H
H Member
A nipple assembly that provides hydraulic communication between strings of tubing installed in the wellbore.
H2s
SEE: Hydrogen Sulfide.
Half Life
The period of time required for a radioactive substance to lose half of its active characteristics; used especially in radiological work.
Hand Hole
A small opening for inspection purposes in a pressure vessel or boiler.
Hand Tight
Threaded joint that has been madeup by hand without the aid of tools or tongs.
Hand Tight Standoff
The length at hand tight engagement from the face of the coupling to vanish point of the pipe. Positive values indicate vanish point is exposed. Negative values indicate vanish point is buried.
Handling Cost
SEE: Marketing Cost.
Handling Damage
Cuts, gouges, dents, or flattened crests (mashes) that occurred during handling; e.g., loading; unloading; shifts in transit.
Handling Tight
The coupling is sufficiently tight that it cannot be removed except by use of a wrench.
Handy
A connection that can be unscrewed by hand.
Hang The Rod
To pull the sucker rod out of the wellbore and hang it in the derrick.
Hangdown
The weight of drillstem suspended below a dogleg.
Hanger
SEE: Casing Hanger; Tubing Hanger.
Hanger Mandrel
That portion of a casing or tubing hanger which is attached by a threaded connection to the tubular string and forms the upper end of that tubular string.
Hanging Wall
The portion of the fault block above the fault plane.
Hard Banding
A hard metal deposited on tool joints to resist abrasion from contact of the tool joint to the wall of the borehole.
Hard Hat
Molded plastic hat worn in the field for protection.
Hard Spot
An area in the pipe with a hardness level considerably higher than that of the surrounding metal, usually due to localized quenching.
Hardness (metal)
A measure of the hardness of a metal, as determined by pressing a hard steel ball or diamond penetrator into a smooth surface under standard conditions. Results are often expressed in terms of Rockwell Hardness Number (HRB or HRC) or Brinell Hardness Number (BHN).
Hardness Test (metal)
Any of several arbitrary methods for determining the hardness of metals. Usually an indentation is made under specified conditions and the hardness is indicated by the diameter (Brinell hardness) or the depth (Rockwell hardness) of the indentation.
Hardness (water)
Undesirable scale-forming salts, principally calcium and magnesium.
Harmonics
Those vibrations which are integral multiples of the fundamental frequency.
Hash
Numerous, small indications appearing on the oscilloscope of the ultrasonic instrument indicative of many small inhomogeneities in the material or background noise. Also referred to as grass.
Hatch
A covered opening in the top of a tank or storage vessel.
Hazardous Air Pollutant
According to law, a pollutant to which no ambient air quality standard is applicable and that may cause or contribute to an increase in mortality or in serious illness; e.g., asbestos; beryllium; and mercury have been declared hazardous air pollutants.
Hazardous Substance
Any substance which by reason of being explosive, flammable, toxic, corrosive, oxidizing, irritating, or otherwise harmful, has the potential to cause injury, illness, or death.
Head
(1) Pressure of liquid upon a unit area due to the height of the liquid column above the point at which the pressure is measured.(2) A single flow of a well when flowing intermittently.
Head Well Puller
An individual directly in charge of a well servicing rig and crew. Also referred to as crew chief or pulling unit operator.
Header
(1) A large diameter pipe into which a number of smaller pipes are perpendicularly welded or screwed.(2) A collection point for oil or gas gathering lines.
Heading
Alternating fluid slugs separated by gas which causes pressure variation at wellhead.
Heat Affected Zone
That portion of the base metal which has not been melted, but whose mechanical properties or microstructure has been altered by the heat of welding or cutting.
Heat Capacity
The amount of heat required to raise the temperature of a unit volume of borehole or tubular material by one degree.
Heat Checking Of Tool Joint
A condition that exists when a tool joint is excessively heated by the friction caused by rotation against the wall in the borehole.
Heat Density
The heat release through the cross section of the firetube, usually expressed as British thermal unit (BTU)/hour/square inch of cross sectional area.
Heat Duty
Heat absorbed by the process, usually expressed as British thermal unit (BTU)/hour.
Heat Exchanger
Technically, any equipment used for the indirect transfer of heat. Conventionally, a specific piece of equipment used to conserve energy by transferring heat from a process stream being cooled to one being heated.
Heat Flux
The average transfer rate through the firetube, usually expressed as British thermal unit (BTU)/hour/square foot of exposed area.
Heat Sensitive Lockopen Device
A device installed on a subsurface safety valve actuator to maintain the valve in a full open position, until exposed to sufficient heat to cause the device to release and allow the valve to close.
Heat Treatment
Alternate steps of controlled heating and cooling of materials for the purpose of changing physical or mechanical properties. Also referred to as heat treating.
Heat Treatment Load
Material placed on loading or carrying devices moved as a batch through one heat treatment cycle.
Heater
A vessel in which heat is applied to a series of internal coils or tubes to increase temperature of fluid flowing through coils or tubes.
Heater Bath
The indirect heating medium is referred to as the heater bath and within a particular scope is limited to water or water solutions. When freezing is possible, ethylene glycol may be added for antifreeze protection. Other additives to the water bath may include corrosion inhibitors.
Heater Treater
A vessel that heats an emulsion and removes water and gas from the oil to raise it to a quality acceptable for pipeline transmission. A heater treater is a combination of a heater, free water knockout, and oil and gas separator.
Heater Treater Count
The number (count) of heater treaters on a facility.
Heating Shroud
Baffle surrounding firetubes in treaters designed to increase emulsion heating efficiency by minimizing the heating of free water which separates from the emulsion before heating. Also referred to as heating hood.
Heating System Cost
Costs include construction costs, buildings, and equipment, such as pipe, fittings, furnace, and boilers in a central heating system, from and including the central heating plant to outside walls of buildings served. This is applicable only when a central haating plant serves two or more buildings.
Heating Value
The heat energy derived from a unit volume of gas.
Heating Value, Higher Or Gross
The heat energy derived from the combustion of a unit quantity of a fuel when the reaction products are cooled to 60 degrees fahrenheit.
Heating Value, Lower Or Net
The gross heating value less the heat of condensation of any water formed in combustion.
Heave
The vertical motion of a ship or an offshore drilling rig.
Heavies
SEE: High Specific Gravity Solids.
Heaving
The partial or complete collapse of borehole walls resulting from internal pressures due primarily to swelling from water absorption or formation of gas pressures.
Heavy Crude Oil
Crude oil of 20 degrees API gravity or less.
Heavy Metal
Metallic element with high atomic weight, which may be toxic to plant and animal life depending on their oxidation and chemical state. Such metals may be residual in the environment and exhibit biological accumulation; e.g., arsenic; cadmium; chromium; mercury; lead.
Heavy Weight Drill Pipe
An intermediate drillstem member used between the relatively heavy and rigid drill collars, and the relatively light and flexible drill pipe. The heavy weight drill pipe consists of heavy walled tubes attached to special extra length tool joints. For ease of handling, the heavy weight drill pipe retains similar external dimensions to that of regular drill pipe.
Hedge Book
The paper portfolio or paper trade balances used to offset the physical (i.e., cash) portfolio or trading activity.
Held-by Reason
Describes the method by which the company's interest in a property is maintained; e.g., Co-owner or co-tenant pays rent on nonproducing property (during primary term); Co-owner or co-tenant pays rent on producing property (during/beyond primary term); Co-owner or co-tenant pays rent for a specific period on nonproducing acreage also part of HBP (during/beyond primary term).
Helical Buckling
Buckling in which the pipe forms a helix or spiral shape.
Helicopter
A rotary wing aircraft which depends principally for its support and motion in the air upon the lift generated by one or more power driven rotors, rotating on substantially vertical axes.
Helicopter Gross Weight
The certified maximum takeoff weight of the helicopter for which the heliport is designed to accommodate.
Heliport
An area on a structure used for the landing and takeoff of helicopters and which includes some or all of the various facilities useful to helicopter operation; e.g., parking; tiedown; fueling; maintenance.
Helix
SEE: Flute.
Helix Angle
The angle made by the conical spiral of the thread at the pitch diameter with a plane perpendicular to the axis.
Henry Hub
The location designated by NYMEX as the standard delivery point for its natural gas futures contracts, which is located at the tailgate of Texaco's Henry Gas Plant in southern Louisiana.
Hermetic Seal
SEE: Hermetically Sealed Device.
Hermetically Sealed Device
A device that prevents a hazardous or corrosive gas or vapor from coming in physical contact with an arcing or high temperature component.
Heterogeneous
Nonuniform at the scale of interest. Different parts have different properties.
High Angle Hole
Generally considered to be a wellbore path for which the inclination angle from vertical exceeds 50 degrees.
High Cost Natural Gas
Under the Natural Gas Policy Act (NGPA), 1978, as amended, gas produced from a well, the drilling of which commenced on or after February 19, 1977 and was completed at a depth of more than 15,000 feet (See Section 107 - Natural Gas Policy Act (NGPA), 1978, as amended). Such gas was decontrolled December 1, 1979. Other high cost gas remains controlled, and is defined as that produced from geopressurized brine, coal seams, Devonian shale, and produced under any other conditions deemed by the Federal Energy
High Liquid Level
Liquid level in a process component above the highest operating level.
High Ph Drilling Fluid
A drilling fluid with a pH range above 10.5. A high alkalinity drilling fluid.
High Pressure
Pressure in a process component in excess of the maximum operating pressure but less than the maximum allowable working pressure (for pipelines, maximum allowable operating pressure).
High Pressure Sensor Setting
The setting of a device in a process component set to alarm when the pressure is in excess of the maximum safe or design working pressure. Commonly abbreviated as PSH.
High Specific Gravity Solids
In the petroleum industry, this usually refers to the barite solids (could be Galena or other solids more than 4.2 specific gravity).
High Speed
Indicates screen speed generally in excess of 3,000 revolutions or cycles per minute.
High Temperature
Temperature in a process component in excess of the design operating temperature.
High Temperature Sensor Setting
The setting for a device in a process component on a platform set to alarm when the temperature exceeds the maximum safe or design temperature. Commonly abbreviated as TSH.
Highcut
Frequency designator specific to a frequency where the filter's amplitude response is attenuated 3 decibels (to 70% amplitude or half power) of the total signal amplitude. Frequencies greater than the highcut are reduced by more than 3 decibels, and frequencies less than the highcut are reduced by less.
Highly Volatile Liquid
Liquids whose vapor pressure exceeds 40 pounds per square inch absolute (276 kilopascals) at 100 F (37.8 C).
Hoist
SEE: Hoist Mechanism.
Hoist Mechanism
A hoist drum and rope system used for lifting and lowering loads.
Hoist Rope
Wire rope involved in the process of lifting.
Hoisting
The process of lifting.
Hoisting Equipment
A piece of equipment used to vertically lift materials, supplies, etc., from boats or barges to one of the structure decks. This is usually a crane or stiffleg derrick located on the main deck and may be driven by internal combustion engine or an electric, pneumatic or hydraulic motor.
Hoisting Horsepower
SEE: Hook Horsepower (for formula to calculate).
Hoisting Line
SEE: Drilling Line.
Hold Angle
Maximum deviation of the wellbore path from true vertical, expressed in decimal degrees.
Hold Down
(1) A clamp used on rod line posts to keep the rod from moving in any direction but back and forth.(2) Hydraulic: A device used for anchoring and packing-off a pump in wells when a pump seating nipple has not been provided.(3) Insert Pump: Mechanical arrangement installed with the pump to prevent upward movement.
Hold Down Nipple
Usually a one foot portion of the tubing string in which the pump is seated. Commonly located above the gas anchor. Its function is to hold the stationary part of the pump in place during the upstroke.
Holdup
Refers to the volume fraction of a specific fluid phase in the upward moving flow stream; e.g., water holdup; oil holdup.
Hole
SEE: Borehole; Wellbore.
Hole Axis
SEE: Borehole Axis.
Hole Azimuth Angle
SEE: Borehole Azimuth Angle.
Hole Caving
SEE: Caving.
Hole Change
SEE: Event Sequence.
Hole Change Code
(1) SEE: Event Sequence Code.(2) As used with the Federal Lease Production Reporting System (FLPRS), this item refers to a perforation interval. It is used along with the well completion code (FCBS) to form the FLPRS three character producing interval code.
Hole Change Type
SEE: Event Sequence Code.
Hole Clearance
SEE: Clearance; Borehole Hole Clearance.
Hole Curvature
Refers to the changes in inclination and direction of the borehole axis.
Hole Test Condition
The condition of the wellbore at the time of the production test; e.g., open hole and perforations; open hole; perforations.
Holiday
Areas of metal that have been missed by one or more applications of a coating material, resulting in pinholes or reduced film thickness.
Homing Beacon
A radio transmitter emitting signals for guidance.
Homocline
SEE: Monocline.
Homogeneous
A substance or fluid that has at all points the same property or composition. It is uniform or of similar nature throughout.
Hook Block
Block with hook attached used in lifting service. It may have a single sheave for double or triple line or multiple sheaves for four or more parts of line.
Hook Crack
Metal separations, resulting from imperfections at the edge of the plate or skelp, parallel to the surface, which turn toward the inside or outside pipe surface when the edges are upset during welding.
Hook Horsepower
Weight indicator reading (lb) x length of middle joint (ft) / Time to hoist middle joint (sec) x 550 = Hook Horsepower.
Hook Roller
A roller which prevents the lifting of the revolving upperstructure from the roller path. Hook rollers are the means to connect the upperstructure to the foundation or pedestal.
Hook Strip
A hook on the edge of a screen section which accept the tension member.
Hopper
A large funnel or container through which solids may be passed and mixed with liquids; e.g., cement, drilling mud, etc.
Horizon
(1) Geology: An interface indicative of a particular position in a stratigraphic sequence, usually a distinctive and very thin bed.(2) Seismic: An interface associated with a seismic reflection that can be traced over a broad area.(3) Soil: A layer of soil distinguishable from over and underlying layers of physical or chemical properties and structures.(4) Surveying: One of several lines or planes used as references for observation and measurement relative to a given location on the earth's su
Horizontal Component Distance
The calculated horizontal displacement distance of the lateral from the point of entry of the specified interval to the endpoint, or terminus of the lateral in said interval. This distance may either be expressed as one overall value, or as two values denoting a north/south component and an east/west component.
Horizontal Displacement Measurement
The distance between two points that are projected onto a horizontal plane.
Horizontal Drilling
A special drilling technique used in drilling the horizontal component of a wellbore.
Horizontal Permeability
Absolute permeability measured on a horizontally oriented core or surface sample.
Horizontal Well
A well in which a wellbore path deviates from the vertical by at least 75 degrees.
Horst
The ridge left standing between two grabens or down dropped fault blocks.
Hot Oil
Oil production in violation of state regulations or transported interstate in violation of federal regulations.
Hot Oil Treatment
A treatment using heated oil to melt and remove accumulated paraffin from the tubing, annulus, flow lines or production equipment.
Hot Spot
(1) An abnormally hot place on the tube in a boiler or furnace.(2) A location of active corrosion of buried pipe.
Hot Tapping
Making repairs or modifications on a tank, pipeline, or other installation without shutting down operations.
Hot Wire Analyzer
A device used to detect hydrocarbon gases returned to the surface by the drilling mud.
Hot Working
Deforming metal plastically at a temperature above the recrystallization temperature.
Hp
Abbreviation for Horsepower.
Hub
A connector machined to the top of a subsea wellhead on which the blowout preventor (BOP) and subsequent completion tree is attached.
Humic Acid
Organic acids of indefinite composition in naturally occurring leonardite lignite.
Hunting
(1) The fluctuation observed in a control instrument when it is attempting to establish a stable operating condition.(2) Uneven or cycling operation of an internal combustion engine due to bad timing or erratic fuel injection.
Hybrid Structure
A structure consisting of several different construction materials.
Hydrant
A discharge pipe with a valve and spout through which water may be drawn from a water main.
Hydrate
(1) A chemical compound of water and gaseous hydrocarbons, or hydrogen sulfide. Similar to porous snow in appearance, this solid has a specific gravity close to that of water. Accumulation of hydrates in pipelines and processing equipment results in freeze ups, a considerable source of trouble.(2) A substance containing water combined in the molecular form, such as CaSO4.2H2O.
Hydration
(1) The act of a substance to take up water by means of absorption and/or adsorption.(2) The chemical reaction between hydraulic cement and water forming new compounds most of which have strength producing properties.
Hydraulic
Operated, moved, or affected by a liquid pressure.
Hydraulic Drive
A motor driven hydraulically by a pump.
Hydraulic Efficiency
The percentage relation of hydraulic horsepower output to mechanical horsepower input.
Hydraulic Gradient
The change in pressure head between any two points along a line of flow divided by the length between the points.
Hydraulic Orientating Sub
Used in directional wellbore paths, with inclination greater than six degrees, to find the borehole low side. A ball falls to the low side of the sub and restricts an orifice causing an increase in the circulating pressure. The position of the tool is then known with relation to the borehole low side.
Hydraulically Operated Bent Sub
A deflection sub which is activated by hydraulic pressure of the drilling fluid.
Hydrocarbon
A compound consisting only of molecules of hydrogen and carbon.
Hydrocarbon Acreage
The areal extent of the hydrocarbon zone of a reservoir.
Hydrocarbon Charge
Replacement of nonhydrocarbon pore fluids of a reservoir rock in a reservoir with hydrocarbon fluids.
Hydrocarbon Generation
The conversion of organic material in source rock to hydrocarbons.
Hydrocarbon Generation Stage
The hydrocarbon generation stage interpreted from the vitrinite reflectance data from the source rock sample; e.g., oil; gas; dry gas.
Hydrocarbon Migration
The movement of hydrocarbons through the pores of rock from source rock to reservoir.
Hydrocarbon Prospecting
The search for an oil or gas trap using geological and geophysical methods.
Hydrocarbon Water Contact
The point at which hydrocarbons are encountered above and water below within a reservoir.
Hydrocarbon Wetability
The ability of the process stream to form a protective hydrocarbon film on metal surfaces.
Hydrocyclone
A liquid solids separation device utilizing centrifugal force for settling; obtaining the rotation of slurry and resulting centrifugal acceleration from high velocity tangential entry of the feed into the major circular cross section of the stationary restraining walls.
Hydrocyclone Size
The maximum diameter of a hydrocyclone.
Hydrodynamic Damping
Component of hydrodynamic force proportional to the velocity of the body and 180 degrees out of phase with the velocity.
Hydrodynamic Trap
A reservoir trap having part of its geometrical configuration determined by a fluid potential gradient, caused by movement of fluids in the reservoir rock. Hydrodynamic traps typically have tilted contacts between reservoir fluids.
Hydrodynamics
A branch of Science that deals with the motion of fluids and the forces acting on solid bodies immersed in fluids and in the motion relative to them.
Hydrogen Ion Concentration
Moles of hydrogen ions per mole of liquid.
Hydrogen Sulfide
A gaseous compound, commonly known by its chemical formula, H2S, frequently found in oil and gas reservoirs. It has a distinctive rotten egg odor. It is extremely poisonous and corrosive and quickly deadens the olfactory nerve so that its odor is no longer a warning signal.
Hydrogen Sulfide Encountered Depth
The measured depth at which hydrogen sulfide was encountered.
Hydrogen Sulfide Percentage
The MOL percentage of hydrogen sulfide in a gas stream.
Hydrogenation
In a refinery cracking unit, hydrocarbons are subjected to a high temperature, while simultaneously free hydrogen is being introduced. The hydrogen atoms combine into smaller molecules of the lighter hydrocarbons.
Hydrology
The science dealing with the properties, distribution, and circulation of water and snow.
Hydrolysis
The reaction of a salt with water to form an acid or base.
Hydrometer
A floating instrument for determining the specific gravity or density of liquids, solutions, and slurries. A common example is the Mudwate hydrometer used to determine the density of drilling fluid.
Hydrophile
A substance usually in the colloidal state or an emulsion, which is wetted by water; i.e., it attracts water or water adheres to it.
Hydrophilic
A property of a substance having an affinity for water or one that is wetted by water.
Hydrophilic Lipophilic Balance
The hydrophilic-lipophilic balance (HLB) is one of the most important properties of emulsifiers. It is an expression of the relative attraction of an emulsifier for water and oil, determined largely by the chemical composition and ionization characteristics of a given emulsifier. The HLB of an emulsifier is not directly related to solubility, but it determines the type of an emulsion that tends to be formed. It is an indication of the behavior characteristics and not an indication of emulsifier efficien
Hydrophobe
A substance, usually in the colloidal state, not wetted by water.
Hydrophobic
Descriptive of a substance which repels water.
Hydrophone
A seismic receiver that is sensitive to pressure variations. It is used in marine and marsh environments by placing it a few feet below the water surface.
Hydroprocessing
Used to remove sulfur, nitrogen, and oxygen compounds from both the gasoline and distillate streams. These nonhydrocarbon compounds are hydrogenated (have hydrogen atoms added to their molecules) and are removed later by either stripping or fractionation. Also referred to as hydrotreating.
Hydrostatic Head
The pressure exerted by a column of fluid; i.e., the unit weight of the fluid times the vertical height of the column of that fluid.
Hydrostatic Pressure Measurement
The hydrostatic head measurement.
Hydrostatic Test
To apply hydraulic pressure (usually with water) in order to find leaks in tubing, lines, piping, vessels and equipment.
Hydroxide
A designation that is given for basic compounds containing the OH- radical. When these substances are dissolved in water, they increase the pH of the solution.
Hygrometer
An instrument used for measuring dew points of gases.
Hygroscopic
The property of a substance enabling it to absorb water from the air.
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