Glossary

average reservoir pressure, used in engineering reports.

see bulk tank.

in a semiconductor material such as silicon, the arrangement of atoms in the material in such a manner that few electrons are able to flow between the atoms; a positive charge is thus created. Compare n-type structure.

the difference in pressure between the tubing and the casing annulus.

Petroleum Industry Training Service (Canada).

plug and abandon.

pascal.

polyanionic cellulose.

a solid pack of ice that covers more than half of the visible sea surface.

to place a packer in the wellbore and activate it so that it forms a seal between the tubing and the casing.

a device with an elastomer packing element that depends on pressure below the packing to effect a seal in the annulus. Used primarily to run or pull pipe under low or moderate pressures, this device is not dependable for high differential pressures. Also called a stripper.

a preventer having a unit of packing material whose closure depends on well pressure coming from below. It is used primarily to strip pipe through the hole or allow pipe to be moved with pressure on the annulus.

in a subsea wellhead assembly, a device that, when rotated, actuates a seal assembly to close the annulus between two casing strings.

a fractionation or absorption column filled with small objects that are designed to have a relatively large surface per unit volume (the packing), instead of bubble trays or other devices, to give the required contact between the rising vapors and the descending liquid. In the reboiler still column of a glycol dehydration unit, entrained water flashes into steam when inflowing rich glycol flows over the hot packing. Compare bubble-cap trays.

a bottomhole assembly in which pendulum-length collars are swung below a regular packed-hole assembly. The pendulum portion of the assembly is used to reduce hole angle. It is then removed, and the packed-hole assembly is run above the bit. See packed-hole assembly, pendulum assembly.

a bottomhole assembly consisting of stabilizers and large-diameter drill collars arranged in a particular configuration to maintain drift angle and direction of a hole. This assembly is often necessary in crooked-hole country. See crooked-hole country.

a piece of downhole equipment that consists of a sealing device, a holding or setting device, and an inside passage for fluids. It is used to block the flow of fluids through the annular space between pipe and the wall of the wellbore by sealing off the space between them. In production, it is usually made up in the tubing string some distance above the producing zone. A packing element expands to prevent fluid flow except through the packer and tubing. Packers are classified according to configuration, use, and method of setting and whether or not they are retrievable (that is, whether they can be removed when necessary, or whether they must be milled or drilled out and thus destroyed).

a tool for production logging that employs an inflatable packer. It ensures that all the fluid from the well passes through the measuring devices built into the tool.

a liquid, usually salt water or oil, but sometimes mud, used in a well when a packer is between the tubing and the casing. Packer fluid must be heavy enough to shut off the pressure of the formation being produced, must not stiffen or settle out of suspension over long periods of time, and must be noncorrosive.

see mill.

a squeeze cementing method in which a packer is set to form a seal between the working string (the pipe down which cement is pumped) and the casing. Another packer or a cement plug is set below the point to be squeeze-cemented. By setting packers, the squeeze point is isolated from the rest of the well. See packer, squeeze cementing.

a fluid-pressure test of the casing. Also called a cup test.

a retrievable device anchored on the top of a production packer. It receives a tubing seal assembly. See tubing seal assembly.

1. a material used in a cylinder on rotating shafts of an engine in the stuffing box of a valve, or between flange joints to maintain a leakproof seal. 2. the specially fabricated filling in packed fractionation columns and absorbers.

the arrangement of the downhole tools used in running and setting a packer.

1. a dense rubber, washer-shaped element encircling a packer, which expands against casing or formation face to seal off the annulus. 2. in an annular blowout preventer, the elastomer sealing piece that, when closed, forms a pressure-tight seal around virtually any tool in the wellbore, as well as on open hole—hole with nothing in it.

the metal part that compresses and holds packing in place in a stuffing box. See gland, stuffing box.

piston ring.

1. a device on a logging tool that contacts the wellbore when the log is being taken. 2. fluid placed in a well to serve a special purpose. 3. a concrete foundation on which a drilling rig rests.

the drilling of several wells from a single drilling pad to minimize the environmental impact of drilling. See drilling pad.

a device (e.g., a minilog) designed to measure the resistivity of small volumes of formation near the borehole. It consists of three electrodes embedded in the center of an insulated fluid-filled rubber pad that is held against the side of the borehole. The electrodes produce two curves—one 1.5 inches (3.8 centimetres) in depth and one 4 inches (10.2 centimetres) in depth. The separation between the two curves shows the difference in resistivity between the mud cake and the formation immediately behind the mud cake.

the amount of fluid placed in a well to serve as a pad. See pad.

screened or sifted dirt, clean gravel, or foam placed in a ditch to protect pipe from damage caused by rocky or rough soils.

a steel plate with an opening (the eye) that is usually welded to a heavy object and to which a sling or other lifting line is attached to facilitate the object’s being moved, lifted, or lowered.

an oil and gas lease for which all delay rentals are paid along with the cash bonus and on which no further action is required during the primary term.

the consistency of a paint—for example, its thickness or thinness.

1. the process in which a ray or wave reacts with the nucleus of an atom, converting the wave’s energy into mass to produce an electron and a positron. The positron immediately reacts with an electron within the radioactive material. In the interaction, two new gamma rays are produced with energy levels less than half the original gamma ray. 2. the conversion of a photon into an electron and a positron when the photon traverses a strong electric field, such as that surrounding a nucleus or an electron.

ancient; early; long ago; primitive.

the examination and study of prehistoric air, water, minerals, organisms, and other external factors that surrounded and affected the organisms living at the time.

geography of a specified geologic past.

the science that concerns the life of past geologic periods, especially fossil forms and the chronology of the earth.

a span of time from 600 million to 230 million years ago during which a great diversity of life forms developed.

a diagram of a block of earth in which a series of cross sections are joined and viewed obliquely from above, to give a three-dimensional view. It is useful in showing how formation structure and stratigraphic thickness vary both horizontally and vertically. Also called fence diagram.

the supercontinent comprising all of the principal continental masses near the beginning of the Mesozoic era.

a capacitor whose dielectric (insulating material) is made from paper. See capacitor.

the shape of a PDC bit’s head that resembles a parabolic arc, a curve that looks very much like an arch over a doorway. Compare shallow-cone profile, short parabolic profile.

a saturated aliphatic hydrocarbon having the formula CnH2n + 2 (e.g., methane, CH4; ethane, C2H6). Heavier paraffin hydrocarbons (i.e., C18H38) form a waxlike substance that is called paraffin. These heavier paraffins often accumulate on the walls of tubing and other production equipment, restricting or stopping the flow of the desirable lighter paraffins.

see paraffin.

a chemical that, when injected into the wellbore, prevents or minimizes paraffin deposition.

a tube with guides around it to keep it centered in the hole, and a cylindrical piece with blades attached. Spaces between the blades allow drilling fluid to pass through and carry away the scrapings.

a solid substance resembling beeswax but composed entirely of hydrocarbons. It is obtained from the crude wax that results from the solvent dewaxing or cold pressing of light paraffin distillates. The refined product is of relatively large crystalline structure, is white and brittle, and has little taste or odor.

a crude oil characterized by a high API gravity, a high yield of low-octane gasoline, and a high yield of lubricating oil with a high pour point and a high viscosity index. Popularly, and according to an early classification system, a paraffin-base oil is a crude oil containing little or no asphalt and yielding a residue from distillation that contains paraffin wax. Compare naphthene-base oil.

an interval in the production tubing string where heavy paraffin hydrocarbons are deposited on the inside walls of the tubing. Below or above certain temperatures, depending on the characteristics of the paraffins, paraffin will not form.

of an electrical circuit in which the components are assembled such that current flows through two or more paths. Compare series.

a circuit with two or more paths through which the current flows. The total current equals the sum of the currents through the various paths; the voltage is the same throughout the circuit. Compare series circuit.

see laminar flow.

a type of synthetic rope construction.

in a multiple completion, the arrangement of a separate tubing string for each zone produced, with all zones isolated by packers.

only slightly magnetic. Paramagnetic materials do not react to any signifi-cant extent to a magnetic field. See diamagnetic, ferromagnetic.

the values that characterize and summarize the essential features of measurements.

in underbalanced drilling, a length of tubing that is strapped to the outside of a casing string and is used to minimize or prevent an air- or gas-drilled well from heading, or surging. A hole in the casing at the point where the tubing enters the casing allows gas to be injected. Air or gas is injected only through the tubing and not the casing. The injected air or gas lightens the fluid column above the point of injection, which helps prevent surging.

evidence given verbally rather than in writing.

sucker rods that have been broken and separated in a pumping well because of corrosion, improper loading, damaged rods, and so forth.

a thermometer with a specific length of the bulb and stem immersed in the liquid and the scale above the surface for ease of reading.

the pressure exerted by one specific component of a gaseous mixture.

one who owns all or part of the mineral estate and has the executive rights of a mineral estate owner.

1. one of the extremely small subdivisions of matter, as an atom or mole­cule. 2. a small quantity or fragment, as a single crystal or a substance that is made up of vast quantities of crystals.

the number of times the drilling line is passed (reeved) between a rig’s crown block and its traveling block. Typically, a line may have from four to 12 parts. In the case of a four-part line, the line is passed two times between the crown and traveling blocks; a 12-part line is passed six times between the two blocks. The greater the number of parts, the more weight the line is able to support. Also called falls.

the leader of a group of workers; the person in charge of an assembly of persons; his or her job includes defining tasks, assigning a person or persons to accomplish a task, instructing inexperienced personnel, keeping track of time spent on a job, and seeing to it that the work is done in a timely and economical manner.

the SI metric unit of measurement for pressure and stress and a component in the measurement of viscosity. A pascal is equal to a force of 1 newton acting on an area of 1 square metre.

the process of rendering a metal surface chemically inactive, either by electrochemical polarization or by contact with passivating agents.

detects up and down sea movement on the rig and provides a large cushion of air to keep the motion from affecting the drill string.

an area that develops when a growing ocean basin causes continents to drift apart.

a technique that relies on absorption and diffusion and is used to sample Volatile Organic Compounds (VOCs) and Semi Volatile Organic Compounds (SVOCs). Used to enhance contaminant detection sensitivity.

a material used to cover, fill up, or mend a hole or weak spot. A metal piece extending half-way around a pipe and welded to it is a half-sole patch. Two half-sole patches make a full-sole patch.

see casing-patch tool.

in the case of land, an instrument by means of which a government transfers a fee simple estate to another party.

notches or slots machined into the table part of a rotary table assembly into which a bar on the rotary table assembly’s locking device fits to keep the table from turning. See rotary locking device, rotary table assembly.

see pay sand.

see pay sand.

the producing formation, often one that is not even sandstone. Also called pay, pay zone, and producing zone.

see production casing.

an expression of the vertical height of the formation yielding hydrocarbons in commercial amounts.

see pay sand.

see commercial quantity.

the load carried by a ship or floating offshore rig exclusive of that which is needed for its operation.

1. the point at which the operator of a well has recovered the costs of drilling, completing, and operating the well and can begin to show a profit. 2. (nautical) to extend the mooring lines.

lead.

polished bore receptacle.

polychlorinated biphenyl.

permanent chain chaser.

pounds per cubic foot.

progressing cavity pumps.

positive-displacement meter. It measures the single-phase volume of gas or fluid by filling and emptying chambers of a specific volume.

polycrystalline diamond compact.

a special type of diamond drilling bit that does not use roller cones. Instead, polycrystalline diamond inserts are embedded into a matrix on the bit. PDC bits are often used to drill very hard, abrasive formations, but also find use in drilling medium and soft formations.

perforating depth control log.

paraffin-deposition interval.

Petróleos de Venezuela S.A.

see peak reverse voltage.

the highest load imposed on the polished rod throughout a complete sucker rod pump cycle.

the maximum instantaneous anode-to-cathode voltage in the reverse direction that is applied to a diode in an operating circuit.

the instantaneous increase (peak) in voltage that occurs when voltage flows in an alternating current (AC) circuit. In an AC circuit, the voltage not only reverses direction, but also increases for a moment (peaks) at the point when it reverses direction.

chain connecting link used to connect different chain sizes together. It has a larger jaw or opening at one end.

a holiday detector that checks for coating defects as well as for any metal debris near a buried pipeline. See holiday.

an organic material that forms by the partial decomposition and disintegration of vegetation in tropical swamps and other wet, humid areas. It is believed to be the precursor of coal.

(slang) a field geologist’s (or rock hound’s) assistant.

relatively large stationary crane mounted on an offshore unit.

a wedge or spherical-shaped end of a hammer head, which is usually opposite a flat face on the head. v: to enlarge, straighten, or smooth with a peen.

permanent distortion in the outer wires of a wire rope, often caused by the wire rope’s pounding against a sheave or a machine member, or by heavy operating pressure between the wire rope and a sheave, the wire rope and a drum, or the wire rope and an adjacent wrap of rope.

an analog model of three dimensions used to study the structure and stratigraphy of a subsurface area. It is made by placing pegs of varying heights into a flat platform to represent the structural contours of strata.

permissible exposure limit.

(nautical) a wire rope attached to an anchor and sometimes to the anchor chain and used to pull and lower the anchor. The ends of the pendant not on the anchor are attached to buoys on the surface of the water.

see guy rope.

buoy used to suspend an anchor pendant.

a bottomhole assembly composed of a bit and several large-diameter drill collars and stabilizers placed to allow the bottom drill collar to bend toward the vertical. The assembly works on the principle of the pendulum effect and is used to decrease drift angle. See pendulum effect.

the tendency of the drill stem—bit, drill collars, drill pipe, and kelly—to hang in a vertical position due to the force of gravity.

see rate of penetration.

a geologic time period in the Paleozoic era, from 320 to 280 million years ago. Also, the latter part of the Carboniferous period. It was named for the outcrops of coal in Pennsylvania.

a liquid hydrocarbon of the paraffin series, C5H12.

a hydrocarbon mixture consisting mostly of normal pentane (C5H12) and heavier components that are extracted from natural gas.

increased dispersion of solids in a liquid caused by the addition of electrolytes or other chemical substances. See deflocculation, dispersion.

a clay to which an agent has been added to increase its initial yield.

permeability; used in drilling reports.

a chart for reading differential and static pressures. Its readings reflect a percentage of full scale from 0 to 100 for both static and differential pressure. Readings must be converted, but can be used on any flow recorder, regardless of range.

a gas sales contract under which the buyer processes the gas for recovery of liquid products (ethane and heavier hydrocarbons) and sells the residue under a buyer’s contract with the pipelines.

a switch that turns a motor on for a set percentage of the revolution of a cam and off for the remainder of the revolution.

the tendency for gas to rise in the drilling mud in the annulus, even when the well is shut in and circulation is stopped. It occurs because gas is light in density.

1. cable-tool drilling. 2. rotary drilling in which a special tool called a hammer drill is used in combination with a roller cone bit.

see hammer drill.

perforated; used in drilling reports.

see ideal gas.

to pierce the casing wall and cement of a wellbore to provide holes through which formation fluids may enter or to provide holes in the casing so that materials may be introduced into the annulus between the casing and the wall of the borehole. Perforating is accomplished by lowering into the well a perforating gun, or perforator, which fires electrically detonated bullets or shaped charges. See bullet perforator, jet-perforate, perforating gun.

to perforate the well with a column of fluid in the wellbore, which exerts less pressure on bottom than the formation does, to cause formation fluids to flow into the wellbore immediately after the casing is perforated. The method is also called reverse-pressure perforating. Its purpose is to force debris in the perforation to flow into the wellbore and not restrict flow within the perforation.

1. a well completion method in which the producing zone or zones are cased through, cemented, and perforated to allow fluid flow into the wellbore. Perforations are usually made with bullet- or jet-perforating guns. See perforating gun, perforations. 2. a well completed by this method.

a liner that has had holes shot in it by a perforating gun. See liner.

sections of pipe (such as casing, liner, and tail pipe) in which holes or slots have been cut before it is set.

a ported, extended production tube used as an alternative path for wireline measuring devices.

a device fitted with shaped charges or bullets that is lowered to the desired depth in a well and fired to create penetrating holes in casing, cement, and formation. See perforation.

see perforation.

a special vehicle designed to allow control of a perforating operation within it.

a hole made in the casing, cement, and formation through which formation fluids enter a wellbore. Usually several perforations are made at a time. See perforating gun.

a special type of nuclear log that measures the depth of each casing collar. Knowing the depth of the collars makes it easy to determine the exact depth of the formation to be perforated by correlating casing-collar depth with formation depth.

a device utilizing rubber cups run on the tubing string and used to wash, with water, the perforations of wells completed in unconsolidated sands.

see perforating gun.

see accuracy curve of a volume meter.

perforations in casing for the inflow of hydrocarbons and gas.

the time required for the bow or the stern of a floating offshore drilling rig to start at its lowest position, rise with a wave, and return to its lowest position.

the time required for a floating offshore drilling rig to roll from one side to the other and back.

a volcanic rock that can be extended to many times its original volume by crushing and heating under pressure. Release of the pressure causes expansion when the water in the rock turns to steam. It is used as an extender in cement.

perennially frozen subsoil.

a device that is located around the mooring wire and/or chain that is used to deploy and recover a mooring leg.

a well completion in which production, workover, and recompletion operations can be performed without removing the wellhead.

a structure attached to and installed with the foundation pile when a well is drilled from an offshore floating drilling rig. It is seated in the temporary guide base and serves as a wellhead housing. Guidelines are attached to it so that equipment, such as the blowout preventers, may be guided into place on the wellhead.

a magnet usually made of hardened steel that is strongly magnetized and retains its magnetism after the removal of the magnetizing force.

a nonretrievable type of packer that is very reliable but must be drilled or milled out for removal. Most permanent packers are seal-bore packers or wireline-set packers.

1. a measure of the ease with which a fluid flows through the connecting pore spaces of rock or cement. The unit of measurement is the millidarcy. 2. fluid conductivity of a porous medium. 3. ability of a fluid to flow within the interconnected pore network of a porous medium. See absolute permeability, effective permeability, relative permeability. 4. on offshore drilling rigs, the percentage of a given space in a vessel that can be occupied by water. 5. the property of a magnetizable substance that determines the degree to which it modifies the magnetic lines of force (the flux) in the region occupied by the substance in a magnetic field; specifically, it is the ratio of the induction to the magnetizing force in the substance.

a hindrance to movement of fluids within the formation rock of a reservoir. Permeability barriers include obvious problems, such as shale lenses and calcite or clay deposits, and less obvious ones, such as porosity changes.

allowing the passage of fluid. See permeability.

a porous rock formation in which the individual pore spaces are connected, allowing fluids to flow through the formation.

a device used to determine the permeability of a core sample by forcing dry air through the sample at the flow rate determined by the pressure differential across the sample. The inlet air pressure and the air flow rate are recorded and, with the dimensions of the sample, are used to calculate permeability.

the chamber in a reverse osmosis watermaker where reverse osmosis takes place.

a prolific oil- and gas-producing area in West Texas and eastern New Mexico. So called because many of the rocks from which the oil and gas are withdrawn are of Permian age.

the last geologic time period in the Paleozoic era, 280 million to 225 million years ago.

the concentration of toxic gas to which it is believed all workers may be repeatedly exposed without adverse effects. Set by the American Conference of Governmental and Industrial Hygienists.

in a solid-state diode, a measure of the diode’s ability to handle heat that is generated by voltage and current that occurs where the diode is connected, or joined, to a circuit.

the durability or longevity of inhibitors used in corrosion control.

in relation to the craft/barge/structure, includes the captain or any other person made responsible by the owner for the vessel or facility, its operation, and the safety, health, and welfare of those on board.

equipment worn by workers to protect themselves from chemical or substance hazards while working.

a net attached to a floatable ring on which personnel ride when being transferred from boat to rig on offshore locations. It is usually rigged to a crane.

see personnel basket.

a small valve or faucet for letting out air or for draining liquids.

a chemical manufactured from petroleum and natural gas or from raw materials derived from petroleum and natural gas.

(British) gasoline.

the state-owned oil company of Venezuela.

a substance occurring naturally in the earth in solid, liquid, or gaseous state and composed mainly of mixtures of chemical compounds of carbon and hydrogen, with or without other nonmetallic elements such as sulfur, oxygen, and nitrogen. The compounds that compose it might be in the gaseous, liquid, or solid state, depending on their nature and the existent conditions of temperature and pressure. In some cases, especially in the measurement of oil and gas, petroleum refers only to oil—a liquid hydrocarbon—and does not include natural gas or gas liquids such as propane and butane. The API Measurement Coordination Department prefers that petroleum mean crude oil and not natural gas or gas liquids.

one who searches for oil and gas reservoirs, usually employing seismic techniques.

the study of oil- and gas-bearing rock formations. It deals with the origin, occurrence, movement, and accumulation of hydrocarbon fuels.

an industry-controlled and industry-operated training organization maintained specifically to assist Canadian companies with their training. Address: 1538 25th Avenue NE; Calgary, Alberta T2E 8Y3, Canada; 403-250-9606.

an estimate of the amount of recoverable oil and gas a reservoir or reservoirs may contain. Often, the term refers to the amount of recoverable oil and gas a country or, sometimes, the world has that exists in petroleum reservoirs.

a rock formation that holds oil and gas.

sandstone, limestone, dolomite, fractured shale, and other porous rock formations where accumulations of oil and gas may be found.

the conditions of temperature and pressure under which petroleum will form. Also called oil window.

containing petroleum (said of rocks).

a branch of geology dealing with the origin, occurrence, structure, and history of rocks, principally igneous and metamorphic rocks. Compare lithology.

the assessment (evaluation) of reservoir rock properties by analyzing well logs, cores, seismic sections, and combining them with geology and geophysics to understand the reservoir.

professionals in the oil and gas industry who are typically employed in helping engineers and other geoscientists understand the rock properties of reservoirs.

the study of the physical and chemical properties that describe the occurrence and behavior of rocks, soils, and fluids. In the oil industry, petrophysics mainly involves the study of oil and gas reservoirs in order to understand the properties of the rock making up a reservoir.

power factor.

manufacturer’s abbreviation for picofarad; sometimes imprinted on the body of a capacitor.

an indicator of the acidity or alkalinity of a substance or solution, represented on a scale of 0–14, 0–6.9 being acidic, 7 being neither acidic nor basic (i.e., neutral), and 7.1–14 being basic. These values are based on hydrogen ion content and activity.

a chemical added to the drilling fluid to control or increase the pH of the mud. Normally, the mud should have a pH higher than seven so that it is alkaline.

see pH value.

a unit of measure of the acid or alkaline condition of a substance. A neutral solution (such as pure water) has a pH of 7; acid solutions are less than 7; basic, or alkaline, solutions are more than 7. The pH scale is a logarithmic scale. A substance with a pH of 4 is more than twice as acid as a substance with a pH of 5. Similarly, a substance with a pH of 9 is more than twice as alkaline as a substance with a pH of 8.

1. a portion of a physical system that is liquid, gas, or solid, that is homogeneous throughout, that has definite boundaries, and that can be separated from other phases. The three phases of H2O, for example, are ice (solid), water (liquid), and steam (gas). 2. in physics, the stage or point in a cycle to which a rotation, oscillation, or variation has advanced. 3. in electronics, the part of a period through which the time variable of a periodic quantity, such as alternating current, has moved. Phase is measured at any point in time from an arbitrary time origin. In the waveform of alternating current, where the waveform is sinusoidal in shape and where positive polarity is above a zero line and negative polarity is below the zero line, phase is measured at the last point at which the quantity passed through a zero position from a negative to a positive direction.

the number of electrical degrees between corresponding points on the sine wave of two or more emfs or currents of the same frequency, or between current and voltage in a circuit.

a change in the phase of a periodic quantity, such as the waveform generated by alternating current. See phase.

C6H5OH, a white, crystalline, water-soluble, poisonous mass obtained from coal tar, or a hydroxyl derivative of benzene.

thermosetting plastic materials formed by the condensation of phenols (containing C6H5OH) with aldehydes (containing CHO) and used as protective coatings for oilfield structures.

1. generic term for any compound that contains phosphorous and oxygen in the form of a phosphate, which is chemically abbreviated as PO4. 2. a salt or ester of phosphoric acid.

a rock of biochemical origin, composed largely of calcium phosphate from bird droppings and vertebrate remains.

the absorption of gamma rays that results in ejection of electrons from an atom. Photoelectric effect occurs when light of sufficient energy falls on an atom and causes it to lose electrons. The energy of the light actually tears electrons away from the atoms of a substance.

the practice of examining aerial and satellite photography of the earth to identify and assess the significance of surface features.

a device used to determine the angle and direction by which a wellbore deviates from the vertical. After the instrument is run into the hole, it takes a photograph that is then brought to the surface, developed, and analyzed. Photographic survey instruments can be single-shot or multishot and magnetic or gyroscopic.

the chemical decomposition of an object or organism brought on by light or other radiant energy.

a quantum, or unit, of electromagnetic radiation energy.

oxidation introduced by sunlight; a very slow process that helps to break down hydrocarbons exposed to sunlight into other components and, eventually, into carbon dioxide and water.

a process by which chlorophyll-bearing plants produce simple sugars from carbon dioxide and water using the energy of sunlight.

capable of producing electricity when exposed to light or other radiant energy.

a device that detects or measures electromagnetic radiation by generating voltage (potential) at the junction between two types of material when radiant energy (as from the sun or other light source) strikes it.

a special solid-state diode to which has been added a special impurity that causes the diode to produce voltage when exposed to bright light, such as the sun.

the building (manufacturing) of materials that are capable of producing voltage (electricity) when exposed to radiant energy, especially light.

in removing contaminants, acid gases physically dissolve in the liquid absorbent, and the natural gas does not.

(OSHA) a chemical for which there is scientifically valid evidence that it is a combustible liquid, a compressed gas, explosive, flammable, an organic peroxide, an oxidizer, pyrophoric, unstable (reactive), or water reactive.

initial pressure; used in engineering reports.

see LC filter.

see productivity index curve.

person in charge.

1. to use the drawworks to lift the bit (or other tool) off bottom by raising the drill stem. 2. to use an air hoist to lift a tool, a joint of drill pipe, or other piece of equipment.

a cylindrical or spherical device that is affixed to the end of a wireline just above the hook to keep the line straight and to provide weight. v: to soak metal pieces in a chemical solution to remove dirt and scale from the metal’s surface.

see transmitter.

a device for converting meter rotor movement into an electrical output signal.

the point at which the floor crew of a drilling rig can latch the elevators around the pipe when it is coming out of the hole.

a boom that lifts pipe from a horizontal position at the V-door and tilts it to vertical and moves it over the mousehole or well center.

1 trillionth (10–12) of a farad. See farad.

proportional, integral, and derivative.

a module that accepts an input reference signal from within a PLC that establishes the desired operating point, compares it to a sensor from the process, and then produces an output signal from the same module to control an output device such as an actuator or proportional valve.

a method of control that utilizes proportional, integral, and derivative techniques to maximize performance and response of the process.

see diapir.

a crystal that generates electrical current as a result of the application of mechanical stress.

a substance or device that converts mechanical stress, such as pressure, into electricity. A microphone is a piezoelectric transducer.

electricity or electric polarity created by pressure in a crystalline substance, such as quartz.

a device that converts pressure into an electrical signal through the piezoelectric crystal principle. See piezoelectricity.

1. a scraping tool that is forced through a pipeline or flow line to clean out accumulations of wax, scale, and debris from the walls of the pipe. It travels with the flow of product in the line, cleaning the pipe walls by means of blades or brushes affixed to it. Also called a line scraper or a go-devil. 2. a batching cylinder with neoprene or plastic cups on either end and used to separate different products traveling in the same pipeline. 3. a neoprene displacement spheroid, automatically launched and received, used to displace liquid hydrocarbons from natural gas pipelines. 4. in hydrostatic testing of a pipeline, a scraper used inside the line to push air out ahead of the test water and to push water out after the test.

(slang) a piece of oilfield equipment made of iron or steel.

an arrangement of pipes that allows pigs to be removed from a pipeline without stopping flow. See pig.

the trip of a pig through a pipeline.

a system used to periodically remove the accumulation of liquids at low spots in the pipeline for pipeline cleaning or inspections.

to force a device called a pig through a pipeline or a flow line for the purpose of cleaning the interior walls of the pipe, separating different products, or displacing fluids. See pig.

(nautical) to install anchors behind each other in tandem on the same mooring line.

in paints, a substance, generally in fine powder form, which is practically insoluble in the paint’s base and which is dispersed in the binder to impart specific physical and chemical properties, such as optical, protective, and decorative.

in the brush holder of a generator, a device composed of several braided copper wires that conduct electricity from a generator’s brush to the generator’s wiring.

on an electronic component, such as a composition resistor, a single wire (a lead) that exits the component from either end and to which the electrical connection to a circuit is made.

a gelled viscous fluid placed at a specific depth in the well, usually to overcome or minimize a problem at that depth. For example, a special bentonite pill may be spotted (placed) at or near a formation to which drilling fluid is being lost. The pill may seal the formation and reduce or stop the lost circulation problem.

a rodlike or tubelike extension below a downhole tool, such as a mill, that serves to guide the tool into or over another downhole tool or fish.

in meteorology, a small balloon whose ascent is followed by a special optical instrument (a theodolite) that measures horizontal and vertical angles in order to obtain data for the computation of the speed and direction of upper level winds. See theodolite.

a bit placed on a special device called a hole opener that serves to guide the device into an already existing hole that is to be opened (made larger in diameter). The pilot bit merely guides, or pilots, the cutters on the hole opener into the existing hole so that the hole-opening cutters can enlarge the hole to the desired size.

in marine navigation, a special map of given offshore areas that contains information about safe routes, ocean currents, winds, sea ice, storm tracks, and the like. Ships and mobile offshore drilling units use pilot charts when moving from one offshore location to another.

in pipeline construction, the hole drilled as the first step of a directionally drilled river crossing. It establishes a pathway for the pipeline.

a device on a floating offshore drilling rig’s accumulator that receives regulated pressure of 2,000 psi (14,000 kPa) and that contains several G-in. (6.35-mm) pilot control valves. The control valves send a pilot signal to the subsea control pods to operate the subsea blowout preventers.

a special mill that has a heavy tubular extension below it called a pilot or stinger. The pilot, smaller in diameter than the mill, is designed to go inside drill pipe or tubing that is lost in the hole. It guides the mill to the top of the pipe and centers it, thus preventing the mill from by-passing the pipe. Also called a piloted mill.

the machined extension on the very end of the bearing pin that fits into the nose of the cone of a roller cone bit.

a special valve (a regulator) on a floating rig’s accumulator that sends variable pressure pilot signals, from 0 to 3,000 psi (21,000 kPa), to regulators mounted on the subsea control pod. A pilot regulator is pneumatically operated and has a 30 to 1 ratio, which means that the hydraulic output pressure is 30 times the air pilot signal.

the recorded observations of aircraft pilots and crewmembers of such phenomena as icing, turbulence, and weather and sky conditions. The National Oceanographic and Atmospheric Administration (NOAA) distributes the reports on http://adds.aviationweather.noaa.gov/pireps. They update the reports every two hours and keep data for six hours.

joints of small-diameter pipe attached to the drill assembly and used to bore a pilot hole when laying pipe. After the route has been established, the pilot string is replaced by the work string.

a method of predicting behavior of mud or cement systems by mixing small quantities of mud and mud additives or cement and cement additives and then testing the results.

see pilot mill.

1. the male threaded section of a tool joint. 2. on a bit, the threaded bit shank. 3. one of the pegs that is fitted on each side into the link plates (side bars) of a chain link of roller chain and that serve as the stable members onto which bushings are press-fitted and around which rollers move. See wrist pin.

see journal angle.

in floating offshore drilling operations, a tool that connects the marine riser to the subsea casinghead on the seafloor.

in roller chain, about 5⁄16  of the pitch. See pitch.

a link of roller chain consisting of four parts—two side bars and two pins. The pins are press-fitted into the side bars (pin link plates).

in roller chain, the plate into which the pin link pins ends are immovably fixed. The pins are riveted to the link plate on one side and either riveted or fixed with cotters to the other pin link plate.

a packer in which the packing element is held in position by brass or steel pins. When weight is put on the packer, two metal sleeves telescope, shearing the pins and allowing the element to fold and pack off.

a short, threaded device made up on the bottom of drill pipe or tubing and used to screw into the box of a stand of drill pipe or drill collars lost in the hole. Once the pin tap is engaged, the lost pipe can be retrieved.

a master bushing that has four drive holes corresponding to the four pins on the bottom of the pin-drive kelly bushing.

a steel lever with a pointed projection at one end; it is used to lift a heavy load.

to decrease the size of the opening of an adjustable choke when a kick is being circulated out of a well.

to end or terminate by a narrowing and tapering off. When a formation pinches out, it narrows and tapers off.

an oil-bearing stratum that forms a trap for oil and gas by narrowing and tapering off within an impervious formation.

a roller cone bit on which the legs of the bit have been forced inward by a great force, such as that caused by jamming the bit into undergauge hole.

a sound-emitting device that is used to detect an underwater site or object.

tiny holes in a dry paint film that form during the application and drying of paint.

1. a gear with a small number of teeth designed to mesh with a larger wheel or rack. 2. the smaller of a pair or the smallest of a train of gear wheels.

a long, hollow cylinder, usually steel, through which fluids are conducted. Oilfield tubular goods are casing (including liners), drill pipe, tubing, or line pipe.

the process of bending joints so that a pipeline will conform to the topography of a right-of-way. Pipe bends are made by the cold-work process.

a special material that coats pipe for pipelines and prevents water from coming into contact with the steel of the pipe. The most widely used types of pipe coatings are bituminous enamels, epoxy resins, and tapes.

any device equipped with rollers and used to move drill pipe or collars. It is usually placed under one end of the pipe while the pipe is being lifted from the other end by an air hoist line.

see dope.

an auxiliary part (such as a coupling, elbow, tee, or cross) used for connecting lengths of pipe.

in pipeline construction, the workers responsible for positioning the pipe, aligning it, and making the initial welds. The pipe gang sets the pace that determines the progress of the rest of the spread.

in a top drive, the power and spinning wrenches built into the unit that spins, makes up, breaks out, and backs up the pipe. See top drive.

1. a circular device with a frictional gripping arrangement used to suspend casing and tubing in a well. 2. a device used to support a pipeline.

in underbalanced drilling, the condition in which the weight of the drill stem in the wellbore is great enough to overcome well pressure from below. In a pipe heavy situation, the pipe can be stripped into or out of the hole because well pressure is not great enough to force it out of the hole.

a hand tool used to lift and move a stand of pipe that is set back in the derrick. It has a handle on one end and two semicircular pieces on the other end that are designed to fit under the shoulder of a joint of pipe and avoid damage as the pipe is lifted with the tool.

in underbalanced drilling, the condition in which the weight of the drill stem in the wellbore is not great enough to overcome well pressure from below. In a pipe light situation, the pipe must be snubbed into or out of the hole against pressure in the wellbore.

a national trade organization of American pipeline contractors. Address: 1700 Pacific Ave., Suite 4100; Dallas, TX 75201-4675; 214-969-2700.

a device used in leakage surveys to locate affected pipe. It sends out radio signals underground and traces the signal the length of the pipe. Works for both steel and plastic pipe, as plastic pipe has a metal wire running its entire length.

prevents drill pipe from rubbing against the hole or against the casing.

1. an accurately calibrated, usually U-shaped, pipe used to check, or prove, the accuracy of a meter on a lact unit or other oil measuring installation. 2. a type of continuous-flow volumetric prover comprising a length of pipe from which a known volume is displaced by a displacer to or from a meter being proved at normal operating conditions.

a horizontal support for tubular goods.

1. (obsolete) a worker who places pipe to one side in the derrick. 2. a pneumatic or hydraulic device often used on drill ships that, on command from an operator, either picks up pipe from a rack and lifts it into the derrick or takes pipe from out of the derrick and places it on the rack. It eliminates the need to stand pipe in the derrick or mast while it is out of the hole, which is desirable for maintaining the vessel’s center of gravity as low as possible and for minimizing the possibility of capsizing.

a sealing component for a blowout preventer that closes the annular space between the pipe and the blowout preventer or wellhead. See annular space, blowout preventer.

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

a clamp used to make a temporary repair of a leak in a pipeline.

a fitting made in parts to clamp onto a pipe to stop a leak or to provide an outlet.

see spinning wrench.

the number of pieces of pipe used in the construction of a well.

in an orifice meter installation, the threaded hole into which is screwed a small pipe to connect the orifice fitting to the flow recorder. Two taps are usually employed: the upstream tap center is located two and one-half times the published inside pipe diameter upstream of the nearest plate face; the downstream tap center is located eight times the published inside pipe diameter downstream of the nearest plate face. See orifice-flange tap, orifice meter.

a braking device used on a lay barge to control the descent rate of the pipe. Tensioners also support the entire submerged weight of the pipe as it approaches the bottom.

see tongs.

that part of the pipe that has an abrupt increase of dimension.

a flexible disk-shaped device, usually made of rubber, with a hole in the center through which drill pipe or tubing passes. It is used to wipe off mud, oil, or other liquid from the pipe as it is pulled from the hole.

material applied on top of pipeline coating to protect the coating from damage. Materials used for wrapping include felt, fiberglass, fiberglass-reinforced felt, and kraft paper.

in pipeline construction, a track-mounted hydraulic machine that bends a joint to the precise angle specified by the bending engineer. The bend is made by a set of clamps that grip the outside surface of the pipe and prevent slippage while a winch cable hooked to the free end of the pipe maintains upward pull and guides the pipe through the machine.

mechanized devices used to rack pipe.

extensions within a pipe rack for keeping individual pipes separated.

see bury barge.

a vessel that can be positioned and held in place by either anchors or a dynamic positioning system. Pipe segments are loaded on the barge either by joint or on a spool. If the pipe is loaded on by joint, the pipe is welded together and travels down the side of the barge in an assembly-line process.

a system of connected lengths of pipe, usually buried in the earth or laid on the seafloor, that is used for transporting petroleum, petroleum products, chemicals, and natural gas. A pipeline serves as both a conveyor and a temporary container.

a collection of flow lines, umbilical cables, and other devices accompanying a pipeline that are packaged inside an external carrier, which can also be filled with an insulating material.

the outlet from a well or a tank by which oil or gas is transferred to a pipeline for transportation away from the field.

the person who communicates with other points on the pipeline system. Using a computer console, the dispatcher controls pumping stations hundreds of miles (kilometres) away. Sometimes called a line operator or oil movement controller.

gas that meets the minimum specifications of a transmission company.

an employee of a pipeline company who measures the quantity and quality of crude oil in a tank before the oil is pumped into a pipeline.

a design that provides an integrated natural gas delivery system to the consumer.

a crude oil whose S&W content is low enough to make the oil acceptable for pipeline shipment.

the volume of gas in a pipeline.

a watch, usually maintained from an airplane, to check the route of a pipeline for leaks or other abnormal conditions.

see mainline plant.

the person who slates a shipment to leave a certain point of origin on a set date and to be delivered to a destination point on a set date.

a system that transitions the pipe safely from the barge deck to the seabed without bending the pipe beyond its limits or otherwise adversely affecting the integrity of the pipe.

the process of proving the structural soundness of an installed pipeline and its capability to fulfill safely the function for which it was designed. The most common testing method is hydrostatic testing.

a gauge that measures inferential pressure and is concerned with certain electrical effects that are observed in an environment of rarefied air or other gas. The gauge consists of a battery, ammeter, and a pressure-controlled glass bulb containing a quantity of resistance wire whose resistance is a function of temperature. Current flowing in the resistance element causes it to heat up, thus changing its resistance.

pilot reports.

a cylindrical sliding piece that is moved by or that moves against fluid pressure within a confining cylindrical vessel.

the metal body of a piston over which the piston rubber fits.

see crown.

the actual volume displaced by a piston in a cylinder as it moves from the beginning of the compression stroke to the end of it.

see reciprocating engine.

a pin that forms a flexible link between the piston and the connecting rod. This bearing area has the highest load per square inch (square millimetre) of any in an engine, perhaps as high as 50,000 pounds per square inch (345 megapascals). Also called a wrist pin.

a yielding ring, usually metal, that surrounds a piston and maintains a tight fit inside a cylinder.

1. a metal shaft that joins the piston to the crankshaft in an engine. 2. a metal shaft in a mud pump, one end of which is connected to the piston and the other to the pony rod.

the flexible rubber or synthetic sealing element of a piston.

the length of movement, in inches (millimetres), of the piston of an engine from top dead center (TDC) to bottom dead center (BDC).

1. a temporary containment, usually excavated earth, for wellbore fluids. 2. a mud tank. 3. a reserve pit.

an increase in the average level of mud maintained in each of the mud pits, or tanks. If no mud or other substances have been added to the mud circulating in the well, then a pit gain is an indication that formation fluids have entered the well and that a kick has occurred.

height of drilling mud in the mud tanks, or pits.

trade name for a type of pit-level indicator. See pit-level indicator.

on offshore drilling rigs, the derrickhand or an assistant who monitors the mud tanks and drilling mud properties, mixes mud, and transfers mud from one tank to another.

one of a series of devices that continuously monitor the level of the drilling mud in the mud tanks. The indicator usually consists of float devices in the mud tanks that sense the mud level and transmit data to a recording and alarm device (a pit-volume recorder) mounted near the driller’s position on the rig floor. If the mud level drops too low or rises too high, the alarm sounds to warn the driller of lost circulation or to prevent a blowout.

see pit-level indicator.

the gauge at the driller’s position that records data from the pit-level indicator.

1. in wireline spooling, the degree of slope that the wireline travels in going from one wrap to the next. 2. in roller chain, the distance (in inches or millimetres) between the centers of two members next to one another, i.e., the distance between the centers of the bushings or rollers. 3. on offshore floating rigs, the up-and-down movement of the hull from the bow to the stern.

root diameter of drum, lagging, or sheave, plus the diameter of the rope.

the arm that connects the crank to the walking beam on a pumping unit by means of which rotary motion is converted to reciprocating motion.

an open-ended tube arranged to face the current of a stream of fluid. It is used in measuring the velocity of a flowing medium.

a meter that uses a Pitot tube and a manometer or other differential-pressure mechanism to measure flowing fluids. The difference between the pressure on the Pitot tube and the static pressure is the velocity of the flow, which is directly related to the rate of flow.

the basic and smallest part of the composition of an image on a television screen, computer monitor, or similar cathode-ray tube.

pink; used in drilling reports.

packer; used in drilling reports.

pipeline; used in drilling reports.

a common rock-forming mineral varying in composition from sodium aluminum silicate (NaAlSi3O8) to calcium aluminum silicate (CaAl2Si2O8).

see journal bearing.

a view of a well plan showing the proposed wellbore from above, with true north (geographic, not magnetic) at the top of the page.

an instrument for measuring the area of a plane figure. As the point on a tracing arm is passed along the outline of a figure, a graduated wheel and disk indicate the area encompassed.

light hydrocarbons lost to the atmosphere in a gas plant.

see tail gate.

a phenomenon in which a decrease in the diameter of the borehole occurs because a plastic substance, such as salt, is being drilled. Since the temperature of the salt is higher than normal for a given depth (high temperature causes the salt to expand) and since mud weight is usually decreased when drilling such formations to maintain high penetration rates (thus decreasing the hydrostatic pressure exerted on the salt), the section of borehole in the salt zone can expand and possibly stick the drill stem. Also called salt squeeze.

see plastic fluid.

a complex, nonNewtonian fluid in which the shear force is not proportional to the shear rate. Most drilling muds are plastic fluids.

the procedure by which a quantity of resinous material is squeezed into a sandy formation to consolidate the sand and to prevent its flowing into the well. The resinous material is hardened by the addition of special chemicals, which creates a porous mass that permits oil to flow into the well but holds back the sand at the same time. See sand consolidation.

an absolute flow property indicating the flow resistance of certain types of fluids. It is a measure of shearing stress.

the ability of a substance to retain a shape that it has attained after being deformed. Compare elasticity.

chemical added, especially to rubbers and resins, to impart flexibility, workability, and stretchability.

a map of a particular tract, group of tracts, or area of land.

a type of friction clutch that has metal plates that may or may not have a friction material on them and an air-operated diaphragm that presses the plates together. Springs push the plates apart when the clutch is disengaged. Compare drum clutch.

a device that creates a non-leaking union between orifice plate and fitting; keeps gas from leaking around the plate.

movement of great crustal plates of the earth on slow currents in the plastic mantle, similar to the movement of boxes on a conveyor belt. Today geologists believe that the earth’s crust is divided into six major plates and several smaller ones atop some of which the continents are carried away from a system of midocean ridges and toward another system of deep-sea trenches. The theory of plate tectonics explains most of the mysteries that confounded earlier geologists. Compare continental drift.

see platform rig.

a support that is firmly secured to the ocean floor and to which the legs of a platform are anchored.

an immobile offshore structure from which development wells are drilled and produced. Platform rigs may be built of steel or concrete and may be rigid or compliant. Rigid platform rigs, which rest on the seafloor, are the caisson-type platform, the concrete gravity platform, and the steel-jacket platform. Compliant platform rigs, which are used in deeper waters and yield to water and wind movements, are the guyed-tower platform, the tension-leg platform, and the compliant piled tower platform.

1. the extent of a petroleum-bearing formation. 2. the activities associated with petroleum development in an area.

the flat bottom of an undrained desert basin that at times becomes a shallow lake. Also called sebkha or sabkha.

programmable logic controller.

Pipe Line Contractors Association.

1. of or relating to the geologic epoch from about 2.5 million to 10 thousand years ago, the first part of the Quaternary period of the Cenozoic era, sometimes called the Ice Age, which extended from the end of the Tertiary period until the last retreat of the northern continental ice sheets. 2. of or relating to the rocks or sediments formed during this epoch.

an enclosure in which air or other gas is at a pressure higher than that outside the enclosure.

a mark placed on the side of a floating offshore drilling rig or ship to denote the maximum depth to which it may be loaded or ballasted. The line is set in accordance with local and international rules for safety of life at sea (SOLAS).

high-quality, high-strength steel used to make the wire for wire rope.

any object or device that blocks a hole or passageway (such as a cement plug in a borehole), or the movable part of a valve used to block or restrict the passageway of fluids in the valve.

to place cement plugs into a dry hole and abandon it.

to place cement in or near the bottom of a well to exclude bottom water, to sidetrack, or to produce from a formation higher in the well. Plugging back can also be accomplished with a mechanical plug set by wireline, tubing, or drill pipe.

1. a device used to plug the tubing at some point along the string. A plug choke may be set to test for packer leakage, to stop production when wellhead equipment must be removed, to test for tubing corrosion or other damage, or to separate zones for production or stimulation treatments. 2. a type of well-control choke in which hydraulic pressure moves a cylinder, the plug, into an upset in a 2-in. pipe. The choking plug is on the end of a rod controlled by a pressure balance diaphragm. On various models, the plug may not be pressure tight when closed but generally retracts to a full-open position. Failure of the operating mechanism generally leaves the choke fully open.

see cementing head.

a fluid moving as a unit in which all shear stress occurs at the pipe wall and hole wall. The stream thus assumes the shape of several telescopic layers of fluid with lowest velocities near the pipe and hole walls and the fastest in the middle.

a tool used with a mill to retrieve the milled debris.

a geologic configuration in which an intrusive body of rock has penetrated and deformed one or more surrounding rock layers in such a way that conditions exist for hydrocarbons to accumulate.

see valve.

a secondary-cementing operation in which a plug of cement is positioned at a specific point in the well and allowed to set. Compare squeeze cementing.

a substance used to block off zones temporarily or permanently while treating or working on other portions of the well.

see plumb line.

a string from which a weight (a plumb bob) is suspended and which is used to indicate vertical direction.

1. a basic component of the sucker rod pump that serves to draw well fluids into the pump. See sucker rod pump. 2. the rod that serves as a piston in a reciprocating pump. 3. the device in a fuel-injection unit that regulates the amount of fuel pumped on each stroke.

a method of artificial lift that utilizes a plunger that travels up and down inside the tubing. Internally, the plunger contains a bypass valve that is opened when it hits the top of the tubing and closed when it hits the bottom. The plunger’s fit with the tubing reduces liquid slippage back through the well fluid and the gas that is propelling it. Plunger lift is used in less than 1 percent of all artificially produced wells. It is particularly applicable, however, in high gas-liquid ratio oilwells or in gas wells with low bottomhole pressure and low productivity.

an increase in the effective stroke length of the plunger of a sucker rod pump caused by the elongation of the rod string due to the dynamic loads imposed by the pumping cycle.

a fold of rock whose long axis is not horizontal.

see noninverting input.

a large subterranean body of igneous rock.

the phenolphthalein alkalinity of the mud reported as the number of millilitres of 0.02 Normal (n/50) acid required per millilitre of mud. Pm, like Pf, is a measure of the alkalinity of drilling muds. Usually, muds require high pH values (alkalinity) to perform well.

operated by air pressure.

a control valve that is actuated by air. Several pneumatic controls are used on drilling rigs to actuate and control rig components (such as clutches, hoists, engines, and pumps).

any hose or line, usually reinforced with steel, that conducts air from an air source (such as a compressor) to a component that is actuated by air (such as a clutch).

a reciprocal pumping unit in which one or more power cylinders are placed over the wellhead and a counterbalance system using compressed air or gas is provided. On the upstroke, high-pressure gas is applied to the underside of the pistons of the inside power cylinders, and low-pressure gas above the pistons is exhausted to the sales line. On the down-stroke, high-pressure gas is applied to the top of the pistons, and the low-pressure gas below the pistons is exhausted to the sales line.

a system that can detect fires in open spaces, consisting of a length of flexible plastic or metal tubing that forms a loop around the outside of the structure it protects.

a depth measuring device consisting of an open-end hose fixed to the diver, with the surface end connected to a gas supply and pressure gauge (usually marked in fsw). Gauge measures pressure required to water to displace depth of diver. Also called a kluge or pneumo.

a transistor in which p-type material is placed on each side of n-type material. One side of the p-type material is an emitter and the other side is a collector. The n-type material is sandwiched in between the two p-type materials in the base. The emitter is positive with respect to the base, while the collector is negative with respect to the base.

see hydraulic control pod.

an analytical procedure for hydrocarbon gases and liquids whereby the various components are quantitatively separated by low-temperature distillation for identi­fication and measurement.

in a marine riser system on floating offshore rigs, a device on a retrievable control pod that allows the pod to be remotely connected and disconnected from the lower marine riser package’s baseplate.

a special valve (a regulator) that reduces and maintains (regulates) accumulator supply pressure to a subsea blowout preventer’s normal working pressure. Two pod regulators exist, one designated as the BOP manifold regulator, and one designated as the annular regulator.

on a floating offshore drilling rig using a subsea blowout preventer stack and marine riser system, a control device (a valve) that distributes accumulator fluid from the surface to a selected subsea control pod located on the lower marine riser package.

1. an accumulation of sediment on the inside of a river bend, usually consisting of sand, silt, and clay. 2. a stratigraphic trap for petroleum formed by the burial and lithification of such a sedimentary deposit.

a force that counteracts another force at a single point.

rotary steerable drilling tools that steer the bit by tilting it in the direction of the desired curve. Compare push-the-bit rotary steerables.

1. value that indicates hook load or force, read from a weight indicator; 1 point = 1,000 pounds, or 500 decanewtons. 2. in mud density measurement, the portion of the mud’s weight expressed in decimal points. For example, a mud that weighs 12.2 pounds per gallon (1,461.8 kilograms per cubic metre) weighs two points more than 12 pounds (1,438 kilograms). Also, if a 12.2 pound-per-gallon mud’s density is increased to 12.5 pounds per gallon (1,497.8 kilograms per cubic metre), the density has been raised by 3 points.

the viscosity of a liquid in which a force of 1 dyne (a unit of measurement of small amounts of force) exerted tangentially on a surface of 1 square centimetre of either of two parallel planes 1 centimetre apart will move one plane at the rate of 1 centimetre per second in reference to the other plane, with the space between the two planes filled with the liquid.

when a rod is stretched by applying force at each end of the rod and the force is parallel to the rod’s axis, the ratio of the transverse contracting strain to the elongation strain.

movement that results from structural compression caused by pressure exerted on the ends of the male (pin) portion of a box-and-pin connection.

circumference measured through the north and south poles of a sphere.

a compound (such as water) with a molecule that behaves as a small magnet with a positive charge on one end and a negative charge on the other.

see Antarctic front, Arctic front.

a 300-mile-wide current of wind (a jet stream) that lies at an altitude of 40,000 feet (12,000 metres), and which blows at speeds of 217 knots and faster. Generally, it stays near 40° latitude in the summer months and moves south in the winter months.

a molecule whose atoms are arranged so that all positive and negative share a common orientation within the molecule.

see electrovalent reaction.

the quality of being either negative or positive; in magnetism, the north or south pole of a magnet.

1. either end of an axis through a sphere. 2. either of the regions bordering the extremities of the earth’s rotational axis, which are the North Pole and the South Pole. 3. a magnetic pole. 4. in electricity, either of two oppositely charged terminals, as in an electric cell or battery. 5. a long, slender, and usually cylindrical object, such as fishing pole.

a portable mast constructed of tubular members. A pole mast may be a single pole, usually of two different sizes of pipe telescoped together to be moved or extended and locked to obtain maximum height above a well. Double-pole masts give added strength and stability. See mast.

a device made up in the casing string into which the bottom of the tubing string is placed, or landed.

the topmost por­tion of a string of sucker rods. It is used for lifting fluid by the rod-pumping method. It has a uniform diameter and is smoothly polished to seal pressure effectively in the stuffing box attached to the top of the well.

fastening device for connecting the polished rod to the bridle of a beam pumping unit.

a device that indicates the variation in load on the polished rod as the rod string reciprocates. A continuous record of the result of forces acting along the axis of the polished rod is provided on a dynamometer card, from which the performance of the well-pumping equipment is analyzed.

a state practice of trading the air emissions from new facilities for the reduction or elimination of air emissions from old facilities. Offset emissions are bought from other sources to balance the emissions from the new facility. The object is to improve air quality while allowing for new business. This encourages the use of the best technology at new sites and the retrofitting of old sites to improve air quality.

a polymer whose basic repeating unit, or monomer, is a combination of carbon, hydrogen, oxygen, and nitrogen. Polyacrylamides are used to adjust the viscosity of water slugs during chemical flooding operations. They can also adhere to the walls of rock pores, decreasing the effective permeability of established channels, forcing the injection fluid into new channels, and thus improving sweep efficiency.

a chemical compound used to reduce water loss in muds that are affected by salt contamination.

a family of highly toxic chemical compounds consisting of two benzene rings in which chlorine takes the place of two or more hydrogen atoms; known to cause skin diseases and suspected of causing birth defects and cancer.

a disk (a compact) of very small synthetic diamonds, metal powder, and tungsten carbide powder that are used as cutters on PDC bits. Compare thermally stable polycrystalline diamond bit.

very small synthetic diamonds formed by applying great heat and pressure to carbon.

a thermosetting or thermoplastic material formed by esterification of polybasic organic acids with polyhydric acids.

a substance that consists of large molecules formed from smaller molecules in repeating structural units (monomers). In oilfield operations, various types of polymers are used to thicken drilling mud, fracturing fluid, acid, water, and other liquids. See micellar-polymer flooding, polymer mud. In petroleum refining, heat and pressure are used to polymerize light hydrocarbons into larger molecules, such as those that make up high-octane gasoline. In petrochemical production, polymer hydrocarbons are used as a feedstock for plastics.

a type of miscible drive in which a polymer is injected into an injection well to allow oil and water to mix and flow to a producing well. See miscible drive. Compare alkaline (caustic) flooding, waterflooding.

a drilling mud to which a polymer has been added to increase the viscosity of the mud.

units in a refinery that polymerize propylene and ethylene in the presence of a catalyst and in a liquid solvent. Polypropylene and polyethylene are produced. Following polymerization, the product is removed from the reactor and processed through a purification facility for removal of catalyst residue and separation of the solvent. The powdered product is then conveyed in a pneumatic conveyor to the finishing area, where additives are blended with powder and the mixture is processed through an extruder to form pellets.

the bonding of two or more simple molecules to form larger molecular units.

to form polymer chains by reacting monomer molecules to form polymer chains. See monomer, polymer.

in electronics, a phenomenon in which a circuit has several alternating electromotive forces (emfs) of the same frequency and sine wave form. A polyphase generator has two or more circuits in the field windings. adj: having or utilizing two or more phases of an alternating-current power line. See phase.

a carbohydrate composed of many monosaccharides. Polysaccharides are used to adjust the viscosity of water slugs in chemical flooding operations.

1. an attachment, added to a stinger, that is flooded to lower pipeline toward the seafloor at an angle that will not overstress it. 2. on many semisubmersible drilling rigs, one of two or more structures, or hulls, on which the rigs floats. Columns rise from the top of the pontoons and support the main deck and equipment. The pontoons may be ballasted or deballasted (water may be added or removed) from the pontoons to adjust the depth at which the rig floats.

1. a sucker rod, shorter than usual, used to make up a sucker rod string of desired length. Pony rods are usually placed just below the polished rod. 2. the rod joined to the connecting rod and piston rod in a mud pump.

pull-out-of-hole.

a reservoir or group of reservoirs. The term is a misnomer in that hydrocarbons seldom exist in pools, but, rather, in the pores of rock. v: to combine small or irregular tracts into a unit large enough to meet state spacing regulations for drilling.

the combining of small or irregular tracts into a unit large enough to meet state spacing regulations for drilling. Compare unitization.

in an oil and gas lease, the clause that permits the lessee to pool or unitize the leased tract.

to make do; to do something on a shoe-string. adj: homemade.

usually, a mud-gas separator that is fabricated by the personnel on a drilling rig’s location, or by welders employed by the drilling contractor in the contractor’s storage yard. It is a steel, air-tight cylinder into which drilling mud is piped to provide a space for gas in the mud to escape.

a bradenhead pack; a method of gravel packing in which no packer is used.

see finger-type junk basket.

putting on the pump; used in drilling reports.

see percentage of proceeds contract.

a spring-loaded safety valve that opens automatically when pressure exceeds the limits for which the valve is set. It is used as a safety device on pressurized vessels and other equipment to prevent damage from excessive pressure. Also called a relief valve, safety relief valve, or safety valve.

(slang) having the quality of being substandard, unsafe, or cheap.

a device that controls the rate of flow of fluid in a line or opens or shuts off the flow of fluid completely. When open, the sealing surface of the valve is moved away from a seat; when closed, the sealing surface contacts the seat to shut off flow. The direction of movement of the valve is usually perpendicular to the seat. Poppet valves are used extensively as pneumatic (air) controls on drilling rigs and as intake and exhaust valves in most internal-combustion engines.

porosity or pores; used in drilling reports.

name for a polycrystalline diamond compact (PDC) bit that has a particularly large number of PDC cutters installed on the head of the bit.

an opening or space within a rock or mass of rocks, usually small and often filled with some fluid (water, oil, gas, or all three). Also called pore spaces. Compare vug.

see formation pressure.

connections between pores.

the total volume of pore space in a reservoir formation.

a device used to determine porosity of a formation by measuring a known volume of gas at a known pressure compressed into a core sample. The gas is measured at atmospheric pressure and at an elevated pressure. These measurements are used to calculate gain volume and pore volume.

1. the condition of being porous (such as a rock formation). 2. the ratio of the volume of empty space to the volume of solid rock in a formation, indicating how much fluid a rock can hold. See absolute porosity, effective porosity, pore.

having pores, or tiny openings, as in rock.

a rock or rock formation containing small openings or spaces within the rock. The spaces are often filled with fluid (such as water, oil, gas, or all three).

1. (nautical) left side of vessel (determined by looking toward the bow). 2. the opening in the side of a liner in a two-stroke cycle engine.

a place where a person or goods may lawfully enter a country. Typically, in cases where people enter, government employees check entry papers such as passports and inspect luggage to assure that contraband is not imported. In cases where goods are entering, government personnel check the goods to ensure that they do not violate the country’s laws concerning imported goods.

a mast mounted on a truck and capable of being erected as a single unit. See telescoping mast.

a device made up in a tubing or workover string that has openings (ports) through which fluid can be circulated.

the cement most widely used in oilwells. It is made from raw materials such as limestone, clay or shale, and iron ore.

congressional act that protects navigational safety and the resources of navigable waters. Under the act, vessel operators must notify port authorities of any “hazardous condition,” which includes fire, leaking cargoes, or anything that could adversely affect the environmental quality of any U.S. port, harbor, or navigable water.

any system or method by which surveillance is maintained on the position of a floating offshore drilling rig in relation to the subsea wellhead when the rig is dynamically positioned. The rig should always be directly over the wellhead to minimize wear on subsea equipment and to facilitate operations involved with the equipment. See acoustic position reference, tautline position-reference system.

a device used where friction between a valve stem and its packing causes unsatisfactory response. Where friction becomes troublesome, a positioner and an actuator ensure that the valve is positively positioned at the setting required by the process under control.

solid or stranded wire or cable that connects a float to a tape or that drives a dial indicator or transmitter.

a phenomenon that occurs at the atomic level of elements whereby the element has a deficiency of electrons—that is, it has a higher electric potential. Compare negative charge.

a choke in which the orifice size must be changed to change the rate of flow through the choke.

a clutch in which jaws or claws interlock when pushed together, e.g., the jaw clutch and the spline clutch.

a valve installed on an engine that, when open, directs gases from inside the engine through piping to the intake manifold. At the intake manifold, the crankcase gases enter the engine’s combustion chamber and are burned. Burning crankcase gases in this manner not only cuts down on air pollution, but also scavenges corrosive fumes from the engine to prevent sludge from forming.

on the record made by a gravity survey, basement rock (usually denser than overlying sedimentary rock) shows up as a positive gravity anomaly.

the position a ship or offshore floating rig assumes when the vessel’s metacenter is above its center of gravity. When the vessel is in a positive state, it is stable and is able to right itself. See center of gravity, metacenter.

the terminal of a battery or other voltage source toward which electrons flow and from which holes flow. See holes, terminal.

see reciprocating compressor.

a device used to rotate the bit without rotating the drill stem. Basically, the motor comprises a spiral rod that is housed inside a helical-shaped chamber—the rod and chamber are a pump. Circulating mud down the drill stem and to the motor causes the rod to rotate. Since the bit is mechanically connected to the motor, as the motor rotates, so does the bit. This method of bit rotation eliminates the need to rotate the entire drill stem and thus is especially useful in directional drilling.

a mechanical fluid-measuring device that measures by filling and emptying chambers of a specific volume. The displacement of a fixed volume of fluid may be accomplished by the action of reciprocating or oscillating pistons, rotating vanes or buckets, nutating disks, or tanks or other vessels that automatically fill and empty. Also called a volume meter or volumeter.

see Dyna-Drill.

a reciprocating or a rotary pump that moves a measured quantity of liquid with each stroke of a piston or each revolution of vanes or gears.

a face mask and portable air tank used for the purpose of breathing in contaminated atmospheres.

a relatively small tank with an accurately calibrated volume used to prove a meter. Liquid is flowed from the meter and into the tank until the calibrated level is achieved. The volume of liquid in the tank is then compared with the volume the meter recorded. If required, the meter is adjusted or a special factor is used to correct the meter. Also called a closed stationary tank prover.

a particle similar to an electron but carrying a positive charge of the same mass and magnitude as the charge of an electron. Positrons are emitted when there is an excess of protons in the nucleus of an atom.

the mineral estate regarded as fee ownership of the minerals in place.

1. a receiving tank situated at the end of the mud return line. The flow of mud comes into the bottom of the device and travels over baffles to control mud flow over the shale shaker. 2. a metal box under a truck bed that holds pipeline repair tools.

see posted barge submersible rig.

see posted barge submersible rig.