Oil & Gas Glossary 1.0

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

A 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 squeeze cement job with open perfs above the packer.

A method of squeeze cementing in which cement is pumped in and the pumps are stopped for a few minutes. Pumping is started and stopped until the desired pressure is obtained.

A drillable service packer, a retainer.

The forcing of cement slurry by pressure to specified points in a well to cause seals at the points of squeeze. It is a secondary cementing method that is used to isolate a producing formation, seal off water, repair casing leaks, and so forth.

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 packer used for the well completion method of gravel packing.

A generic term to describe a retrievable service packer.

A heavy-mandrel service squeeze tool with on-off tool used in drilling operations during storm interruptions.

A method for killing well pressure in which circulation is commenced immediately and mud weight is brought up in steps, or increments, usually a point at a time. Also called circulate-and-weight method.

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 packer equipped with friction blocks or drag springs and slips and designed so that rotation of the pipe unlatches the slips. The friction springs prevent the slips from turning with the pipe and assist in advancing the slips up a tapered sleeve to engage the wail of the outside pipe as weight is put on the packer. Also called a wall-hook packer. See packer.

A method of killing a well that has kicked, in which the choke size is adjusted to maintain a constant casing pressure. This method does not work unless the kick is all or nearly all salt water. if the kick is gas, this method will not maintain a constant bottomhole pressure, because gas expands as it rises in the annulus. In any case, it is not a recommended well-control procedure.

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.

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.

A type of manifold used in squeeze jobs.

See concurrent method

A sub with a ball seat run on top of a hydraulically set packer to set the packer.

A special-purpose packer placed in the casing to permit a sidetrack operation.

An accessory or integral part of a packer used to limit the packer's upward movement under pressure.

A type of gravel pack where the wells production packer is removed and a service packer is run in with the gravel pack assembly. After packing, the service tool is retrieved and the production packer rerun.

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

Spring-loaded buttons on a packer that provide friction with casing to retard movement of one section of a packer while another section rotates for setting.

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.

A type of packer used for open-hole work, with inflatable packing elements

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

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.

Two packers separated by a spacer of variable length. A straddle packer may be used to isolate sections of open hole to be treated or tested or to isolate certain areas of perforated casing from the rest of the perforated section.

A trademark for a retrievable squeeze tool.

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 generic term used to describe a retrievable service squeeze tool; used in remedial cementing.

2. the increasing of external pressure on a diver's body caused by improper diving technique.

A method of improved recovery in which steam is injected into a reservoir through injection wells and driven toward production wells. The steam reduces the viscosity of crude off, causing it to flow more freely. The heat vaporizes lighter hydrocarbons; as they move ahead of the steam, they cool and condense into liquids that dissolve and displace crude oil The steam provides additional gas drive. This method is used to recover viscous oils. Also called continuous steam injection or steam flooding.

A remedial well-servicing activity whereby a cement slurry is pumped into open perfs, split casing, etc., to effect a blockage.

1. a cementing operation in which cement is pumped behind the casing under high pressure to recement channeled areas or to block off an uncementred zone.

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.

A circular seal common in the oilfield; requires deformation (squeeze) to energize and seal.

A bentonite and diesel oil mixture that is pumped down the drill pipe and into the annulus to mix with drilling mud. The stiff, putty-like material is squeezed into lost circulation zones to seal them.

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.

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.

A method of predicting behavior of mud

To perform one or more of a variety of remedial operations on a producing oil well to try to increase production. Examples of workover opera6tions are deepening, plugging back, pulling and resetting liners, squeeze cementing, and so on.

A tool set temporarily in the casing or well to prevent the passage of cement, thereby forcing it to follow another designated path. It is used in squeeze cementing and other remedial cementing jobs.

A compression-set packer

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

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

The area above a packer between casing ID and tubing OD

A method for indicating hook load or force, read off rig's indicator; 1 point = 1,000 pounds

A special tool with a rubber packer or lead seal that is used to repair casing. When casing is damaged downhole, a cut is made below the damaged casing, the damaged casing and the casing above it are pulled from the well, and the damaged casing is removed from the casing string. The tool is made up and lowered into the well on the casing until it engages the top of the casing that remains in the well, and a rubber packer or lead seal in the tool forms a seal with the casing that is in the well. The casing-patch tool is an over-shot-like device and is sometimes called a casing overshot.

Tubular components attached to the bottom of a packer to extend it bore.

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.

A component of a downhole tool, such as a packer, used to wedge slips into the casing wall.

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

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.

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

Position the correct number of feet or joints of pipe from the packer to the surface tree, or from the rig floor to the stack.

A cutoff pup joint below a packer used as a fluid entry device and/or seal assemblies guide

A method of severing steel pipe in a well by applying high-pressure jets of a very corrosive substance against the wall of the pipe. The resulting cut is very smooth.

The set of dense rubber, washer-shaped pieces encircling a packer, which are designed to expand against casing or formation face to seal off the annulus.

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

A retrievable or drillable packer in which sufficient pipe weight is not available to set the tool in compression.

Extensions of the producing string with seals to travel within a packer bore and/or extensions.

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

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

Term to describe the passage entry of seal assemblies into a packer seal bore not locking into place.

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

A device made up in the drill stem and lowered into the well to allow the casing and blowout preventers to b pressure-tested. The sealing device is cup-shaped and is therefore called a cup.

One of the pioneer companies in electric well logging, named for the French scientist who first developed the method. Today, many companies provide logging services of all kinds.

1. a pipe run in a well blow a packer.

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.

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

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

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.

A method of determining the amount of pressure that is allowed to appear on the casing pressure gauge as a kick is circulated out of a well. In general, it is determined by slowly pumping mud into the well while it is shut in and observing the pressure at which the formation begins to take mud.

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

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

A method of well completion in which a slotted or perforated liner, often wire-wrapped, is placed in the well and surrounded by gravel. If open hole, the well is sometimes enlarged by underreaming at the point where the gravel is packed. The mass of gravel excludes sand from the wellbore but allows continued production.

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.

An exploration method in which an instrument that measures the intensity of the earth's gravity is passed over the surface or through the water. In places where the instrument detects stronger or weaker than normal gravity forces, a geologic structure containing hydrocarbons may exist.

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

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.

A drilling method in which a hole is drilled by a rotating bit to which a downward force is applied. The bit is fastened to and rotated by the drill stem, which also provides a passageway through which the drilling fluid is circulated. Additional joints of drill pipe are added as drilling progresses.

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

The gathering of pressure data and fluid samples from a formation to determine its production potential before choosing a completion method. Testing tools include formation testers and drill stem test tools.

The component in a blowout preventer that cuts, or shears, through drill pipe and forms a seal against well pressure. Shear rams are used in floating offshore drilling operations to provide a quick method of moving the rig away from the hole when there is no time to trip the drill stem out of the hole.

An exploration method in which an instrument that measure the intensity of the natural magnetic forces existing in the earth's subsurface is passed over the surface or through the water. The instrument can detect deviations in magnetic forces, and such deviations may indicate the existence of an underground hydrocarbon reservoir.

A drilling method in which the hole is drilled by dropping a sharply pointed bit on bottom. The bit is attached to a cable, and the cable is repeatedly dropped as the hole is drilled.

See packer test.

A method by which a floating offshore drilling rig is maintained in position over an offshore well location without the use of mooring anchors. Generally, several propulsion units, called thrusters, are located on the hulls of the structure and are actuated by a sensing system. A computer to which the system feeds signals directs the thrusters to maintain the rig on location.

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. An open-hole completion has limited use in rather special situations. Also called a barefoot completion.

A device that stores hydraulic fluid under pressure in special containers and provides a method to open and close the blowout preventers quickly and reliably. Usually, compressed air and hydraulic pressure provide the opening and closing force in the unit. See blowout preventer.

An oil-recovery process which involves the injection of a solvent followed by a displacing fluid. - A method of secondary recovery of fluids from a reservoir by injection of fluids that are miscible with the reservoir fluids.

The tool man; a packer hand; a service company hand.

To create holes in casing and cement set through a productive formation. A common method of completing a well is to set casing through the oil-bearing formation and cement it. A perforating gun is then lowered into the hole and fired to detonate high-powered jets or shoot steel projectiles (bullets) through the casing and cement and into the pay zone. The formation fluids flow out of the reservoir through the perforations and into the wellbore. See perforating gun.

A method of improved recovery in which water is injected into a reservoir to remove additional quantities of oil that have been left behind after primary recovery. Waterflooding usually involves the injection of water through wells specially set up for water injection and the removal of water and oil from production wells drilled adjacent to the injection wells.

A coring technique in which core samples are obtained from the hole wall in a zone that has already been drilled. A hollow bullet is fired into the formation wall to capture the core and then retrieved on a flexible steel cable. Core samples of this type usually range from 3/4 to 1-3/16 inches (20 to 30 millimeters) in diameter and from 3/4 to 4 inches (20 to 100 millimeters) in length. This method is especially useful in soft-rock areas.

A logging method that records rift angle, or deflection from the vertical, and direction of the drift. A single-shot directional-survey instrument makes a single photograph of a compass reading of the draft direction and the number of degrees the hole is off vertical. A multishot survey instrument obtains numerous readings in the hole as the device is pulled out of the well. See directional drilling.

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

An acoustic survey or sonic logging method that records the quality or hardness of the cement used in the annulus to bond the casing and the formation. Casing that is well bonded to the formation transmits an acoustic signal quickly; poorly bonded casing transmits a signal slowly. See acoustic survey, acoustic well logging.

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.

A method of improved oil recovery in which chemicals dissolved in water are pumped into a reservoir through injection wells to mobilize off left behind after primary or secondary recovery and to move it toward production wells. The chemical solution includes surfactants or surfactant-forming chemicals that reduce the interfacial and capillary forces between oil and water, releasing the oil and carrying it out of the pores where it has been trapped. The solution may also contain cosurfactants to match the viscosity of the solution to that of the oil to stabilize the solution and to prevent its absorption by reservoir rock. An electrolyte is often added to aid in adjusting viscosity. Injection of the chemical solution is followed by a slug of water thickened with a polymer, which pushes the released oil through the reservoir, decreases the effective permeability of established channels so that new channels are opened, and serves as a mobility buffer between the chemical solution and the final injection of water.