Oil & Gas Glossary 1.0

A device that increases the pressure on a fluid or raises it to a higher level. Various types of pumps include the bottomhole pump, centrifugal pump, hydraulic pump, jet pump, mud pump, reciprocating pump, rotary pump, sucker rod pump, and submersible pump

The downhole assembly used to lift fluid to the surface by the reciprocating action of the sucker rod string. Basic components are barrel, plunger, valves, and hold-down. Two types of sucker rod pumps are the tubing pump, in which the barrel is attached to the tubing, and the rod, or insert, pump, which is run into the well as a complete unit.

A sucker rod pump in which the barrel is attached to the tubing. See sucker rod pump.

A device to provide running the tubing dry with a packer released by elevating tubing pressure, thereby opening the tubing to formation pressure.

A large, high-pressure reciprocating pump used to circulate the mud on a drilling rig. A typical mud pump is a two-cylinder, double-acting or a three-cylinder, single-acting piston pump whose pistons travel in replaceable liners and are driven by a crankshaft actuated by an engine or a motor. Also called a slush pump.

A reciprocating pump with two pistons or plungers and used extensively as a mud pump on drilling rigs.

To install a pump or pumping unit, sucker rods, and bottom-hole pump.

To pump so rapidly that the oil level drops below the standing valve on the pump.

A spherical object used to pump down the drill string or tubing to trip, release, or otherwise operate certain hydraulic-type tools.

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

1. a basic component of the sucker rod pump that serves to draw well fluids into the pump.

Any little pump; used for many kinds of small temporary pumping operations.

To have too long a length of rods between the pumping unit and the pump seat so that the pump hits bottom on the down stroke.

A tube mounted at the bottom of a sucker rod pump and inside a gas anchor to provide a conduit into the pump for well fluids that contain little or no gas.

A reciprocating pump with three pistons or plungers

A sucker rod pump that is run into the well as a complete unit.

A process used to repair a hole in the casing by pumping cement down tubing or drill pipe. First, the casinghead, or bradenhead, is closed to prevent fluids from moving up the casing. Then the rig's pumps are started. Pump pressure moves the cement out of the tubing or pipe and, since the top of the casing is closed, the cement goes into the hole in the casing. The tubing or pipe is pulled from the well and the cement allowed to harden. The hardened cement seals the hole in the casing. Although the term "bradenhead squeezing" is still used, the term "bradenhead" is obsolete. See annular space, casinghead, squeeze.

A surface unit similar to a pumping unit but having no individual power plant. Usually, several pump jacks are operated by pull rods or cables from one central power source. Commonly, but erroneously, beam pumping units are called pump jacks. Compare beam pumping unit.

Descriptive of any tool or device that can be pumped down a wellbore. Pump-down tools are not lowered into the well on wireline; instead, they are pumped down the well with the drilling fluid.

An electric or hydraulic pump on an accumulator that pumps hydraulic fluid under high pressure to the blowout preventers so that they may be closed or opened.

A tubular, perforated device attached to the bottom of sucker-rod pump that helps to prevent gas lock. The device works on the principle that gas, being lighter than oil, rises. As well fluids enter the anchor, the gas breaks out of the fluid and exits from the anchor through perforations near the top. The remaining fluids enter the pump through a mosquito bill (a tube with the anchor), which has an opening near the bottom. In this way, all or most of the gas escapes before the fluids enter the pump.

Gas that enters the wellbore when the mud pump is shut down and pipe is being pulled from the wellbore. The gas may enter because of the reduction in bottomhole pressure when the pump is shut down, because of swabbing, or because of both.

The relatively small amount of gas that enters a well when the mud pump is stopped for a connection to be made. Since bottomhole pressure decreases when the pump is stopped, gas may enter the well.

A pump with an impeller or rotor, an impeller shaft, and a casing, which discharges fluid by centrifugal force.

An arrangement of slips and packing rings used to suspend tubing from a tubing head.

A device that holds the lower end of a tubing string in place by means of slips, used to prevent tubing movement when no packer is present.

An undesirable whipping motion in the sucker rod string that occurs when the string is not properly attached to the sucker rod pump or when the pump is operated at a resonant speed.

See sucker rod pump

To start the mud pump for restoring circulation of the mud column. Because the stagnant drilling fluid has thickened or gelled during the period of no circulation, high pump pressure is usually required to break circulation.

A workover performed with a continuous steel tube, normally 3/4 inch to 1 inch outside diameter, which is run into the well in one piece inside the normal tubing. Lengths of the tubing up to 16,000 feet are stored on the surface on a reel in a manner similar to that used for wireline. The unit is rigged up over the wellhead. The tubing is injected through a control head that seals off the tubing and makes a pressure-tight connection. A unique feature of the unit is that it allows continuous circulation while it is being lowered into the hole.

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.

A workover performed with a small-diameter tubing work string inside the normal tubing. Equipment needed is essentially the same as that for a conventional workover except that it is smaller and lighter.

A machine designed specifically for sucker rod pumping. An engine or motor (prime mover) is mounted on the unit to power a rotating crank. The crank moves a horizontal member (walking beam) up and down to produce reciprocating motion. This reciprocating motion operates the pump. Compare pump jack

A diagnostic tool used to ascertain whether there is a gas leak in the tubing of a gas lift well. If there is a tubing leak, the pressure on the annulus will equal the pressure on the tubing.

A device installed on a gas lift mandrel, which in turn is put on the tubing string of a gas lift well. Tubing and casing pressures cause the valve to open and close, thus allowing gas to be injected into the fluid in the tubing to cause the fluid to rise to the surface.

To pump a quantity of heavy mud into the drill pipe. Before hoisting drill pipe, it is desirable (if possible) to pump into its top section a quantity of heavy mud (a slug) that causes the level of the fluid to remain below the rig floor so that the crew members and the rig floor are not contaminated with the fluid when stands are broken out.

A string of tubing used to produce the well, providing well control and energy conservation.

Large wrenches used to break out and make up tubing. They may be operated manually, hydraulically, or pneumatically.

A device used with slips to prevent tubing from falling into the hole when a joint of pipe is being unscrewed and racked.

Lighter-duty well maintenance than hydraulic workover, employing small OD tubing capable of descending down the production string under well pressure

A tubing sub made of abrasion-resistant material. It is used in a tubing string where high-velocity flow through perforations may cause external erosion.

A pump consisting of a piston that moves back and forth or up and down in a cylinder. The cylinder is equipped with inlet (suction) and outlet (discharge) valves. On the intake stroke, the suction valves are opened, and fluid is drawn into the cylinder. On the discharge stroke, the suction valves close, the discharge valves open, and fluid is forced out of the cylinder.

The act of pulling tubing out of and running it back into a well.

A tubing sub made of abrasion-resistant material and used in a tubing string where turbulent flow may cause internal erosion.

A flared-end sub run on the end of the tubing string to permit easy access of wireline tools into the tubing ID.

A flared-end sub run on the end of the tubing string to permit easy access of wireline tools into the tubing ID.

See reeled tubing

A mechanically operated (tubing rotation) valve u used to shut off formation pressure above a packer, thus testing all connections form the packer to the tree.

Said of a well that is being pumped.

A damping apparatus used to pull tubing. The elevators latch onto the pipe just below the top collar. The elevators are attached to the hook by steel links or bails.

2. the rod joined to the connecting rod and piston rod in a mud pump

2. the rod that serves as a piston in a reciprocating pump.

A pressure-multiplier-type well servicing mobile pump.

Connection of treating line during well servicing, from pump trucks to tree/well

The part of a pump valve which holds the ball to limit its movement.

The main parts of the valves in a plunger-type oil-well pump.

3. trying to pump out a gas influx before the expansion of gas reduces pressure allowing the well to kick.

A piece of downhole equipment, consisting of a sealing device, a holding or setting device, and an inside passage for fluids, used to block the flow of fluids through the annular space between the tubing and the wall of the wellbore by sealing off the space between them. 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 inside bore of the packer and into the 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 special device placed in a string of tubing that can be operated by a wireline tool to open or close orifices to permit circulation between the tubing and the annulus. It may also be used to open or shut off production from various intervals in a well. Also called circulation sleeve.

To pull rods and tubing from a well at the same time. Tubing must be "stripped" over the rods a joint at a time.

Slips designed specifically to be used with tubing.

An arrangement of valves and piping that permits a wide choice in the routing of suction and discharge fluids among two or more pumps

A rapid increase in n pressure downhole that occurs when the drill stem is lowered too fast or when the mud pump is brought up to speed after starting.

To measure drill pipe or tubing as it is pulled out of the hole, usually to determine the depth of the well or the depth to which the pipe or tubing was run.

A device used to form a seal around a reciprocating or rotating rod (as in a pump) to prevent fluid leakage. Specifically, the movable part of a stuffing box by which the packing is compressed.

A vertical pipe rising along the side of the derrick or mast, which joins the discharge line leading from the mud pump to the rotary hose and through which mud is pumped going into the hole.

A cast-iron or magnesium drillable tool consisting of a packing assembly and a back-pressure valve. It is used to close off the annular space between tubing or drill pipe and casing to allow the placement of cement or fluid through the tubing or drill pipe at any predetermined point behind the casing or liner, around the shoe, or into the open hole around the shoe.

A small platform with finger-like steel projections attached to the side of the mast on a well servicing unit. When a string of sucker rods or tubing is pulled from a well, the top end of the rods or tubing is placed (racked) between the steel projections and held in a vertical position in the mast.

A device used to suspend a rod string after the pump has been spaced or when the weight of the rod string must be taken off the pumping equipment.

A clamp used to hold the rod string in pumping position when the well is in the final stages of being put back on the pump.

A short length of sucker rod that is attached to the top of the sucker rod pump

The process of raising or lifting fluid from a well by injecting gas down the well through tubing or through the tubing-casing annulus. Injected gas aerates the fluid to make it exert less pressure than the formation does; consequently, the higher formation pressure forces the fluid out of the wellbore. Gas may be injected continuously or intermittently, depending on the producing characteristics of the well and the arrangement of the gas-lift equipment.

A well-servicing unit whose mast consists of two steel tubes. Double-pole masts provide racking platforms for handling rods and tubing in stands and extend from 65 to 67 feet (20 meters) so that rods can be suspended as 50-foot (15 meter) doubles and tubing set back as 30-foot (9-meter) singles. See pole mast.

A heavy-duty steel, T-shaped pipe fitting that is screwed or flanged to the top of a pumping well. The polished rod works through a stuffing box on top of the tee and in the run of the tee to operate a sucker rod pump in the well. Pumped fluid is discharged through the side opening of the tee.

A mechanical arrangement that prevents the upward movement of certain pieces of equipment installed in a well. A sucker rod pump may use a mechanical hold-down for attachment to a seating nipple.

An arrangement for producing a well in which one wellbore penetrates two or more petroleum-bearing formations. In one type, multiple tubing strings are suspended side by side in the production casing string, each a different length and each packed to prevent the commingling of different reservoir fluids. Each reservoir is then produced through its own tubing string. Alternatively, a small-diameter production casing string may be provided for each reservoir, as in multiple miniaturized or multiple tubingless completions.

To pump a designated quantity of a substance (such as acid or cement) into a specific interval in the well. For example, 10 barrels of diesel oil may be spotted around an area in the hole in which drill collars are stuck against the wall of the hole in an effort to free the collars.

The equipment included in the drilling fluid circulating system of a rotary rig. Basically, the components consist of the mud pump, rotary hose, swivel, drill stem, bit, and mud return line.

2. the cylindrical part of a sucker rod pump in which the piston-like plunger moves up and down. Operating as a piston inside a cylinder, the plunger and barrel create pressure energy to lift well fluids to the surface.

A cylindrical, accurately machined, metallic section that forms the working barrel of some reciprocating pumps. Liners are an inexpensive means of replacing worn cylinder surface, and in some pumps they provide a method of conveniently changing the displacement and capacity of the pumps.

A single well that produces from two separate formation at the same time. Production from each zone is segregated by running two tubing strings with packers inside the single string of production casing, or by running one tubing string with a packer through one zone while the other is produced through the annulus. In a miniaturized dual completion, two separate 4 1/2-inch or smaller casing strings are run and cemented in the same wellbore.

1. to collect a mass of sticky consolidated material, usually drill cuttings, on drill pipe, drill collars, bits, and so forth. A bit with such material attached to it is called a balled-up bit. Balling up is frequently the result of inadequate pump pressure or insufficient drilling fluid.

A special wrench designed for use in connecting the cage of a sucker rod pump to the sucker rod string.

A sucker rod string, that is, the entire length of sucker rods, which usually consist of several single rods screwed together. The rod string serves as a mechanical link from the beam pumping unit on the surface to the sucker rod pump near the bottom of the well.

2. the amount of pressure indicated by a drill pipe pressure gauge when drilling fluid is being circulated by the mud pump. Pressure losses occur as the fluid is circulated.

A fixed ball-and-seat valve at the lower end of the working barrel of a sucker rod pump. The standing valve and its cage do not move, as does the traveling valve. Compare traveling valve.

A method of killing a well in which the mud level in the pits is held constant while the choke size is reduced and the pump speed slowed. It is not effective, and therefore, is not recommended, because casing pressure increases to the point at which the formation fractures or casing ruptures, and control of the well is lost.

Abbreviation: tubing conveyed perforator.

Very small tubing or pipe.

A component of a packer to which the tubing is connected.

A portable servicing or workover outfit, usually mounted on wheels and self-propelled. A well servicing unit consists of a hoist and engine mounted on a wheeled chassis with a self-erecting mast. A workover rig is basically the same, with the addition of a substructure with rotary, pump, pits, and auxiliaries to permit handling and working a drill string.

V: 1. to operate a swab on a wireline to bring well fluids to the surface when the w4ell does not flow naturally. Swabbing is a temporary operation to determine whether the well can be made to flow. If the well does not flow after being swabbed, a pump is installed a a permanent lifting device to bring the oil to the surface.

A tubing safety valve.

A spring-loaded finger in a tubing end locator.

2. the process of putting tubing into a well under pressure.

2. the process of removing tubing from the well under pressure.

The area above a packer between casing ID and tubing OD

The displacing of wellbore fluids from the annulus up the tubing

2. of a hole, having no drill pipe or tubing suspended in it.

A device into which fit the slips or wedges which support tubing.

To measure and record length of pipe of tubing

The buckling of tubing in a large-diameter pipe or casing.

Oil-well, casing, tubing, or drill pipe.

An unloader; provides a means to equalize tubing and annulus pressure.

Running pipe or tubing and landing it on a downhole tool.

The lowering of pipe or tubing into the bore of a downhole tool.

To pump drilling fluid into the wellbore while the pipe is being withdrawn to ensure that the wellbore remains full of fluid even though the pipe is withdrawn. Filling the hole lessens the danger of a kick or of caving of the well or the wellbore.

Material used on threads of pipe or tubing to lubricate and prevent leakage.

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.

A special steel pumping rod. Several rods screwed together make up the mechanical link from the beam pumping unit on the surface to the sucker rod pump at the bottom of a well. Sucker rods are threaded on each end and manufactured to dimension standards and metal specifications set by the petroleum industry. Lengths are 25 or 30 feet (7.6 or 9.1 meters); diameter varies from 1/2 to 1-1/8 inches (12 to 30 millimeters). There is also a continuous sucker rod (tradename: Corod).

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

The treatment of a producing well with heated oil to melt accumulated paraffin in the tubing and the annulus.

To lower the drill stem, tubing, casing, or sucker rods in to the wellbore.

A diagnostic tool used to ascertain the position of a gas leak in the tubing of a gas lift well.

A diagnostic tool used to ascertain the position of a gas leak in the tubing of a gas-lift well.

The depth in the hole at which the tubing, casing, or drill pipe is stuck.

A method for completing a well in which tubing is set inside 4-1/2-inch or larger casing.

2. to force a wireline tool or tubing down the hole by using a reciprocating motion.

A device used to clean deposits of paraffin from tubing or flow lines (see pig or rabbit).

A device set in tubing, particular collars, to facilities the landing of pressure bombs (recorders).

To obtain an accurate measurement of the depth reached in a well by measuring the drill pipe or tubing as it is run into the well.

To lower pipe or tubing onto a downhole tool, transferring all or part of the hook load.

A string of pipe used in workover of well-servicing operations; not typically considered as production tubing.

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

An emergency mechanism component enabling the retrieval of a packer (or tubing) if stuck.

A length of drill or line pipe, tubing, or casing considerably shorter than 30 feet.

Wedge-shaped toothed pieces of metal that fit inside a bowl and are used to support tubing or other pipe.

A hydraulically powered device used in lieu of a rotary to turn the drill pipe, tubing, or casing in a well.

A hinged closure mechanism operating in a pivot manner, used to shut off tubing flow.

A device in a rotary table or other tool into which tubing, drill pipe, or slips can be inserted.

The driller or head well puller in charge of operations on a well servicing rig that is used to pull sucker rods or tubing

Removing fluid from the tubing in a well, often by means of a swab, to lower the bottomhole pressure in the wellbore at the perforations and induce the well to flow.

A section of drill pipe, casing, or tubing consisting of four joints screwed together. Compare double, single, thribble.

A method of lifting oil using a swab or free piston propelled by compressed gas from the lower end of the tubing string to the surface.

Equipment operated hydraulically or by compressed air for making up and breaking out drill pipe, casing, tubing, and rods.

A cycle, or down the hole and back, is the time required for the pump to move the drilling fluid in he hole. The cycle in minutes equals the barrels of mud in the hole divided by barrels per minute.

A blowout prevention device consisting of a gland and packing arrangement bolted to the wellhead. It is often used to seal the annular space between tubing and casing.

To bleed pressure from casing of a dead well, then from tubing, then from casing, and so on so that the well will start to flow.

The operation during which stuck drill stem or tubing is freed using washover pipe.

Running of a gauge on tubing or slickline to verify casing dimensions.

The depth in the hole at which the drill stem, tubing, or casing is stuck.

A well-servicing outfit used in pulling rods and tubing from the well. See production rig.

Drill pipe, tubing, sucker rods, and so forth with the diameter near the top of the well larger than the diameter below.

A blanking valve placed in a gas lift mandrel to block off annular communication to the tubing.

Commonly referred to as snubbing; running of tool and/or pulling of tubing under well pressure.

A device closed around the rods when the well may flow through the tubing while the rods are being pulled. It is a form of blowout preventer.

A special-purpose valve used to facilitate spacing out and ranging up the well, run in on the tubing string.

Tubing pressure acting on the net piston area and causing a force to be exerted on a mandrel.

A device with a restricted opening placed in the lower end of the tubing to control the rate of flow. See choke.

An accessory employed above a packer, to permit annulus-to-tubing circulation or vice versa.

Blade tool used to scrape away junk or debris from inside casing; run on pipe or tubing.

A string of tubing or pipe, usually 3/4 or 1 inch in diameter.

Sealing members at the production tubing for landing inside the packer's seal bore.

Abbreviation: polished bore receptacle, a section in the casing string to facilitate landing of the production tubing (casing).

A finger-like device used to lock or position certain tool components by manipulating the tubing string or downhole tool

A flow-control device employing a ball with a rotating mechanism to open or close the tubing medium.

Clamps that grip a stand of casing, tubing, drill pipe, or sucker rods so that the stand can be raised or lowered into the hole.

The string of drill pipe tubing suspended in a well to which is attached a special tool or device that is used to carry out a certain task, as squeeze cementing or fishing.

The string of drill pipe or tubing suspended in a well to which is attached a special tool or device that is used to carry out a certain task, such as squeeze cementing or fishing.

A circular steel device that holds slips supporting a suspended string of drill pipe, casing, or tubing. A spider may be split or solid.

An accessory attached o the top of the drill pipe or tubing to form a connection with the mud system to permit circulation of the drilling mud. In some cases, it is also a rotating head.

A sleeve designed to shut off tubing-to-annulus flow should the sliding sleeve become inoperative.

1. a condition sometimes encountered in a pumping well when dissolved gas, released from solution during the upstroke of the plunger, appears as free gas between the valves. If the gas pressure is sufficient, the standing valve is locked shut, and no fluid enter the tubing.

A length of pipe whose bottom edge is serrated or dressed with a hard cutting material and that is run into the wellbore around the outside of stuck casing, pipe, or tubing to mill away the obstruction.

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

A device that prevents leakage along a piston, rod, propeller shaft, or other moving part that passes through a hole in a cylinder or vessel. It consists of a box or chamber made by enlarging the hole and a gland containing compressed packing. On a well being artificially lifted by means of a sucker rod pump, the polished rod operates through a stuffing box, preventing escape of oil and diverting it into a side outlet to which is connected the flow line leading to the oil and gas separator or to the field storage tank. For a bottomhole pressure test, the wireline goes through a stuffing box and lubricator, allowing the gauge to be raised and lowered against well pressure. The lubricator provides a pressure-tight grease seal in the stuffing box.

A series of hydraulic rams to restrain and pull tubing under well pressure, temporarily attached to the wellhead for workover.

A tube extending the effective packer seal bore; used where excessive tubing expansion or contraction is anticipated.

A retrievable receptacle anchored into the top of a production packer to land a tubing seal assembly

1. a rubber disk surrounding drill pipe or tubing that removes mud as the pipe is brought out of the hole.

A bottomhole choke run on wireline and landed in a nipple profile in the tubing string.

The action of pull out and subsequently running back into the hole a string of drill pipe or tubing. Making a round trip is also called tripping.

To displace the wellbore fluid back to the surface; to displace tubing volume back to the pit.

A single length (30 feet or 9 meters) of drill pipe, drill collar, casing, or tubing that has threaded connections at both ends. Several joints screwed together constitute a stand of pipe.

Heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe approximately 30 feet (9 meters) long are coupled together by means of tool joints.

A method of producing a well in which only production casing is set through the pay zone, with no tubing or inner production string used to bring formation fluids to the surface. This type of completion has its best application in low-pressure, dry-gas reservoirs.

Any packer designed to make a seal between the tubing and the casing during production

A casing sub containing a seal bore and a left-handed thread, run as a crossover between casing sizes, to provide a tubing anchor.

A type of corrosion that occurs when a small electric current flows from one piece of metal equipment to another. It is particularly prevalent when two dissimilar metals are present in an environment in which electricity can flow (as two dissimilar joints of tubing in an oil or gas well).

A rubber or rubber-like device on a special rod (a swab), which forms a seal between the swab and the wall of the tubing or casing.

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.

A special nipple made up in the tubing, casing, or drill pipe string the configuration of which is such that a tool contacting it can pass through only if the tool is in the proper position or configuration.

The equipment installed at the surface of the wellbore. A wellhead includes such equipment as the casinghead and tubing head. adj: pertaining to the wellhead (e.g., wellhead pressure).

Specialized tools used to run equipment in a well, such as a wireline running tool for installing retrievable gas lift valves. Various tubing-type running tools are also used.

An explosive method utilizing primacord, which is an instantaneous textile-covered fuse with a core of very high explosive. It is used to create an explosive jar inside st5uck drill pipe or tubing so that the pipe may be backed off at the joint immediately above where it is stuck.

Any kind of pipe. Oilfield tubular goods include tubing, casing, drill pipe, and line pipe. Also called tubulars.

A workover rig, usually lightweight, that is specially built to run a string of 3/4 inch or 1-inch tubing. See macaroni string.

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 as spiral grapple, firmly grips the pipe, allowing the fish to be pulled from the hole.

Gas pressure built up between the casing and tubing.

See casing hanger, tubing hanger

The derrickman's working platform. As pipe of tubing is run into or out of the hole, the derrickman must handle the top end of the pipe, which may be as high as 90 feet (27 m) in the derrick or mast. The monkeyboard provide a small platform to raise him to the proper height for handling the top of the pipe.

A part of the brake mechanism consisting of a flexible steel band lined with a material that grips a drum when tightened. On a drilling rig, the brake band acts on the flanges of the drawworks drum to control the lowering of the traveling block and its load of drill pipe, casing, or tubing.

The pressure in a well between the casing and the tubing or the casing and the drill pipe.

A block with lead or another relatively soft material on its bottom. It is made up of 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 and indicates the fish's position in the hole, i.e., whether it is centered or off to one side. From this information, the correct fishing tool can be selected.

Drill pipe, drill collars, casing, or tubing that has inadvertently become immovable in the hole. Sticking may occur when drilling is in progress, when casing is being run in the hole, or when the drill pipe is being hoisted.

The large wrenches used to make up or break out drill pipe, casing, tubing, or other pipe; variously called casing tongs, pipe tongs, and so forth, according to the specific use. Power tongs are pneumatically or hydraulically operated tools that serve to spin the pipe up tight and, in some instances, to apply the final makeup torque.

A downhole tool with rough, sharp, extremely hard cutting surfaces for removing metal by grinding or cutting. Mills are run on drill pipe or tubing to grind up debris in the hole, remove stuck portions of drill stem or sections of casing for sidetracking, and ream out tight spots in the casing. They are also called junk mills, reaming mills, and so forth, depending on what use they have.

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 bypassing the pipe. Also called a piloted mill.

A tool composed of a mandrel on which are mounted several heavy-duty rollers with eccentric roll surfaces. It is used to restore buckled, collapsed, or dented casing in a well to normal diameter and roundness. Made up on tubing or drill pipe and run into the well to the depth of the deformed casing, the tool is rotated slowly, allowing the rollers to contact all sides of the casing and restore it to roughly its original condition.

A large, hook-shaped device from which the swivel is suspended. It is designed to carry maximum loads ranging from 100 to 650 tons (90 to 590 tonnes) and turns on bearings in its supporting housing. A strong spring within the assembly cushions the weight of a stand (90 feet, about 27 meters) of drill pipe, thus permitting the pipe to be made up and broken out with less damage to the tool join threads. Smaller hooks without the spring are used for handling tubing and sucker rods. See stand and swivel.

A device made up in the drill string that, when actuated, delivers a heavy downward blow to the string. A bumper jar has a hollow body that moves upward when the drill string is picked up. When the string is dropped quickly, the jar body produces a sharp downward blow on the tubing or pipe made up below the jar. If downward blows can free a fish, a bumper jar can be very effective.

A variation of squeeze cementing for wells with two producing zones in which (1) the upper fluid sand is perforated; (2) tubing is run with a packer, and the packer is set between the two perforated intervals; (3) water is circulated between the two zones to remove as much mud as possible from the channel; (4) cement is pumped through the channel and circulated; (5) the packer is released and picked up above the upper perforation, a low squeeze pressure is applied, and the excess cement is circulated out. The process is applicable where there is communication behind the pipe between the two producing zones because of channeling of the primary cement or where there is essentially no cement in the annulus.

A method of stimulating production by opening new flow channels in the rock surrounding a production well. Often call a frac job. Under extremely high hydraulic pressure, a fluid (such as distillate, diesel fuel, crude oil, dilute hydrochloric acid, water, or kerosene) is pumped downward through production tubing or drill pipe and forced out below a packer or between two packers. The pressure causes cracks to open in the formation, and the fluid penetrates the formation through the cracks. Sand grains, aluminum pellets, walnut shells, or similar materials (propping agents) are carried in suspension by the fluid into the cracks. When the pressure is released at the surface, the fracturing fluid returns to the well. The cracks partially close on the pellets, leaving channels for oil to flow around them to the well. See explosive fracturing, hydraulic fracturing.