Oil and Gas Terms Beginning with “H” — Page 2

A particular frequency at which a data set has a resonance, or the frequency has special significance. Read more →

A nonlinear change in waveform in which simple multiples of (1,2, ... n times) the input frequencies, or harmonics, are generated. Read more →

An opening in the top of a tank through which samples are taken or inspection is made. Read more →

The device that connects the end of the loggingcable or the bridle to the top of the logging tool. It contains the weak point, so that when the weak point is broken and the cable removed, the uppermost assembly left in… Read more →

A pressurewave in the borehole fluid generated by the passage of either the acousticcompressional wave or the shear wave in the formation. These pressure waves are recorded by logging tools using hydrophones and are the… Read more →

In a gathering system, a pipe arrangement that connects flowlines from several wellheads into a single gathering line. A header has production and testing valves to control the flow of each well, thus directing the… Read more →

A small box mounted on a shaker screen that takes drilling fluid from the return flow line and distributes it across the surface of the screens via adjustable weirs. Read more →

The first page or pages on a log print, which include information about the well, the survey, the mud properties and other relevant data. Read more →

Equipment that transfers heat to the produced gas stream.Heaters are especially used when producing natural gas or condensate to avoid the formation of ice and gas hydrates. These solids can plug the wellhead, chokes… Read more →

What Is a Heater-Treater in Oil and Gas? A heater-treater is a surface production vessel that combines applied heat with gravity separation and chemical treatment to break stable oil-water emulsions that cannot be… Read more →

In general chemistry, the term refers to metals that are more dense than iron, although some texts and chemical dictionaries do not recognize this as a chemical term. Read more →

Crude oil with high viscosity (typically above 10 cp), and high specific gravity. The API classifies heavy oil as crudes with a gravity below 22.3° API. In addition to high viscosity and high specific gravity, heavy… Read more →

An operating condition during a snubbing operation in which the force resulting from the weight of the pipe or tubing string is greater than the wellheadpressure and the buoyancy forces acting to eject the string from… Read more →

A type of drillpipe whose walls are thicker and collars are longer than conventional drillpipe. HWDP tends to be stronger and has higher tensile strength than conventional drillpipe, so it is placed near the top of a… Read more →

A claymineral similar in structure to bentonite but with more negative charges on its surface. Organophilic hectorite, made by the wet process, is a premium performance additive for use in oil-base drilling mud. Read more →

A provision in an oil, gas and minerallease that perpetuates a companys right to operate a property or concession as long as the property or concession produces a minimum paying quantity of oil or gas. Also abbreviated… Read more →

The mineral form of ferric oxide [Fe2O3]. The hematite ore used as a weighting material in drilling muds has a mica-like crystal structure that grinds to particle size suitable for use in drilling fluids. To check for… Read more →

The unit of measurement of frequency, equivalent to one cycle per second and symbolized by Hz. The unit is named after German physicist Heinrich Hertz (1857 to 1894), who discovered electromagnetic waves. Read more →

A technique used in squeezecementing whereby a portion of the slurry is pumped, then pumping stops to expose the slurry to differential pressure against the zone of interest in stages over a period from several minutes… Read more →

The quality of variation in rock properties with location in a reservoir or formation. Shale gas reservoirs are heterogeneous formations whose mineralogy, organic content, natural fractures, and other properties vary… Read more →

Formation with rock properties changing with location in the reservoir. Some naturally fractured reservoirs are heterogeneous formations. Read more →

A cessation in deposition of sediments during which no strata form or an erosional surface forms on the underlying strata; a gap in the rock record. This period might be marked by development of a lithified sediment… Read more →

A method of cluster analysis in which the distance between every pair of data points is determined and the relative distances displayed on a dendogram. This method is completely accurate but is very CPU intensive when… Read more →

Chemical explosive material having an extremely high reaction rate that creates very high combustion pressures, unlike low explosives that have a much lower reaction rate and are commonly used as propellants. High… Read more →

Equipment or systems used for completion of wells in thermal production of heavy oil. Read more →

Dense solids, such as barite or hematite, which are added to a mud to increase its density, also known as weighting material. The concentration of high-gravity solids in a weighted mud is measured by the mud engineer… Read more →

An enhanced oil recovery process utilizing compressed air that is injected into a reservoir. Oxygen in the gas reacts exothermically with some of the oil, producing highly mobile flue gas. The flue gas advances ahead of… Read more →

A squeeze-cementing technique involving the application of treatment pressure that is higher than the fracture pressure of the formation. This procedure may be necessary to force the slurry into microcracks or annuli… Read more →

Pertaining to wells that are hotter or higher pressure than most. The term came into use upon the release of the Cullen report on the Piper Alpha platform disaster in the UK sector of the North Sea, along with the… Read more →

A test to measure static filtration behavior of water mud or oil mud at elevated temperature, up to about 380°F [193°C] maximum (450°F [227°C] maximum if a special cell is used), usually according to the specifications… Read more →