Oil & Gas Glossary 1.0

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 globe valve that contains a sharp, pointed, needle-like plug that is driven into and out of a cone-shaped seat to control accurately a relatively small rate of fluid flow. In a fuel injector, the fuel pressure forces the needle valve off its seat to allow injection.

See valve

A temporary plug set of a PSA, landed in a production packer to convert it to a bridge plug.

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 valve that permits flow in one direction only. if the gas or liquid starts to reverse, the valve automatically closes, preventing reverse movement. Commonly referred to as a one-way valve.

Any object or device that blocks a hole or passageway (such as a cement plug in a borehole).

A valve that opens at a preset pressure to relieve excessive pressures within a vessel or line. Also called a relief valve, safety valve, or safety relief valve.

A rubber plug used in primary cementing operations to displace cement slurry from the casing into the borehole annulus.

A downhole tool, composed primarily of slips, a plug mandrel, and a rubber sealing element, that is run and set in casing to isolate a lower zone while an upper section is being tested or cemented.

A tool used to open or close a downhole valve; a tool used to set or release a downhole tool, such as a retrievable bridge plug.

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

1. an automatic valve that opens or closes when an abnormal condition occurs (e.g., a pressure relief valve on a separator that opens if the pressure exceeds the set point, or the shutdown valve at the wellhead that closes if the line pressure becomes too high or too low).

See gunk plug

2. a valve used to regulate automatically a uniform pressure on the inlet side of the valve.

A special drill stem valve that, when in open position, allows fluid to flow through it, thus allowing the valve to be stabbed into the drill stem.

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.

A rubber-bodied, plastic- or aluminum-cored device used to separate cement and drilling fluid as they are being pumped down the inside of the casing during cementing operations. A wiper plug also removes drilling mud that adheres to the inside of the casing.

Any cementing operation after the primary cementing operation. Secondary cementing includes a plug-back job, in which a plug of cement is positioned at a specific point in the well and allowed to set. Wells are plugged to shut off bottom water or to reduce the depth of the well for other reasons.

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

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

The part of a valve that packs off and encloses the valve stem.

A valve that will open automatically when pressure gets too high.

Operates on the same principle as an annular valve, except it requires pipe rotation for opening and closing operations.

A special valve installed below the kelly. Usually, the valve is open so that drilling fluid can flow out of the kelly and down the drill stem. It can, however, be manually closed with a special wrench when necessary. In one case, the valve is closed and broken out, still attached to the kelly to prevent drilling mud in the kelly from draining onto the rig floor. In another case, when kick pressure inside the drill stem exists, the drill stem safety valve is close to prevent the pressure from escaping up the drill stem.

A valve in the bottom of a retainer. See wireline.

To barely open a valve so that it leaks just a little.

A poppet spring-loaded subsurface valve run in on wireline, landed in a profile, to shut the well if injection ceases.

2. a valve installed at the top of the drill stem to prevent flow out of the drill pipe if a kick occurs during tripping operations.

A surge valve.

1. a large valve located on the Christmas tree and used to control the flow of oil and gas from a well. Also called master gate. 2. the blind or blank rams of a blowout preventer (obsolete).

A valve that employs a sliding gate to open or close the passage in it.

An essentially full-opening valve installed immediately below the kelly, with outside diameter equal to the tool joint outside diameter.

An essentially full-opening valve installed immediately below the kelly, with outside diameter equal to the tool joint outside diameter.

A pin shaped like a carpenter's nail and placed in a pressure relief valve. When the pin shears, it opens the valve to relieve pressure inside a vessel.

1. a valve used to regulate back-pressure on equipment or systems through which a fluid flows.

2. the part of the fuel system of an engine that has small holes in it to permit fuel to enter the cylinder. Properly known as a fuel-injection nozzle, but also called a spray valve. The needle valve is directly above the nozzle.

Abbreviation: plug and abandon

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.

See cementing head.

To shut off lower formation in a well bore.

1. to cease efforts to produce oil or gas from a well, and to plug a depleted formation and salvage all material and equipment.

A threaded nipple with a rounded, closed end used to stop up a hole or close off the end of a line.

A tube placed around the retrieving neck of a retrievable bridge plug to "catch" debris.

The valve on the choke and flow line that is nearest to the preventer assembly. Its purpose is to stop the flow through the choke and flow line.

A bull plug or blind flange at the end of a tee to prevent erosion at a point where change in flow direction occurs.

A tool used to mill over permanent bridge plugs/cement retainers while retrieving the milled-out debris

A retrievable tool used to suspend drilling temporarily during a storm offshore.

A portion of cement placed at some point in the wellbore to seal it. See cementing.

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. Popper valves are used extensively as pneumatic (air) controls on drilling rigs and as intake and exhausts valves in most internal-combustion engines.

A small plug that is run through a flow line by pressure to clean the line or test for obstructions (see pig).

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

A plug in the flow line at the well head which has a small hole drilled through it through which oil flows, and which keeps a well from flowing at too high a rate.

To close off, such as with a blank flange or bull plug.

To plug open perforations by using ball sealers.

A reservoir formation in which fluid or plastic masses of rock material originated at unknown depths and pierced or lifted the overlying sedimentary strata.

A slurry in crude or diesel oil containing any of the following materials or combinations: bentonite, cement, attapulgite, and guar gum (never with cement). Used primarily in combating lost circulation.

A settled volume of barite particles from a barite slurry placed in the wellbore, usually to seal off a pressured zone.

Abbreviation: surface safety valve.

A valve or pipe through which bleeding is done.

An extension of a retrievable tool, i.e., a retrievable bridge plug, used to set and release the tool.

A tubing safety valve.

See inside blowout preventer.

A large valve used to shut in a well.

A storm choke

2. gas injected in gas lift operations.

Monovalent. See valence, unloader. Same as a circulation valve

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

Abbreviation: surface-controlled subsurface safety valve.

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

2. a hole or opening in a line or vessel into which a gauge or valve may be inserted and screwed tight.

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

A device placed or hung in the casing below the blowout preventer stack to form a pressure tight seal. Pressure is then applied to the blowout preventer stack to test it for leaks

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 bailing device with a release valve, usually of the disk or flapper type, used to place, or spot material (such as cement slurry) at the bottom of the well.

A bradenhead pack; no packer, very limited pack pressure capability.

See lost circulation. lower kelly cock n: see drill stem safety valve

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

See lost circulation. lower kelly cock n: see drill stem safety valve

To control a blowout by placing a very strong valve on the wellhead. See blowout.

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

A small hydraulic line used to communicate fluid from the surface to a downhole tool, such as a subsurface safety valve.

A loss of pressure that results from friction sustained by a fluid passing through a line, valve, fitting, or other device.

1. a pipe connection around a valve or other control mechanism that is installed to permit passage of fluid through the line while adjustments or repairs are being made on the control.

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.

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

A valve installed above the kelly that can be closed manually to protect the rotary hose from high pressure that may exist in the drill stem

A device employed with a packer to surge, or clean, open perforations; also called surge disk.

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.

The state in fluid dynamics of a fluid in motion is determined by the type of fluid (e.g., Newtonian, plastic, pseudoplastic, dilatant); the properties of the fluid such as viscosity and density; the geometry of the system; and the velocity. Thus, under a given set of conditions and fluid properties, the fluid flow can be described as plug flow, laminar (called also Newtonian, streamline, parallel, or viscous) flow, or turbulent flow.

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

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.

The closing and sealing components of a preventer, like the gate in a gate valve.

A permanent packer, drillable in nature, capable of withstanding extreme working pressures, for remedial work. It has a positive flow-control valve built in.

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.

To drain off liquid or gas, generally slowly, through a valve called a bleeder. To bleed down, or bleed off, means to release pressure slowly from a well or from pressurized equipment.

A check valve in the drill string that will allow fluid to be pumped into the well but will prevent flow from entering the string.

A hollow, rubber-faced cylinder mounted on a hollow mandrel with a pin joint on the upper end to connect to the swab line. A check valve that opens upward on the lower end provides a way to remove the fluid from the well when pressure is insufrficien5t to support flow.

A short, heavy, cylindrical steel section with a rounded bottom and 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 in the casing.

Any valve installed in the drill stem to prevent a blowout through the stem. Mud can be pumped in but flow back up the stem is prevented. Also called an internal blowout preventer.

An item of production equipment used to separate liquid components of the well stream from gaseous elements. Separators are either vertical or horizontal and either cylindrical or spherical in shape. Separation is accomplished principally by gravity, the heavier liquids falling to the bottom and the gas rising to the top. A float valve or other liquid-level control regulates the level of oil in the bottom of the separator.

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.

2. to recover liquid hydrocarbons from natural or refinery gas in a gas-absorption plant. The wet gas enters the absorber at the bottom and rises to the top, encountering a stream of absorption oil (a light oil) traveling downward over bubble-cap trays, valve trays, or sieve trays. The light oil removes, or absorbs, the heavier liquid hydrocarbons from the wet gas.

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 mat. A float collar also prevents backflow of cement during a cementing operation.

A device used to restrict fluid flow to one direction. It consists of a polished sphere, or ball, usually or 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 presented, while flow in in the opposite direction overcomes the force and unseats the ball.

A formation fluid sampling device, actually run on conductor line rather than wireline, that also logs flow and shut-in pressure in rock near the borehole. A spring mechanism holds a pad firmly against the sidewall while a piston creates a vacuum in a test chamber. Formation fluids enter the tes5t chamber through a valve in the pad. A recorder logs the rate at which the test chamber is filled. Fluids may also be drawn to fill a sampling chamber. Wireline formation tests may be done any number of times during one tip in the hole, so they are very useful in formation testing.

The conventional method of formation testing. The basic drill stem test tool consists of a packer or packers, valve or ports that may be opened and closed from the surface, and two or more pressure-recording devices. The tool is lowered on the drill string to the zone to be tested. The packer or packers are set to isolate the zone from the drilling fluid column. The valves or ports are then opened to allow for formation flow while the recorders chart static pressures. A sampling chamber traps dean formation fluids at the end of the test. Analysis of the pressure charts is an important part of formation testing.