Monday, September 28, 2015

drilling fluids glossary N

Natural clay. Natural clay, as opposed to commercial clay, are clay that are encountered when drilling various formations. The yield of these clay varies greatly, and they may or may not be purposely incorporated into the drilling fluid system. See: attapulgite clay, bentonite, high-yield clay, low-yield clay, clay.
Near-size plugging. A term used in describing screen plugging, referring to particles with a dimension slightly larger than the screen opening. See: blinding, plugging.
Neat cement. A slurry composed only of Portland cement and water.
Negative deck angle. The angle of adjustment to a screen deck that causes the screened solids to travel ‘‘downhill’’ (usual travel) to reach the discharge end of the screen surface. This downhill travel decreases the fluid throughput of a screen but usually lengthens the life of a screen. See: positive deck angle.
Neutralization. A reaction in which the hydrogen ion of an acid and the hydroxyl ion of a base unite to form water, the other ionic product being a salt.
Newtonian flow. See: Newtonian fluid.
Newtonian fluid. The basic and simplest fluids from the standpoint of viscosity, in which the shear force is directly proportional to the shear rate. These fluids will immediately begin to move when a pressure or force in excess of zero psi is applied. Examples of Newtonian fluids are water, diesel oil, and glycerine. The yield point as determined by direct-indicating viscometer is zero. See: Newtonian flow.
Non-conductive drilling fluid. Any drilling fluid, usually oil-based or invert emulsion drilling fluid, whose continuous phase does not conduct electricity. The spontaneous potential (SP) and normal resistivity cannot be logged, although such other logs as the gamma rays, induction, acoustic velocity, etc., can be run.
Non-dispersed. A condition in which the clays do not separate into individual platelets. Dispersion is inhibited.
Normal solution. A solution of such a concentration that it contains 1 gram equivalent of a substance per liter of solution. 

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.

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.

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.

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.

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.

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.

Sunday, September 6, 2015

Drilling fluids processing glossary F

Fault. Geological term denoting a formation break across the trend of a subsurface strata. Faults can significantly affect the drilling fluid and casing programs due to possibilities for lost circulation, sloughing hole, or kicks
Feed. A mixture of solids and liquid (including dilution liquid) entering a liquid/solids separation device.
Feed capacity. The maximum volume flow rate at which a solids-control device is designed to operate without detriment to separation efficiency.This capacity will be dependent on particle size, particle concentration,viscosity, and other variables of the feed. See: capacity, flow capacity, solids discharge capacity.
Feed chamber. That part of a device that receives the mixture of diluents, drilling fluid, and solids to be separated.
Feed head. The equivalent height, in feet or meters, of a column of fluid at the cyclone feed header.
Feed header. A pipe, tube, or conduit to which two or more hydrocyclones have been connected and from which they receive their feed slurry.
Feed inlet. The opening through which the feed fluid enters a solids separation device. Also known as feed opening.
Feed mud. See: feed.
Feed opening. See: feed inlet.
Feed pressure. The actual gauge pressure measured as near as possible to, and upstream of, the feed inlet of a device.
Feed slurry. See: feed.
Fermentation. Decomposition process of certain substances, for example, starch, in which a chemical change is brought about by enzymes, bacteria, or other microorganisms. Often referred to as ‘‘souring.’’
Fibrous materials. Any tough, stringy material used to prevent loss of circulation or to restore circulation. In field use, ‘‘fiber’’ generally refers to the larger fibers of plant origin.
Filter cake. The suspended solids that are deposited on a porous medium during the process of filtration. See: wall cake.
Filter cake texture. The physical properties of a cake as measured by toughness, slickness, and brittleness. See: cake consistency.
Filter paper. Porous paper without surface sizing for filtering solids from liquids. The API filtration test specifies 9-cm-diameter filter paper Whatman No. 50, S&S No. 576, or equivalent.
Filtrate. The liquid that is forced through a porous medium during the filtration process. See: fluid loss.
Fill-up line. The line through which fluid is added to the annulus to maintain the fluid level in the well bore during the extraction of the drilling assembly.
Filter cake. (1) The soild residue deposited by a drilling fluid against a porous medium, usually filter paper, according to the standard API filtration test. (2) The soild residue deposited on the wall of a borehole during the drilling of permeable formations. See: wall cake.
Filter cake thickness. See: cake thickness.
Filter press. A device for determining the fluid loss of a drilling fluid having specifications in accordance with API RP 13B. See: API RP 13B.
Filter run. The interval between two successive backwashing operations of a filter.
Filterability. The characteristic of a clear fluid that denote both the ease of filtration and the ability to remove solids while filtering.
Filtrate loss. See: fluid loss.
Filtration. (1) The process of separation of suspended solids from liquid by forcing the liquid a porous medium while screening back the solids.Two types of fluid filtration occur in a well: dynamic filtration while circulating, and static filtration when the fluid is at rest. (2) The process of drilling fluid losing a portion of the liquid phase to the surrounding formation. See: water loss.
Filtration rate. See: fluid loss.
Fine-screen shaker. A vibrating screening device designed for screening drilling fluids through screen cloth finer than 80 mesh.
Fine-screen shale shakers. Usually refers to shale shakers that vibrate screens with a balanced elliptical or linear motion. These are usually capable of processing large flow rates of drilling fluid through 120 to 250 mesh screens.
Fine solids. Solids 44–74 microns in diameter, or sieve size 325–200 mesh. See: API RP 13C.
Fishing. Operations on the rig for the purpose of retrieving sections of pipe, collars, or other obstructive items that are in the hole and would interfere with drilling or logging operations.
Flat decked. Shaker screens that do not have a crowned, or bowed, surface.
Flat gel. A condition wherein the gel strength does not increase appreciably with time and is essentially equal to the initial gel strength. Opposite of progressive gel. See:progressive gel, zero-zero gel.
Flight. On a decanting centrifuge, one full turn of a spiral helix, such as a flute or blade of a screw-type conveyor. See: blade, flute.
Flipped. A slang term for an extreme imbalance in a drilling fluid. In a water-in-oil emulsion, the emulsion is identified as ‘‘flipped’’ when the continuous and dispersed phases separate and the solids begin to settle.
Floc. Small gelatinous masses of solids formed in a liquid.
Flocculates. A group of aggregates or particles in a suspension formed by electrostatic attraction forces between negative and positive charges. Bentonite clay particles have negatively charged surfaces that will attract positive charges such as those of other bentonite positive edge charges.
Flocculating agent. Substances, for example, most electrolytes, a few polysaccharides, certain natural or synthetic polymers, that bring about the thickening of a drilling fluid. In Bingham plastic fluids, the yield point and gel strength increase with flocculation.
Flocculation. (1) Loose association of particles in lightly bonded groups, sometimes called ‘‘flocs,’’ with nonparallel association of clay platelets. In concentrated suspensions, such as drilling fluids, flocculation results in gelation. In some drilling fluids, flocculation may be followed by irreversible precipitation of colloids and certain other substances from the fluid, such as red beds and polymer flocculation. (2) A process in which dissimilar electrical charges on clay platelets are attracted to each other. This increases the yield point and gel strength of a slurry.
Flooding. (1) The effect created when a screen, hydrocyclone, or centrifuge is fed beyond its capacity. (2) Flooding may also occur on a screen as a result of blinding.
Flowback pan. A pan or surface below a screen that causes fluid passing through one screen to flow back to the feed end of a lower screen.
Flow capacity. The rate at which a shaker can process drilling fluid and solids. This depends on rnany variables, including shaker configuration,design and motion, drilling fluid rheology, solids loading, and blinding by near-size particles. See: feed capacity.
Flow drilling. Drilling in which there is a constant flow of formation fluid.
Flowline. The pipe (usually) or trough that conveys drilling fluid from the rotary nipple to the solids-separation section of the drilling fluid tanks on a drilling rig.
Flow rate. The volume of liquid or slurry moved through a pipe in one unit of time, that is, gpm, bbl/min, etc. See: circulation rate.
Flow streams. With respect to centrifugal separators, all liquids and slurries entering and leaving a machine, such as feed drilling fluid stream plus dilution stream equals overflow stream plus underflow stream.
Fluid. Any substance that will readily assume the shape of the container in which it is placed. The term includes both liquids and gases. It is a substance in which the application of every system of stress (other than hydrostatic pressure) will produce a continuously increasing deformation without any relation between time rate of deformation at any instant and the magnitude of stress at the instant.
Fluid flow. The state of dynamics of a fluid in motion as determined by the type of fluid (e.g., Newtonian plastic, pseudoplastic, dilatant), the properties of the fluid such as viscosity and density, the geometry of the system, and the velocity. Thus, under a given set of conditions and fluid properties, the fluid flow can be described as plug flow, laminar (called also Newtonian, streamline, parallel, or viscous) flow, or turbulent flow. See: Reynolds number.
Fluid loss. Measure of the relative amount of fluid loss (filtrate) through permeable formations or membranes when the drilling fluid is subjected to a pressure differential. See: filtrate loss, API RP 13B.
Fluidity. The reciprocal of viscosity. The measure of rate with which a fluid is continuously deformed by a shearing stress. Ease of flowing.
Fluorescence. Instantaneous re-emission of light of a greater wavelength than that of the light originally absorbed.
Flute. A curved metal blade wrapped around a shaft as on a screw conveyor in a centrifuge. See: blade, flight.
Foam. (1) A two-phase system, similar to an emulsion, in which the dispersed phase is a gas or air. (2) Bubbles floating on the surface of the drilling fluid. The bubbles are usually air but can be formation gas.
Foaming agent. A substance that produces fairly stable bubbles at the air/liquid interface due to agitation, aeration, or ebullition. In air or gas drilling, foaming agents are added to turn water influx into aerated foam. This is commonly called ‘‘mist drilling.’’
Foot. Unit of length in British (foot-pound-second) system.
Foot-pound. Unit of work or of mechanical energy, which is the capacity to do work. One foot is the work performed by a force of 1 pound acting through a distance of 1 foot; or the work required to lift a 1-pound weight a vertical distance of 1 foot.
Foot valve. A check valve installed at the suction end of a suction line.
Formation. A bed or deposit composed throughout of substantially the same kind of rock.
Formation damage. Damage to the productivity of a well as a result of invasion of the formation by drilling-fluid particles, drilling-fluid filtrates, and/or cement filtrates. Formation damage can also result from changes in pH and a variety of other conditions. Asphalt from crude oil will also damage some formations. See: mudding off.
Formation fluid. The fluid—brine, oil, gas—that is in the pores of a formation.
Formation sensitivity. The tendency of certain producing formations to adversely react with the drilling and completion process.
Free liquid. The liquid film that can be removed by gravity draining or centrifugal force. See: absorb, absorption, adsorption, adsorb, bound liquid.
Free-water knockout. A water/gas separator ahead of the flare line.
Freshwater drilling fluid. A drilling fluid in which the liquid phase is freshwater.
Freshwater mud. See: freshwater drilling fluid.
Friction loss. See: pressure drop, pressure loss.
Functions of drilling fluids. Drilling fluids in rotary drilling must remove cuttings from the bottom of the hole, bring those cuttings and any material from the side of the hole to the surface, subsurface formation pressures, cool the drill bit, lubricate the drill string, create an impermeable filter cake, refrain from invading the formations with excessive quantities of drilling-fluid filtrate, and provide a well bore that can be evaluated and produce hydrocarbons.
Funnel viscosity. See: kinematic viscosity, marsh funnel viscosity.

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