-shaped barges and are used extensively to drill wildcat wells in rough waters such as the North Sea. Two types of semisubmersible rigs are the bottle-type and the column-stabilized. See floating offshore drilling rig.

a type of pipe-laying vessel with a submerged pontoon hull and an elevated work area. Semisubmersible lay vessels remain relatively steady in high seas and are used in areas where conditions are expected to be continually rough.

a floating offshore unit with pontoons and columns that, when flooded, cause the unit to submerge to a predetermined depth. Two types of semisubmersible platforms are bottle-type and column-stabilized.

the person under HAZWOPER who responds to an emergency and is the individual in charge of the ICS. As such, he or she is responsible for coordinating and controlling all emergency responders and their communications.

a one-piece orifice fitting that allows the orifice plate in it to be changed without depressuring the meter run or shutting off the flow of gas.

the heat that changes the temperature of a fluid without changing its phase to gas or solid.

the part of a measuring device that is responsive to the absolute value or change in a physical quantity, such as temperature, pressure flow rate, pH, light, or sound. It converts that change into an input signal for an information-gathering system.

a measure of an engine governor’s ability to sense a change in an engine’s speed and make an adjustment to correct the speed change.

the estate that is owned separately by one spouse before marriage.

1. the process of removing gas from liquid and liquid from gas. 2. after recovery and rejection, the third system in oil-absorption plants that is used to separate gas products. See recovery, rejection. v: processing various marketable products from natural gas.

a metal sleeve that shuts off tubing-to-annulus flow if a packer’s sliding sleeve fails. See sliding sleeve.

see tower with trays.

a cylindrical or spherical vessel used to isolate the components in mixed streams of fluids. See oil and gas separator.

the discharge from a separator, such as oil or water.

gas remaining after being separated from condensate.

suction embedment plate anchor.

automatic process by which a series of operations are initiated sequentially when certain requirements have been met.

a time switch that starts motors in sequence after a power outage or shutdown. It prevents excessive voltage drop, which would occur if several motors were started simultaneously.

a sequence, or order, of formations. Geologists take information from seismic surveys and analyze it to deduce the environment that existed when a rock layer first formed.

a component or element that has at least one input channel, at least one output channel, and at least one internal state variable, so designed and constructed that the output signals depend on the past and present states of the inputs.

a chemical used with an acid in well treatment to inhibit the precipitation of insoluble iron hydroxides, which form when the acid contacts scales or iron salts and oxides, such as are found in corrosion products on casing.

the formation of stable calcium, magnesium, iron compounds by treating water or mud with phosphates.

State Emergency Response Commission.

of or pertaining to an end-to-end arrangement of electrical components in a circuit that forms a single path for current to travel.

a circuit that has two or more electrical devices connected to form a single path for the electric current. The current is the same throughout the circuit; the total voltage is the sum of the voltages across each element of the circuit.

a winding that is connected in series with another winding or device in the same circuit, as in a series motor. See series circuit.

an igneous rock composed in part of hydrated magnesium silicate. Hydrocarbons may be associated with serpentine, but not usually.

a company that provides a specialized service, such as a well-logging service or a directional drilling service.

a percentage multiplier of rated horsepower at which a motor may be operated without exceeding the temperature rise limit.

see production rig.

1. a nonproducing well used for injecting liquid or gas into the reservoir for enhanced recovery. 2. a saltwater disposal well or a water supply well.

short for well servicing. See well servicing.

the mineral estate regarded as subject to a specified use by one party, even though the surface is owned by another.

a device consisting of a sensing element, a power device, and an amplifier that is used to automatically control a mechanical device. The power device is usually called a servomotor.

an electric motor or hydraulic piston that powers a servo-mechanism.

an ocean current’s direction of motion. v: to harden; for example, when cement sets, it hardens.

to place stands of drill pipe and drill collars in a vertical position to one side of the rotary table in the derrick or mast of a drilling or workover rig. Compare lay down pipe.

to run and cement casing at a certain depth in the wellbore. Sometimes called set pipe.

see set casing.

1. in drilling, the depth at which the bottom of the casing extends into the wellbore when it is ready to be cemented. 2. in process control, the desired value or output in a control system. It establishes the reference in a closed-loop control system.

to harden (as cement).

a packer that is set by applying weight from the tubing string.

the location on the rig floor where crewmembers place stands of drill pipe and drill collars in a vertical position.

the depth at which the bottom of the casing extends in the wellbore when it is ready to be cemented.

a tool used to set drillable or permanent tools, such as packers, retainers, or plugs; it can be mechanical, electric, or hydraulic.

oil and gas production from longtime fields that produce at approximately the same rate every day.

the separation of substances because of different sizes and specific gravities of components in the substances.

the depth that sediment achieves when it settles out of a fluid.

a pit into which mud flows from the well and in which heavy solids in the mud are allowed to settle out. Steel mud tanks are more often used today, along with auxiliary equipment (such as desanders) for controlling solids quickly and efficiently. Also called settling tank.

1. the steel mud tank in which solid material in mud is allowed to settle out by gravity. It is used only in special situations today, for solids control equipment has superseded such a tank in most cases. Sometimes called a settling pit. 2. a cylindrical vessel on a lease into which produced emulsion is piped and in which water in the emulsion is allowed to settle out of the oil.

a term, now obsolete, that denoted the seven largest international oil companies. The companies were Exxon, Royal Dutch Shell, British Petroleum, Mobil, Gulf, Texaco, and Chevron. Mergers and name changes have reduced the number to Exxon Mobil, BP Amoco, Chevron-Texaco, and Shell. The future, no doubt, will herald additional changes.

the separation of a mineral or royalty interest from other interests in that land given by grant or reservation.

see production tax.

nonexpense-bearing interest in minerals produced and saved from a tract owned by someone other than the surface owner. Owner of severed royalty interest gets a share of production from wells, but does not have to share the costs of production. The interest may be set up prior or subsequent to the leasing of the land, granted or reserved for years, for life, in fee simple defeasible, or in perpetuity.

a system on offshore locations used to render human and other wastes biologically inert before the wastes are discharged overboard.

gas saturation; used in reservoir engineering.

Southern Gas Association.

shale; used in drilling reports.

a U- or anchor-shaped fitting with pin. It is attached to one end of a wire rope and is used to attach the wire rope to other ropes or devices.

the power delivered to the propeller shaft of a ship powered by a system.

to spin a sample of oil at high speed, usually in a centrifuge, to determine its S&W content.

see centrifuge.

an operation that uses a centrifuge to spin small samples of crude oil gathered from a storage tank or other vessel and to determine the amount of sediment and water (S&W) in the sample. See shake out.

shortened form of shale shaker. See shale shaker.

see shaker tank.

the mud tank adjacent to the shale shaker, usually the first tank into which mud flows after returning from the hole. Also called a shaker pit.

a fine-grained sedimentary rock composed mostly of consolidated clay or mud. Shale is the most frequently occurring sedimentary rock.

natural gas that occurs in the sedimentary rock called shale. In general, shale’s permeability shale is very low although its pores may contain natural gas. Consequently, when drilling for shale gas, the wells are often drilled horizontally and the shale must be hydraulically fractured to provide a pathway for the gas to flow into the well.

see oil shale.

a vibrating screen used to remove cuttings from the circulating fluid in rotary drilling operations. The size of the openings in the screen should be selected carefully to be the smallest size possible to allow 100 per cent flow of the fluid. Also called a shaker.

a special wire mesh installed in a shale shaker that allows liquid mud to pass through but traps the cuttings and larger solid particles the mud carries from the hole. Often, more than one screen is installed in the shale shaker; also, the screens are usually vibrated to help remove the cuttings and solids on top of the screen.

a slanted trough that collects cuttings that fall onto the shaker and vibrate off.

the termination of a shale bed.

natural gas deposit located near enough to the surface that a conductor or surface hole will penetrate the gas-bearing formations. Shallow gas is potentially dangerous because, if encountered while drilling, the well usually cannot be shut in to control it. Instead, the flow of gas must be diverted. See diverter.

the shape of a PDC bit’s head that resembles two short and rounded cones placed side by side. The compacts are placed on the surface of the head. Compare parabolic profile, short parabolic profile.

a relatively small container of high explosive that is loaded into a perforating gun. On detonation, the charge releases a small, high-velocity stream of particles (a jet) that penetrates the casing, cement, and formation. See perforating gun.

a stoppering device for wire or chain used on the back deck of an AHTS vessel. Usually can be retracted into the deck when not in use.

action or stress that results from applied forces and that causes or tends to cause two adjoining portions of a substance or body to slide relative to each other in a direction parallel to their plane of contact.

see fixed-head bit.

mechanical support of casing by cement in the borehole. Shear bond is determined by measuring the force required to initiate pipe movement and dividing that figure by the cement-casing contact surface area.

the breakdown of molecules of a substance such as a polymer when subjected to shear stress. See shear.

a coefficient of elasticity that expresses the ratio of the force per unit area that deforms the substance laterally and the shear produced by this force.

a pin that is inserted at a critical point in a mechanism and designed to shear when subjected to excess stress. The shear pin is usually easy to replace.

the com­ponent in a blowout preventer that cuts, or shears, through drill pipe and forms a seal against well pressure. Shear rams are used in floating 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.

a blowout preventer that uses shear rams as closing elements. See shear ram.

the rate of shear due to stress.

a type of pressure relief valve in which excess pressure causes a shearing action on a pin to relieve pressure. See pressure-relief valve.

1. a unit that is used to measure soil strength (e.g., lbs/ft2). 2. see gel strength.

force applied to a liquid to cause it to flow.

viscosity reduction of non-Newtonian fluids (e.g., polymers, most slurries and suspensions, and lube oils with viscosity-index improvers) under conditions of shear stress.

distortional, equivolumnar, secondary, or transverse wave.

a blind-shear ram. See shear ram.

an instrument used to measure the shear strength, or gel strength, of a drilling fluid. See gel strength.

(pronounced “shiv”) 1. a grooved pulley. 2. support wheel over which tape, wire, or cable rides.

a measuring instrument used to determine the size of sheaves on a block. It has sized metal fingers which are placed inside sheave grooves to calibrate the grooves.

an individual groove in a sheave.

the longitudinal curve of a vessel’s deck in a vertical plane. As a result of sheer, a vessel’s deck height above the baseline is higher (or lower) at the ends than amidships.

a smooth, thin layer of ice on the water’s surface.

1. the body of a tank. 2. the horizontal tank on a tank car that contains the liquid being transported. 3. the steel backing of a precision insert bearing on a bit. 4. a hypothetical spherical surface centered on the nucleus of an atom that contains orbiting electrons.

a process for improving the efficiency of a Sulfur Recovery Unit (SRU; Claus Unit). Sulfur recovery of the SRU can reach about 95%–99.9%.

used to describe a tank that is filled to its shell capacity.

the distance between the bottom of the bottom angle of the tank and the top of the top angle.

see Twister™ Supersonic separator.

a type of heat exchanger consisting of tubes in a container called a shell. Transfers heat from a fluid on one side of a barrier to a fluid on the other side, without bringing the fluids into direct contact.

a biodesulfurization process. A gas stream containing H2S contacts an aqueous soda solution containing thiobacillus bacteria in an absorber. The soda absorbs the H2S and is transferred to an aerated atmospheric tank where the bacteria biologically converts the H2S to elemental sulfur. This process is ideally suited to environmentally sensitive areas where venting, incineration, or reinjection of H2S are not desirable options. See thiobacillus bacteria.

an earth-resistivity meter used to measure the resistance of soil to the passage of electrical current.

see chicken hook.

see chicken hook.

single or multiple conductors surrounded by a flexible metal shield for the purpose of preventing spurious signals from being carried.

A process by which the electrode is placed in a holder called a stinger and manually manipulated by the diver-welder. During the process, the electrode is consumed, which provides the filler metal for the weld. Commonly referred to as stick-welding.

a welding technique in which the rod coating involves an inert gas shield that protects the weld from the rapid oxidation caused by contact with oxygen in the atmosphere. Shielded-arc welds are fine grained, free of oxides and nitrides, and have great ductility and toughness.

an inert gas that is used as a shielding medium in pipe welding. Its primary purpose is to prevent oxidation of the weld at the point of contact with the pipe metal by excluding oxygen in the air from the area around the molten metal.

a thin, often tapered piece of material used to fill in space between things (such as for support, leveling, or adjustment of fit).

a method that uses a ship itself as an instrument to measure currents. Navigation equipment on board measures the current’s effect on the vessel.

a floating offshore drilling structure that is towed to and from the drilling site. The unit has a streamlined bow and squared-off stern, a drilling derrick usually located near the middle of the barge, and a moon pool below the derrick through which drilling tools pass to the seafloor. It is identical in appearance to a drill ship, but is not self-propelled. It must therefore be towed to the drill site. Ship-shaped barges are most often used for drilling wells in deep, remote waters. See floating offshore drilling rig.

drill ship.

any company that transports oil or gas.

the part of a drilling bit on which the cone is anchored. Shirttails extend below the threaded pin of the bit and are usually rounded on bottom, thus acquiring the name.

see vibrator hose.

the sudden application of force by a moving body on a resisting body so that a great deal of stress is produced in the resisting body.

a vibration dampener.

a device placed at the end of or beneath an object for various purposes (e.g., casing shoe, guide shoe).

a narrow, often sinuous, sand deposit, usually a buried sandbar or filled channel.

a special access road constructed to link a right-of-way with existing roads. Shooflies are necessary only in remote areas.

1. to explode nitroglycerine or other high explosives in a hole to shatter the rock and increase the flow of oil; now largely replaced by formation fracturing. 2. in seismographic work, to discharge explosives to create vibrations in the earth’s crust. See seismograph.

the process of using explosives to clear rock from a pipeline right-of-way or from the ditch line. Also called blasting.

a congressional act that requires ships transporting garbage and refuse to assure that the garbage and refuse are properly contained on board so that it will not be lost in the water as a result of inclement wind or water conditions.

that part of the seashore seaward of the low-tide mark that is affected by wave action.

see short circuit.

a phenomenon that occurs in electrical circuits wherein two components carrying current inadvertently come into contact and interrupt the current path. For example, if two bare wires in a circuit accidentally touch, current flows directly back to the source of electricity without traveling its normal path. Often, because so little resistance exists, current flow is high enough to melt wires and other components.

angled grooves on a drum.

in conventional electric logging, measures resistivity in the formation only a short distance from the borehole. Used for shallow investigation of the formation.

the shape of a PDC bit’s head in which the head resembles a short parabolic arc. A para­bolic arc is an arch-shaped curve that looks similar to the arch over a doorway or other structure. Compare parabolic profile, shallow-cone profile.

in a dual well, the tubing string for the shallower zone.

a unit of measure of mass (weight) that is equal to 2,000 pounds (907.2 kilograms). Compare long ton.

the displacing of wellbore fluids from the annulus up the tubing. Compare long way.

a full-sized ell or tee upstream and downstream of a meter.

a weather forecast covering 48 hours or less.

see shortwave radiation.

radiation that is visible as light.

1. a charge of high explosive, usually nitroglycerine, detonated in a well to shatter the formation and expedite the recovery of oil. Shooting has been almost completely replaced by formation fracturing and acid treatments. 2. a point at which a photograph is made in a single-shot survey. See directional survey.

the use of steel shot (ball bearings) in the drilling mud to hit the bottom of the hole as the shot leaves the bit jet with the mud. Experiments have shown that the rate of penetration is improved in some circumstances, but difficulties with handling the shot in the mud system have precluded wide use.

the drilling of relatively small holes into the earth, the purpose of which is to provide a means for lowering an explosive shot in order to create shock waves for seismic analysis.

1. the flat portion machined on the base of the bit shank that meets the shoulder of the drill collar and serves to form a pressure-tight seal between the bit and the drill collar. 2. the flat portion of the box end or the pin end of a tool joint; the two shoulders meet when the tool joint is connected and form a pressure-tight seal.

the appearance of oil or gas in drilling fluids, cuttings, samples, or cores from a drilling well.

shaft horsepower.

a tool joint made to fit the pipe by the process of shrinking on, that is, by heating the outer member to expand the bore for easy assembly and then cooling it so that it contracts around the inner member.

1. a decrease in oil volume caused by evaporation of solution gas or by lowered temperature. 2. the reduction in volume or heating value of a gas stream due to removal of some of its constituents. 3. the unaccounted loss of products from storage tanks.

a special type of jet nozzle that is manufactured with a projection (the shroud), which serves to minimize the erosion of the nozzle by the high-velocity jet of drilling fluid being forced through it.

a conductor joining two points in an electrical circuit to form a parallel or alternate path through which a portion of the current may pass.

a winding that is connected in parallel with another winding or device in the same circuit, as in a shunt-wound DC motor. See parallel circuit.

to stop work temporarily or to stop a machine or operation.

1. to close the valves on a well so that it stops producing. 2. to close in a well in which a kick has occurred.

to stop or decrease the production of water in an oilwell by cementing or mudding off the water-producing interval.

shut off to prevent flow. Said of a well, plant, pump, and so forth, when valves are closed at both inlet and outlet.

the pressure at the bottom of a well when the surface valves on the well are completely closed. It is caused by formation fluids at the bottom of the well.

a bottomhole pressure test that measures pressure after the well has been shut in for a specified period of time. See bottomhole pressure test.

pressure of the annular fluid on the casing at the surface when a well is shut in.

pressure of the drilling fluid on the inside of the drill stem. It is used to measure the difference between hydrostatic pressure and formation pressure when a well is shut in after a kick and the mud pump is off and to calculate the required mud-weight increase to kill the well.

potential natural gas production curtailed because of state conservation orders (prorationing), unfavorable economics, lack of buyers at existing prices, failure of committed buyers to take gas, or other reasons.

an interval during which a well is shut in to allow pressure buildup while pressure behavior is being measured during a formation test.

the pressure when the well is completely shut in, as noted on a gauge installed on the surface control valves. When drilling is in progress, shut-in pressure should be zero, because the pressure exerted by the drilling fluid should be equal to or greater than the pressure exerted by the formations through which the wellbore passes. On a flowing, producing well, however, shut-in pressure should be above zero.

payment to royalty owners in lieu of production, rentals, or other consideration on a shut-in gas well that is capable of producing but does not have a market.

clause in a lease specifying the payments that must be made on a gas well capable of producing but shut in for lack of a market or pending connection with a pipeline.

usually, a gas well shut in for lack of a market or pending connection with a pipeline.

the act of stopping a machine or device from running. For example, engine operators perform a shutdown when they stop an engine.

a rate provision that is usually contained in a drilling contract and that specifies the compensation to the independent drilling contractor when drilling is suspended at the request of the operator.

on an engine, a series of devices that sense an abnormality in the engine’s operation and automatically shut off the fuel and air supply to the engine to make it stop running.

a device installed in a line, which, when closed, stops flow in the line and, when open, allows flow.

a flow control device (a valve) with two inlet ports and one outlet port in an accumulator, which is employed in a subsea blowout preventer system. Hoses from the lower marine riser package’s yellow and blue control pods are connected to the shuttle valve’s inlet port. The outlet port is connected directly to the blowout preventer’s inlet port.

a tank ship capable of navigating shallow ports, usually 30,000–70,000 dead weight tons (27,216–63,504 dead weight tonnes). It shuttles between anchored large vessels and port.

silicon.

see International System of Units.

shut-in bottomhole pressure; used in drilling reports.

standard industrial classification.

shut-in casing pressure.

an opening in the wall of the riser adapter to which a mud booster line is attached. See mud booster line, riser adapter.

an opening usually located in the blowout preventer stack below a ram preventer, to which a choke line or a kill line is attached. Typically, outlets are provided in pairs, one on each side of the bore. Usually, outlets are provided for a choke line and a kill line.

an offset heavy-wall sub in the production string for placing gas-lift valves, and so on.

in a PDC bit, the left-to-right orientation of the cutter with respect to the bit’s face; usually, the cutters are angled toward the outside of the bit to help direct cuttings to the annulus.

the joining of another pipe to the main body of a pipeline.

a bit especially designed for use in drilling a hole around an obstruction in the main borehole. Usually, a cement plug is set on top of the obstruction, the side tracking bit is run into the hole on a whipstock or other directional drilling device, and the new borehole begun. Because the new borehole goes off to the side of the plugged borehole, the operation is called side tracking.

elevators arranged so that they are latched and unlatched from the side instead of in the middle. Compare center-latch elevators.

see gas-lift mandrel.

imaging radar used in airplanes.

see gas-lift mandrel.

to use a whipstock, turbo-drill, or other mud motor to drill around broken drill pipe or casing that has become lodged permanently in the hole.

to drill around broken drill pipe or casing that has become lodged permanently in the hole, using a whipstock, turbodrill, or other mud motor.

a coring technique in which core samples are obtained from the hole wall in 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. Core samples of this type usually range from 3⁄4 to 13⁄16 inches (20 to 30 millimetres) in diameter and from 3⁄4 to 4 inches (20 to 100 millimetres) in length.  This method is especially useful in soft-rock areas.

a device in which a neutron source and a detector are in a pad using the same hardware as the density log. The pad is pushed against the side of the borehole wall. The log measures porosity.

a logging device that is held firmly against the wall of the hole and that measures the porosity of a formation.

used to obtain a core sample. The sampler is activated to fire several small cylinders into the wall of the hole. The cylinders penetrate a short distance into the rock and cut a small core.

a type of wireline unit in which power is transferred by means of a pulley and a belt from the left rear wheel of the wireline truck to the spool of wire that is pulled from the left side of the truck. The spool is used to run the wireline downhole and bring it back up again.

shut-in drill pipe pressure; used in drilling reports.

the determination of the percentage of particles that pass through several screens of graduated fineness.

a tray, installed in an absorber tower or fractionating column, that is similar to a bubble-cap tray, except that it has only holes but no bubble caps through it. This type of tray is more efficient than the bubble-cap tray or the valve tray and less expensive than either; however, it does not operate properly over a wide range of flow rates. See molecular sieve.

a draft or order for payment that must be picked up on the day that it arrives at the drawer’s bank. For example, if a lessee pays a lessor a cash bonus by means of a sight draft, the lessee must pick up that draft on the same day that it arrives at his or her bank from the lessor’s bank.

a glass tube or a glass-faced section on a process line or vessel; used for visual reading of liquid levels or of manometer pressures.

information about a variable that can be transmitted.

an electronic test instrument that delivers a sinusoidal output at an accurately calibrated frequency ranging anywhere from audible to microwave frequencies. The frequency and amplitude of the device’s output are adjustable over a wide range. The output may be frequency- or amplitude-modulated.

an operational amplifier that senses electronic signals in a circuit and electronically arranges the signals so that they function together in an efficient and logical way. See operational amplifier.

the ratio of the magnitude of the electrical signal to that of the electrical noise.

a classification of larger spills released into navigable waters that can cause substantial environmental damage.

a statistical wave that has a height equal to the average of the highest one-third of the waves in a particular area.

a mineral that has the chemical formula SiO2 (silicon dioxide). It is relatively hard and insoluble. Quartz is a form of silica, but usually contains impurities that give it color.

a silica (SiO2) ground to a fineness equal to that of portland cement.

highly adsorbent, gelatinous form of silica used chiefly as a dehumidifying and dehydrating agent.

a dehydration process used for water as well as hydrocarbon dew-point control in which water and heavy hydrocarbons are removed from feed gas on multiple beds of silica gel adsorbent.

crystalline compound composed largely of silicon in chemical combination with aluminum, magnesium, oxygen, and other common elements.

containing abundant silica, or silicon dioxide (SiO2).

a nonmetallic element occurring extensively in the earth’s crust in the form of silicon dioxide, or sand. Silicon usually occurs as dark-brown crystals. It is used in glass, steel, semiconducting devices, concrete, brick, and other materials.