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converting a drilled well to a condition that can be left indefinitely without further attention and will not damage freshwater supplies, potential petroleum reservoirs or the environment .
abnormal pressure:-
pressure outside the normal or expected range.
wearing away by friction.
the storage device for nitrogen pressurized hydraulic fluid, which is used in operating the blowout preventers.acetic
an organic acid compound sometimes used to acidize oilwells.
acid fracture:- 
to part or open fractures in limestone formations by using fluid under hydraulic pressure.

abiogenic theory:-

a theory that maintains petroleum originated from hydrocarbons that were trapped inside the Earth during the planet’s formation and are slowly moving upwards.


the injection of acids under pressure into the rock formation to create channels that allow the hydrocarbons to flow more easily into the well bore.

air drilling :-

the use of compressed air instead of mud as a drilling fluid to remove the cuttings; air drilling increases penetration rates but offers no  control over water in the subsurface formations or downhole gas pressure.
Annulus :-
the space between two concentric lengths of pipe or between pipe and the hole in which it is located.
associated gas :-
gas that is produced from the same reservoir along with  crude oil, either as free gas or in solution.
the logo of the American Petroleum Institute (API) that is placed on certain pieces of oilfield equipment by the equipment manufacturer. API licenses the use of the monogram on equipment that meets the API’s minimum standards. It offers publications regarding standards, recommended practices, and other industry related information. Address: 1220 L Street NW; Washington, DC 20005; (202) 682-8000

line with a Babbitt metal. n: a lead/tin alloy with some copper and antimony.
reverse backlash of tongs, left on a pipe or collar, during the pipe spinning operations.
back off:- 
to unscrew one threaded piece (such as a section of pipe) from another.
back-in unit:-
a portable servicing or workover rig that is self-propelled, using the hoisting engines for motive power. Because the driver’s cab is mounted on the end opposite the mast support, the unit must be backed up to the wellhead.
a cylindrical steel bar (similar to the handle or bail of a bucket, only much larger) that supports the swivel and connects it to the hook.
a long, cylindrical container fitted with a valve at its lower end, used to remove water, sand, mud, drilling cuttings, or oil from a well in cable-tool drilling.
ball-and-seat valve:-
a device used to restrict fluid flow to one direction. It consists of a polished sphere, or ball, usually of metal, and an annular piece, the seat, ground and polished to form a seal with the surface of the ball. Gravitational force or the force of a spring holds the ball against the seat. Flow in the direction of the force is prevented, while flow in the opposite direction overcomes the force and unseats the ball.
to plug open perforations by using ball sealers.
barium sulfate, BaSO4; a mineral frequently used to increase the weight or density of drilling mud. Its relative density is 4.2 (meaning that it is 4.2 times denser than water). See barium sulfate, mud.barium sulfaten: a chemical compound of barium, sulfur, and oxygen (BaSO4), which may form a tenacious scale that is very difficult to remove. Also called barite.
a measure of volume for petroleum products in the United States. One barrel is the equivalent of 42 U.S. gallons or 0.15899 cubic meters (9,702 cubic inches).

Benzene :-

a volatile organic compound that occurs naturally in petroleum  and is also produced by the combustion of petroleum products.
biogenic theory :-
the most widely accepted theory explaining the origins of petroleum: as organic materials become deeply buried over time, heat and  pressure transform them into
bitumen :-
petroleum that exists in the semisolid or solid phase in natural deposits.
an uncontrolled flow of gas, oil or other fluids from a well .

Canadian Association of Oilwell Drilling Contractors The CAODC is a trade association representing upstream Canadian petroleum drilling contractors land based and offshore, service rig contractors and associate companies Its member companies work together to ensure that this sector is the world’s most efficient, well trained and best equipped .
cabletool rig :-
a type of drilling device used from the 1850s to the 1930s that employed a heavy
like bit which was suspended on a cable and dropped repeatedly into the rock at the bottom of the hole.
carbon dioxide (CO2):- a non:-
toxic gas produced from decaying materials, respiration of plant and animal life, and combustion of
organic matter, including fossil fuels; carbon dioxide is the most common greenhouse gas produced by human activities.
carbonate :-
rock formed from the hard parts of marine organisms mainly consisting of calcite, aragonite and dolomite.
casing:-head gasoline (naphtha):-
a highly volatile liquid which is separated from natural gas at the wellhead and was once used as
unrefined  gasoline.
cat cracking (catalytic cracking):-
a refinery process that uses catalysts in addition to pressure and heat to convert heavier fuel oil
into lighter  products such as gasoline and diesel fuel.
materials that assist chemical reactions.
cathodic protection :-
a technique for preventing corrosion in metal pipelines and tanks that uses weak electric currents to offset the current  associated with metal corrosion.
centrifugal pump :-
a rotating pump, commonly used for large:-volume oil and natural gas pipelines, that takes in fluids near the centre and accelerates  them as they move to the outlet on the outer rim.
clastic :-
made up of pieces (clasts) of older rock; rock derived from  mechanical process; generally sandstone, siltstone or shale.
coal bed methane (CBM) :-
natural gas generated and trapped in coal  seams.
coal gas :-
a mixture of hydrogen, carbon monoxide and methane, produced  by distilling coal, that was once used for heating and lighting.
co:-generation :-
the production of steam to drive turbines producing electrical energy for plant use or sale and for the provision of heat for  buildings and industrial processes.
coiled tubing :-
a continuous, jointless hollow steel cylinder that is stored on a reel and can be uncoiled or coiled repeatedly as required; coiled tubing is increasingly being used in well completion and servicing instead of  traditional tubing, which is made up of joined sections of pipe.
coke :-
solid carbon that remains in the refining process after cracking of  hydrocarbons.
coking :-
a process used to break down heavy oil molecules into lighter ones  by removing the carbon which remains as a coke residue.
common depth point method :-
a method of recording and processing seismic signals so that signals belonging to the same subsurface
point are  brought together.
completion :-
the process of finishing a well so that it is ready to produce oil  or gas.
compressor :-
a machine used to boost natural gas pressure to move it  through pipelines or other facilities.
condensate :-
hydrocarbons, usually produced with natural gas, that are  liquid at normal pressure and temperature.
conventional crude oil :-
petroleum found in liquid form, flowing naturally  or capable of being pumped without further processing or dilution.
core :-
a continuous cylinder of rock, usually from five to 10 centimetres in diameter, cut from the bottom of a wellbore as a sample of an underground  formation.
cracking :-
a refining process for increasing the yield of gasoline from crude oil; cracking involves breaking down the larger, heavier and more complex hydrocarbon molecules into simpler and lighter molecules through the use of  heat and pressure, and sometimes a catalyst.
critical sour gas wells :-
a sour gas well that has the potential to release  unsafe levels of hydrogen sulphicle, which might affect nearby residents.
critical zone :-
the zone in a well where sour gas will likely be encountered.
 Crown rights:-
government:-owned surface or mineral rights.
cuttings :-
chips and small fragments of rock cut by the drill bit and brought  to the surface by the flow of drilling mud.

daily drilling report:-
a record made each day of the operations on a working drilling rig and, traditionally, phoned, faxed, emailed, or radioed in to the office of the drilling company and possibly the operator every morning
an air or inert gas device that minimizes pressure surges in the output line of a mud pump. Sometimes called a surge dampener.
daylight tour(pronounced “tower”):-
in areas where three eight-hour tours are worked, the shift of duty on a drilling rig that starts at or about daylight. Compare evening tour, morning (graveyard) tour.
day tour(pronounced “tower”):-
in areas where two 12-hour tours are worked, a period of 12 hours, usually during daylight, worked by a drilling or workover crew when equipment is being run around the clock.

Density :-
the heaviness of crude oil, indicating the proportion of large, carbonrich molecules, generally measured in kilograms per cubic metre (kg/M3) or degrees on the American Petroleum Institute (API) gravity scale in Western Canada oil up to 900 kg/m3 is considered light to medium crude   oil above this density is deemed as heavy oil or bitumen.
development well :-
a well drilled in or adjacent to a proven part of a pool  to optimize petroleum production.
dolomite :-
calcium carbonate:-rich sedimentary rock in which oil or gas  reservoirs are often found.
downstream :-
the refining and marketing sector of the petroleum industry.
drilling mud :-
fluid circulated down the drill pipe and up the annulus during drilling to remove cuttings, cool and lubricate the bit, and maintain desired  pressure in the well.
dry gas :-
natural gas from the well that is free of liquid hydrocarbons, or  gas that has been treated to remove all liquids pipeline gas.
dry hole :-
an unsuccessful well a well not capable of producing commercial  quantities of oil or gas.

electric well log:
a record of certain electrical characteristics (such as resistivity and conductivity) of formations traversed by the borehole. It is made to identify the formations, determine the nature and amount of fluids they contain, and estimate their depth. Also called an electric log or electric survey.
elevator links:
cylindrical bars that support the elevators and attach them to the hook.
on rotary rigs and top drive rigs, hinged steel devices with manual operating handles that crew members latch onto a tool joint (or a sub).
a machine for converting the heat content of fuel into rotary motion that can be used to power other machines. Compare motor.
the process by which material (such as rock or soil) is worn away or removed (as by wind or water).
evening tour (pronounced “tower”):
the shift of duty on a drilling rig that generally starts in the afternoon and runs through the evening. Sometimes called afternoon tour. Compare daylight tour.
external cutter:
a fishing tool containing metalcutting knives that is lowered into the hole and over the outside of a length of pipe to cut it. The severed part of the pipe can then be brought to the surface. Also called an outside cutter. Compare internal cutter.
enhanced recovery :-
the increased recovery from a pool achieved by  artificial means, including injection of fluids, chemicals or heat.
established reserves :-
those reserves recoverable under current  technology and present and anticipated economic conditions.

a rack that supports the stands of pipe being stacked in the derrick or mast. It has several steel fingerlike projections that form a series of slots into which the derrickman can place a stand of drill pipe or collars after it is pulled out of the hole and removed from the drill string.
fire flooding:
a thermal recovery method in which the oil in the reservoir is ignited, the heat vaporizes lighter hydrocarbons and water pushes the warmed oil toward a producing well. Also called in situ combustion. See thermal recovery.
an object that is left in the wellbore during drilling or workover operations and that must be recovered before work can proceed. It can be anything from a piece of scrap metal to a part of the drill stem.
the procedure of recovering lost or stuck equipment in the wellbore.
fishing magnet:
a powerful magnet designed to recover metallic objects lost in a well.
fishing tool:
a tool designed to recover equipment lost in a well.
fishing-tool operator:
the person (usually a service company employee) in charge of directing fishing operations.
a small, often standardized, part (such as a coupling, valve, or gauge) installed in a larger apparatus.
float collar:
a special coupling device inserted one or two joints above the bottom of the casing string that contains a check valve to permit fluid to pass downward but not upward through the casing. The float collar prevents drilling mud from entering the casing while it is being lowered, allowing the casing to float during its descent and thus decreasing the load on the derrick or mast.
float shoe:
a short, heavy, cylindrical steel section with a rounded bottom that is attached to the bottom of the casing string. It contains a check valve and functions similarly to the float collar but also serves as a guide shoe for the casing.
1. to drive oil from a reservoir into a well by injecting water under pressure into the reservoir formation. See waterflooding.
2. to drown out a well with water.
a current or stream of fluid or gas.
floor crew:
those workers on a drilling or workover rig who work primarily on the rig floor. See rotary helper.
see rotary helper.
see rotary helper.
flowing well:
a well that produces oil or gas by its own reservoir pressure rather than by use of artificial means (such as pumps).
flow line:
the surface pipe through which oil or gas travels from a well to processing equipment or to storage.
flow rate:
the speed, or velocity, of fluid or gas flow through a pipe or vessel.
fluid injection:
injection of gases or liquids into a reservoir to force oil toward and into producing wells.
fluid loss:
the unwanted migration of the liquid part of the drilling mud or cement slurry into a formation, often minimized or prevented by the blending of additives with the mud or cement.

field :-
the geographical area encompassing a group of one or more  underground petroleum pools sharing the same or related infrastructure.
field price :-
the amount received by petroleum producers after deducting  transportation and distribution costs.
formation :-
a designated subsurface layer that is composed throughout of  substantially the same kind of rock or rock types.
fracturing (or fracing) :-
the practice of pumping special fluids down the well under high pressure; fracturing causes the formation to crack open, creating passages for the reservoir fluids to more easily flow into the  well bore.

gas transmission systems :-
pipelines that carry natural gas at high  pressure from producing areas to consuming areas.
gathering lines :-
pipelines that move raw petroleum from wellheads to  processing plants and transmission facilities.
geochemistry :-
the science of chemistry applied to rocks and minerals; geochemists analyze the contents of subsurface rocks for the presence of  organic matter associated with oil deposits.
geophones (or jugs) :-
sensitive vibration:-detecting instruments used in  conducting seismic surveys; marine versions are known as hydrophones.
geophysics :-
the science that deals with the relations between the physical features of the Earth and forces that produce them; geophysics includes the  study of seismology and magnetism.
greenhouse effect :-
the warming of the Earth’s surface caused by the presence of carbon dioxide and other gases in the atmosphere that trap the  heat of the sun.
greenhouse gases :-
a wide variety of gases that trap heat near the Earth’s surface, preventing its escape into space; greenhouse gases, such as carbon dioxide, methane, nitrous oxide and water vapour, occur naturally or result from human activities such as the burning of fossil fuels ground:-level ozone see volatile organic compounds.
gusher :-
a well that comes in with such great pressure that the oil or gas blows out of the wellhead like a geyser; gushers are rare today because of improved drilling technology, especially the use of drilling mud to control  down hole pressure.

heavy oil :-
dense, viscous oil, with a high proportion of bitumen, that is  difficult to extract with conventional techniques and is more costly to refine.
horizontal drilling :-
drilling a well which deviates from the vertical and  travels horizontally through a producing layer.
horizontal laterals :-
a series of drainage wells branching off from a  horizontal well bore.
hot water process :-
a method for separating bitumen from oil sand using hot water and caustic soda, developed by Karl Clark of the Alberta Research  Council.
hydrocarbons :-
a large class of liquid, solid or gaseous organic compounds, containing only carbon and hydrogen, that are the basis of  almost all petroleum products.
hydrocracking :-
a refining process which adds hydrogen to the carbon rich molecules of heavier oil, in the presence of a catalyst, to produce high:- octane gasoline.
hydrogen sulphide (H2S):-
a naturally occurring, highly toxic gas with the  odour of rotten eggs.
hydro:-transport :-
a process that uses hot water to transport oil sand  through a pipeline to a processing plant.
hydrotreating :-
the process of adding hydrogen to heavy oil or bitumen  molecules during the upgrading process.

IADC International Association of Drilling Contractors:
a trade association that represents the interests of members of the drilling segment of the oil and gas industry. It offers publications regarding recommended industry practices and training materials.
a set of mounted blades used to impart motion to a fluid air or gas (such as, the rotor of a centrifugal pump).
preventing the passage of fluid. A formation may be porous yet impermeable if there is an absence of connecting passages between the voids within it. See permeability.
impression block:
a block with lead or another relatively soft material on its bottom. It is made up on drill pipe or tubing at the surface, run into a well, and set down on the object that has been lost in the well. The block is retrieved and the impression is examined. The impression is a mirror image of the top of the fish; it also indicates the fish’s position in the hole, for example, whether it is centered or off to one side. From this information, the correct fishing tool may be selected.
induction log:
an electric well log in which the conductivity of the formation rather than the resistivity is measured. Because oil-bearing formations are less conductive of electricity than water-bearing formations, an induction survey, when compared with resistivity readings, can aid in determination of oil and water zones.
inflatable packer:
a packer with an element that inflates by means of gas or liquid pumped from the surface through a line. It is deflated by means of slots that can be opened to allow the gas or liquid to flow out. They are used when a temporary packer is needed in a hole.
injection gas:
1. a high-pressure gas injected into a formation to maintain or restore reservoir pressure.
2. gas injected in gas-lift operations.
injection log:
a survey used to determine the injection profile, that is, to assign specific volumes or percentages to each of the formations taking fluid in an injection well. The injection log is also used to check for casing or packer leaks, proper cement jobs, and fluid migration between zones.
injection water:
water that is introduced into a reservoir to help drive hydrocarbons to a producing well.

infill drilling :-
wells drilled between established producing wells on a lease  in order to increase production from the reservoir.
injection well :-
a well used for injecting air, steam or fluids into an  underground formation.

jarmout :-
a percussion tool operated manually or hydraulically to deliver a heavy upward or downward blow to fish stuck in the borehole. v: to apply a heavy blow to the drill stem by use of a jar or bumper sub.
jar accelerator:
a hydraulic tool used in conjunction with a jar and made up on the fishing string above the jar to increase the power of the jarring force.
jerk line:
a wire rope, one end of which is connected to the end of the tongs and the other end of which is attached to the cathead.
1. a hydraulic device operated by a centrifugal pump used to clean the mud pits, or tanks, and to mix mud components.
2. in a perforating gun using shaped charges, a highly penetrating, fast-moving stream of exploded particles that forms a hole in the casing, cement, and formation.
jet cutoff:
a procedure for severing pipe stuck in a well by detonating special shaped-charge explosives similar to those used in jet perforating. The explosive is lowered into the pipe to the desired depth and detonated. The force of the explosion makes radiating horizontal cuts around the pipe, and the severed portion of the pipe is retrieved.
jet cutter:
a fishing tool that uses shaped charges to sever casing, tubing, or drill pipe stuck in the hole. See jet cutoff. Compare chemical cutter.
jet gun:
an assembly, including a carrier and shaped charges, that is used in jet perforating.
to create holes through the casing with a shaped charge of high explosives instead of a gun that fires projectiles. The loaded charges are lowered into the hole to the desired depth. Once detonated, the charges emit short, penetrating jets of high-velocity gases that make holes in the casing and cement for some distance into the formation. Formation fluids then flow into the wellbore through these perforations. See bullet perforator, gun-perforate.
journal bearing:
a machine part in which a rotating shaft (a journal) revolves or slides. Also called a plain bearing.

joint implementation :-
a means of reducing global greenhouse gas emissions whereby a country receives credit for supporting emissions reductions elsewhere for example, planting trees or replacing inefficient  power generation facilities in developing countries.
joint of pipe:
a length of drill pipe or casing. Both come in various lengths.
metal debris lost in a hole. Junk may be a lost bit, pieces of a bit, pieces of pipe, wrenches, or any relatively small object that impedes drilling or completion and must be fished out of the hole. v: to abandon (as a nonproductive well).
junk basket:
a device made up on the bottom of the drill stem or on wireline to catch pieces of junk from the bottom of the hole. Circulating the mud or reeling in the wireline forces the junk into a barrel in the tool, where it is caught and held. When the basket is brought back to the surface, the junk is removed. Also called a junk sub or junk catcher.
junk mill:
a mill used to grind up junk in the hole. See mill.
junk retriever:
a special tool made up on the bottom of the drill stem to pick up junk from the bottom of the hole. Most junk retrievers are designed with ports that allow drilling fluid to exit the tool a short distance off the bottom. This flow of fluid creates an area of low pressure inside the tool so that the junk is lifted and caught in the retriever by the higher pressure outside the tool. See junk, junk basket.

the heavy square or hexagonal steel member suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns.
kelly bushing:
a device fitted to the rotary table through which the kelly passes and the means by which the torque of the rotary table is transmitted to the kelly and to the drill stem. Also called the drive bushing.
kelly bypass:
a system of valves and piping that allows drilling fluid to be circulated without the use of the kelly.
kelly cock:
a valve installed at one or both ends of the kelly. When a high-pressure backflow occurs inside the drill stem, the valve is closed to keep pressure off the swivel and rotary hose.
kelly drive bushing:
see kelly bushing.
kelly driver:
a device that fits inside the head and inside of which the kelly fits. The kelly driver rotates with the kelly.
kelly saver sub:
a heavy and relatively short length of pipe that fits in the drill stem between the kelly and the drill pipe. The threads of the drill pipe mate with those of the sub, minimizing wear on the kelly.
kelly spinner:
a pneumatically operated device mounted on top of the kelly that, when actuated, causes the kelly to turn or spin.

kerosene :-
a mixture of hydrocarbons produced by distilling petroleum, that  is used as a lamp oil or jet fuel.
kick :-
when fluids with a higher pressure than that exerted by the drilling mud enter the wellbore; this creates the potential for a well to blow out of  control.

landman :-
a member of the exploration team whose primary duties are formulating and carrying out exploration  strategies and managing an oil company’s relations with its landowners and partners, including securing and  administering oil and gas leases and other agreements.
 light crude oil :-
liquid petroleum which has freely at room temperature.
calcium carbonate rich sedimentary rocks in which oil or gas  reservoirs are often found.
liquefled natural gas (LNG):-
supercooled natural gas that is maintained as a liquid at 160′ Celsius; LNG occupies 1/640th of its original volume and  is therefore easier to transport if pipelines cannot be used.
logs :-
detailed depth:-related records of certain significant details of an oil or  gas well; usually obtained by lowering measurement instruments into a well.
log a well:
to run any of the various logs used to ascertain downhole information about a well.
logging devices:
any of several electrical, acoustical, mechanical, or radioactivity devices that are used to measure and record certain characteristics or events that occur in a well that has been or is being drilled.
long string:
1. the last string of casing set in a well.
2. the string of casing that is set at the top of or through the producing zone, often called the oil string or production casing.
lost circulation:
the quantities of whole mud lost to a formation, usually in cavernous, pressured, or coarsely permeable beds. Evidenced by the complete or partial failure of the mud to return to the surface as it is being circulated in the hole.
lost pipe:
drill pipe, drill collars, tubing, or casing that has become separated in the hole from the part of the pipe reaching the surface, necessitating its removal before normal operations can proceed; for example, a fish.
lost time incident:
an incident in the workplace that results in an injury serious enough that causes the person injured to be unable to work for a day or more.
a specially fabricated length of casing or tubing usually placed temporarily above a valve on top of the casinghead or tubing head. It is used to run swabbing or perforating tools into a producing well and provides a method for sealing off pressure and thus should be rated for highest anticipated pressure.

measurement:-while:-drilling (MWD) tool :-
technology that transmits information from downhole measuring devices to the surface while drilling is  ongoing.
medium crude oil :-
liquid petroleum with a density between that of light  and heavy crude oil.
methane (CH4)
:- the simplest hydrocarbon and the main component of  natural gas; methane is also produced when organic matter decomposes.
midstream :-
the processing, storage and transportation sector of the  petroleum industry.
mineral rights :-
the rights to explore for and produce the resources below  the surface.
miscible flooding :-
an oil:-recovery process in which a fluid, capable of mixing completely with the oil it contacts, is injected into an oil reservoir to  increase recovery.
mousehole :-
a hole drilled to the side of the wellbore to hold the next joint of drill pipe to be used; when this joint is pulled out and screwed onto the drill string, another joint of pipe is readied and slipped into the mousehole to  await its turn.
mud motor :-
a downhole drilling motor that is powered by the force of the  drilling mud pushed through the motor by the mud pumps at the surface.
multiple entry :-
a technique for drilling several horizontal wells from a single vertical, directional or horizontal wellbore naphtha :- a light fraction of  crude oil used to make gasoline.

natural gas liquids (NGLs) :- liquids obtained during natural gas production and processing; they include ethane, propane, butane and  condensate.
neutron log:
a radioactivity well log used to determine formation porosity. The logging tool bombards the formation with neutrons. When the neutrons strike hydrogen atoms in water or oil, gamma rays are released. Since water or oil exists only in pore spaces, a measurement of the gamma rays indicates formation porosity. See radioactivity well logging.
night toolpusher:
an assistant toolpusher whose duty hours are typically during nighttime hours. Also known as a tourpusher.
a tubular pipe fitting threaded on both ends used for making connections between pipe joints and other tools.
nipple up:
in drilling, to assemble the blowout preventer stack on the wellhead at the surface.
nitro shooting:
a formation-stimulation process first used about 100 years ago in Pennsylvania. Nitroglycerine is placed in a well and exploded to fracture.
nitrous oxide (N20) :- a very potent greenhouse gas which has a large number of natural sources and is a secondary product of the burning of  organic material and fossil fuels.
normal circulation:
the smooth, uninterrupted circulation of drilling fluid down the drill stem, out the bit, up the annular space between the pipe and the hole, and back to the surface.
a passageway through jet bits that causes the drilling fluid to be ejected from the bit at high velocity.
nuclear log:
see radioactivity log.
nuclear tracer:
a gas, liquid, or solid material that emits gamma rays.

octane :-
a performance rating of gasoline; the higher the octane number,  the greater the anti:-knock quality of the gasoline.
a simple or complex liquid mixture of hydrocarbons that can be refined to yield gasoline, kerosene, diesel fuel, and various other products.
oil-base mud:
a drilling or workover fluid in which oil is the continuous phase and which contains from less than 2 percent and up to 5 percent water. This water is spread out, or dispersed, in the oil as small droplets. See oil mud.
oil-emulsion mud:
a water-base mud in which water is the continuous phase and oil is the dispersed phase.
the surface area overlying an oil reservoir or reservoirs. The term usually includes not only the surface area, but also the reservoir, the wells, and the production equipment.
oil mud:
a drilling mud, such as, oil-base mud and invert-emulsion mud, in which oil is the continuous phase. It is useful in drilling certain formations that may be difficult or costly to drill with waterbase mud. Compare oil-emulsion mud.
oil sand:
1. a sandstone that yields oil.
2. (by extension) any reservoir that yields oil, whether or not it is sandstone.
oil saver:
a gland arrangement that mechanically or hydraulically seals by pressure. It is used to prevent leakage and waste of gas, oil, or water around a wireline (as when swabbing a well).
oil spotting:
pumping oil, or a mixture of oil and chemicals, to a specific depth in the well to lubricate stuck drill collars.
oil string:
the final string of casing set in a well after the productive capacity of the formation has been determined to be sufficient. Also called the long string or production casing.
a well from which oil is obtained.
oil zone:
a formation or horizon of a well from which oil may be produced. The oil zone is usually immediately under the gas zone and on top of the water zone if all three fluids are present and segregated.
open formation:
a petroleum-bearing rock with good porosity and permeability.
open hole:
1. any wellbore in which casing has not been set.
2. open or cased hole in which no drill pipe or tubing is suspended.
3. the portion of the wellbore that has no casing.
open-hole completion:
a method of preparing a well for production in which no production casing or liner is set opposite the producing formation. Reservoir fluids flow unrestricted into the open wellbore.
open-hole fishing:
the procedure of recovering lost or stuck equipment in an uncased wellbore.
open-hole log:
any log made in uncased, or open hole.
the person or company, either proprietor or lessee, actually operating a well or lease, generally the oil or gas company that engages the drilling, service, and workover contractors.
Organization of Petroleum Exporting Countries (OPEC):
an organization of the countries of the Middle East, Southeast Asia, Africa, and South America that produce oil and export it. Update – members as of 1997 are Algeria, Ecuador, Gabon, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates, and Venezuela. The organization’s purpose is to negotiate and regulate production and oil prices.
out-of-gauge bit:
a bit that is no longer of the proper diameter.
out-of-gauge hole:
a hole that is not in gauge; that is, it is smaller or larger than the diameter of the bit used to drill it.
a fishing tool that is attached to tubing or drill pipe and lowered over the outside wall of pipe or sucker rods lost or stuck in the wellbore. A friction device in the overshot, usually either a basket or a spiral grapple, firmly grips the pipe, allowing the fish to be pulled from the hole.
overthrust fault:
a low-dip angle (nearly horizontal) reverse fault along which a large displacement has occurred. Some overthrusts, such as many of those in the Rocky Mountain Overthrust Belt, represent slippages of many miles.
a circular seal common in the oil field. O-rings may be made of elastomer, rubber, plastic, or stainless steel. To seal properly, they all require enough pressure to make them deform against a sealing surface.

PVT :-
Pit Volume Totalizer :- equipment used to measure the volume of  drilling mud in the mud tanks/pits.
packer :-
an expanding plug used in a well to seal off certain sections of the tubing or casing when cementing and acidizing or when a production  formation is to be isolated.
perforate :-
make holes through the casing opposite the producing  formation to allow the oil or gas to flow into the well.
perforating gun :-
a special tool used downhole for shooting holes in the  well’s casing opposite the producing formation.
permeability :-
the capacity of a reservoir rock to transmit fluids; how easily  fluids can pass through rock.
petrochemicals :-
chemicals derived from petroleum that are used as feedstocks for the manufacture of a variety of plastics and other products  such as synthetic rubber.
petroleum :-
a naturally occurring mixture composed predominantly of  hydrocarbons in the gaseous, liquid or solid phase.
pig :-
a cylindrical device inserted into a pipeline to inspect the pipe or to sweep the line clean of water, rust or other foreign matter; pipeline inspection and cleaning devices are called pigs because early models  squealed as they moved through the pipe.
pinnacle reef :-
a conical formation, higher than it is wide, usually  composed of limestone, in which hydrocarbons might be trapped.
pool :-
a natural underground reservoir containing an accumulation of  petroleum.
porosity :-
the volume of spaces within rock that might contain oil and gas like  (the amount of water a sponge can hold;( the open or void space within rock.
Precambrian :-
formed prior to the Cambrian era approximately 600 million  years ago.
primary recovery :-
the production of oil and gas from reservoirs using the  natural energy available in the reservoirs and pumping techniques.
probable reserves :-
hydrocarbon deposits believed to exist with reasonable  certainty on the basis of geological information.
production casing :-
the last string of casing set in a well; production casing is tubular steel pipe connected by threads and couplings that lines the total length of the wellbore to ensure safe control of production, prevent water from entering the wellbore and keep rock formations from “sloughing” into the  well bore.
production tubing :-
steel pipe inside the casing used to flow the petroleum  from the producing zone to the surface.
productive capacity :-
the estimated maximum volume which can be produced from known reserves based on reservoir characteristics, economic considerations, regulatory limitations and the feasibility of infill drilling or  additional production facilities; also known as available supply.
proved reserves :-
hydrocarbons in known reservoirs that can be recovered with a great degree of certainty under existing technological and economic  conditions.
public consultation :-
the process of involving all affected parties in the design, planning and operation of a seismic program, an oil and gas well,  pipeline, processing plant or other facility.

rathole :-
a slanted hole drilled near the wellbore to hold the kelly joint when not in use; the kelly is unscrewed from the drill string and lowered into the  rat hole.
recoverable resources :-
hydrocarbon reserves that can be produced with  current technology including those not economical to produce at present.
reservoir (pool) :-
a porous and permeable underground rock formation containing a natural accumulation of crude oil or natural gas that is confined by  impermeable rock or water barriers, and is separate from other reservoirs.
residuum :-
a heavy, black, tar:-like substance that remains after crude oil has  been fully refined to distil all usable fractions or components.
rod string :-
a string of steel rods used to provide up and down motion for a  bottom:-hole pump to lift oil to the surface.
rotary rig :-
a modern drilling unit capable of drilling a well with a bit attached  to a rotating column of steel pipe.
rotary table :-
a heavy, circular casting mounted on a steel platform just  above the rig floor which rotates the drill string and thus turns the bit.

sandstone :-
a compacted sedimentary rock composed mainly of quartz or  feldspar; a common rock in which oil, natural gas and/or water accumulate.
secondary recovery :-
the extraction of additional crude oil, natural gas and related substances from reservoirs through pressure maintenance techniques  such as water flooding and gas injection.
sedimentary rocks :-
rocks formed by the accumulation of sediment or  organic materials and therefore likely to contain hydrocarbons.
seismic surveys :-
refers to studies done to gather and record patterns of induced shock wave reflections from underground layers of rock which are  used to create detailed models of the underlying geological structure.
service rig :-
a truck:-mounted rig, usually smaller than a drilling rig, that is brought in to complete a well or to perform maintenance, replace equipment or  improve production.
rock formed from clay.
shale shaker :-
a vibrating screen for sifting out rock cuttings from drilling  mud.
sidetrack :-
a section of a well drilled on a curve to bypass debris or other  obstructions.
smart pig :-
sophisticated instrument packages sent through pipelines to test  for corrosion and buckling.
sour gas :-
natural gas containing hydrogen sulphide in measurable  concentrations.
sour oil :-
crude oil containing free sulphur, hydrogen sulphide or other  sulphur compounds.
steam injection :-
an improved recovery technique in which steam is injected  into a reservoir to reduce the viscosity of the crude oil.
steam:-assisted gravity drainage (SAGD) :-
a recovery technique for extraction of heavy oil or bitumen that involves drilling a pair of horizontal wells one above the other, one well is used for steam injection and the other  for production.
stimulating the formation :- a technique for improving production from a reservoir; stimulation may involve acidizing, fracturing or simply cleaning out  sand.
straddle extraction plant :-
a gas processing plant located on or near a gas transmission line that removes natural gas liquids from the gas and returns it  to the line.
sulphur :-
a yellow mineral extracted from petroleum for making fertilizers,  pharmaceuticals and other products.
sulphur dioxide (S02):-
a poisonous gas formed by burning hydrogen  sulphide.
surface casing :-
the first string of casing put into a well; it is cemented into place and serves to shut out shallow water formations and as a foundation for  well control.
surface rights:-
the rights to work on the surface of the land.
sustainable development :-
development that meets the needs of the present without compromising the ability of future generations to meet their own needs (as defined by United Nations World Commission on Environment) and Development.
sweeten :-
remove hydrogen sulphide and carbon dioxide from sour gas to  make it marketable.
synthetic crude oil :-
a mixture of hydrocarbons, similar to crude oil, derived  by upgrading bitumen from oil sands.

tertiary recovery :-
the third major phase of crude oil recovery which involves using more sophisticated techniques, such as steam flooding or  injection of chemicals, to increase recovery.
thermal recovery:
a type of improved recovery in which heat is introduced into a reservoir to lower the viscosity of heavy oils and to facilitate their flow into producing wells. The pay zone may be heated by injecting steam (steam drive) or by injecting air and burning a portion of the oil in place (in situ combustion).
throw the chain:
to jump the spinning chain up from a box end tool joint so that the chain wraps around the pin end tool joint after it is stabbed into the box. The stand or joint of drill pipe is turned or spun by a pull on the spinning chain from the cathead on the drawworks.
tight formation:
a petroleum- or water-bearing formation of relatively low porosity and permeability.
tight sand:
sand or sandstone formation with low permeability.
tight spot:
a section of a borehole in which excessive wall cake has built up, reducing the hole diameter and making it difficult to run the tools in and out. Compare keyseat.
the large wrenches used for turning when making up or breaking out drill pipe, casing, tubing, or other pipe; variously called casing tongs, rotary tongs, and so forth according to the specific use. Power tongs or power wrenches are pneumatically or hydraulically operated tools that serve to spin the pipe up and, in some instances, to apply the final makeup torque.
an employee of a drilling contractor who is in charge of the entire drilling crew and the drilling rig. Also called a rig superintendent, drilling foreman, or rig supervisor.
top drive:
a device similar to a power swivel that is used in place of the rotary table to turn the drill stem.
top plug:
a cement wiper plug that follows cement slurry down the casing. It goes before the drilling mud used to displace the cement from the casing and separates the mud from the slurry. See cementing, wiper plug.
the turning force that is applied to a shaft or other rotary mechanism to cause it to rotate or tend to do so. Torque is measured in foot-pounds, joules, newton-metres, and so forth.
total depth (TD):
the maximum depth reached in a well.
tour(pronounced “tower”):
a working shift for drilling crew or other oilfield workers. Some tours are 8 hours; the three daily tours are called daylight, evening (or afternoon), and graveyard (or morning). 12-hour tours may also be used; they are called simply day tour and night tour.
tourly(pronounced “towerly”):
during each shift. See tour.
a substance added to reservoir fluids to permit the movements of the fluid to be followed or traced. Dyes and radioactive substances are used as tracers in underground water flows and sometimes helium is used in gas. When samples of the water or gas taken some distance from the point of injection reveal signs of the tracer, the route of the fluids can be mapped.
tracer log:
a survey that uses a radioactive tracer such as a gas, liquid, or solid having a high gamma ray emission. When the material is injected into any portion of the wellbore, the point of placement or movement can be recorded by a gamma ray instrument. The tracer log is used to determine channeling or the travel of squeezed cement behind a section of perforated casing.
trailer rig:
a rig mounted on a wheeled and towed trailer. It has a mast, a rotary, and one or two engines.
the gear or chain arrangement by which power is transmitted from the prime mover to the drawworks, the mud pump, or the rotary table of a drilling rig.
traveling block:
an arrangement of pulleys, or sheaves, through which drilling cable is reeved, which moves up or down in the derrick or mast.
traveling valve:
one of the two valves in a sucker rod pumping system. It moves with the movement of the sucker rod string. On the upstroke, the ball member of the valve is seated, supporting the fluid load. On the downstroke, the ball is unseated, allowing fluid to enter into the production column. Compare standing valve.
the operation of hoisting the drill stem from and returning it to the wellbore. v: to insert or remove the drill stem into or out of the hole. Shortened form of “make a trip.”
trip in:
to go in the hole.
trip out:
to come out of the hole.
the operation of hoisting the drill stem out of and returning it into the wellbore.
truck-mounted rig:
a well-servicing and workover rig that is mounted on a truck chassis.
relatively small-diameter pipe that is run into a well to serve as a conduit for the passage of oil and gas to the surface.
tubing coupling:
a special connector used to connect lengths of tubing.
tubing hanger:
an arrangement of slips and packing rings used to suspend tubing from the tubing head.
tubing head:
a flanged fitting that supports the tubing string, seals off pressure between the casing and the outside of the tubing, and provides a connection that supports the Christmas tree.
tubing pump:
a sucker rod pump in which the barrel is attached to the tubing. See sucker rod pump.
tubular goods:
any kind of pipe. Oilfield tubular goods include tubing, casing, drill pipe, drill collars and line pipe. Also called tubulars.
tungsten carbide:
a fine, very hard, gray crystalline powder, a compound of tungsten and carbon. This compound is bonded with cobalt or nickel in cemented carbide compositions and used for cutting tools, abrasives, and dies.
tungsten carbide bit:
a type of roller cone bit with inserts made of tungsten carbide. Also called tungsten carbide insert bit.

underbalanced drilling :-
using mud lightened by the addition of nitrogen or  other gas to minimize damage to the producing reservoir by drilling fluids.
unitization :-
process whereby owners of adjoining properties pool reserves into a single unit operated by one of the owners , production is divided among  the owners according to the unitization agreement.
upgrading :-
the process of converting heavy oil or bitumen into synthetic  crude oil.
upstream :-
the exploration and production sector of the petroleum industry.

a device used to control the rate of flow in a line to open or shut off a line completely, or to serve as an automatic or semiautomatic safety device. Those used extensively include the check valve, gate valve, globe valve, needle valve, plug valve, and pressure relief valve.
a belt with a trapezoidal cross section, made to run in sheaves, or pulleys, with grooves of corresponding shape.
an opening at floor level in a side of a derrick or mast. The V-door is opposite the drawworks and is used as an entry to bring in drill pipe, casing, and other tools from the pipe rack.
Vibroseis :-
the process of producing seismic shock waves with “thumpers” or  vibrator vehicles .

waiting on cement (WOC):
pertaining to the time when drilling or completion operations are suspended so that the cement in a well can harden sufficiently.
an area cleared for moving through by personnel.
walking beam:
the horizontal steel member of a beam pumping unit that has rocking or reciprocating motion.
wash over:
to release pipe that is stuck in the hole by running washover pipe. The washover pipe must have an outside diameter small enough to fit into the borehole but an inside diameter large enough to fit over the outside diameter of the stuck pipe. A rotary shoe, which cuts away the formation, mud, or whatever is sticking the pipe, is made up on the bottom joint of the washover pipe, and the assembly is lowered into the hole. Rotation of the assembly frees the stuck pipe. Several washovers may have to be made if the stuck portion is very long.
washover pipe:
an accessory used in fishing operations to go over the outside of tubing or drill pipe stuck in the hole because of cuttings, mud, and so forth, that have collected in the annulus. The washover pipe cleans the annular space and permits recovery of the pipe. It is sometimes called washpipe.
washover string:
the assembly of tools run into the hole during fishing to perform a washover. A typical washover string consists of a washover back-off connector, several joints of washover pipe, and a rotary shoe.
water drive:
the reservoir drive mechanism in which oil is produced by the expansion of the underlying water and rock, which forces the oil into the wellbore. In general, there are two types of water drive: bottom-water drive, in which the oil is totally underlain by water; and edgewater drive, in which only a portion of the oil is in contact with the water.
water pump:
on an engine, a device, powered by the engine, that moves coolant (water) through openings in the engine block, through the radiator or heat exchanger, and back into the block.
water tank:
the water tank is used to store water that is used for mud-mixing, cementing, and rig cleaning.
water well:
a well drilled to obtain a fresh water supply to support drilling and production operations or to obtain a water supply to be used in connection with an enhanced recovery program.
weight indicator:
an instrument near the driller’s position on a drilling rig that shows both the weight of the drill stem that is hanging from the hook (hook load) and the weight that is placed on the bottom of the hole (weight on bit). Weight Indicator
the hole made by the drilling bit, which can be open, cased, or both. Also called borehole, hole, or wellbore.
wellbore :-
a hole drilled or bored into the earth, usually cased with metal  pipe, for the production of gas or oil.
wellbore soak:
an acidizing treatment in which the acid is placed in the wellbore and allowed to react by merely soaking. It is a relatively slow process, because very little of the acid actually comes in contact with the formation. Also called wellbore cleanup. Compare acid fracture.
well completion:
1. the activities and methods of preparing a well for the production of oil and gas or for other purposes, such as injection; the method by which one or more flow paths for hydrocarbons are established between the reservoir and the surface.
2. the system of tubulars, packers, and other tools installed beneath the wellhead in the production casing; that is, the tool assembly that provides the hydrocarbon flow path or paths.
well control:
the methods used to control a kick and prevent a well from blowing out. Such techniques include, but are not limited to, keeping the borehole completely filled with drilling mud of the proper weight or density during operations, exercising reasonable care when tripping pipe out of the hole to prevent swabbing, and keeping careful track of the amount of mud put into the hole to replace the volume of pipe removed from the hole during a trip.
well fluid:
the fluid, usually a combination of gas, oil, water, and suspended sediment, that comes out of a reservoir. Also called well stream.
wellhead :-
the equipment used to maintain surface control of a well.
well logging:
the recording of information about subsurface geologic formations, including records kept by the driller and records of mud and cutting analyses, core analysis, drill stem tests, and electric, acoustic, and radioactivity procedures.
well:-logging instruments :-
instruments lowered into a well to provide  specific information on the condition of the well.
well servicing:
the maintenance work performed on an oil or gas well to improve or maintain the production from a formation already producing. It usually involves repairs to the pump, rods, gas-lift valves, tubing, packers, and so forth.
well-servicing rig:
a portable rig, truck-mounted, trailer-mounted, or a carrier rig, consisting of a hoist and engine with a self-erecting mast. See carrier rig. Compare workover rig.
well stimulation:
any of several operations used to increase the production of a well, such as acidizing or fracturing. See acidize.
Western Canada Sedimentary Basin:-
Canada’s largest region of  sedimentary rocks ‘ the largest source of current oil and gas production.
broken or frayed strands of the steel wire that makes up the outer wrapping of wire rope.
a well drilled in an area where no oil or gas production exists.
a slotted opening or a full section removed in the pipe lining (casing) of a well, usually made to permit sidetracking.
wireline logging tools :-
special tools or equipment, such as logging tools, packers or measuring devices, designed to be lowered into the well on a (wireline (small:-diameter steel cable.

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