V-G meter. See: direct-indicating viscometer.
VAC. Alternating current voltage.
Valence. A number representing the combining power of an atom, that is, the number of electrons lost, gained, or shared by an atom in a compound. It is also a measure of the number of hydrogen atoms with which an atom will combine or replace, for example, an oxygen atom combines with two hydrogens, hence has a valence of 2. Thus, there are mono-, di-, tri-, etc., valent ions.
Valence effect. In general, the higher the valence of an ion, the greater
the loss of stability to emulsions, colloidal suspensions, etc., these polyvalent ions will impart.
Showing posts with label drilling mud. Show all posts
Showing posts with label drilling mud. Show all posts
Wednesday, October 12, 2016
Friday, October 9, 2015
Drilling fluid process glossary O
Oblong mesh. A screen cloth that has more openings per inch in one direction than in the perpendicular direction. For example, a 70×30 mesh has 70 openings per inch in
one direction and 30 openings per inch in the perpendicular direction, creating a rectangular opening. The smaller opening dimension controls the sizing of spherical
material. See: rectangular screen.
Oblong weave. See: oblong mesh.
OD. Outside diameter of a pipe.
Ohm. The measurement of resistance or electrical friction.
Oil-based drilling fluid. The term ‘‘oil-based mud’’ is applied to a special type of drilling fluid in which oil is the continuous phase and water the dispersed phase.
Oil-based drilling fluid contains from 1 to 5% water emulsified into the system with lime and emulsifiers. Oil-based muds are differentiated from invert emulsion muds
(both water-in-oil emulsions) by the amounts of water used, the method of controlling viscosity, the thixotropic properties, wall-building materials, and fluid loss. See:
invert oil emulsion drilling fluid.
Oil breakout. Oil that has risen to the surface of a drilling fluid. This oil had been previously emulsified in the drilling fluid or may derive from oil-bearing formations
that have been penetrated.
Oil content. The oil content of any drilling fluid is the amount of oil in volume percentage.
Oil immersion. An oil-filled construction in which an electrical device has no electrical connections, joints, terminals, or arcing parts at or above the normal oil level.
Oil wet. A surface on which oil easily spreads. If the contact angle of an oil droplet on a surface is less than 90 , the surface is oil wet. See: lipophilic, water wet.
Oil-in-water emulsion drilling fluid. Any conventional or special waterbase drilling fluid to which oil has been added. A drilling fluid in which the oil content is usually
kept between 3 and 7% and seldom over 10% (it can be considerably higher). Commonly called ‘‘emulsion mud.’’ The oil becomes the dispersed phase and may be
emulsified into the mud either mechanically or chemically. The oil is emulsified into freshor saltwater with a chemical emulsifier
Overflow. The discharge stream from a centrifugal separation that normally contains a higher percentage of liquids than does the feed.
Overflow header. A pipe into which two or more hydrocyclones discharge their overflow.
Overslung. Field terminology denoting that the support ribs for the shaker screen are located below the screen surface. See: underslung.
one direction and 30 openings per inch in the perpendicular direction, creating a rectangular opening. The smaller opening dimension controls the sizing of spherical
material. See: rectangular screen.
Oblong weave. See: oblong mesh.
OD. Outside diameter of a pipe.
Ohm. The measurement of resistance or electrical friction.
Oil-based drilling fluid. The term ‘‘oil-based mud’’ is applied to a special type of drilling fluid in which oil is the continuous phase and water the dispersed phase.
Oil-based drilling fluid contains from 1 to 5% water emulsified into the system with lime and emulsifiers. Oil-based muds are differentiated from invert emulsion muds
(both water-in-oil emulsions) by the amounts of water used, the method of controlling viscosity, the thixotropic properties, wall-building materials, and fluid loss. See:
invert oil emulsion drilling fluid.
Oil breakout. Oil that has risen to the surface of a drilling fluid. This oil had been previously emulsified in the drilling fluid or may derive from oil-bearing formations
that have been penetrated.
Oil content. The oil content of any drilling fluid is the amount of oil in volume percentage.
Oil immersion. An oil-filled construction in which an electrical device has no electrical connections, joints, terminals, or arcing parts at or above the normal oil level.
Oil wet. A surface on which oil easily spreads. If the contact angle of an oil droplet on a surface is less than 90 , the surface is oil wet. See: lipophilic, water wet.
Oil-in-water emulsion drilling fluid. Any conventional or special waterbase drilling fluid to which oil has been added. A drilling fluid in which the oil content is usually
kept between 3 and 7% and seldom over 10% (it can be considerably higher). Commonly called ‘‘emulsion mud.’’ The oil becomes the dispersed phase and may be
emulsified into the mud either mechanically or chemically. The oil is emulsified into freshor saltwater with a chemical emulsifier
Overflow. The discharge stream from a centrifugal separation that normally contains a higher percentage of liquids than does the feed.
Overflow header. A pipe into which two or more hydrocyclones discharge their overflow.
Overslung. Field terminology denoting that the support ribs for the shaker screen are located below the screen surface. See: underslung.
Friday, September 25, 2015
Drilling fluids processing glossary M
Main shaker. The shale shaker that processes drilling fluid from the flowline through the finest-mesh screen.
Manifold. (1) A length of pipe with multiple connections for collecting or distributing fluid. (2) A piping arrangement through which liquids, solids, or slurries from one or more sources can be fed to or discharged from a solids-separation device.
Market grade cloth. A group of industrial wire cloth specifications selected for general-purpose work, made of high-strength, square mesh cloth in several types of metals. The common metal for oilfield use is 304 or 316 stainless steel. The wire diameters are marginally larger than mill grade cloth, resulting in a lower percentage of open area. Market grade and mill grade cloths are used mostly as support screens for fine-mesh screens. See: mill grade cloth, tensile bolting cloth, ultrafine wire cloth, support screen, and calendered.
Marsh funnel. An instrument used in determining the Marsh funnel viscosity. The Marsh funnel is a container with a fixed orifice at the bottom so that when filled with 1500 cc freshwater, 1 qt (946 ml) will flow out in 26±0.5 sec. For 1000 cc out, the efflux time for water is 27.5 ±sec. It is used for comparison values only and not to diagnose drilling fluid problems. See: API Bulletin RP 13B, funnel viscosity,
Marsh funnel viscosity, kinematic viscosity.
Marsh funnel viscosity. Commonly called funnel viscosity. The Marsh funnel viscosity is reported as the time, in seconds, required for 1 qt of fluid to flow through an API standardized funnel. In some areas, the efflux quantity is 1000 cc. See: API RP 13B, funnel viscosity, kinematic viscosity, Marsh funnel.
Martin’s radii. The distance from the centroid of an object to its outer boundary. The direction of this measurement is specified by the azimuth orientation of the line (the radii in the 0°, 90°, 180°, 270°angle from horizontal).
Mass. The inertial resistance of a body to acceleration, considered in classical physics, to a conserved quantity independent of speed. The weight of a body is the product of the mass of the body and the acceleration of gravity for the specific location. In space the mass would stay constant but the weight would disappear as the gravitational acceleration approaches zero.
MBT. Methylene blue test. See: methylene blue test.
Mechanical agitator. A device used to mix, blend, or stir fluids by means of a rotating impeller blade. See: agitator, mechanical stirrer.
Mechanical stirrer. See: agitator, mechanical agitator.
Median cut. The median cut is the particle size that reports 50% of the weight to the overflow 50% of the weight to the underflow. Frequently identified as the D50 point. See: cut point.
Medium (solids). Particles whose diameter is between 74 and 250 microns.
Membrane nitrogen. Air from which water and oxygen have been removed by a filter (membrane) system.
Meniscus. The curved upper surface of a liquid column, concave when the containing walls are wetted by the liquid and convex when they are not wetted.
Mesh. (1) The number of openings (and fraction thereof) per linear inch in a screen, counted in both directions from the center of a wire. (2) An indication of the weave of a woven material, screen or sieve. A 200 mesh sieve has 200 openings per linear inch. A 200 mesh screen with a wire diameter of 0.0021 inch (0.0533 mm) has an opening of 0.0029 in. (0.074) mm and will pass a spherical particle of 74 microns diameter. See: micron.
Mesh count. Such as 30X30, or often 30 mesh, indicating the number of openings per linear inch of screen; and a square mesh. A designation of 70X30 mesh indicates rectangular mesh with 70 openings per inch in one direction and 30 openings per inch in a perpendicular direction.
Mesh equivalent. As used in oilfield drilling applications, the U.S. Sieve number that has the same-size opening as the minimum opening of the screen in use.
Methylene blue test. A test that serves to indicate the amount of active clay in a fluid system, clay sample, or shale sample. Methylene blue is titrated into a slurry until all of the negative charge sites are covered with the methylene blue. This indicates the number of active charge sites present in the slurry. See: base exchange, methylene blue titration,
MBT, cation exchange capacity, CEC.
Methylene blue titration. Methylene blue is a cation that seeks all negative charges on a clay surface after the surface has been properly prepared (see API RP13B). By titrating with a known concentration, this test provides an indication of the amount of clay present in the drilling fluid. See: methylene blue test, MBT, cation exchange capacity, CEC.
Mf. The methyl orange alkalinity of the filtrate, reported as the number of milliliters of 0.02 normal sulfuric acid required per milliliter of filtrate to decrease the pH to reach the methyl orange endpoint (pH 4.3).
Mica. Naturally occurring mineral flake material of various sizes used in controlling lost circulation. An alkali aluminum silicate.
Micelles. Organic and inorganic molecular aggregates occurring in colloidal solutions. chains of individual structural units chemically joined to one another and deposited side by side to form bundles. When bentonite hydrates, certain sodium, or other metallic ions go into solution, the clay particle plus its complement of ions is technically known as a micelle.
Micron. A unit of length equal to one-thousandth of a millimeter. Used to specify particle sizes in drilling fluids and solids control discussions (25,400 microns¼1 inch).
Mil. A unit of length equal to 1/1000 inch.
Milk emulsion. See: oil-in-water emulsion drilling fluid.
Mill grade cloth. A group of industrial wire cloth specifications with lighter wire than market grade cloth. The standard wire diameter of the grade produces a median percentage of open area. Market grade and mill grade cloths are used mostly as support screens for fine-mesh screens. See: market grade cloth, tensile bolting cloth, ultra-fine wire cloth, support screen, and calendered.
Millidarcy. 1/1000 darcy. See: darcy.
Milliliter. A metric system unit for the measurement of volume. Literally 1/1000th of a liter. In drilling-fluid analyses, this term is used interchangeably with cubic centimeter (cc). One quart is equal to approximately 946 ml.
Mini still. An instrument used to distill oil, water, and any other volatile material in a drilling fluid to determine oil, water, and total solids contents as volume percentage. See: distillation, mud still.
Mist drilling. A method of rotary drilling whereby water and/or oil is dispersed in air and/or gas as the drilling fluid. See: foam. ml. See: milliliter.
Molecule. Atoms combine to form molecules. For elements or compounds, a molecule is the smallest unit that chemically still retains the properties of the substance in mass.
Monovalent. See: valence.
Montmorillonite. A clay mineral commonly used as an additive to drilling muds. Sodium montmorillonite is the main constituent of bentonite. Each platelet of the crystalline structure of montmorillonite has two layers of silicon tetrahedra attached to a center layer of alumina octhahedra. The platelets are thin and have a broad surface. Exchangeable cations are located on the clay surfaces between the platelets. Calcium montmorillonite is the main constituent in low-yield clays. See: gel,
bentonite.
Mud. See: drilling fluid, which is the preferred term.
Mud analysis. See: drilling fluid analysis, API RP 13B.
Mud balance. A beam-type balance used in determining drilling-fluid density (mud weight). It consists primarily of a base, a graduated beam with constant volume cup, lid, rider, knife-edge, and counterweight. See: API RP 13B.
Mud box. See: back tank, possum belly.
Mud cleaner. A device that places a screen in series with the underflow of hydrocyclones. The hydrocyclone overflow returns to the mud system, and the underflow reports to a vibrating screen. Solids discharged from the screen are discarded and the screen throughput returns to the system.
Mud compartment. A subdivision of the removal, additions, or check/ suction sections of a surface system. See: mud pits, mud tanks.
Mud ditch. A trough built along the upper edge of many surface systems that is used to direct flow to selected compartments of the surface system. See: mud pits, mud compartment.
Mud engineer. See: drilling fluid engineer.
Mud gun. A submerged nozzle used to stir the drilling fluid with a highvelocity stream. See gunning the pits.
Mud hopper. See: hopper.
Mud house. A structure at the rig to store and shelter sacks of materials used in drilling fluids.
Mud inhibitor. Additives such as salt, lime, lignosulfonate, and calcium sulfate that prevent clay dispersion.
Mud logging. A process that helps determine the presence or absence of oil or gas in the various formations penetrated by the drill bit, and assists with a variety of indicators that assist drilling operations. Drilling fluid and cuttings are continuously tested on their return to the surface, and the results of these tests are correlated with the drilling depth for depth of origin.
Mud mixing devices. The most common device for adding solids to the drilling fluid is by means of the jet hopper. Some other devices to assist mixing are eductors, mechanical agitators, paddle mixers, electric stirrers, mud guns, chemical barrels, etc.
Mud pit. See: mud compartments, mud tanks.
Mud pump. Pumps at the rig used to circulate drilling fluids.
Mud scales. See: mud balance.
Mud still. See: distillation, mini still.
Mud tanks. (1) Drilling-fluid system compartments constructed of metal and mounted so they can be moved from location to location, either as a part of the rig (such as on a semisubmersible rig) or separately on unitized skids (as on most land rigs). (2) Earthen or steel storage facilities for the surface system. Mud pits are of two types: circulating and reserve. Drilling-fluid testing and conditioning is normally done in the circulating pit system.
Mud weight. A measurement of density of a slurry usually reported in lb/gal, lb/cu ft, psi/1000 ft or specific gravity. See: density.
Mud/gas separator. A vessel into which the choke line discharges when a ‘‘kick’’ is being taken. Gas is separated in the vessel as the drilling fluid flows over baffle plates. The gas flows through a line to a flare. The liquid mud discharges into the shale shaker back tank. See: gas buster, poor boy degasser.
Mudding off. A condition promoting reduced production caused by the penetrating, sealing or plastering effect of a drilling fluid. See: formation damage.
Mudding up. Process of mixing drilling fluid additives to a simple, native clay water slurry to achieve some properties not possible with the previous fluid.
MW. Abbreviation for mud weight. See: density, mud weight.
Manifold. (1) A length of pipe with multiple connections for collecting or distributing fluid. (2) A piping arrangement through which liquids, solids, or slurries from one or more sources can be fed to or discharged from a solids-separation device.
Market grade cloth. A group of industrial wire cloth specifications selected for general-purpose work, made of high-strength, square mesh cloth in several types of metals. The common metal for oilfield use is 304 or 316 stainless steel. The wire diameters are marginally larger than mill grade cloth, resulting in a lower percentage of open area. Market grade and mill grade cloths are used mostly as support screens for fine-mesh screens. See: mill grade cloth, tensile bolting cloth, ultrafine wire cloth, support screen, and calendered.
Marsh funnel. An instrument used in determining the Marsh funnel viscosity. The Marsh funnel is a container with a fixed orifice at the bottom so that when filled with 1500 cc freshwater, 1 qt (946 ml) will flow out in 26±0.5 sec. For 1000 cc out, the efflux time for water is 27.5 ±sec. It is used for comparison values only and not to diagnose drilling fluid problems. See: API Bulletin RP 13B, funnel viscosity,
Marsh funnel viscosity, kinematic viscosity.
Marsh funnel viscosity. Commonly called funnel viscosity. The Marsh funnel viscosity is reported as the time, in seconds, required for 1 qt of fluid to flow through an API standardized funnel. In some areas, the efflux quantity is 1000 cc. See: API RP 13B, funnel viscosity, kinematic viscosity, Marsh funnel.
Martin’s radii. The distance from the centroid of an object to its outer boundary. The direction of this measurement is specified by the azimuth orientation of the line (the radii in the 0°, 90°, 180°, 270°angle from horizontal).
Mass. The inertial resistance of a body to acceleration, considered in classical physics, to a conserved quantity independent of speed. The weight of a body is the product of the mass of the body and the acceleration of gravity for the specific location. In space the mass would stay constant but the weight would disappear as the gravitational acceleration approaches zero.
MBT. Methylene blue test. See: methylene blue test.
Mechanical agitator. A device used to mix, blend, or stir fluids by means of a rotating impeller blade. See: agitator, mechanical stirrer.
Mechanical stirrer. See: agitator, mechanical agitator.
Median cut. The median cut is the particle size that reports 50% of the weight to the overflow 50% of the weight to the underflow. Frequently identified as the D50 point. See: cut point.
Medium (solids). Particles whose diameter is between 74 and 250 microns.
Membrane nitrogen. Air from which water and oxygen have been removed by a filter (membrane) system.
Meniscus. The curved upper surface of a liquid column, concave when the containing walls are wetted by the liquid and convex when they are not wetted.
Mesh. (1) The number of openings (and fraction thereof) per linear inch in a screen, counted in both directions from the center of a wire. (2) An indication of the weave of a woven material, screen or sieve. A 200 mesh sieve has 200 openings per linear inch. A 200 mesh screen with a wire diameter of 0.0021 inch (0.0533 mm) has an opening of 0.0029 in. (0.074) mm and will pass a spherical particle of 74 microns diameter. See: micron.
Mesh count. Such as 30X30, or often 30 mesh, indicating the number of openings per linear inch of screen; and a square mesh. A designation of 70X30 mesh indicates rectangular mesh with 70 openings per inch in one direction and 30 openings per inch in a perpendicular direction.
Mesh equivalent. As used in oilfield drilling applications, the U.S. Sieve number that has the same-size opening as the minimum opening of the screen in use.
Methylene blue test. A test that serves to indicate the amount of active clay in a fluid system, clay sample, or shale sample. Methylene blue is titrated into a slurry until all of the negative charge sites are covered with the methylene blue. This indicates the number of active charge sites present in the slurry. See: base exchange, methylene blue titration,
MBT, cation exchange capacity, CEC.
Methylene blue titration. Methylene blue is a cation that seeks all negative charges on a clay surface after the surface has been properly prepared (see API RP13B). By titrating with a known concentration, this test provides an indication of the amount of clay present in the drilling fluid. See: methylene blue test, MBT, cation exchange capacity, CEC.
Mf. The methyl orange alkalinity of the filtrate, reported as the number of milliliters of 0.02 normal sulfuric acid required per milliliter of filtrate to decrease the pH to reach the methyl orange endpoint (pH 4.3).
Mica. Naturally occurring mineral flake material of various sizes used in controlling lost circulation. An alkali aluminum silicate.
Micelles. Organic and inorganic molecular aggregates occurring in colloidal solutions. chains of individual structural units chemically joined to one another and deposited side by side to form bundles. When bentonite hydrates, certain sodium, or other metallic ions go into solution, the clay particle plus its complement of ions is technically known as a micelle.
Micron. A unit of length equal to one-thousandth of a millimeter. Used to specify particle sizes in drilling fluids and solids control discussions (25,400 microns¼1 inch).
Mil. A unit of length equal to 1/1000 inch.
Milk emulsion. See: oil-in-water emulsion drilling fluid.
Mill grade cloth. A group of industrial wire cloth specifications with lighter wire than market grade cloth. The standard wire diameter of the grade produces a median percentage of open area. Market grade and mill grade cloths are used mostly as support screens for fine-mesh screens. See: market grade cloth, tensile bolting cloth, ultra-fine wire cloth, support screen, and calendered.
Millidarcy. 1/1000 darcy. See: darcy.
Milliliter. A metric system unit for the measurement of volume. Literally 1/1000th of a liter. In drilling-fluid analyses, this term is used interchangeably with cubic centimeter (cc). One quart is equal to approximately 946 ml.
Mini still. An instrument used to distill oil, water, and any other volatile material in a drilling fluid to determine oil, water, and total solids contents as volume percentage. See: distillation, mud still.
Mist drilling. A method of rotary drilling whereby water and/or oil is dispersed in air and/or gas as the drilling fluid. See: foam. ml. See: milliliter.
Molecule. Atoms combine to form molecules. For elements or compounds, a molecule is the smallest unit that chemically still retains the properties of the substance in mass.
Monovalent. See: valence.
Montmorillonite. A clay mineral commonly used as an additive to drilling muds. Sodium montmorillonite is the main constituent of bentonite. Each platelet of the crystalline structure of montmorillonite has two layers of silicon tetrahedra attached to a center layer of alumina octhahedra. The platelets are thin and have a broad surface. Exchangeable cations are located on the clay surfaces between the platelets. Calcium montmorillonite is the main constituent in low-yield clays. See: gel,
bentonite.
Mud. See: drilling fluid, which is the preferred term.
Mud analysis. See: drilling fluid analysis, API RP 13B.
Mud balance. A beam-type balance used in determining drilling-fluid density (mud weight). It consists primarily of a base, a graduated beam with constant volume cup, lid, rider, knife-edge, and counterweight. See: API RP 13B.
Mud box. See: back tank, possum belly.
Mud cleaner. A device that places a screen in series with the underflow of hydrocyclones. The hydrocyclone overflow returns to the mud system, and the underflow reports to a vibrating screen. Solids discharged from the screen are discarded and the screen throughput returns to the system.
Mud compartment. A subdivision of the removal, additions, or check/ suction sections of a surface system. See: mud pits, mud tanks.
Mud ditch. A trough built along the upper edge of many surface systems that is used to direct flow to selected compartments of the surface system. See: mud pits, mud compartment.
Mud engineer. See: drilling fluid engineer.
Mud gun. A submerged nozzle used to stir the drilling fluid with a highvelocity stream. See gunning the pits.
Mud hopper. See: hopper.
Mud house. A structure at the rig to store and shelter sacks of materials used in drilling fluids.
Mud inhibitor. Additives such as salt, lime, lignosulfonate, and calcium sulfate that prevent clay dispersion.
Mud logging. A process that helps determine the presence or absence of oil or gas in the various formations penetrated by the drill bit, and assists with a variety of indicators that assist drilling operations. Drilling fluid and cuttings are continuously tested on their return to the surface, and the results of these tests are correlated with the drilling depth for depth of origin.
Mud mixing devices. The most common device for adding solids to the drilling fluid is by means of the jet hopper. Some other devices to assist mixing are eductors, mechanical agitators, paddle mixers, electric stirrers, mud guns, chemical barrels, etc.
Mud pit. See: mud compartments, mud tanks.
Mud pump. Pumps at the rig used to circulate drilling fluids.
Mud scales. See: mud balance.
Mud still. See: distillation, mini still.
Mud tanks. (1) Drilling-fluid system compartments constructed of metal and mounted so they can be moved from location to location, either as a part of the rig (such as on a semisubmersible rig) or separately on unitized skids (as on most land rigs). (2) Earthen or steel storage facilities for the surface system. Mud pits are of two types: circulating and reserve. Drilling-fluid testing and conditioning is normally done in the circulating pit system.
Mud weight. A measurement of density of a slurry usually reported in lb/gal, lb/cu ft, psi/1000 ft or specific gravity. See: density.
Mud/gas separator. A vessel into which the choke line discharges when a ‘‘kick’’ is being taken. Gas is separated in the vessel as the drilling fluid flows over baffle plates. The gas flows through a line to a flare. The liquid mud discharges into the shale shaker back tank. See: gas buster, poor boy degasser.
Mudding off. A condition promoting reduced production caused by the penetrating, sealing or plastering effect of a drilling fluid. See: formation damage.
Mudding up. Process of mixing drilling fluid additives to a simple, native clay water slurry to achieve some properties not possible with the previous fluid.
MW. Abbreviation for mud weight. See: density, mud weight.
Monday, September 14, 2015
Drilling fluids processing glossary L
LCM. Circulation material. See: lost circulation materials.
Lead. In a decanting centrifuge, the slurry-conducting channel formed by the adjacent walls of the flutes or blades of the screw conveyor.
Leonardite. Anaturally occurring oxidized lignite. See: humic acid, lignin.
Light solids. See: low-gravity solids.
Lignin. Mined lignin is a naturally occurring special lignite, for example, leonardite, produced by strip mining from special lignite deposits. The active ingredients are the humic acids. Mined lignins are used primarily as thinners, which may or may not be chemically modified. See: leonardite, humic acid.
Lignosulfonates. Organic drilling-fluid additives derived from by products of the sulfite paper manufacturing process from coniferous woods. Some of the common salts, such as ferrochrome, chrome, calcium, and sodium, are used as deflocculants while other lignosulfonates are used selectively for calcium-treated systems. In large quantities, the ‘‘heavy metal’’ ferrochrome and chrome salts are used for fluid loss control and shale inhibition.
Lime. Ca(OH)2. Commercial form of calcium hydroxide.
Lime-treated drilling fluids. Commonly referred to as ‘‘lime-based’’ muds. These high-pH systems contain most of the conventional freshwater drilling-fluid additives to which slaked lime has been added to impart special inhibition properties. The alkalinities and lime contents of the fluids may vary from low to high. See: calcium-treated drilling fluids.
Limestone. Ca(CO)3. See: calcium carbonate.
Line sizing. Ensuring that the fluid velocity through all piping within the surface system has the proper flow and pipe diameter combination to prevent solids from settling and pipe from eroding. A good rule of thumb is to ensure that fluid flow is between 5 and 9 feet per second, as determined by the following:
Linear motion. Linear motion of a shale shaker screen is produced by two counterrotational motors located above the shaker basket in such a way that a line connecting the two motor axes is perpendicular to a line passing through the center of gravity of the basket. Because the acceleration is applied directly through the center of gravity of the basket, the basket is dynamically balanced; the same pattern of motion will exist at all points along the shaker screen. The resultant screen motion is linear, and the angle of this uniform motion is usually 45° to 60°relative to the shaker screen deck.
Lipophile. Any substance, usually in the colloidal state or an emulsion, that is wetted by oil; that is, it attracts oil or oil adheres to it. See: hydrophile.
Lipophilic. A property of a substance having an affinity for oil or one that is wetted by oil. See: hydrophilic.
Liquid. Fluid that will flow freely and takes the shape of its container.
Liquid-clay phase. See: overflow.
Liquid discharge. See: underflow.
Liquid film. The liquid surrounding each particle discharging from the solids discharge of cyclones and screens. See: bound liquid, free liquid.
Live oil. Crude oil that contains gas and distillates and has not been stabilized or weathered. This oil can cause gas cutting when added to drilling fluid and is a potential fire hazard. See: aromatic hydrocarbons.
Load. A device connected to a motor that is receiving output mechanical power from the motor.
Logging. See: mud logging, electric logging.
Loom. See: warp.
Loss of circulation. See: lost circulation.
Lost circulation. The result of drilling fluid escaping into a formation, usually in fractures, cavernous, fissured, or coarsely permeable beds, evidenced by the complete or partial failure of the drilling fluid to return to the surface as it is being circulated in the hole.
Lost circulation additives. Materials added to the drilling fluid to gain control of or prevent the loss of circulation. These materials are added in varying amounts and are classified as fibrous, flake, or granular.
Lost circulation materials. See: lost circulation additives.
Lost returns. See: lost circulation.
Low-gravity solids. Salts, drilled solids of every size, commercial colloids, lost circulation materials; that is, all solids in drilling fluid, exceptbarite or other commercial weighting materials. Salt is considered a low–specific gravity solid. See: heavy solids, high-gravity solids.
Low-silt drilling fluid. An unweighted drilling fluid that has all the sand and a high proportion of the silts removed and has a substantial content of bentonite or other water–loss–reducing clays.
Low-silt mud. See: low-silt drilling fluid.
Low-solids drilling fluids. A drilling fluid that has polymers, such as ceramic matrix compound (CMC) or xanthan gum (XC) polymer, partially or wholly substituted for commercial or natural clays. For comparable viscosity and densities, a low-solids drilling fluid will have a lower volume percentage solids content. In general, the lower the solids content in a mud, the faster a bit can drill.
Low-solids muds. See: low-solids drilling fluids.
Low-solids nondispersed (LSND) drilling fluids. A drilling fluid to which polymers have been added to simultaneously extend and flocculate bentonite drilled solids. These fluids contain low concentrations of dispersed bentonite and do not contain deflocculants such as lignites, lignosulfonates, etc.
Low-yield clay. Commercial clay chiefly of the calcium montmorillonite type having a yield of approximately 15 to 30 barrels per ton. See: highyield clay, bentonite.
Lyophilic. Having an affinity for the suspending medium, such as bentonite in water.
Lyophlic colloid. A colloid that is not easily precipitated from a solution and is readily dispersible after precipitation by addition of a solvent.
Lyophobic colloid. A colloid that is readily precipitated from a solution and cannot be redispersed by addition of the solution.
Lead. In a decanting centrifuge, the slurry-conducting channel formed by the adjacent walls of the flutes or blades of the screw conveyor.
Leonardite. Anaturally occurring oxidized lignite. See: humic acid, lignin.
Light solids. See: low-gravity solids.
Lignin. Mined lignin is a naturally occurring special lignite, for example, leonardite, produced by strip mining from special lignite deposits. The active ingredients are the humic acids. Mined lignins are used primarily as thinners, which may or may not be chemically modified. See: leonardite, humic acid.
Lignosulfonates. Organic drilling-fluid additives derived from by products of the sulfite paper manufacturing process from coniferous woods. Some of the common salts, such as ferrochrome, chrome, calcium, and sodium, are used as deflocculants while other lignosulfonates are used selectively for calcium-treated systems. In large quantities, the ‘‘heavy metal’’ ferrochrome and chrome salts are used for fluid loss control and shale inhibition.
Lime. Ca(OH)2. Commercial form of calcium hydroxide.
Lime-treated drilling fluids. Commonly referred to as ‘‘lime-based’’ muds. These high-pH systems contain most of the conventional freshwater drilling-fluid additives to which slaked lime has been added to impart special inhibition properties. The alkalinities and lime contents of the fluids may vary from low to high. See: calcium-treated drilling fluids.
Limestone. Ca(CO)3. See: calcium carbonate.
Line sizing. Ensuring that the fluid velocity through all piping within the surface system has the proper flow and pipe diameter combination to prevent solids from settling and pipe from eroding. A good rule of thumb is to ensure that fluid flow is between 5 and 9 feet per second, as determined by the following:
Linear motion. Linear motion of a shale shaker screen is produced by two counterrotational motors located above the shaker basket in such a way that a line connecting the two motor axes is perpendicular to a line passing through the center of gravity of the basket. Because the acceleration is applied directly through the center of gravity of the basket, the basket is dynamically balanced; the same pattern of motion will exist at all points along the shaker screen. The resultant screen motion is linear, and the angle of this uniform motion is usually 45° to 60°relative to the shaker screen deck.
Lipophile. Any substance, usually in the colloidal state or an emulsion, that is wetted by oil; that is, it attracts oil or oil adheres to it. See: hydrophile.
Lipophilic. A property of a substance having an affinity for oil or one that is wetted by oil. See: hydrophilic.
Liquid. Fluid that will flow freely and takes the shape of its container.
Liquid-clay phase. See: overflow.
Liquid discharge. See: underflow.
Liquid film. The liquid surrounding each particle discharging from the solids discharge of cyclones and screens. See: bound liquid, free liquid.
Live oil. Crude oil that contains gas and distillates and has not been stabilized or weathered. This oil can cause gas cutting when added to drilling fluid and is a potential fire hazard. See: aromatic hydrocarbons.
Load. A device connected to a motor that is receiving output mechanical power from the motor.
Logging. See: mud logging, electric logging.
Loom. See: warp.
Loss of circulation. See: lost circulation.
Lost circulation. The result of drilling fluid escaping into a formation, usually in fractures, cavernous, fissured, or coarsely permeable beds, evidenced by the complete or partial failure of the drilling fluid to return to the surface as it is being circulated in the hole.
Lost circulation additives. Materials added to the drilling fluid to gain control of or prevent the loss of circulation. These materials are added in varying amounts and are classified as fibrous, flake, or granular.
Lost circulation materials. See: lost circulation additives.
Lost returns. See: lost circulation.
Low-gravity solids. Salts, drilled solids of every size, commercial colloids, lost circulation materials; that is, all solids in drilling fluid, exceptbarite or other commercial weighting materials. Salt is considered a low–specific gravity solid. See: heavy solids, high-gravity solids.
Low-silt drilling fluid. An unweighted drilling fluid that has all the sand and a high proportion of the silts removed and has a substantial content of bentonite or other water–loss–reducing clays.
Low-silt mud. See: low-silt drilling fluid.
Low-solids drilling fluids. A drilling fluid that has polymers, such as ceramic matrix compound (CMC) or xanthan gum (XC) polymer, partially or wholly substituted for commercial or natural clays. For comparable viscosity and densities, a low-solids drilling fluid will have a lower volume percentage solids content. In general, the lower the solids content in a mud, the faster a bit can drill.
Low-solids muds. See: low-solids drilling fluids.
Low-solids nondispersed (LSND) drilling fluids. A drilling fluid to which polymers have been added to simultaneously extend and flocculate bentonite drilled solids. These fluids contain low concentrations of dispersed bentonite and do not contain deflocculants such as lignites, lignosulfonates, etc.
Low-yield clay. Commercial clay chiefly of the calcium montmorillonite type having a yield of approximately 15 to 30 barrels per ton. See: highyield clay, bentonite.
Lyophilic. Having an affinity for the suspending medium, such as bentonite in water.
Lyophlic colloid. A colloid that is not easily precipitated from a solution and is readily dispersible after precipitation by addition of a solvent.
Lyophobic colloid. A colloid that is readily precipitated from a solution and cannot be redispersed by addition of the solution.
Sunday, September 13, 2015
Drilling fluids processing glossary K
Kelly. A heavy square or hexagonal pipe that passes through rollers in a bushing on the drill floor to transmit rotational torque to the drill string.
Key seat. A section of a hole, usually of abnormal deviation and relatively soft formation, that has been eroded or worn by drill pipe to a size smaller than the tool joints or collars of the drill string. This keyhole-type configuration resists passage of the shoulders of these pipe upset (box) configurations when pulling out of the hole.
Kick. Situation caused when the annular hydrostatic pressure in a drilling well temporarily (and usually relatively suddenly) becomes less than the formation, or pore, pressure in a permeable downhole section. A kick occurs before control of the fluid intrusion is totally lost. A blowout is an uncontrolled influx of formation fluid into the well bore. See: blowout, kill fluid.
Kill fluid. A fluid built with a specific density aimed at controlling a kick or blowout. See: galena.
Kill line. A line connected to the annulus below the blowout preventers for the purpose of pumping into the annulus while the preventers are closed.
Killing a well. (1) Bringing a well kick under control. (2) The procedure of circulating a fluid into a well to overbalance formation fluid pressure after the bottom-hole pressure has been less than formation fluid pressure. See: kick, blowout, kill fluid.
Kilowatt-hour. Horsepower-hour (hp-hr) and kilowatt-hour (kW-hr) are
units of work.
1 hp-hr =1,980,000 ft-lb = 2545 Btu
1 hp-hr =0.7457 kW-hr
1 kW-hour = 1.341 hp-hr= 3413 Btu = 2,655,000 ft-lb:
Kinematic viscosity. The kinematic viscosity of a fluid is the ratio of the viscosity (e.g., cP in g/cm-sec) to the density (e.g., g/cc) using consistent units. In several common commercial viscometers, the kinematic viscosity is measured in terms of the time of efflux, in seconds, of a fixed volume of liquid through a standard capillary tube or orifice. See: marsh funnel viscosity.
In laminar flow, the fluid moves in plates or sections with a differential velocity across the front of the flow profile that varies from zero at the wall to a maximum toward the center for flow. These fluid elements flow along fixed stream lines that are parallel to the walls of the channel of flow. Laminar flow is the first stage of flow in a Newtonian fluid. It is the second stage of flow in a Bingham plastic fluid. This type of motion is also called parallel, streamline, or viscous flow. See: plug flow, parallel flow, turbulent flow.
Key seat. A section of a hole, usually of abnormal deviation and relatively soft formation, that has been eroded or worn by drill pipe to a size smaller than the tool joints or collars of the drill string. This keyhole-type configuration resists passage of the shoulders of these pipe upset (box) configurations when pulling out of the hole.
Kick. Situation caused when the annular hydrostatic pressure in a drilling well temporarily (and usually relatively suddenly) becomes less than the formation, or pore, pressure in a permeable downhole section. A kick occurs before control of the fluid intrusion is totally lost. A blowout is an uncontrolled influx of formation fluid into the well bore. See: blowout, kill fluid.
Kill fluid. A fluid built with a specific density aimed at controlling a kick or blowout. See: galena.
Kill line. A line connected to the annulus below the blowout preventers for the purpose of pumping into the annulus while the preventers are closed.
Killing a well. (1) Bringing a well kick under control. (2) The procedure of circulating a fluid into a well to overbalance formation fluid pressure after the bottom-hole pressure has been less than formation fluid pressure. See: kick, blowout, kill fluid.
Kilowatt-hour. Horsepower-hour (hp-hr) and kilowatt-hour (kW-hr) are
units of work.
1 hp-hr =1,980,000 ft-lb = 2545 Btu
1 hp-hr =0.7457 kW-hr
1 kW-hour = 1.341 hp-hr= 3413 Btu = 2,655,000 ft-lb:
Kinematic viscosity. The kinematic viscosity of a fluid is the ratio of the viscosity (e.g., cP in g/cm-sec) to the density (e.g., g/cc) using consistent units. In several common commercial viscometers, the kinematic viscosity is measured in terms of the time of efflux, in seconds, of a fixed volume of liquid through a standard capillary tube or orifice. See: marsh funnel viscosity.
In laminar flow, the fluid moves in plates or sections with a differential velocity across the front of the flow profile that varies from zero at the wall to a maximum toward the center for flow. These fluid elements flow along fixed stream lines that are parallel to the walls of the channel of flow. Laminar flow is the first stage of flow in a Newtonian fluid. It is the second stage of flow in a Bingham plastic fluid. This type of motion is also called parallel, streamline, or viscous flow. See: plug flow, parallel flow, turbulent flow.
Thursday, September 10, 2015
drilling fluids glossary I&J
ID. Inside diameter of a pipe.
Ideal nozzle. Orifice that will pass fluid without friction loss, theoretically.
Impeller. A spinning disc in a centrifugal pump with protruding vanes used to accelerate the fluid in the pump casing.
Indicator. Substances in acid/base titrations that in solution change color or become colorless as the hydrogen ion concentration reaches a definite value. These values vary with the indicator. In other titrations such as chloride, hardness, and other determinations, these substances change color at the end of the reaction.Common indicators are phenolphthalein, methyl orange, and potassium chromate.
Inertia. Force that makes a moving particle tend to maintain its direction or a particle at rest to remain at rest.
Inhibited drilling fluid. A drilling fluid having an aqueous phase with a chemical composition that tends to retard and even prevent (inhibit) appreciable hydration (swelling) or dispersion formation clays and shales through chemical and/or physical reactions. See: calcium-treated drilling fluids, saltwater drilling fluid.
Inhibited mud. See: inhibited drilling fluid.
Initial gel. See: gel strength.
Inlet. The opening through which the feed mud enters a solids-control device. See: feed inlet, feed opening.
Interfacial tension. The force required to break the surface definition between two immiscible liquids. The lower the interfacial tension between the two phases of an emulsion, the greater the ease of emulsification. When the values approach zero, emulsion formation is spontaneous. See: emulsion, surface tension.
Intermediate (solids). Particles whose diameter is between 250 and 2000 microns.
Intercalation. A shale stabilization mechanism that involves penetration of a foreign material, such as a glycol, between clay lamellae in a shale to retard interaction of the clay with water.
Interstitial water. Water contained in the interstices or voids of formations.
Intrinsic safety. A feature of an electrical device or circuit in which any spark or thermal effect from the electrical device or circuit is incapable of causing ignition of a mixture of flammable or combustible material in air.
Invert drilling fluid. See: invert oil emulsion drilling fluid.
Invert oil emulsion drilling fluid. A water-in-oil emulsion in which water (sometimes containing sodium or calcium chloride) is the dispersed phase, and diesel oil, crude oil, or some other oil is the phase. Water addition increases the emulsion viscosity, and oil reduces the emulsion viscosity. The water content exceeds 5% by volume. See. oil-based drilling fluid
Iodine number. The number indicating the amount of iodine absorbed by oils, fats, and waxes, giving a measure of the unsaturated linkages present. Generally, the higher the iodine number, the more severe the destructive action of the oil on rubber.
Ions. Molecular condition due to loss or gain of electrons. Acids, bases, and salts electrolytes), when dissolved in certain solvents, especially water, are more or less dissociated into electrically charged ions or parts of the molecules. Loss of electrons results in positive charges, producing a cation. A gain of electrons in the formation of an anion, with negative charge. The valence of an ion is equal to the number of charges borne by the ion. See: anion, cation.
Irreducible fraction. See: adsorbed liquid, bound liquid.
Jet. See: eductor.
Jet hopper. A device that has a jet that facilitates the addition of drillingfluid additives to the system. See: hopper, mud hopper.
Jetting. The process of periodically removing a portion of the water, drilling fluid, and/or solids from the pits, usually by means of pumping through a jet nozzle to agitate the drilling fluid while simultaneously removing it from the pit.
Jones effect. The net surface tension of all salt solutions first decreases with an increase in concentration, passes through a minimum, and then increases as the concentration is raised. The initial decrease is called the Jones effect.
Ideal nozzle. Orifice that will pass fluid without friction loss, theoretically.
Impeller. A spinning disc in a centrifugal pump with protruding vanes used to accelerate the fluid in the pump casing.
Indicator. Substances in acid/base titrations that in solution change color or become colorless as the hydrogen ion concentration reaches a definite value. These values vary with the indicator. In other titrations such as chloride, hardness, and other determinations, these substances change color at the end of the reaction.Common indicators are phenolphthalein, methyl orange, and potassium chromate.
Inertia. Force that makes a moving particle tend to maintain its direction or a particle at rest to remain at rest.
Inhibited drilling fluid. A drilling fluid having an aqueous phase with a chemical composition that tends to retard and even prevent (inhibit) appreciable hydration (swelling) or dispersion formation clays and shales through chemical and/or physical reactions. See: calcium-treated drilling fluids, saltwater drilling fluid.
Inhibited mud. See: inhibited drilling fluid.
Initial gel. See: gel strength.
Inlet. The opening through which the feed mud enters a solids-control device. See: feed inlet, feed opening.
Interfacial tension. The force required to break the surface definition between two immiscible liquids. The lower the interfacial tension between the two phases of an emulsion, the greater the ease of emulsification. When the values approach zero, emulsion formation is spontaneous. See: emulsion, surface tension.
Intermediate (solids). Particles whose diameter is between 250 and 2000 microns.
Intercalation. A shale stabilization mechanism that involves penetration of a foreign material, such as a glycol, between clay lamellae in a shale to retard interaction of the clay with water.
Interstitial water. Water contained in the interstices or voids of formations.
Intrinsic safety. A feature of an electrical device or circuit in which any spark or thermal effect from the electrical device or circuit is incapable of causing ignition of a mixture of flammable or combustible material in air.
Invert drilling fluid. See: invert oil emulsion drilling fluid.
Invert oil emulsion drilling fluid. A water-in-oil emulsion in which water (sometimes containing sodium or calcium chloride) is the dispersed phase, and diesel oil, crude oil, or some other oil is the phase. Water addition increases the emulsion viscosity, and oil reduces the emulsion viscosity. The water content exceeds 5% by volume. See. oil-based drilling fluid
Iodine number. The number indicating the amount of iodine absorbed by oils, fats, and waxes, giving a measure of the unsaturated linkages present. Generally, the higher the iodine number, the more severe the destructive action of the oil on rubber.
Ions. Molecular condition due to loss or gain of electrons. Acids, bases, and salts electrolytes), when dissolved in certain solvents, especially water, are more or less dissociated into electrically charged ions or parts of the molecules. Loss of electrons results in positive charges, producing a cation. A gain of electrons in the formation of an anion, with negative charge. The valence of an ion is equal to the number of charges borne by the ion. See: anion, cation.
Irreducible fraction. See: adsorbed liquid, bound liquid.
Jet. See: eductor.
Jet hopper. A device that has a jet that facilitates the addition of drillingfluid additives to the system. See: hopper, mud hopper.
Jetting. The process of periodically removing a portion of the water, drilling fluid, and/or solids from the pits, usually by means of pumping through a jet nozzle to agitate the drilling fluid while simultaneously removing it from the pit.
Jones effect. The net surface tension of all salt solutions first decreases with an increase in concentration, passes through a minimum, and then increases as the concentration is raised. The initial decrease is called the Jones effect.
Tuesday, September 8, 2015
Drilling fluid glossary H
Hardness (water). The hardness of water is due principally to calcium and magnesium ions. The total hardness is measured in terms of parts per million of calcium carbonate or calcium and sometimes epm of calcium. See: API RP 13B.
Head. The height a column of fluid would stand in an open-ended pipe if it was attached to the point of interest. The head at the bottom of a 1000-ft well is 1000 ft, but the pressure would be dependent on the density of the drilling fluid in the well.
Heaving. The partial or complete collapse of the walls of a hole resulting from internal pressures due primarily to swelling from hydration or formation pressures or from internal stresses. See: sloughing.
Heavy solids. See: high-gravity solids.
Hertz. A unit of frequency: cycles per second.
Heterogeneous. A substance that consists of more than one phase and is not uniform, such as colloids, emulsions, etc. It has different properties in different parts.
High-gravity solids (HGS). Solids purchased and added to a drilling fluid specifically and solely to increase drilling-fluid density. Barite (4.2 specific gravity) and hematite (5.05 specific gravity) are the most common additives used for this purpose. See: low-gravity solids.
High-pH drilling fluid. A drilling fluid with a pH range above 10.5. A high-alkalinity drilling fluid. See: pH.
High-yield clay. A classification given to a group of commercial drilling clay preparations having yield of 35 to 50 bbl/ton, an intermediate rating between bentonite and low-yield clays. High-yield drilling clays are usually prepared by peptizing low-yield calcium montmorillonite clays or, in a few cases, by blending some bentonite with the peptized low-yield clay. See: low-yield clay, bentonite.
HLB. Hydrophilic-lipophilic balance. See: hydrophilic-lipophilic balance.
Homogeneous. Of uniform or similar nature throughout, or a substance or fluid that has at all points the same property or composition.
Hook strips. The hooks on the edges of a screen section of a shale shaker that accept the tension member for screen mounting.
Hook-strip panel. One of the two main screen panel types, which consists of one to three layers of screen bordered by metal strips running parallel to the loom. The metal strips have a U-shaped cross section that allows them to be secured and stretched by the shaker tensioning drawbars. These screens are nonpretensioned. See: Rigid frame panel.
Hopper. A large funnel-shaped or cone-shaped device for mixing dry solids or liquids into a drilling-fluid stream in order to uniformly mix these materials into the slurry. The solids are wetted prior to entry into the drilling-fluid system. The system usually consists of a jet nozzle, an open top hopper, and a downstream venturi. See: mud hopper.
Horsepower. The rate of doing work or of expending mechanical energy; that is, horsepower is work performed per unit of time.
1 hp= 550 ft-lb per sec= 0:7067 Btu per sec:
= 0:7457 kilowatt (rated horsepower, converted to kilowatts
= horsepower x 0:746= kilowatts)
Motor nameplate horsepower is the maximum steady load that the motor can pull without damage.
Horsepower-hour. Horsepower-hour (hp-hr) and kilowatt-hour (kW-hr) are units of work.
1 hp-hr= 1,980,000 ft-lb= 2545 Btu
1 hp-hr= 0.7457 kW-hr
1 kW-hr= 1.341 hp-hr= 3413 Btu= 2,655,000 ft-lb
Horseshoe effect. The U shape formed by the leading edge of drilling fluid moving down a shale shaker screen. The drilling fluid usually tends to pass through the center of a crowned screen faster than it passes through the edges, creating the U shape.
HTHP. High temperature high pressure.
HTHP filter press. A device used to measure the fluid loss under HTHP conditions. See: HTHP fluid loss.
HTHP fluid loss. The fluid loss measured under HTHP conditions, usually 300 Fahrenheit and 500 psi differential pressure. See: HTHP filter press.
Humic acid. Organic acids of indefinite composition found in naturally occurring leonardite lignite. The humic acids are the active constituents that assist in the positive adjustment of drilling-fluid properties. See: lignin.
Hydrate. A substance containing water combined in molecular form (such as CaSO4 .2H2O). A crystalline substance containing water of crystallization.
Hydration. The act of a substance to take up water by means of absorption and/or adsorption; usually results in swelling, dispersion and disintegration into colloidal particles. See: absorb, absorption, adsorb, adsorbed liquid.
Hydroclone. See: cyclone, hydrocyclone.
Hydrocyclone. Aliquid/solids separation device utilizing centrifugal force for settling. Fluid tangentially and spins inside the cone. The heavier solids settle to the walls of the cone and move downward until they are discharged at the cone bottom (cone apex). The spinning fluid travels partway down the cone and back up to exit out the top of the cone through the vortex finder.
Hydrocyclone balance point. (1) That adjustment of the apex that creates an opening about the same diameter as the air cylinder inside of the hydrocyclone. (2) In the field, to adjust a balanced design hydrocyclone during the setup of the solids-control system so that it discharges only a slight drip of water at the underflow opening.
Hydrocyclone size. The maximum inside working diameter of the cone part of a hydrocyclone.
Hydrocyclone underflow. The discharge stream from a hydroclone that contains a higher percentage of solids than does the feed. See: solids discharge.
Hydrogen ion concentration. A measure of either the acidity or alkalinity of a solution, normally expressed as pH. See: pH.
Hydrolysis. Hydrolysis is the reaction of a salt with water to form an acid or base. For example, soda ash (Na2CO3) hydrolyzes basically, and hydrolysis is responsible for the increase in the pH of water when soda ash is added.
Hydrometer. A floating instrument for determining the specific gravity or density of liquids, solutions, and slurries.
Hydrophile. Any substance, usually in the colloidal state or an emulsion, that is wetted by water; that is, it attracts water or water adheres to it. See: lipophile.
Hydrophilic. A property of a substance having an affinity for water or one that is wetted by water. See: lipophilic.
Hydrophilic lipophilic balance. The relative attraction of an emulsifier for water and for oil. It is determined largely by the chemical composition and ionization characteristics of a given emulsifier. The HLB of an emulsifier is not directly related to its solubility, but it determines the type of an emulsion that tends to be formed. It is an indication of the behavioral characteristics and not an indication of emulsifier efficiency.
Hydrophobe. Any substance, usually in the colloidal state, that is not wetted by water.
Hydrophobic. Any substance, usually in the colloidal state or an emulsion, that is not wetted by water; that is, it repels water or water does not adheres to it.
Hydrostatic pressure head. The pressure exerted by a column of fluid, usually expressed in pounds per square inch. To determine the hydrostatic head in psi at a given depth, multiply the depth in feet by the density in pounds per gallon by the conversion factor, 0.052.
Hydroxide. Designation that is given basic compounds containing the OH– radical. When these substances are dissolved in water, the pH of the solution is increased. See: base, pH.
Hygroscopic. The property of a substance enabling it to absorb water from the air.
Head. The height a column of fluid would stand in an open-ended pipe if it was attached to the point of interest. The head at the bottom of a 1000-ft well is 1000 ft, but the pressure would be dependent on the density of the drilling fluid in the well.
Heaving. The partial or complete collapse of the walls of a hole resulting from internal pressures due primarily to swelling from hydration or formation pressures or from internal stresses. See: sloughing.
Heavy solids. See: high-gravity solids.
Hertz. A unit of frequency: cycles per second.
Heterogeneous. A substance that consists of more than one phase and is not uniform, such as colloids, emulsions, etc. It has different properties in different parts.
High-gravity solids (HGS). Solids purchased and added to a drilling fluid specifically and solely to increase drilling-fluid density. Barite (4.2 specific gravity) and hematite (5.05 specific gravity) are the most common additives used for this purpose. See: low-gravity solids.
High-pH drilling fluid. A drilling fluid with a pH range above 10.5. A high-alkalinity drilling fluid. See: pH.
High-yield clay. A classification given to a group of commercial drilling clay preparations having yield of 35 to 50 bbl/ton, an intermediate rating between bentonite and low-yield clays. High-yield drilling clays are usually prepared by peptizing low-yield calcium montmorillonite clays or, in a few cases, by blending some bentonite with the peptized low-yield clay. See: low-yield clay, bentonite.
HLB. Hydrophilic-lipophilic balance. See: hydrophilic-lipophilic balance.
Homogeneous. Of uniform or similar nature throughout, or a substance or fluid that has at all points the same property or composition.
Hook strips. The hooks on the edges of a screen section of a shale shaker that accept the tension member for screen mounting.
Hook-strip panel. One of the two main screen panel types, which consists of one to three layers of screen bordered by metal strips running parallel to the loom. The metal strips have a U-shaped cross section that allows them to be secured and stretched by the shaker tensioning drawbars. These screens are nonpretensioned. See: Rigid frame panel.
Hopper. A large funnel-shaped or cone-shaped device for mixing dry solids or liquids into a drilling-fluid stream in order to uniformly mix these materials into the slurry. The solids are wetted prior to entry into the drilling-fluid system. The system usually consists of a jet nozzle, an open top hopper, and a downstream venturi. See: mud hopper.
Horsepower. The rate of doing work or of expending mechanical energy; that is, horsepower is work performed per unit of time.
1 hp= 550 ft-lb per sec= 0:7067 Btu per sec:
= 0:7457 kilowatt (rated horsepower, converted to kilowatts
= horsepower x 0:746= kilowatts)
Motor nameplate horsepower is the maximum steady load that the motor can pull without damage.
Horsepower-hour. Horsepower-hour (hp-hr) and kilowatt-hour (kW-hr) are units of work.
1 hp-hr= 1,980,000 ft-lb= 2545 Btu
1 hp-hr= 0.7457 kW-hr
1 kW-hr= 1.341 hp-hr= 3413 Btu= 2,655,000 ft-lb
Horseshoe effect. The U shape formed by the leading edge of drilling fluid moving down a shale shaker screen. The drilling fluid usually tends to pass through the center of a crowned screen faster than it passes through the edges, creating the U shape.
HTHP. High temperature high pressure.
HTHP filter press. A device used to measure the fluid loss under HTHP conditions. See: HTHP fluid loss.
HTHP fluid loss. The fluid loss measured under HTHP conditions, usually 300 Fahrenheit and 500 psi differential pressure. See: HTHP filter press.
Humic acid. Organic acids of indefinite composition found in naturally occurring leonardite lignite. The humic acids are the active constituents that assist in the positive adjustment of drilling-fluid properties. See: lignin.
Hydrate. A substance containing water combined in molecular form (such as CaSO4 .2H2O). A crystalline substance containing water of crystallization.
Hydration. The act of a substance to take up water by means of absorption and/or adsorption; usually results in swelling, dispersion and disintegration into colloidal particles. See: absorb, absorption, adsorb, adsorbed liquid.
Hydroclone. See: cyclone, hydrocyclone.
Hydrocyclone. Aliquid/solids separation device utilizing centrifugal force for settling. Fluid tangentially and spins inside the cone. The heavier solids settle to the walls of the cone and move downward until they are discharged at the cone bottom (cone apex). The spinning fluid travels partway down the cone and back up to exit out the top of the cone through the vortex finder.
Hydrocyclone balance point. (1) That adjustment of the apex that creates an opening about the same diameter as the air cylinder inside of the hydrocyclone. (2) In the field, to adjust a balanced design hydrocyclone during the setup of the solids-control system so that it discharges only a slight drip of water at the underflow opening.
Hydrocyclone size. The maximum inside working diameter of the cone part of a hydrocyclone.
Hydrocyclone underflow. The discharge stream from a hydroclone that contains a higher percentage of solids than does the feed. See: solids discharge.
Hydrogen ion concentration. A measure of either the acidity or alkalinity of a solution, normally expressed as pH. See: pH.
Hydrolysis. Hydrolysis is the reaction of a salt with water to form an acid or base. For example, soda ash (Na2CO3) hydrolyzes basically, and hydrolysis is responsible for the increase in the pH of water when soda ash is added.
Hydrometer. A floating instrument for determining the specific gravity or density of liquids, solutions, and slurries.
Hydrophile. Any substance, usually in the colloidal state or an emulsion, that is wetted by water; that is, it attracts water or water adheres to it. See: lipophile.
Hydrophilic. A property of a substance having an affinity for water or one that is wetted by water. See: lipophilic.
Hydrophilic lipophilic balance. The relative attraction of an emulsifier for water and for oil. It is determined largely by the chemical composition and ionization characteristics of a given emulsifier. The HLB of an emulsifier is not directly related to its solubility, but it determines the type of an emulsion that tends to be formed. It is an indication of the behavioral characteristics and not an indication of emulsifier efficiency.
Hydrophobe. Any substance, usually in the colloidal state, that is not wetted by water.
Hydrophobic. Any substance, usually in the colloidal state or an emulsion, that is not wetted by water; that is, it repels water or water does not adheres to it.
Hydrostatic pressure head. The pressure exerted by a column of fluid, usually expressed in pounds per square inch. To determine the hydrostatic head in psi at a given depth, multiply the depth in feet by the density in pounds per gallon by the conversion factor, 0.052.
Hydroxide. Designation that is given basic compounds containing the OH– radical. When these substances are dissolved in water, the pH of the solution is increased. See: base, pH.
Hygroscopic. The property of a substance enabling it to absorb water from the air.
Monday, September 7, 2015
drilling fluids processing gloccary G
Galena. Lead sulfide (PbS). Technical grades (specific gravity about 7.0) are used for increasing the density of drilling fluids to points impractical or impossible with barite. Almost entirely used in preparation of ‘‘kill fluids.’’ See: kill fluid.
Gas buster. See: poor boy degasser, mud/gas separator.
Gas cut. Gas entrained by a drilling fluid. See: air cutting, aeration.
Gel. (1) A state of a colloidal suspension in which shearing stresses below a certain finite value fail to produce permanent deformation. The minimum shearing stress that will produce permanent deformation is known as the shear or gel strength of the gel. Gels commonly occur when the dispersed colloidal particles have a great affinity for the dispersing medium, that is, are lyophilic. Thus, gels commonly occur with bentonite in water. (2) A term used to designate highly colloidal, high-yielding, viscosity-building, commercial clays, such as bentonite and attapulgite. See: gel strength.
Gelation. Association of particles forming continuous structures at low shear rates.
Gel cement. Cement having a small to moderate percentage of bentonite added as a filler and/or reducer of the slurry weight. The bentonite may be dry-blended into the mixture or added as a prehydrated slurry.
Gel strength. (1) The ability or measure of the ability of a colloid to form gels. Gel strength is a pressure unit usually reported in lb/100 sq ft. It is a measure of the same interparticle forces of a fluid as determined by the yield point, except that gel strength is measured under static conditions, whereas the yield point is measured under dynamic conditions. The common gel strength measurements are initial, 10-minute, and 30-minute gels. (2) The measured initial gel strength of a fluid is the maximum reading (deflection) taken from a direct-reading viscometer after the fluid has been quiescent for 10 seconds. It is reported in lb/100 sq ft. See: API RP 13B, shear rate, shear stress, thixotropy.
Gelled up. Oilfield slang usually referring to any fluid with a high gel strength and/or highly viscous properties. Often a state of severe flocculation. See: clabbered.
g Factor. The acceleration of an object relative to the acceleration of gravity.
g Force. The centrifugal force exerted on a mass moving in a circular path. See g factor.
Glosses. Explanations or comments to elucidate some difficulty or obscurity in the text; or annotations.
Grains per gallon (gpg). Ppm equals gpgX17.1.
Greasing out. In some cases, certain organic substances, usually fatty acid derivatives, that are added to drilling fluids as emulsifiers, EPLs, etc., may react with ions such as calcium and magnesium to form a water-insoluble, greasy material that separates out from the drilling fluid. This separation process is called greasing out.
Guar gum. A naturally occurring hydrophilic polysaccharide derived from the seed of the guar plant. The gum is chemically classified as a galactomannan. Guar gum slurries made up in clear fresh- or brine water possess pseudoplastic flow properties.
Gum. Any hydrophilic plant polysaccharides or their derivatives that, when dispersed in water, swell to produce a viscous dispersion or solution. Unlike resins, they are soluble in water and insoluble in alcohol.
Gumbo: Small, sticky drilled solids that hydrate as they move up an annulus, forming large of cuttings. Gumbo is characteristically observed with water-based drilling fluids during drilling of shales containing large quantities of smectite clay.
Gunk plug. A volume of bentonite in oil that is pumped in a well to combat lost circulation. the bentonite encounters water, it expands and creates a gunk plug with a very high viscosity and gel structure. The plug may or may not be squeezed. See: diesel oil plug.
Gunning the pits. Mechanical agitation of the drilling fluid in a pit by means of a mud gun. See: mud gun.
Gyp. Gypsum.
Gypsum. Calcium sulfate, CaSO4 2H2O, frequently encountered while drilling. It may occur as thin stringers or in massive formations. See: anhydrite, calcium
sulfate.
Gas buster. See: poor boy degasser, mud/gas separator.
Gas cut. Gas entrained by a drilling fluid. See: air cutting, aeration.
Gel. (1) A state of a colloidal suspension in which shearing stresses below a certain finite value fail to produce permanent deformation. The minimum shearing stress that will produce permanent deformation is known as the shear or gel strength of the gel. Gels commonly occur when the dispersed colloidal particles have a great affinity for the dispersing medium, that is, are lyophilic. Thus, gels commonly occur with bentonite in water. (2) A term used to designate highly colloidal, high-yielding, viscosity-building, commercial clays, such as bentonite and attapulgite. See: gel strength.
Gelation. Association of particles forming continuous structures at low shear rates.
Gel cement. Cement having a small to moderate percentage of bentonite added as a filler and/or reducer of the slurry weight. The bentonite may be dry-blended into the mixture or added as a prehydrated slurry.
Gel strength. (1) The ability or measure of the ability of a colloid to form gels. Gel strength is a pressure unit usually reported in lb/100 sq ft. It is a measure of the same interparticle forces of a fluid as determined by the yield point, except that gel strength is measured under static conditions, whereas the yield point is measured under dynamic conditions. The common gel strength measurements are initial, 10-minute, and 30-minute gels. (2) The measured initial gel strength of a fluid is the maximum reading (deflection) taken from a direct-reading viscometer after the fluid has been quiescent for 10 seconds. It is reported in lb/100 sq ft. See: API RP 13B, shear rate, shear stress, thixotropy.
Gelled up. Oilfield slang usually referring to any fluid with a high gel strength and/or highly viscous properties. Often a state of severe flocculation. See: clabbered.
g Factor. The acceleration of an object relative to the acceleration of gravity.
g Force. The centrifugal force exerted on a mass moving in a circular path. See g factor.
Glosses. Explanations or comments to elucidate some difficulty or obscurity in the text; or annotations.
Grains per gallon (gpg). Ppm equals gpgX17.1.
Greasing out. In some cases, certain organic substances, usually fatty acid derivatives, that are added to drilling fluids as emulsifiers, EPLs, etc., may react with ions such as calcium and magnesium to form a water-insoluble, greasy material that separates out from the drilling fluid. This separation process is called greasing out.
Guar gum. A naturally occurring hydrophilic polysaccharide derived from the seed of the guar plant. The gum is chemically classified as a galactomannan. Guar gum slurries made up in clear fresh- or brine water possess pseudoplastic flow properties.
Gum. Any hydrophilic plant polysaccharides or their derivatives that, when dispersed in water, swell to produce a viscous dispersion or solution. Unlike resins, they are soluble in water and insoluble in alcohol.
Gumbo: Small, sticky drilled solids that hydrate as they move up an annulus, forming large of cuttings. Gumbo is characteristically observed with water-based drilling fluids during drilling of shales containing large quantities of smectite clay.
Gunk plug. A volume of bentonite in oil that is pumped in a well to combat lost circulation. the bentonite encounters water, it expands and creates a gunk plug with a very high viscosity and gel structure. The plug may or may not be squeezed. See: diesel oil plug.
Gunning the pits. Mechanical agitation of the drilling fluid in a pit by means of a mud gun. See: mud gun.
Gyp. Gypsum.
Gypsum. Calcium sulfate, CaSO4 2H2O, frequently encountered while drilling. It may occur as thin stringers or in massive formations. See: anhydrite, calcium
sulfate.
Tuesday, August 25, 2015
Drilling fluids processing glossary D
Darcy. A unit of permeability. A porous medium has a permeability of 1 darcy when a pressure of 1 atm on a sample 1 cm long and 1 sq cm in cross section will force a liquid of 1 cP viscosity through the sample at the rate of 1 cc per sec. See: millidarcy, permeability.
Decanter. See: decanting centrifuge.
Decanting centrifuge. A centrifuge that removes solids from the feed slurry and discharges them as damp underflow. Ultra-fine colloidal solids are discharged with the liquid overflow. The decanting centrifuge has an internal auger that moves the solids that have been settled to the bowl walls, out of a pool of liquid, and to the underflow. See: centrifuge.
Deck. The screening surface in a shale shaker basket.
De-duster. A tank at the end of the blooie line in air or gas drilling in which water is injected to settle the dust caused by drilling.
Deflocculant. Chemical that promotes deflocculation. See: thinner.
Deflocculation. (1) The process of thinning the drilling fluid by bonding with (neutralizing or covering) the positive electrical charges of drillingfluid additives to prevent one particle of drilling fluid from being attracted to another particle. (2) Breakup of flocs of gel structures by use of a thinner.
Defoamer. Any substance used to reduce or eliminate foam by reducing the surface tension of a liquid. See: antifoam. degasser. A device that removes entrained gas from a drilling fluid, especially the very small bubbles that do not float readily in viscous drilling fluid.
Dehydration. Removal of free or combined water from a compound.
Deliquescence. The liquification of a solid substance due to the solution of the solid by absorption of moisture from the air, for example, calcium chloride deliquesces in humid air.
Density. Mass per unit volume expressed in pounds per gallon (ppg), grams per cubic (g/cc), or pounds per cubic ft (lb/cu.ft). Drilling-fluid density is commonly referred to as mud weight.
Desand. To remove most API sand (>74 microns) from drilling fluid.
Desander. A hydrocyclone with an inside diameter of 6 inches or larger that can remove a very high proportion of solids larger than 74 micrometers.Generally,
desanders are used on unweighted muds. See: cyclone, hydrocyclone, hydroclone, desilter.
Desilt. To remove most silt particles greater than 15–20 microns from an unweighted fluid. The desilter is not normally not used on weighted drilling fluids because it can remove large amounts of barite.
Desilter. A hydrocyclone with an inside diameter less than 6 inches. It can remove a large fraction of solids larger than 15–20 microns.See: cyclone, hydrocyclone, hydroclone, desander.
Destabliziation. A condition in which colloidal particles no longer remain separate and discrete, but contact and agglomerate with other particles.
Diatomaceous earth. A very porous natural earth compound composed of siliceous skeletons. Sometimes used for controlling lost circulation and seepage losses and as an additive to cement.
Diesel oil plug. See: gunk plug.
Differential angle deck. A screen deck in which successive screening surfaces of the same deck are at different angles.
Differential pressure. The difference in pressure between two points. It is usually the difference in pressure at a given point in the well bore between the hydrostatic pressure of the drilling-fluid column and the formation pressure. Differential pressure can be positive, zero, or negative with respect to the formation pressure. See: backpressure.
Differential pressure sticking. Sticking that occurs when a portion of the drill string (usually the drill collars) becomes embedded in the filter cake resulting in a nonuniform distribution of pressure around the circumference of the pipe. The conditions essential for sticking require a permeable formation and a positive pressure (from well bore to formation) differential across a drill string embedded in a poor filter cake. See: stuck.
Diffusion. The spreading, scattering, or mixing of material (gas, liquid, or solid).
Dilatant fluid. Opposite of shear thinning. A dilatant or inverted plastic fluid is usually made up of a high concentration of welldispersed solids that exhibit a nonlinear consistency curve passing through the origin. The apparent viscosity increases instantaneously with increasing shear rate. The yield point, as determined by conventional calculations from the direct-indicating viscometer readings, is negative. See: apparent viscosity, viscosity, Bingham model, plastic viscosity, yield point, gel strength.
Diluent. Liquid added to dilute or thin a solution or suspension.
Dilution. (1) Decreasing the percentage of drilled-solids concentration by addition of liquid phase. (2) Increasing the liquid content of a drilling fluid by addition of water or oil. Dilution fluid may be a clean drilling fluid or the liquid phase of a drilling fluid.
Dilution factor. The ratio of the actual volume of drilling fluid required to drill a specified interval of footage using a solids-removal system versus a calculated volume of drilling fluid required to maintain the same drilled-solids fraction over the same specified interval of footage with no drilled-solids removal.
Dilution rate. The rate, in gpm or bbl/hr, at which fluids and/or premix is added to the circulating system for the purpose of solids management.
Dilution ratio. Ratio of volume of dilution liquid to the volume of raw drilling fluid in the feed prior to entering a liquid/solids separator.
Dilution water. Water used for dilution of water-based drilling fluid.
Direct-indicating viscometer. Commonlycalleda‘‘V-Gmeter.’’The directindicating viscometer shears fluid between a rotating outer cylinder and a stationary cylindrical bob in the center of the rotating cylinder. The bob is constrained from rotating by a spring. The spring reads the drag force on the bob, which is related to the shear stress. The rotational speed of the outer cylinder and the spacing between the bob and the cylinder the shear rate. Viscosity is the ratio of shear stress to shear rate, so this instrument may be used to determine viscosity of a fluid at a variety of shear rates. Gel strengths may also be determined after a quiescent period of a drilling fluid between the bob and the cylinder. See: API RP 13B.
Discharge. Material removed from a system. See: effluent.
Discharge spout. Extension at the discharge area of a screen. It may be vibrating or stationary. Also called discharge lip.
Dispersant. (1) Any chemical that promotes the subdivision of a material phase. (2) Any chemical that promotes dispersion of particles in a fluid. Frequently, a deflocculant is inaccurately called a dispersant. Caustic soda is a dispersant but not a deflocculant.
Disperse. To separate into component parts. Bentonite disperses by hydration into many smaller pieces.
Dispersed phase. The scattered phase (solid, liquid, or gas) of a dispersion. The particles are finely divided and completely surrounded by the continuous phase.
Dispersion. (1) Process of breaking up, scattering (as in reducing particle size), and causing to spread apart. (2) Subdivision of aggregates.Dispersion increases the specific surface of the particle, which results in an increase in viscosity and gel strength.
Dispersoid. A colloid or finely divided substance.
Disassociation. The splitting of a compound or element into two or more simple molecules, atoms, or ions. Applied usually to the effect of the action of heat or solvents upon dissolved substances. The reaction is reversible and not as permanent as decomposition; that is, when the solvent is removed, the ions recombine.
Distillation. Process of first vaporizing a liquid and then condensing the vapor into a liquid (the distillate), leaving behind nonvolatile solid substances of a drilling fluid. The distillate is the water and/or oil content of a fluid.
Divided deck. A deck having a screening surface longitudinally divided by partition(s).
Dog leg. The elbow caused by a sharp change of drilling direction in the well bore.
Double flute. The flutes or leads advancing simultaneously at the same angle and 180 apart. See: flute, flight, blade.
Downstream venturi. See: venturi.
Drill bit. The cutting or boring element at the end of the drill string.
Drill stem test (DST). A postdrilling and preproduction test that allows formation fluids to flow into the drill pipe under controlled conditions, to determine whether oil and/or gas in commercial quantities have been encountered in the penetrated formations.
Drill string. The column of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly to the drill collars and bit.
Drilled solids. Formation solids that enter the drilling-fluid system, whether produced by a bit or from the side of the borehole. See lowgravity solids, cuttings.
Drilled-solids fraction. The average volume fraction of drilled solids maintained in the drilling fluid over a specified interval of footage.
Drilled-solids removal system. All equipment and processes used while drilling a well that remove the solids generated from the hole and carried by the drilling fluid, that is, settling, screening, desanding,desilting, centrifuging, and dumping.
Drilling fluid. Term applied to any liquid or slurry pumped down the drill string and up the annulus of a hole to facilitate drilling. See: drilling mud, mud.
Drilling-fluid additive. Any material added to a drilling fluid to achieve a particular effect.
Drilling-fluid analysis. Examination and testing of the drilling fluid to determine its physical and chemical properties and functional ability. See: API RP 13B.
Drilling-fluid cycle time. The time necessary to move a fluid from the kelly bushing to the flowline in a borehole. The cycle, in minutes, equals the barrels of drilling fluid in the hole minus pipe displacement divided by barrels per minute of circulation rate:
Drilling-fluid engineer. One versed in drilling fluids, rig operations, and solids and waste management, whose duties are to manage and maintain the drilling-fluid program at the well site.
Drilling-fluid program. A proposed plan or procedure for application and properties of drilling fluid(s) used in drilling a well with respect to depth. Some factors that influence the drilling-fluid program are the casing program and formation characteristics such as type, competence, solubility, temperature, pressure, etc.
Drilling in. The drilling operation starting at the point of drilling into the producing formation.
Drilling mud. See: drilling fluid, which is the preferred term.
Drilling out. The operation of drilling out of the casing shoe after the cementing of a casing or liner in place. Drilling out of the casing is done before further hole is made or completion attempted.
Drilling rate. The rate at which hole depth progresses, expressed in linear units per unit of time (including connections) as feet/minute or feet/hour. See: ROP, rate of penetration, penetration rate.
Dry bottom. An adjustment to the underflow opening of a hydrocyclone that causes a dry beach, usually resulting in severe plugging. See: dry plug.
Dry plug. The plugging of the underflow opening of a hydrocyclone caused by operating with a dry bottom.
Dryer. A shale shaker with a fine mesh screen that removes excess fluid and fine solids from discarded material from other shale shakers and hydrocyclones. Typically, this is used to decrease the liquid waste from a drilling fluid to decrease discarded volumes. See mud cleaner.
Dual wound motors. Motors that may be connected to either of two voltages and starter configurations.
Dynamic. The state of being active or in motion, as opposed to static.
Decanter. See: decanting centrifuge.
Decanting centrifuge. A centrifuge that removes solids from the feed slurry and discharges them as damp underflow. Ultra-fine colloidal solids are discharged with the liquid overflow. The decanting centrifuge has an internal auger that moves the solids that have been settled to the bowl walls, out of a pool of liquid, and to the underflow. See: centrifuge.
Deck. The screening surface in a shale shaker basket.
De-duster. A tank at the end of the blooie line in air or gas drilling in which water is injected to settle the dust caused by drilling.
Deflocculant. Chemical that promotes deflocculation. See: thinner.
Deflocculation. (1) The process of thinning the drilling fluid by bonding with (neutralizing or covering) the positive electrical charges of drillingfluid additives to prevent one particle of drilling fluid from being attracted to another particle. (2) Breakup of flocs of gel structures by use of a thinner.
Defoamer. Any substance used to reduce or eliminate foam by reducing the surface tension of a liquid. See: antifoam. degasser. A device that removes entrained gas from a drilling fluid, especially the very small bubbles that do not float readily in viscous drilling fluid.
Dehydration. Removal of free or combined water from a compound.
Deliquescence. The liquification of a solid substance due to the solution of the solid by absorption of moisture from the air, for example, calcium chloride deliquesces in humid air.
Density. Mass per unit volume expressed in pounds per gallon (ppg), grams per cubic (g/cc), or pounds per cubic ft (lb/cu.ft). Drilling-fluid density is commonly referred to as mud weight.
Desand. To remove most API sand (>74 microns) from drilling fluid.
Desander. A hydrocyclone with an inside diameter of 6 inches or larger that can remove a very high proportion of solids larger than 74 micrometers.Generally,
desanders are used on unweighted muds. See: cyclone, hydrocyclone, hydroclone, desilter.
Desilt. To remove most silt particles greater than 15–20 microns from an unweighted fluid. The desilter is not normally not used on weighted drilling fluids because it can remove large amounts of barite.
Desilter. A hydrocyclone with an inside diameter less than 6 inches. It can remove a large fraction of solids larger than 15–20 microns.See: cyclone, hydrocyclone, hydroclone, desander.
Destabliziation. A condition in which colloidal particles no longer remain separate and discrete, but contact and agglomerate with other particles.
Diatomaceous earth. A very porous natural earth compound composed of siliceous skeletons. Sometimes used for controlling lost circulation and seepage losses and as an additive to cement.
Diesel oil plug. See: gunk plug.
Differential angle deck. A screen deck in which successive screening surfaces of the same deck are at different angles.
Differential pressure. The difference in pressure between two points. It is usually the difference in pressure at a given point in the well bore between the hydrostatic pressure of the drilling-fluid column and the formation pressure. Differential pressure can be positive, zero, or negative with respect to the formation pressure. See: backpressure.
Differential pressure sticking. Sticking that occurs when a portion of the drill string (usually the drill collars) becomes embedded in the filter cake resulting in a nonuniform distribution of pressure around the circumference of the pipe. The conditions essential for sticking require a permeable formation and a positive pressure (from well bore to formation) differential across a drill string embedded in a poor filter cake. See: stuck.
Diffusion. The spreading, scattering, or mixing of material (gas, liquid, or solid).
Dilatant fluid. Opposite of shear thinning. A dilatant or inverted plastic fluid is usually made up of a high concentration of welldispersed solids that exhibit a nonlinear consistency curve passing through the origin. The apparent viscosity increases instantaneously with increasing shear rate. The yield point, as determined by conventional calculations from the direct-indicating viscometer readings, is negative. See: apparent viscosity, viscosity, Bingham model, plastic viscosity, yield point, gel strength.
Diluent. Liquid added to dilute or thin a solution or suspension.
Dilution. (1) Decreasing the percentage of drilled-solids concentration by addition of liquid phase. (2) Increasing the liquid content of a drilling fluid by addition of water or oil. Dilution fluid may be a clean drilling fluid or the liquid phase of a drilling fluid.
Dilution factor. The ratio of the actual volume of drilling fluid required to drill a specified interval of footage using a solids-removal system versus a calculated volume of drilling fluid required to maintain the same drilled-solids fraction over the same specified interval of footage with no drilled-solids removal.
Dilution rate. The rate, in gpm or bbl/hr, at which fluids and/or premix is added to the circulating system for the purpose of solids management.
Dilution ratio. Ratio of volume of dilution liquid to the volume of raw drilling fluid in the feed prior to entering a liquid/solids separator.
Dilution water. Water used for dilution of water-based drilling fluid.
Direct-indicating viscometer. Commonlycalleda‘‘V-Gmeter.’’The directindicating viscometer shears fluid between a rotating outer cylinder and a stationary cylindrical bob in the center of the rotating cylinder. The bob is constrained from rotating by a spring. The spring reads the drag force on the bob, which is related to the shear stress. The rotational speed of the outer cylinder and the spacing between the bob and the cylinder the shear rate. Viscosity is the ratio of shear stress to shear rate, so this instrument may be used to determine viscosity of a fluid at a variety of shear rates. Gel strengths may also be determined after a quiescent period of a drilling fluid between the bob and the cylinder. See: API RP 13B.
Discharge. Material removed from a system. See: effluent.
Discharge spout. Extension at the discharge area of a screen. It may be vibrating or stationary. Also called discharge lip.
Dispersant. (1) Any chemical that promotes the subdivision of a material phase. (2) Any chemical that promotes dispersion of particles in a fluid. Frequently, a deflocculant is inaccurately called a dispersant. Caustic soda is a dispersant but not a deflocculant.
Disperse. To separate into component parts. Bentonite disperses by hydration into many smaller pieces.
Dispersed phase. The scattered phase (solid, liquid, or gas) of a dispersion. The particles are finely divided and completely surrounded by the continuous phase.
Dispersion. (1) Process of breaking up, scattering (as in reducing particle size), and causing to spread apart. (2) Subdivision of aggregates.Dispersion increases the specific surface of the particle, which results in an increase in viscosity and gel strength.
Dispersoid. A colloid or finely divided substance.
Disassociation. The splitting of a compound or element into two or more simple molecules, atoms, or ions. Applied usually to the effect of the action of heat or solvents upon dissolved substances. The reaction is reversible and not as permanent as decomposition; that is, when the solvent is removed, the ions recombine.
Distillation. Process of first vaporizing a liquid and then condensing the vapor into a liquid (the distillate), leaving behind nonvolatile solid substances of a drilling fluid. The distillate is the water and/or oil content of a fluid.
Divided deck. A deck having a screening surface longitudinally divided by partition(s).
Dog leg. The elbow caused by a sharp change of drilling direction in the well bore.
Double flute. The flutes or leads advancing simultaneously at the same angle and 180 apart. See: flute, flight, blade.
Downstream venturi. See: venturi.
Drill bit. The cutting or boring element at the end of the drill string.
Drill stem test (DST). A postdrilling and preproduction test that allows formation fluids to flow into the drill pipe under controlled conditions, to determine whether oil and/or gas in commercial quantities have been encountered in the penetrated formations.
Drill string. The column of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly to the drill collars and bit.
Drilled solids. Formation solids that enter the drilling-fluid system, whether produced by a bit or from the side of the borehole. See lowgravity solids, cuttings.
Drilled-solids fraction. The average volume fraction of drilled solids maintained in the drilling fluid over a specified interval of footage.
Drilled-solids removal system. All equipment and processes used while drilling a well that remove the solids generated from the hole and carried by the drilling fluid, that is, settling, screening, desanding,desilting, centrifuging, and dumping.
Drilling fluid. Term applied to any liquid or slurry pumped down the drill string and up the annulus of a hole to facilitate drilling. See: drilling mud, mud.
Drilling-fluid additive. Any material added to a drilling fluid to achieve a particular effect.
Drilling-fluid analysis. Examination and testing of the drilling fluid to determine its physical and chemical properties and functional ability. See: API RP 13B.
Drilling-fluid cycle time. The time necessary to move a fluid from the kelly bushing to the flowline in a borehole. The cycle, in minutes, equals the barrels of drilling fluid in the hole minus pipe displacement divided by barrels per minute of circulation rate:
Drilling-fluid program. A proposed plan or procedure for application and properties of drilling fluid(s) used in drilling a well with respect to depth. Some factors that influence the drilling-fluid program are the casing program and formation characteristics such as type, competence, solubility, temperature, pressure, etc.
Drilling in. The drilling operation starting at the point of drilling into the producing formation.
Drilling mud. See: drilling fluid, which is the preferred term.
Drilling out. The operation of drilling out of the casing shoe after the cementing of a casing or liner in place. Drilling out of the casing is done before further hole is made or completion attempted.
Drilling rate. The rate at which hole depth progresses, expressed in linear units per unit of time (including connections) as feet/minute or feet/hour. See: ROP, rate of penetration, penetration rate.
Dry bottom. An adjustment to the underflow opening of a hydrocyclone that causes a dry beach, usually resulting in severe plugging. See: dry plug.
Dry plug. The plugging of the underflow opening of a hydrocyclone caused by operating with a dry bottom.
Dryer. A shale shaker with a fine mesh screen that removes excess fluid and fine solids from discarded material from other shale shakers and hydrocyclones. Typically, this is used to decrease the liquid waste from a drilling fluid to decrease discarded volumes. See mud cleaner.
Dual wound motors. Motors that may be connected to either of two voltages and starter configurations.
Dynamic. The state of being active or in motion, as opposed to static.
Wednesday, August 19, 2015
Drilling fluids processing glossary B
Backpressure. The frictional or blocking pressure opposing fluid flow ina conduit. See: differential pressure.
Back tank. The compartment on a shale shaker that receives drillingfluid from the flowline. See: possum belly, mud box.
Backing plate. The plate attached to the back of screen cloth(s) for support.
Backup screen. See: support screen.
Baffles. Plates or obstructions built into a compartment to change thedirection of fluid flow.
Balanced design hydrocyclone. A hydrocyclone that has the lower apex adjusted to the diameter of the cylinder of air formed within the cone by the cyclonic forces of drilling fluid spinning within cone. This tends to minimize liquid discharge when there are no separable solids.
Balanced elliptical motion. An elliptical motion of a shale shaker screen such that all ellipse axes are tilted at the same angle toward the discharge end of the shale shaker.
Ball valve. A valve that uses a spherical closure with a hole through its center and rotates 90 to open and close.
Barite. Natural barium sulfate, BaSO4, is used for increasing the density of drilling fluids. The API standard requires a minimum of 4.20 specific gravity. Commercial barium sulfate ore can be produced from a single ore or a blend of ores and may be a straight-mined product or processed by flotation methods. It may contain minerals other than barium sulfate. Because of mineral impurities, commercial barite may vary in color from off-white to gray to red or brown. Common accessory minerals are silicates such as quartz and chert, carbonate compounds such as siderite and dolomite, and metallic oxide and sulfide compounds.
Barite recovery efficiency. Barite recovery efficiency is the ratio of the mass flow rate of barite returning to a drilling fluid from a solids control device divided by the mass flow rate of barite in the feed to the solids-control device.
Barium sulfate. BaSO4. See: barite.
Barrel (bbl). A volumetric unit of measure used in the petroleum industry consisting of 42 U.S. gallons.
Barrel equivalent. One gram of material in 350 ml of fluid is equivalent to a concentration of 1 lb of that material in an oilfield barrel of fluid.See: barrel, pound equivalent.
Base. A compound of a metal, or a metal-like group, with hydrogen and oxygen in the proportions that form an OH– radical, when ionized in an aqueous solution, yielding excess hydroxyl ions. Bases are formed when metallic oxides react with water. Bases increase the pH. Examples of bases are caustic soda, NaOH; and lime, Ca(OH)2.
Base exchange. The replacement of the cations associated with the surface of a clay particle by another species of cation, for example,the substitution of sodium cations by calcium cations on the surface of a clay particle. See: methylene blue titration, methylene blue test, MBT, cation exchange capacity, CEC.
Basicity. pH value above 7. Ability to neutralize or accept protons from acids. See: pH.
Basket. That portion of a shale shaker containing the deck upon which the screen(s) is mounted; supported by vibration isolation members connected to the bed.
Beach. Area between the liquid pool and the solids discharge ports in a decanting centrifuge or hydrocyclone.
Bed. Shale shaker support member, consisting of mounting skid or frame with or without bottom, flow diverters to direct screen underflow to either side of the skid, and mountings for vibration isolation members.
Bentonite. A colloidal clay, largely made up of the mineral sodium montmorillonite, a hydrated aluminum silicate. Used for developing a low shear rate viscosity and/or good filtration characteristics in water-based drilling fluids. The generic term ‘‘bentonite’’ is not an exact mineralogical name, nor is the clay of definite mineralogical
composition. See: gel, montmorillonite.
Bentonite (clay) extender. Additive that interacts with clay in a drilling fluid to boost viscosity; usually this at a low to moderate concentration of polymer and depends on the polymer/clay ratio.
Bernoulli Principle. One means of expressing Newton’s Second Law of Physics, that is, concerning conservation of energy. Roughly stated,this principle demonstrates that the sum of pressure and velocity through or over a device represents equal quantities, neglecting the effects of losses due to friction and/or increases by adding energy with external devices such as pumps.
Bicarb. See: sodium bicarbonate.
Bingham model. A mathematical description that relates shear stress to shear rate in a linear manner. This model requires only two constants (plastic viscosity and yield point) and is the simplest rheological model possible to describe a non-Newtonian liquid. It is very useful for analyzing drilling fluid problems and treatment. See: viscosity, pseudoplastic fluid, plastic viscosity, yield point, gel strength.
Blade. See: flight, flute.
Blinding: A reduction of open area in a screening surface caused by coating or plugging. See: coating, plugging.
Blooie line. The flowline for air or gas drilling.
Blowout. An uncontrolled escape of drilling fluid, gas, oil, or water from the well caused by the formation pressure being greater than the hydrostatic head of the fluid being circulated in the well bore. See: kick, kill fluid.
Bonded screens. Multiple screens bonded together with plastic to form a multilayered screen or screens bonded to a metal support plate.
Bonding material. Material used to secure screen cloth to a backing plate or support screen.
Bottom flooding. The behavior of a hydrocyclone when the underflow discharges whole drilling fluid rather than separated solids.
Bound liquid. Adsorbed liquid. See: absorb, absorption, adsorb, adsorption, adsorbed liquid.
Bow. See: crown.
Bowl. The outer rotating chamber of a decanting centrifuge.
Brackish water. Water containing low concentrations of any soluble salts.
Break circulation. To start movement of the drilling fluid after it has been quiescent in a borehole.
Bridge. An obstruction in a well formed by the intrusion of subsurface formations and/or cuttings or material, which prevents a tubular string from moving down a borehole.
Brine. Water containing a high concentration of common salts such as sodium chloride, calcium chloride, calcium bromide, zinc bromide, etc.
Bromine value. The number of centigrams of bromine that are absorbed by 1 gram of oil under certain conditions. The bromine check is a test for the degree of unsaturation of a given oil.
Brownian movement. Continuous, irregular motion exhibited by particles suspended in a liquid or gaseous medium, usually as a colloidal dispersion.
BS&W. Base sediment and water.
Buffer. Any substance or combination of substances that, when dissolved in water, produces a solution that resists a change in its hydrogen ion concentration upon the addition of an acid or base.
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