Coal Bed Methane Terms and Definitions

acidizing: A procedure in which acid ( often hydrochloric acid) is pumped into a reservoir to dissolve calcite in order to increase oil or gas production.

aromatics : Hydrocarbons that are characterized by unsaturated ring structures of carbon atoms. Commercial petroleum aromatics are benzene, toluene, and xylene.

basin : A large natural depression on the earth's surface in which sediments, typically waterborne, accumulate.

Bcf : The abbreviation for billion cubic feet of gas.

benzene : An aromatic hydrocarbon present to a minor degree in most crude oils. Used in manufacturing detergents, synthetic fibers, and petrochemicals, as a solvent, and as a component of high-octane gasoline. Is a known carcinogen.

bit : The cutting or boring element used in drilling oil and gas wells.

blowout : An uncontrolled flow of gas, oil, or other well fluids or materials from a well.

bond : A financial guarantee supplied by the oil or gas company to ensure the reclamation of the lands disturbed by oil and gas development. If required reclamation is not completed, the state or federal agencies or surface owner can use the money supplied by the bond to complete the necessary work.

borehole : The hole created in the earth when a well is drilled or bored.

brine : Water that has a quantity of salt, especially sodium chloride, dissolved in it; salt water.

carcinogenic : Causes cancer.

casing : Steel pipe that is placed in the borehole and cemented in to prevent the hole from collapsing; and to prevent movement of drilling fluids from the borehole into the formation, or fluids from one formation to another. Casing operations occur periodically throughout the drilling process starting with the surface casing and ending with production string which takes place during well completion.

cementing : The application of a liquid slurry of cement and water to various points inside or outside the casing in order to support the casing and prevent fluid migration between permeable zones.

compressor : A device that raises the pressure of a compressible substance such as vapor or gas, and creates a pressure differential to move the vapor or gas.

covenant : A promise to do something. Under a lease there are two types of covenants: (a) stipulated, i.e., set out in the lease, (b) implied, i.e., interpreted by the courts to be present in the lease whether written out or not. Implied covenants may include fully developing the property, diligence in marketing of the production, etc.

cuttings : The fragments of rock cut from the formation by the drill bit and brought to the surface in the drilling mud. Used by geologists to obtain information about the formations.

deed : A written document transferring ownership of a piece of property. A mineral deed conveys only an interest in the minerals.

development well : A well drilled within the proved area of an oil or gas reservoir to the depth of a geological formation known to be productive.

directional drilling : Drilling at an angle from the vertical. Controlled directional drilling makes it possible to reach subsurface areas laterally distant from the point where the drill bit enters the earth.

disposal well : Well used for disposal of produced water into an underground formation.

drilling fluid : Specially formulated liquid circulated through the wellbore during rotary drilling operations. Used to bring cuttings from the wellbore to the surface; to lubricate and cool the drill bit, string, line, and walls of the well; and provides weight to counteract downhole formation pressure. Also known as drilling mud.

flaring : Burning of hydrocarbon gases for commercial or technical reasons.

fracing fluid : A fluid such as water, oil or acid, used in the hydraulic fracturing process. Under extremely high hydraulic pressure these fluids are pumped downward through production tubing. The pressure causes cracks to open in the formation, and the fluid penetrates the formation through the cracks. The fluid also carries substances called proppants that hold open the formation cracks after hydraulic pressure dissipates. Also known as frac, fracturing or hydraulic fracturing fluid.

fracturing : A method of stimulating oil or gas production by opening new flow channels in the formation surrounding a production well. It involves pumping of crude oil, diesel, water, or chemical into a reservoir with such force that the reservoir rock is broken and results in greater flow of oil or gas from the reservoir. Also known as hydraulic fracturing or fracing.

gas injection : A secondary recovery method whereby dry natural gas or carbon dioxide is injected into an oil reservoir to increase pressure around the injection will and thus increase flow and oil production from nearby wells.

horizontal drilling : A drilling technique where a well is drilled vertically to a certain depth and then drilled at a right angle so that the borehole penetrates a productive formation in a manner parallel to the formation.

hydraulic fracturing : An operation in which a specially blended liquid is pumped down a well and into a formation under pressure high enough to cause the formation to crack open, forming passages through which oil or gas can flow into the wellbore. See also fracturing.

hydrocarbons : Organic compounds composed of hydrogen and carbon. Their densities, boiling points, and freezing points increase as their molecular weights increase. The smallest molecules of hydrocarbons are gaseous; the largest are solids. Petroleum is a mixture of many different hydrocarbons.

hydrogen sulfide : Chemical formula H2S, also known as sour gas. It is a flammable, colorless gas that is often associated with oil and gas development. Hydrogen sulfide is toxic and at low concentrations, smells like rotten eggs. It is heavier than air, and may accumulate in low-lying areas.

impermeable : Preventing the passage of fluid. A formation may be porous yet impermeable if there is an absence of connecting passages between the voids within it.

injection water : Water that is introduced into a reservoir to help drive hydrocarbons to a producing well. May also refer to produced water that is introduced into a formation other than the one from which it was extracted.

injection well : A well through which fluids are injected into a subsurface formation to increase reservoir pressure and to displace oil (e.g., during oil enhancement or waterflooding operations). Also called an input well.

lease: A legal instrument that could be a contract, profit-share agreement, joint venture or other agreement between a mineral owner (lessor) and another party (lessee) that grants exclusive right to the lessee to explore for, drill, produce and remove oil or gas from a piece of land.

monitoring : The periodic observation and orderly collection of data to evaluate the effects of oil and gas development.

mud : The liquid circulated through the wellbore during rotary drilling and workover operations. Also known as drilling fluid.

NOx : Nitrogen oxides, which are gases containing nitrogen and varying number of oxygen atoms. Some sources of these gases include motor vehicle exhaust, burning of diesel fuel, coal and flaring of methane. The brown haze sometimes seen over cities is mainly nitrogen oxides. These gases are also partly responsible for the generation of ozone. Exposure to high levels of nitrogen dioxide can interfere with the ability of blood to carry oxygen, leading to dizziness and shortness of breath. Prolonged exposure can lead to respiratory failure.

ozone : A gas containing three oxygen atoms in each molecule, chemical formula O 3 . Ozone forms in atmosphere when nitrogen oxides and organic gases emitted by automobiles and industrial sources are exposed to sunlight.

PAH : Abbreviation for polynuclear aromatic hydrocarbon; also called polycyclic aromatic hydrocarbons. PAHs are hydrocarbon compounds with multiple benzene rings. Typically, they are components of asphalts, crude oil, coal, coal tar pitch, fuels, and greases. Also, PAHs are formed during the incomplete burning of coal, oil and gas. Studies of people show that individuals exposed by breathing or skin contact for long periods to mixtures that contain PAHs and other compounds can also develop cancer. EPA has determined that the PAHs benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, chrysene, dibenz[a,h]anthracene, and indeno[1,2,3-c,d]pyrene are probable human carcinogens.

paraffin : A saturated aliphatic hydrocarbon having the formula CnH 2 n+2. Heaver paraffin hydrocarbons form a waxlike substance that is called paraffin. These heavier paraffins often accumulate on the walls of tubing and other production equipment, restricting or stopping the flow of the desirable lighter paraffins.

permeability : Ability of rock to transmit fluids through pore spaces.

petroleum : A substance occurring naturally in the earth in solid, liquid, or gaseous state and composed mainly of mixtures of chemical compounds of carbon and hydrogen. Petroleum may contain nonmetallic elements such as sulfur, oxygen, and nitrogen. In some cases, petroleum refers only to oil. When used more generally, however, it is the name for hydrocarbons, including crude oil and natural gas and their projects.

pit : Hole dug out in the ground surface for temporary storage of fluids during drilling operations.

particulate matter : A collective name for fine solid or liquid particles added to the atmosphere. Particulate matter includes dust, smoke, soot, pollen and soil particles.

porosity : The percentage of rock volume that can be occupied by oil, gas or water.

produced water : Liquids produced during the drilling and production operations. Produced water usually is composed of groundwater and by-products of the drilling operations, e.g., mud, drilling lubricants, and oil. The volume of coal bed methane produced water is orders of magnitude greater than water associated with conventional oil and gas production.

proppants : Sand grains, aluminum pellets, walnut shells, or similar materials that are carried by fracing fluid during hydraulic fracturing. When the pressure is released at the surface, the fracturing fluid returns to the well but leaves behind the propping agents to hold open the formation cracks.

proved reserves : The estimated quantities of oil or natural gas that geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic and operating conditions.

reclamation : The restoration of lands disturbed by oil and gas activity to some specified end, e.g., productive use. Activities usually include recontouring and reseeding the land.

record title : The ownership of an interest which is determinable from the county records in which the property is located. Record title may be different than actual ownership where there are assignments or letter agreements unrecorded. Under federal leases, the official chain of title is kept by the government. Each time lease ownership changes, the changes must be made with the government and an instrument also filed in the county records to update both.