Glossary of Terms

Acreage: Land leased for oil and gas exploration and/or land for which the mineral rights are owned.

Aquifer: An underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, silt, or clay) from which groundwater can be extracted using a water well.

Barrel: A standard barrel of oil holds about 42 U.S. gallons, or roughly 159 liters. The barrel was adopted in the early days of U.S. oil and gas production to transport oil. It’s used today to measure transport volumes and pricing around the world.

Barrel of Oil Equivalent (BOE): A measure used to aggregate oil and gas resources or production, with one BOE equaling approximately 6,000 cubic feet of natural gas.

Basin: A large, natural depression on the Earth’s surface in which sediments accumulate, generally brought by water.

BCF: One billion cubic feet of natural gas.

Bitumen: Heavy, viscous oil that must be processed extensively to be converted into a crude oil before it can be used by refineries to produce gasoline and other petroleum products.

BOE/D: Barrels of oil equivalent per day.

Borehole: A hole in the Earth made by a drilling rig.

British Thermal Unit (BTU): The heat required to raise the temperature of a one-pound mass of water by one degree Fahrenheit.

CAPEX: Capital expenditures.

Carbon Capture and Storage (CCS): The process by which carbon dioxide emissions are captured and removed from the atmosphere and then stored, normally via injection, into a secure underground geological formation.

Carbon Sequestration: The process of capturing and storing atmospheric carbon dioxide.

Casing: Thick-walled steel pipe placed in wells to isolate formation fluids (such as fresh water) and to prevent borehole collapse.

Completion: The process of making a well ready to produce natural gas or oil. Completion involves installing permanent equipment, such as a wellhead, and often includes hydraulic fracturing.

Conventional Crude Oil: Petroleum found in liquid form, flowing naturally or capable of being pumped without further processing or dilution.

Directional Drilling: The application of special tools and techniques to drill a wellbore at a predetermined angle. Horizontal drilling is a form of directional drilling where the wellbore is drilled at +/- 90 degrees to the vertical direction.

Downstream: The refining and marketing sector of the petroleum industry (e.g., refineries, gas stations).

Drilling Rig: The machine used to drill a wellbore.

E&P: Exploration and production.

Enhanced Oil Recovery (EOR): Any method that increases oil production by using techniques or materials that are not part of normal pressure maintenance or water flooding operations.

Feedstock: Raw material supplied to a refinery or oil sands upgrader. For example, crude oil is a feedstock in a refining process that produces gasoline.

Flaring: The burning of natural gas for safety reasons or when there is no way to transport the gas to market or to use the gas for other beneficial purposes (such as EOR or reservoir pressure maintenance).

Flow Line: The pipe, usually buried, through which oil or gas travels from a well to a processing facility.

Formation: A rock layer that has distinct characteristics (e.g., rock type, geologic age).

Fossil Fuel: A fuel source (such as oil, condensate, natural gas, natural gas liquids, or coal) formed in the earth from plant or animal remains.

Greenhouse Gases (GHGs): Types of gas that contribute to the greenhouse effect by absorbing infrared radiation. GHG emissions from oil and natural gas development include carbon dioxide (CO2), methane, nitrous oxide, and ozone.

Groundwater: The water found underground in the cracks and spaces in soil, sand, and rocks called aquifers.

Horizontal Drilling: A drilling technique whereby a well is progressively turned from vertical to horizontal to allow for greater exposure to an oil or natural gas reservoir. Horizontal laterals can be more than a mile long. Horizontal drilling technology has been extensively used since the 1980s and is appropriate for many, but not all, developments.

Hydraulic Fracturing (also called Fracking): A government-regulated technology used safely for more than 60 years to recover shale or tight natural gas that is trapped in deep underground rock. A fluid or gas is pumped down a well, which causes the surrounding rocks to crack and allow natural gas or oil to be produced from tight formations.

Hydraulic Fracturing Fluids: Fluids pumped into a well to create conductive fractures and increase hydrocarbon flow. These fluids comprise primarily water and sand (~98.5%) and a small number of additives (~1.5%).

Hydrocarbon: An organic compound containing only carbon and hydrogen and often occurring in nature as petroleum, natural gas, coal, and bitumens, or in refined products such as gasoline and jet fuel.

Injection Well: Used to inject fluid (steam, carbon dioxide, water, or other substances) underground into porous geologic formations to help maintain reservoir pressure, heat the oil, or lower its viscosity, allowing it to flow to a producing well nearby.

Lease: A legal document executed between a mineral owner and a company or individual that conveys the right to explore for and develop hydrocarbons and/or other products for a specified period over a given area.

Liquefied Natural Gas: Natural gas, when produced and used domestically, is shipped in its vapor form through a network of distribution pipelines to local distribution companies, then delivered to customers.

Methane: The principal constituent of natural gas; the simplest hydrocarbon molecule, containing one carbon atom and four hydrogen atoms.

Midstream: The processing, storage, and transportation (primarily via pipelines) sector of the petroleum industry.

Mud (also Drilling Mud): Fluid circulated down the drill pipe and up the annulus during drilling to remove cuttings, cool and lubricate the bit, and maintain desired pressure in the well.

Natural Gas: Naturally occurring hydrocarbon gases found in porous rock formations.

Natural Gas Liquids (NGLs): Highly volatile liquid products separated from natural gas in a gas processing plant. NGLs include ethane, propane, butane, and condensate.

Oil Sands: A deposit of sand saturated with bitumen.

Oil Terminal (also called a Tank Farm, Tankfarm, Oil Installation, or Oil Depot): An industrial facility for the storage of oil, petroleum, and petrochemical products, from which these products are transported to end users or other storage facilities. Cushing, Oklahoma, is the largest oil terminal in the world. It holds 73 million barrels of working capacity, about 13% of total U.S. storage.

OPEC (Organization of the Petroleum Exporting Countries): A multinational organization established to coordinate the petroleum policies of its members and to provide member states with technical and economic aid.

Operator: The company or individual responsible for managing an exploration, development, or production operation.

Orphan Well: A well or associated site that does not have a legally responsible and/or financially viable party to deal with its decommissioning and reclamation.

Permeability: The capacity of a reservoir rock to transmit fluids; how easily fluids can pass through rock.

Petroleum: A naturally occurring mixture of hydrocarbons found in geological formations beneath the Earth’s surface that can be refined into a variety of products (e.g., gasoline, diesel).

Play: An area in which hydrocarbon accumulations or prospects with similar characteristics occur.

Porosity: The volume of spaces within rock that might contain oil and gas (like the amount of water a sponge can hold); the open or void space within rock.

Primary Recovery: The production of oil and gas from reservoirs using pumping techniques and the natural energy available in reservoirs.

Produced Water: Water naturally present in a reservoir that is recovered during oil and gas production.

Pump Jack: A device used in the petroleum industry to extract crude oil from an oil well where there is not enough pressure in the well to force the oil to the surface. Pump jacks physically extract the oil for use.

Reclamation: The process of restoring a well site’s surface area, access road, and related facilities to their original conditions.

Reclamation Certified: Well sites that have been remediated and reclaimed to the current regulatory standard.

Refinery: An industrial process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, and liquefied petroleum gas.

Reformulated Fuels: Gasoline, diesel, or other fuels that have been modified to reflect environmental concerns, performance standards, government regulations, customer preferences, or new technologies.

Reserves: An estimate of the amount of crude oil located in a specific region. Reserves must be accessible with current technology.

Reservoir: A porous and permeable underground formation containing a natural accumulation of producible oil and/or gas that is confined by impermeable rock or water barriers and is individual and separate from other reservoirs.

Royalty: An owner’s share of production or revenues retained by government or freehold mineral rights holders. In natural gas operations, royalties are usually based on a percentage of the total production.

Seismic Studies: A low-impact, noninvasive method of gathering information about a location and the characteristics of geological structures beneath the Earth’s surface.

Shale: Rock formed from clay. Shale is frequently a “tight” type of rock, having small or widely spaced pores that trap oil or natural gas.

Strategic Reserves: The Strategic Petroleum Reserve (SPR) is a U.S. government complex of four sites with deep underground storage caverns created in salt domes along the Texas and Louisiana Gulf Coast.

Surface Water: Water collected on the ground or in a stream, river, lake, sea, or ocean.

Sweet Gas: Natural gas that contains little or no hydrogen sulfide.

Sweet Oil: Petroleum containing little or no hydrogen sulfide.

Synthetic Crude Oil: A mixture of hydrocarbons, similar to crude oil, derived by upgrading bitumen from oil sands.

TCF: One trillion cubic feet of natural gas.

Tight Gas: Gas with very low flow rates. Getting tight gas out usually requires enhanced technology like “hydraulic fracturing,” in which fluid is pumped into the ground to make it more permeable.

Upstream: The sector of the petroleum industry that consists of companies that explore for, develop, and produce petroleum. Also known as “E&P.”

Viscosity: The resistance to flow, or “thickness,” of a fluid. Honey, for example, has a greater viscosity than water.

Volatile Organic Compounds (VOCs): Gases and vapors, such as benzene, released by petroleum refineries, petrochemical plants, plastics manufacturing, and the distribution and use of gasoline.

Wellbore: A hole drilled or bored into the Earth, usually cased with metal pipe, to produce gas or oil.

West Texas Intermediate (WTI): A light, sweet crude oil, produced in the U.S., that serves as a benchmark grade for global oil pricing.

Wet Gas: Produced gas that contains natural gas liquids.