Oil & Gas Glossary : Back to Resources
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Choose from the following oil and gas and related investment terms for their definition.

H

Hang the rods - To pull pump rods out of the well and hang them in the derrick on rod hangers. ^ top...

Heating oil - Oil use for residential heating. ^ top...

Heavy oil - A type of crude petroleum characterized by high viscosity and a high carbon-to-hydrogen ration. It is usually difficult and costly to produce by conventional techniques. ^ top...

Held by production - Refers to an oil and gas property under lease, in which the lease continues to be in force, because of production from the property. ^ top...

History of a well - A written account of a well's drilling and operation, required by law in some states. ^ top...

Horizon - A specific sedimentary layer in a cross section of land, especially one in which a petroleum reservoir is found. ^ top...

Horizontal drilling - The newer and developing technology that makes it possible to drill a well from the surface, vertically down to a certain level, and then to turn at a right angle, and continue drilling horizontally within a specified reservoir, or an interval of a reservoir. ^ top...

Horsehead - The curved guide or head piece on the well end of a pumping jack's walking beam. The guide holds the short loop of cable, called the bridle, attached to the well's pump rods. ^ top...

Hydraulic fracturing - A method of stimulating production from a low-permeability formation by creating fractures and fissures by applying very high fluid pressure. ^ top...

Hydrocarbons - A large class of organic compound of hydrogen and carbon. Crude oil, natural gas, and natural gas condensate are all mixtures of various hydrocarbons, among which methane is the simplest. ^ top...

Hydrometer - An instrument that measures the specific gravity of liquids. ^ top...

Hydrostatic head - The height of a column of liquid. The difference in height between two points in a body of liquid. ^ top...

I

In situ - In its original place. Refers to methods of producing synfuels underground, such as underground gasification of a coal seam or heating oil shale underground to release its oil. ^ top...

Independent producer - 1. A person or corporation that produces oil for the market, who has no pipeline system or refining. 2. An oil entrepreneur who secures financial backing and drills his own wells ^ top...

Infill drilling - Wells drilled to fill in between established producing wells to increase production. ^ top...

Initial potential - Flow rate measured during the initial completion of a well in a specific reservoir (initial daily rate of production). ^ top...

Injection well - A well employed for the introduction into an underground stratum of water, gas or other fluid under pressure. Injection well are employed for the disposal of salt water produced with oil or other waste. They are also use for a variety of other purposes: 1) Pressure maintenance, to introduce a fluid into a producing formation to maintain underground pressures which would otherwise be reduced by virtue of the production or oil or gas, 2)Secondary recovery operations, to introduce a fluid to decrease the viscosity of oil, reduce its surface tension, lighted its specific gravity, and drive oil into producing wells, resulting in greater production of oil. ^ top...

Intangible drilling costs - Expenditures, deductible for federal income tax purposes, incurred by an operator for labor, fuel, repairs, hauling, and supplies used in drilling and completing a well for production. ^ top...

Investment Tax Credit (ITC) - A credit against income taxes, usually computed as a percent of the cost of investment in certain types of assets. ^ top...

Isopachous map - A geological map showing the thickness and shape of underground formations. A tool used to determine underground oil and gas reservoirs. ^ top...

J

Jack or Unit - An oil-pumping unit. The pumping jack's walking beam provides the up-and-down motion to the well's pump rods. ^ top...

Jack-up rig - A floating platform with legs on each corner that can be lowered to the sea bottom to raise or jack up the platform above the water. ^ top...

Jet fuel - See Kerosene. ^ top...

Jetting - Injecting gas into a subsurface formation for the purpose of maintaining reservoir pressure. ^ top...

Joint - A single section of drill pipe, casing, or tubing, usually about 30 feet long. ^ top...

Joint Operating Agreement - A detailed written agreement between the working interest owners of a property which specifies the terms according to which that property will be developed. ^ top...

Joint venture - A large-scale project in which two or more parties (usually oil companies) cooperate. One supplies funds and the other actually carries out the project. Each participant retains control over his share, including liability and the right to sell. ^ top...

Junk basket - A magnet used to retrieve small tools lost in the well. A fishing instrument. ^ top...

K

Kelly bushing - Part of the drilling rig, the Kelly is a long hollow steel bar that connects to the upper end of the drill string. ^ top...

Kerogen - The hydrocarbon in oil shale. Scientists believe that kerogen was the precursor of petroleum and that petroleum development in shale was somehow prematurely arrested. ^ top...

Kerosene - The petroleum fraction containing hydrocarbons that are slightly heavier than those found in gasoline and naphtha. Kerosene (also spelled kerosene) was the most important petroleum product because of its use for home and commercial lighting; in recent years demand has risen again as a result of kerosene's use in gas turbines and jet engines. ^ top...

Keyseating - A condition in which the drill collar of another part of the drill string becomes wedged in a section of crooked hole. ^ top...

Kick Occurs - when the pressure encountered in a formation exceeds the pressure exerted by the column of drilling mud circulating through the hole. If uncontrolled, a kick leads to a blowout. ^ top...

Kill a well - To overcome downhole pressure by adding weighting elements to the drilling mud. ^ top...

L

Lag time - The time it takes for cuttings to be carried (circulate) from the bottom of the borehole up to the surface by the mud system. ^ top...

Landman - A self-employed individual or company employee who secures oil and gas leases, checks legal titles, and attempts to cure title defects so that drilling can begin. ^ top...

Landowner royalty - The share of the gross production of the oil and gas on a property without deducting any of the cost of producing the oil or gas. The usual landowner's royalty is one-eighth of gross production. ^ top...

Law of capture - A legal concept on which oil and gas law in some states is based: since petroleum is liquid, and hence mobile, it is not owned until it is produced. ^ top...

Lead lines - The lines through which production from individual wells is run to tanks. ^ top...

Lease (Oil and Gas) - A contract by which the owner of the mineral rights to a property conveys to another party, the exclusive right to explore for and develop minerals on the property, during a specified period of time. ^ top...

Lease acquisition costs - Bonus payments. ^ top...

Lease broker - An individual engaged in obtaining leases for speculation or resale. ^ top...

Lease hound - Someone who goes out and aggressively acquires oil and gas leases from the landowner, and then turns around and sells or trades them to an oil company planning to drill a well in the area. ^ top...

Lease offering (lease sale) - An area of land offered for lease - usually by the U.S. Department of Interior - for the exploration for and production of specific natural resources such as oil and gas. Such a lease conveys no title or occupancy rights apart from the right to search for and produce petroleum or other natural resources subject to the conditions stated in the lease. ^ top...

Lease or Sublease - Any transaction in which the owner of operating rights in a property assigns all or a portion of these rights to any other party. ^ top...

Lifting costs - The costs of producing oil from a well or lease; the operating expenses. ^ top...

Lignite - A solid fuel of a grade higher than peat but lower than bituminous coal. ^ top...

Limestone - Sedimentary rock largely consisting of calcite. On a world-wide scale, limestone reservoirs probably contain more oil and gas reserves than all other types of reservoir rock combined. ^ top...

Limited partner - In a limited partnership, a partner whose liability is limited to the amount of his investment in the partnership (plus any assessments and his share of undistributed partnership earnings). ^ top...

Limited partnership - A partnership in which the general partner manages the partnership's activities and is solely liable for them. The limited partners are liable only to the extent of their contributions. ^ top...

LNG (liquefied natural gas) - Natural gas that has been converted to a liquid through cooling to -260 degrees Fahrenheit at atmospheric pressure. ^ top...

Logs - Records made from data-gathering devices lowered into the wellbore. The devices transmit signals to the surface which are then recorded on film and used to make the record describing the formation's porosity, fluid saturation, and lithology. The filing of a log is required by the federal government if the drill site is on federal land. ^ top...

Lost circulation - A serious condition that occurs when drilling mud pumped into the well does not return to the surface, but goes into the porous formation, crevices, or caverns instead. ^ top...

LPG (liquefied petroleum gases) - Hydrocarbon fractions lighter than gasoline, such as ethane, propane and butane, kept in a liquid state through compression and/or refrigeration, commonly referred to as "bottled gas." ^ top...