Oil & Gas Glossary 1.0

Any tough, stringy material of threadlike structure used to prevent loss of circulation or to restore circulation in porous or fractured formations.

The fibrous, flaky, or granular material added to a cement slurry or drilling fluid to aid in sealing formations in which lost circulation has occurred. See lost circulation, lost circulation material.

1. the emptying or depressurizing of material in a vessel. 2. the material thus discarded.

An elastic material made of synthetic rubber or plastic; often the main component of the packing material in blowout preventers and downhole packers.

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 laboratory unit used for evaluating or testing drilling fluids. One gram of material, when added to 350 milliliters of fluid, is equivalent to 1 pound of material when added to one 42-gal barrel of fluid.

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

Any material added to drilling fluid to change some of its characteristics or properties.

The cohesion of the individual particles of a given material (i.e., its ability to deform or its resistance to flow).

Usually paraformaldehyde. Any material used to prevent starch or any other substance from fermenting through bacterial action.

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

Any material (i.e., paper, cork, asbestos, or rubber) used to seal two essentially stationary surfaces.

2. a tool place in the hole to retain cement or other material; it may later be removed, drilled out, or left permanently.

An arbitrarily defined measure of resistance of a material to indentation under static or dynamic load

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 given point at a certain temperature and pressure at which no more solid material will dissolve in a liquid.

To increase the weight or density of drilling fluid by adding weighting material.

Material or chemical agent that enhances flocculation.

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.

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 substance added to cement slurries or drilling mud to prevent the loss of cement or mud to the formation. See bridging materials.

A substance added to cement slurries or drilling mud to prevent the loss of cement or mud to the formation. See bridging materials.

A piece of pipe that has been twisted off inside a female connection; or a short section of material, such as belting or pipe, used to lengthen existing equipment.

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.

In drilling-fluid terminology, a chemical is any material that produces changes in the viscosity, yield point, gel strength, fluid loss, and surface tension.

A substance or composition that, when added to a liquid, increases the spreading of the liquid on a surface or the penetration of the liquid into a material.

A drilling mud that contains a minimum amount of solid material (sand, silt, and so on) and that is used in rotary drilling when possible because it can provide fast drilling rates.

A drilling mud that contains a minimum amount of solid material (sand, silt, and so on) and that is used in rotary drilling when possible because it can provide fast drilling rates.

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.

Pertaining to packers and other tools left in the wellbore to be broken up later by the drill bit. Drillable equipment is made of cast iron, aluminum, plastic, or other soft, brittle material.

1. an abrasive material composed of small quartz grains formed from the disintegration of preexisting rocks. Sand consists of particles less than 2 millimeters and greater than 1/16 millimeter in diameter.

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

The presence in a drilling fluid of any foreign material that may tend to produce detrimental properties of the drilling fluid.

A silicate mineral characterized by sheet cleavage; i.e., it separates in thin sheets. Biotite is ferromagnesian black mica, and muscovite is potassic white mica. Sometimes mica is used as a lost circulation material in drilling.

A granular substance (sand grains, aluminum pellets, or other material) that is carried in suspension by the fracturing fluid and that serves to keep the cracks open when fracturing fluid is withdrawn after a fracture treatment.

A rock mass formed by the solidification of material poured (when molten) into the earth's crust or onto its surface. Granite is an igneous rock.

1. compacted solid or semisolid material remaining on a filter after pressure filtration of mud with a standard filter press. Thickness of the cake is reported in thirty-seconds of an inch or in millimeters.

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

Any of various materials, such as mica flakes or walnut hulls, that cure lost circulation. See lost circulation, lost circulation material.

Material that exhibits little or no swelling and whose particle size generally falls between 2 microns and API sand size, or 74 microns (200-mesh) A certain portion of dispersed clays and barite for the most part also fall into this same particle-size range.

A measure of fineness of a woven material, screen, or sieve; e.g., a 200-mesh sieve has 200 openings per linear inch. A 200-mesh screen with a wire diameter of 0.0021 in. (0.0533 mm) has an opening of 0.074 mm, or will pass a particle of 74 microns. See micron.

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.

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.

An explanation of the origin of petroleum, which holds that the hydrogen and the carbon that make up petroleum come from plants and animals of land and sea. Furthermore, the theory holds that more of this organic material comes from very tiny creatures of swamp and sea than comes from larger creatures of land.

A material that causes water and oil to form an emulsion. Water normally occurs separately from oil; if, however, an emulsifying agent is present, the water becomes dispersed in the oil as tiny droplets. Or, rarely, the oil may be dispersed in the water. In either case, the emulsion must be treated to separate the water and the oil.

A drilling contract that calls for the payment of a stipulated amount to the drilling contractor on completion of the well. In a turnkey contract, the contractor furnishes all material and labor and controls the entire drilling operation, independent of operator supervision. A turnkey contract does not, as a rule, include the completion of a well as a producer.