The World's Most Misleading Industry
Oil & Gas Glossary
- Acid Fracking
- A variation of hydraulic fracturing in which an acid solution is pumped into a well to dissolve rock and widen existing fractures, increasing the flow of oil and gas to the surface.
- Barrel / Blue Barrel (BBL)
- The standard unit of measurement for oil. One barrel equals 42 US gallons (159 liters).
- Benzene
- A colorless, flammable liquid chemical found naturally in crude oil and gasoline. Benzene evaporates easily, making its vapors an inhalation hazard. It is commonly released into the air and water during fossil fuel extraction. Even low levels of exposure are dangerous: long-term contact is linked to leukemia, bone marrow damage, and anemia, while short-term exposure can cause respiratory problems, dizziness, and headaches.
- Blowout
- An uncontrolled release of oil, gas, or other hydrocarbons at the surface of a well, typically caused by high underground pressure overwhelming wellhead valves or by equipment failure.
- Blowout Preventers (BOPs)
- High-pressure safety valves installed at the wellhead during drilling and completion. They are designed to automatically shut off if dangerous pressure is detected, preventing an uncontrolled release of oil and gas.
- BTEX Compounds
- The acronym for four toxic volatile organic compounds (VOCs) commonly associated with oil and gas production: benzene, toluene, ethylbenzene, and xylene. See also: VOCs.
- Capping
- Sealing a well with a cover or valve system, either temporarily or as a permanent closure, to prevent leaks, contamination, or unauthorized access.
- Casing
- Steel pipes inserted into the wellbore to prevent the walls from collapsing, stop underground liquids from entering the well, and help manage pressure buildup inside the borehole.
- Class II Well
- Underground injection wells used to dispose of fluids associated with oil and gas extraction. Types include wastewater disposal wells, enhanced oil recovery wells, and hydrocarbon storage wells.
- COGCC (Colorado Oil and Gas Conservation Commission)
- The former name of Colorado’s oil and gas regulatory agency, now known as the ECMC (Colorado Energy & Carbon Management Commission). The agency was renamed in 2023. See also: ECMC.
- Completion
- The phase of well construction in which permanent equipment is installed at the wellhead to allow oil and gas production to begin.
- Comprehensive Area Plan (CAP)
- A detailed planning and permitting process required for large-scale oil and gas projects in Colorado. A CAP may encompass one or more Oil & Gas Development Plans (OGDPs).
- Compressor / Compressor Station
- Equipment at or near well pads that increases the pressure of extracted gas so it can be moved through pipelines to processing facilities or markets.
- Condensate
- Liquid hydrocarbons (along with water and chemicals) that are separated from gas after being brought to the surface and stored in tanks at the well pad.
- Conventional Drilling
- The traditional method of oil and gas extraction using vertical wells, without hydraulic fracturing. Conventional drilling is generally simpler and less expensive than unconventional methods and tends to produce oil and gas at a steadier rate over a longer period of time.
- Deep Well Injection
- The disposal of contaminated fracking wastewater by pumping it into extremely deep underground wells. This practice is known to reactivate dormant earthquake faults and increase seismic activity. Nearly 1,000 deep injection wells operate in Colorado.
- Diesel Rig
- A drilling rig powered by internal combustion engines running on diesel fuel. Compared to electric rigs, diesel rigs are louder, less energy-efficient, and produce more air pollution.
- Directional Drilling
- The intentional drilling of a wellbore at an angle (rather than straight down) in order to reach oil and gas deposits located laterally away from the wellhead. Often used in combination with hydraulic fracturing.
- Disproportionately Impacted Community (DIC)
- A community (often low-income households, communities of color, or indigenous groups) that bears a disproportionate share of the negative environmental, health, and economic effects of industrial activity such as oil and gas development. These burdens are often the result of systemic and historical inequities.
- Downhole
- Refers to anything occurring below ground inside the wellbore, as opposed to at the surface. Local governments in Colorado are generally unable to regulate downhole activities at oil and gas sites within their jurisdiction.
- Drill Cuttings
- Fragments of soil and rock produced during drilling that must be removed from the wellbore. Cuttings are often contaminated with drilling fluids and toxic materials and may require special handling and disposal.
- Drilling Mud
- A thick mixture of clay, water, oil, and synthetic chemicals used to lubricate and cool the drill bit, carry drill cuttings to the surface, support the walls of the borehole, and maintain pressure to prevent oil and gas from escaping. Used drilling mud is contaminated with chemicals and toxic metals and must be disposed of as hazardous waste. (Drilling mud is used during the drilling phase; fracking fluid is used later to release oil and gas from the rock formation.)
- Drilling Rig
- The above-ground structure used to position and operate the machinery that drills a well.
- Dry Hole
- A well that was drilled but found not to produce enough oil or gas to justify extraction. Advances in subsurface mapping have made dry holes relatively rare.
- ECMC (Colorado Energy & Carbon Management Commission)
- Colorado’s state agency responsible for regulating the oil and gas industry. Formerly known as the Colorado Oil and Gas Conservation Commission (COGCC), the agency was renamed in 2023.
- Electric Rig
- A drilling rig powered by electricity rather than diesel fuel. Electric rigs are quieter, cleaner, and more energy-efficient than diesel rigs, and allow for greater control during drilling operations. Use of electric rigs is sometimes required by local governments as a condition of drilling permits.
- Flaring
- The controlled burning of natural gas (mostly methane) that operators cannot or choose not to capture or sell. Flaring converts methane into carbon dioxide and water, which is less harmful to the climate than releasing raw methane directly into the air. Colorado laws enacted in 2022 prohibit both flaring and venting except in emergencies, requiring operators to capture gas or route it to a gathering line. See also: Venting.
- Flowback Fluid
- The mixture of fracking fluid, brine, chemicals, and naturally occurring groundwater that returns to the surface during the first 90 days after a well is drilled. Flowback fluid is typically contaminated with chemicals, dissolved minerals, hydrocarbons, and naturally occurring radioactive materials and cannot safely re-enter the water supply. See also: Produced Water.
- Flowline
- A pipeline at the surface of a well pad that carries raw oil, gas, and water from an individual wellhead to processing equipment or storage tanks. Flowlines serve a single well and are shorter and smaller than gathering lines.
- Forced Pooling
- A legal process (permitted in approximately 40 states) that allows an oil and gas operator to combine non-consenting mineral rights owners into a drilling unit with consenting owners, effectively compelling participation in oil and gas development. This allows operators to drill horizontal wells across large tracts of land even when some landowners object.
- Frac Interference (Frac Hits)
- An underground interaction between two or more wells that disrupts oil and gas extraction. When a new well is pressurized during fracking, nearby wells can experience pressure changes that damage equipment, reduce production, injure workers, and release contamination into the air or groundwater.
- Fracked Gas
- Natural gas extracted using hydraulic fracturing, as distinguished from gas produced by conventional drilling methods.
- Fracking
- Short for hydraulic fracturing. A process used to extract oil and gas from deep rock formations by injecting large volumes of water, sand, and chemicals at high pressure. This fractures the rock, releasing trapped oil and gas that flows back up the well to be collected at the surface. See also: Hydraulic Fracturing.
- Fracking Fluid / Frac Fluid
- The liquid mixture pumped into a well at high pressure during fracking. It typically consists of water, sand (proppant), and chemical additives. The fluid fractures surrounding rock, and the sand remains behind to hold the cracks open so oil and gas can flow to the surface. Most of the liquid that returns to the surface is contaminated and must be disposed of as hazardous waste.
- Fugitive Emissions
- Unintentional releases of gas or vapor during the extraction, processing, storage, or transport of fossil fuels. Fugitive emissions often include methane and other volatile organic compounds (VOCs), contributing to air pollution and climate change. They are frequently underreported and can go undetected for long periods.
- Gathering Line
- A pipeline that collects oil and gas from multiple wells and transports it to a compressor station or central processing facility. Gathering lines are larger and longer than flowlines and often connect to high-pressure transmission pipelines.
- Greenhouse Gases (GHGs)
- Gases (including carbon dioxide, methane, nitrous oxide, and water vapor) that trap heat in the Earth’s atmosphere. Human activities such as burning fossil fuels release excess greenhouse gases, driving global warming and climate change.
- Groundwater
- Freshwater stored underground in soil, rock pores, and aquifers. Fed by rain and snowmelt, groundwater is a primary source of drinking water, irrigation, and ecosystem support and is vulnerable to contamination from nearby oil and gas operations.
- Horizontal Drilling
- A drilling technique that begins vertically and then curves to travel horizontally through an underground rock formation. Horizontal drilling allows a single well pad to access oil and gas across a much larger area than a vertical well and is almost always used in combination with hydraulic fracturing.
- Hydraulic Fracturing
- The technical term for fracking. A process that extracts oil and gas from deep rock formations by injecting large volumes of water, sand, and chemicals at high pressure, fracturing the rock and releasing trapped hydrocarbons. See also: Fracking.
- Hydrocarbon Storage Well
- Specialized underground wells used to inject, store, and later retrieve liquefied hydrocarbons (such as oil, liquefied natural gas, or liquefied petroleum gas) in geologic formations like salt caverns.
- Hydrocarbons
- A broad term for oil, natural gas, and condensate. Chemically, hydrocarbons are organic compounds made up entirely of hydrogen and carbon.
- Liquefied Natural Gas (LNG)
- Natural gas (composed mostly of methane) that has been cooled and pressurized into liquid form for easier storage and transport.
- Low Producing/Marginal Well
- An oil or gas well producing on average less than 2 barrels of oil (or the equivalent in natural gas) per day over the past year, making it minimally economical to operate. Wells that are completely inactive also fall into this category. Marginal wells represent up to 75% of all onshore US wells and are responsible for approximately 60% of US methane emissions. Aging and poorly maintained, they often leak VOCs and are frequently sold by large operators to smaller companies that may neglect upkeep or go bankrupt, leaving behind orphaned wells. Also known as stripper wells.
- Memorandum of Understanding (MOU)
- A non-binding preliminary agreement between parties (typically an oil and gas operator and a government) that outlines the terms and expectations of a planned arrangement before a formal contract is signed.
- Methane
- A colorless, odorless gas (CH4) and the primary component of natural gas. When methane leaks into the atmosphere during fossil fuel extraction or combustion, it acts as a potent greenhouse gas that is far more heat-trapping than carbon dioxide over the short term. Methane emissions also contribute to ground-level ozone formation, which is linked to asthma, heart disease, cancer, and strokes.
- Mineral Rights
- The legal rights to extract minerals (including oil, gas, coal, and metals) from beneath the surface of a parcel of land. Mineral rights can be owned separately from surface rights. See also: Split Estate.
- Moratorium
- A temporary ban on initiating new oil and gas extraction projects in a specified area.
- Natural Gas
- A non-renewable fossil fuel composed primarily of methane (70-90%), along with other hydrocarbons such as ethane, propane, and butane. It forms over millions of years from buried organic material and is often found alongside oil deposits. Natural gas is widely used for heating, cooking, electricity generation, and industrial processes.
- Oil & Gas Development Plan (OGDP)
- The formal application that oil and gas companies submit to the ECMC to obtain state approval for extraction projects in Colorado. An OGDP can cover a single well or dozens of wells across multiple locations and is submitted using a Form 2C. Larger projects may require a Comprehensive Area Plan (CAP).
- Orphaned Well
- An oil or gas well that has been abandoned by its operator, typically because the well became unprofitable, the operator went bankrupt, or ownership was never established. Without a responsible owner, the cost of plugging and reclaiming the site falls to landowners or taxpayers. Orphaned wells often leak greenhouse gases and contaminate nearby land and groundwater. Colorado has approximately 950 officially orphaned wells, with as many as 27,000 low-producing wells at risk of joining them.
- Permeability
- A measure of how easily fluids and gases can move through the pores and cracks of a rock formation. High permeability means oil and gas flow more freely into the wellbore; low permeability (as in shale) typically requires hydraulic fracturing to release trapped hydrocarbons.
- Pipeline
- A series of metal tubes (usually with pumps and valves) used to transport oil, gas, or water over long distances, either above or below ground.
- Produced Water
- Water (mostly naturally occurring groundwater) that flows back to the surface from a well after the first 90 days of production and throughout the well’s lifetime. Like flowback fluid, produced water is typically contaminated with fracking chemicals, dissolved minerals, hydrocarbons, and naturally occurring radioactive materials and cannot safely re-enter the water supply. See also: Flowback Fluid.
- Production
- The phase of oil and gas operations in which hydrocarbons are extracted from underground reservoirs, brought to the surface, separated, and stored for transport. Production volumes are measured in barrels for oil and cubic feet for gas.
- Proppant
- A solid material (usually sand or man-made ceramic or aluminum pellets) mixed into fracking fluid. Once injected into the well under high pressure, proppant lodges in fractured rock to hold cracks open after the fluid pressure is released, allowing oil and gas to flow to the surface.
- Reverse Setback
- A regulation specifying the minimum distance between a proposed new residential development and existing oil and gas facilities. Reverse setbacks are intended to protect future residents from hazardous sites. Colorado does not currently have a statewide reverse setback law, though local governments may enact their own.
- Royalty Payment
- A payment made by an oil and gas operator to the owner of the mineral rights, typically calculated as a percentage of production revenue.
- Separator
- A large pressurized tank at the well pad that divides the mix of liquids brought up from the well into separate streams of oil, gas, and produced water. Separation is a necessary first step before oil and gas can be transported or sold.
- Setback
- A legally required minimum distance between new oil and gas facilities and existing homes, schools, water sources, and other occupied areas. Colorado increased its statewide setback from 500 feet to 2,000 feet in 2020, though operators may apply for exceptions. Local governments may adopt stricter requirements.
- Split Estate
- A situation in which one party owns the surface rights to a parcel of land while another owns the mineral rights beneath it. This becomes contentious when a mineral rights owner authorizes an oil and gas company to drill under a surface owner’s land, sometimes without the surface owner’s knowledge or consent.
- Spud Date
- The date on which drilling begins at a well site, marking the official start of well construction.
- Stripper Well
- See: Marginal Well.
- Suspended Well
- A well that has been temporarily sealed at the surface but not permanently decommissioned.
- Tank Battery
- A cluster of tanks and processing equipment at or near a well site used to receive, separate, store, and measure oil, gas, and produced water from one or more wells before transport.
- Tankless Facility
- An oil and gas production site that routes oil, gas, and water directly into pipelines rather than storing them in surface tanks. This approach reduces methane and VOC emissions, eliminates the need for haul trucks, and can shrink the overall footprint of a well pad. It comes with higher costs and increased risk of shutdown if a downstream pipeline fails.
- Total Depth (TD)
- The maximum depth reached by a well during drilling.
- Unconventional Drilling
- A method of oil and gas extraction that combines directional (horizontal) drilling with hydraulic fracturing to access hydrocarbons trapped in deep, low-permeability rock formations (such as shale) that cannot be economically extracted by conventional vertical wells. See also: Fracking, Horizontal Drilling.
- Upset Condition
- An unplanned disruption to normal oil and gas operations caused by equipment malfunction, power failure, or accident. Upset conditions can result in spills, toxic emissions, fires, explosions, and worker injuries.
- Venting
- The direct release of natural gas (mostly methane) into the open air without burning it. Venting is used to relieve pressure or dispose of unwanted gas. Because methane is a potent greenhouse gas, venting is more harmful to the climate than flaring. Colorado laws enacted in 2022 prohibit venting except in emergencies, requiring operators to capture gas or route it to a gathering line. See also: Flaring.
- Vertical Well
- A traditional well drilled straight down into the ground to access oil and gas reserves directly below the drill site. Vertical wells work best for shallow, concentrated hydrocarbon deposits and are still the standard method for offshore drilling.
- Volatile Organic Compounds (VOCs)
- Carbon-containing chemicals that evaporate easily at room temperature. VOCs are released during all phases of oil and gas drilling and processing and contribute to ground-level ozone and air pollution. Common VOCs include benzene, toluene, ethylbenzene, and xylene (BTEX compounds). Exposure is linked to short-term symptoms such as headaches, nausea, and dizziness, as well as long-term health risks including liver, kidney, and nervous system damage and cancer.
- Wastewater Disposal Wells
- Underground wells used to inject and permanently dispose of oil and gas wastewater (including produced water, flowback fluid, drill cuttings, and sludge). These wells are known to cause induced earthquakes by increasing underground pressure and lubricating geological faults. Also called injection wells or Class II wells.
- Well Pad
- The cleared and prepared surface area (usually 5 to 10 acres) where oil and gas drilling and production operations take place. A well pad can host multiple wellheads, storage tanks, processing equipment, and support structures and remains in use for the lifetime of the well.
- Well Stimulation
- Any technique used to increase the flow of oil and gas from a well. The most common methods are hydraulic fracturing and acidizing, or a combination of both.
- Wellbore
- The hole drilled into the ground to create a well. Also called a borehole. Wellbores can be vertical or horizontal depending on the type of well and the location of the oil and gas reservoir.
- Wellbore Integrity
- The ability of a wellbore’s casing, cement, and equipment to remain structurally sound and withstand high pressures without leaking fluids, gas, or contaminants. Good wellbore integrity protects workers, groundwater, and the surrounding environment, both during active production and after a well is plugged and abandoned.
- Wellhead
- The assembly of pipes, valves, and gauges installed at the surface of a wellbore to control the flow of oil and gas and monitor well pressure.
- Workover RIg
- A significant maintenance or repair operation performed on an existing well to restore or improve production. Workovers typically involve replacing or overhauling downhole equipment.
Fracking Acronyms
COGCC
AQCC
CDPHE