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basin: or sedimentary basin, a concave-upward shaped geologic feature into which sediments are deposited in great thicknesses.
British Thermal Unit (BTU): is the amount of heat energy needed to raise the temperature of one pound of water by one degree F.
cement: new material precipitated around sediments buried below Earth's surface.
crude oil: see petroleum.
compressed natural gas (CNG): natural gas at pressures between 2900-3600 psi to reduce its volume to around 1% and used as a substitute for gasoline in motor vehicles
condensate: are a portion of natural gas that remain as gas under pressure in reservoirs, but transform to liquid phases (natural gas liquids) at surface pressure and temperature.
downstream: relates to oil and gas refining, marketing and distribution activities. (see also upstream.)
dry gas: natural gas that does not contain any condensates or one that has been treated to remove all liquids.
dry hole: a well that does not produce enough oil or gas to be economical.
faults: fractures in rocks along which displacement occurs.
folds: buckle-shaped structures in rocks formed by compression.
gas laws: scientific laws which describe how gases behave when their pressure, volume, or temperature changes. Charles's Gas Laws and Boyle's Law are two examples.
geophysics: branch of science that applies physical principles to study of planet Earth.
hydraulic fracturing: a method used to increase the flow of petroleum or gas from a reservoir by using pressurized fluids to artificially increase the permeability of the rocks.
hydrocarbons: family of organic compounds, composed entirely of carbon and hydrogen (for example, coal, crude oil and natural gas).
impermeable: Rocks where cracks and pore spaces are very small or are blocked by mineral growth. Fluids cannot flow through clays, cemented sandstone or salt.
liquefied natural gas (LNG): gas, mainly methane, liquefied under pressure and low temperature.
mercaptan: strong-smelling compounds of carbon, hydrogen and sulphur found naturally in oil and gas. They are added to natural gas for safety reasons to highlight leakages.
methanol: a simple alcohol produced from methane. Its uses range from antifreeze and solvents to an industrial ingredient (feedstock) in the manufacture of biodiesel and other compounds.
methane: CH4, a naturally occurring gas composed of carbon and hydrogen, first member of paraffin series of hydrocarbons. Also a greenhouse gas.
mid-stream: the processing, storage, and transportation component of fossil fuel industry. It is commonly included in downstream processes.
natural gas: a gas consisting mainly of methane produced by the burial and heating of organic matter in sediment.
natural gas liquids: see condensates.
oil: mixture of liquid hydrocarbons of different molecular weights, also called crude oil.
permeable: rocks through which fluids can pass because of interconnected pores and fractures.
petroleum: generic name for hydrocarbons contained in sedimentary rocks, including crude oil, as well as natural gas and their products.
porous rocks: rocks that contain spaces between their grains or particles, e.g. sandstone.
seal or cap: rocks (salt, clays or cemented sandstone) in right shapes and relative positions to form traps.
sedimentary rock: rock formed by consolidation of deposits formed by settlement of sand, silt, and other materials.