Abandoned well: A well that is no longer in use, whether dry, inoperable, or no longer productive.
Acreage: Land leased for oil and gas exploration and/or land containing underlying oil and gas or mineral rights.
Annulus: The space between the casing and the wall of the borehole, between two strings of casing, or between tubing and casing.
Anticline: A convex-upward formation of rock layers, which may form a trap for hydrocarbons.
Appraisal Well: A well drilled as part of an exploration drilling program which is carried out to determine the physical extent, reserves and likely production rate of a field.
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.
Azimuth: Direction a horizontal well is drilled relative to magnetic North
Barrel (BBL): A unit of volume measurement used for petroleum and its products or water used or produced by the industry (1 barrel = 42 gallons).
Barrel of oil equivalent (BOE): A measure used to aggregate oil and gas resources or production, with one BOE being approximately equal to 5,800 cubic feet of natural gas.
BCF: One billion cubic feet of natural gas.
BCFE: One billion cubic feet of natural gas “equivalent”.
Bitumen: Naturally-occurring, inflammable organiz matter formed from kerogen in the process of petroleum generation which includes hydrocarbons such as asphalt and mineral wax a sticky, black and highly viscous liquid or semi-solid form of petroleum.
Blow-out preventers (BOPs): High pressure wellhead valves designed to prevent the uncontrolled flow of hydrocarbons from an oil or gas well.
Blow-out: When well pressure exceeds the ability of the wellhead valves to control it.
BOED: Barrels of oil equivalent per day.
Borehole: The hole in the earth created when drilling a well.
Brine: Naturally-occurring salt water often found in oil and gas reservoirs that is produced along with hydrocarbons after fracturing a well. Brine may also contain metals such as barium or stronium as well as radionuclides and amust be treasted or disposed of as contaminated waste water.
British thermal unit (BTU): The heat required to raise the temperature of a one-pound mass of water by one degree Fahrenheit.
Butane: An organic compound with the forumula C4H10 that is an alkane with four carbon atoms that may be produced along with oil or natural gas as a natural gas liquid. Butane is a highly flammable, colorless gas at room temperature and atmospheric pressure and is often converted to a liquid for use.
CAPEX: Capital expenditures.
Carbon capture and storage (CCS): 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.
Casing string: A long section of steel tubing or pipe that lines a well after it has been drilled. It is formed from sections of steel tube welded or threaded together and often cemented in place.
Casing: Tubing or pipe (typically steel) emplaced and cemented in the well to seal off formation fluids or keep the borehole from caving in.
Cementing: To prepare and pump cement into a wellbore to seal the annulus after a casing string has been run, to seal a lost circulation zone, to set a plug in an existing well, or to plug a well so that it may be properly sealed and abandoned.
Christmas tree: The assembly of fittings and valves on the top of the casing which control the production rate of natural gas or oil.
Completion: The installation of permanent wellhead equipment for the production of oil and gas.
Compressor station: These station increase the gas’s pressure to pump natural gas through pipelines at over significant distances for delivery to markets.
Condensates: Hydrocarbons which are in the gaseous state under reservoir conditions and which become liquid when temperature or pressure is reduced and is typically a mixture of pentanes and higher hydrocarbons.
Conventional resources: Discrete accumulations of hydrocarbons contained in rocks with relatively high matrix permeability, which normally have relatively high recovery factors.
Cracker: The conversion of petroleum hydrocarbons, especially ethane, in order to produce plastics feedstock materials such as ethylene, propylene and other alkenes using high temperature in the presence of steam.
Crude Oil: Liquid petroleum as it comes out of the ground as distinguished from refined oils manufactured out of it.
Cubic foot: A standard unit used to measure quantity of gas (at atmospheric pressure); 1 cubic foot = 0.0283 cubic meters.
Cuttings: Rock chips from the bedrock formation that are cut by the drill bit during borehole drilling and brought to the surface with drilling fluids or air.
Deviated: Change in the wellbore direction from the path it would naturally take
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 ultimately drilled at +/- 90 degrees to the vertical direction.
Drill or Drilling: The using of a drilling rig and crew for deepening and advancing a borehole into the Earth’s subsurface.
Drilling Mud/Fluid: Specially formulated fluids used to aid the drilling of boreholes into the earth that lubricate the drill bit and to counteract the natural pressure of the formation. The three main categories of drilling fluids are water-based muds (which can be dispersed and non-dispersed), non-aqueous muds, usually called oil-based mud, and gaseous drilling fluid, in which a wide range of gases can be used.
Dry Gas: Natural gas composed mainly of methane with only minor amounts of ethane, propane and butane and little or no heavier hydrocarbons in the gasoline range.
Dry hole: A well which has proved to be commercially non-productive.
E&A: Abbreviation for exploration and appraisal.
E&P: Abbreviation for exploration and production.
Enhanced oil recovery (EOR): One or more of a variety of processes that seek to improve recovery of oil from a reservoir after the primary production phase, also known as secondary recovery.
Environmental assessment: A study that can be required to assess the potential direct, indirect and cumulative environmental impacts of a project.
Estimated ultimate recovery (EUR): An approximation of the total quantity of oul or gas that is potentially recoverable or has already been recovered from a reservoir or well.
Ethane: An organic compound with the formula C2H6 that is an alkane with two carbon atoms that may be produced along with oil or natural gas as a natural gas liquid. Ethane is highly flammable, colorless gas at room temperature and atmospheric pressure and is often converted to a liquid for use.
Ethylene: It is a colorless flammable gas widely used in petrochemical/plastics industry.
Exploration drilling: Drilling carried out to determine whether hydrocarbons are present in a particular area or structure.
Exploration phase: The phase of operations which covers the search for oil or gas by carrying out detailed geological and geophysical surveys followed up where appropriate by exploratory drilling.
Exploratory well: A well drilled to find a new field or to find a new reservoir in a field previously found to be productive of oil or gas in another reservoir.
Farm-in: The acquisition of part or all of an oil, natural gas or mineral interest from a third party.
Farm-out: The assignment of part or all of an oil, natural gas or mineral interest to a third party.
FERC: Federal Energy Regulatory Commission
Field: An area consisting of a single hydrocarbon reservoir or multiple geologically related reservoirs all grouped on or related to the same individual geological structure or stratigraphic condition.
Fishing: Retrieving objects from the borehole, such as a broken drill string, or tools.
Flaring: The burning of natural gas for safety reasons or when there is no way to transport the gas to market or use the gas for other beneficial purposes (such as EOR or reservoir pressure maintenance). The practice of flaring is being steadily reduced as pipelines are completed and in response to environmental concerns.
Flowback water: Water generated initially in conjunction with oil and natural gas exploration and development activities after hydraulic fracturing and before the well is brought on line for production. This consists typically of a high percentage of the hydraulic fracturing fluids injected into the well mixed with a relatively low percentage of native formation waters.
Formation pressure: The pressure at the bottom of a well when it is shut in at the wellhead.
Formation water: Naturally occurring brines (salt water) underlying gas and oil in the formation.
Formation: A rock layer which has distinct geological characteristics (e.g. rock type, depositional history, 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.
Frac Plug: A device placed in the wellbore which is designed to separate individual frac stages, through isolation of the interval being fractured from the intervals that have been previously fractured. There are a variety of types and styles of frac plugs and mechanisms to remove frac plugs, which are typically drilled out afer an entire well has been hydraulically fractured.
Frac Stage: An operation where the horizontal wellbore is divided into a number of zones, units or stages for fracturing operations. Stage length may vary but normally ranges from 100-500 feet of horizontal well bore per stage. Frac stages are generally completed from in succession from the toe (furthest point) of the wellbore, moving toward the heel (the horizontal section of the well closest to the vertical section of the well).
Fugitive Emissions: Emissions of gases or vapors from pressurized equipment, including pipelines, due to leakage, unintended or irregular releases of gases.
Gas field: A geologic reservoir containing natural gas but no oil.
Gas/oil ratio: The volume of gas at atmospheric pressure produced per unit of oil produced.
Gathering lines: Natural gas pipelines that move gas from the well to the larger diameter transmission lines.
GGE: Gallon of Gas Equivalent
Global-warming potential (GWP): The relative measure of how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide. GWP is calculated over a specific time interval, commonly 100 years. GWP is expressed as a multiple of that for carbon dioxide (whose GWP is standardized to 1).
Gas Production Unit (GPU): Equipment on a well pad near gas wells that separates fluids such as brine from the gas so it can be transported by pipeline.
Greenhouse gas (GHG): Atmospheric gases that are transparent to solar (short-wave) radiation but opaque to long-wave (infrared) radiation, thus preventing long-wave radiant energy from leaving Earth’s atmosphere. The net effect of these gases is a trapping of absorbed radiation and a tendency to warm the planet’s surface. The greenhouse gases most relevant to the oil and gas industry are carbon dioxide, methane and nitrous oxide.
Heavy oil: Crude oil with an API gravity less than 20°. Heavy oil generally does not flow easily due to its elevated viscosity.
Hedging: Making an investment to reduce risk of adverse price movements in an asset.
Held by production (HBP): A legal process that allows exploration and production companies to extend the terms of the original lease and pay royalties to the oil and gas rights owner for the life of a producing well.
High BTU Gas/Wet Gas: Natural gas with some component of heavier gaseous hydrocarbon(s) present, typically ethane, propane, butane, and condensate that increase the overall BTU content of the gas stream.
Horizontal drilling: A drilling technique whereby a well is progressively turned from vertical to horizontal so as to allow for greater exposure to an oil or natural gas reservoir. Horizontal laterals can be more than a mile long. In general, longer exposure lengths allow for more oil and natural gas to be recovered from a well and often can reduce the number of wells required to develop a field, thereby minimizing surface disturbance. Horizontal drilling technology has been extensively used since the 1980s and is appropriate for many, but not all, developments.
Hydraulic fracturing fluids: A mixture consisting primarily of water (90-95%), sand or proppant (5-10%), and <1% of chemical additives used to optimize the efficiency of the fluids when used for hydraulic fracturing. The additives typically consist of friction reducers, scale inhibitors, biocides, gels, breakers, acids, corrosion inhibitors, and other chemicals dependent on the fracture treatment design.
Hydraulic fracturing: A method of increasing a geologic formation’s permeability by opening up fractures by pumping large volumes of specially-designed fluids at very high pressures. The objective is to increase hydrocarbon production rates from a reservoir.
Hydrocarbon: A compound containing only the elements hydrogen and carbon. May exist as a solid, a liquid or a gas. The term is mainly used in a catch-all sense for oil, gas and condensate.
Hydrostatic pressure: The pressure which is exerted on a portion of a column of water as a result of the weight of the fluid above it.
Impoundment: A structure designed to hold water or production fluids associated with oil and gas development or production.
Infill wells: Wells drilled into the same reservoir between known producing wells to improve or accelerate hydrocarbon recovery. s
Injection well: A well used for pumping fluids or gas into the earth for either disposal, recovery or storage.
Inter-State Transmission: Gas transmission line crossing state boarders.
Intra-State Transmission: Gas transmission line within a state.
Land Agent/Land Man: Individual who acts as a direct employee or subcontractor on behalf of an exploration and production company to negotiate the terms of an oil, gas, and/or mineral lease agreement.
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 of time over a given area.
LEL: Lower Explosive Limit – Air-gas mixtures will only burn or explode within certain limits, known as the flammable (explosive) limits. (LEL) is the minimum percentage of gas mixed with air that will burn or explode. The LEL for natural gas is 5% (50,000 ppm) gas to 95% air.
Lessee: Surface landowner or subsurface mineral owner interested in leasing acreage to an energy company for the purpose of developing the oil and gas resource.
Lessor: An individual or a corporation who has the right to use something of value, gained through a lease agreement with the real owner
Life Cycle Analysis (LCA): LCA is an analytical methodology used to comprehensively quantify and interpret the environmental flows to and from the environment (including air emissions, water effluents, solid waste and the consumption/depletion of energy and other resources) over the life cycle of a product or process.
Liquefied natural gas (LNG): Natural gas that has been converted to a liquid by chilling it to -260°F. Liquefying natural gas reduces the fuel’s volume by 600 times, enabling it to be shipped economically from distant producing areas to markets.
MBBL: One thousand barrels of crude oil, bitumen, condensate or natural gas liquids.
MBOE: One thousand barrels of oil equivalent.
MCF: One thousand standard cubic feet of natural gas. In the United States, standard conditions are defined as gas at 14.7 psia and 60 degrees F.
MCFe: One thousand standard cubic feet of natural gas “equivalent”.
Mechanical Integrity Test (MIT): Testing conducted on production wells and injection wells to ensure there is no significant leakage internal to the well’s casing, tubing or packer or external to the well adjacent to the borehole ina manner protective of the environment and human heath.
Methane: A colorless, odorless gas, hydrocarbon with a formula of CH4. It is the principal constituent of natural gas and it also can be found associated with crude oil. Methane is a greenhouse gas in the atmosphere because it absorbs long-wave length radiation from the Earth’s surface.
Midstream: Midstream operations generally include the movement, measurement and processing of natural gas from the well to city-gate sales point where it is then distributed.
Mineral rights: Legal rights that allow for search and removal of minerals on a particular parcel of land.
MMBBL: One million barrels of crude oil, bitumen, condensate or natural gas liquids.
MMBTU: One million British thermal units.
MMCF: One million standard cubic feet of natural gas.
MMCFD: One million cubic feet per day of natural gas.
Natural gas liquids (NGLs): Those hydrocarbons in natural gas that are separated from the gas as liquids through the process of absorption, condensation, adsorption, cryongenically or other methods in gas processing or cycling plants. Natural gas liquids include ethane, propane, butane, and isobutane and lease condensate (primarily pentanes produced from natural gas at lease separators and field facilities).
Natural gas: Naturally occurring hydrocarbon gases found in porous rock formations. Its principal component is usually methane. Nonhydrocarbon gases such as carbon dioxide and hydrogen sulfide can sometimes be present in natural gas.
Naturally occurring radioactive materials (NORM): All radioactive elements found in the environment, including long-lived radioactive elements such as uranium, thorium, and potassium and any of their decay products, such as radium and radon. NORM that has been removed via treatment and concentrated is known as technically-enhanced NORM or TENORM.
Net acres: The percentage that a company owns in an acreage position with multiple owners. For example, a company that has a 50 percent interest in a lease covering 10,000 acres owns 5,000 net acres.
Net Effective Acreage: An estimate used by some companies in stacked play formations that counts all the layers of rock a company believes they could develop, effectively multiplying the surface acreage by the number of potential formations.
NYMEX: The New York Mercantile Exchange.
O&G: Oil and Gas.
ODNR: Ohio Division of Natural Resources
Odorant: An additive to natural gases to allow leak detection by smell. A common constituent of odorants is mercaptan which has a very low odor threshold.
Oil field: A geographic area under which an oil reservoir lies.
Oil in place : An estimated measure of the total amount of oil contained in a reservoir, of which only a percentage can be recovered, known as recoverable resources.
Oil: A mixture of liquid hydrocarbons of different molecular weights.
Operator: The company that has legal authority to drill wells and undertake the production of hydrocarbons that are found. The Operator is often part of a consortium and acts on behalf of this consortium.
PADEP: Pennsylvania Department of Environmental Protection
Pay zone: The interval of a rock formation in which oil and gas are found in exploitable quantities.
Permeability: The property of a formation which quantifies the flow of a fluid through the pore spaces and into the wellbore. High permeability means fluid passes through the rock easily
Petroleum: A generic name for hydrocarbons, including crude oil, natural gas liquids, natural gas and their products.
PHMSA: Pipeline and Hazardous Material Safety Administration
PIG (Smart Pig and Dumb Pig): A unit that performs various maintenance functions ina pipeline including "Dumb PIGs" that do mechanical works such as pipeline cleaning or segmenting flow and "Smart PIGs" that do pipeline inspction, and/or recording information about the pipeline.
Pipeline: Underground or surface tubing or piping that is installed across states, countries and continents to deliver fuel.
Play: An area in which hydrocarbon accumulations or prospects with similar characteristics occur, such as the Marcellus play in the eastern United States.
Pooling or land pooling: A legal process that allows exploration and production companies to compel unwilling land and mineral rights holders to lease their land and/or mineral rights for exploration and possible drilling if enough of their surrounding neighbors have already agreed. Government agencies may require a minimum number of acres of land before granting a well permit; with pooling, companies can collect smaller tracts of land that will accumulate to this total minimum acreage.
Porosity: The percentage of void in a porous rock compared to the solid formation.
Possible reserves: Those reserves which at present cannot be regarded as ‘probable’ but are estimated to have a significant but less than 50% chance of being technically and economically producible.
Primary recovery: Recovery of oil or gas from a reservoir purely by using the natural pressure in the reservoir to force the oil or gas out.
Probable resources: Those hydrocarbon resources which are not yet proven but which are estimated to have a better than 50% chance of being technically and economically producible.
Produced fluids: Wateror brine generated from a well in conjunction with oil and natural gas production.
Production well: A well that is capable of producing hydrocarbons in sufficient quantities to justify commercial exploitation.
Propane: An organic compound with the formula C3H8 that is an alkane with three carbon atoms that may be produced along with oil or natural gas as a natural gas liquid. Butane is a highly flammable, colorless gas at room temperature and atmospheric pressure and is often converted to a liquid for use.
Proppant: Sand or man-made, sand-sized particles pumped into a formation during a hydraulic fracturing treatment to keep fractures open so that oil and natural gas can flow through the fractures to the wellbore.
Proven field: An oil and/or gas field whose physical extent and estimated reserves have been determined.
Proven reserves: Those reserves which on the available evidence are virtually certain to be technically and economically producible (i.e. having a better than 90% chance of being produced).
RBC: River Basin Commission
Recompletion: The process of entering an existing wellbore and performing work designed to establish production from a new zone or improve production from existing pay zones.
Recoverable reserves: That proportion of the oil and/gas in a reservoir that can be removed using currently available techniques.
Recovery factor: That proportion of the oil and/gas in a reservoir that can be removed using currently available techniques.
Reserves: Estimated remaining quantities of oil and gas and related substances anticipated to be economically producible, as of a given date, by application of development projects to known accumulations. In addition, there must exist, or there must be a reasonable expectation that there will exist, the legal right to produce or a revenue interest in production, installed means of delivering oil and gas or related substances to market and all permits and financing required to implement the project.
Reservoir: The underground formation where oil and gas has accumulated. It consists of a porous rock to hold the oil or gas, and a cap rock that prevents its escape.
Resources: Quantities of oil and gas estimated to exist in naturally occurring accumulations. A portion of the resources maybe estimated to be recoverable, and another portion may be considered to be unrecoverable. Resources include both discovered and undiscovered accumulations
Rig Down: Disassembling oil and gas field equipment for transportation or storage.
Rig-up: Assembling oil and gas field equipment to make ready for use.
ROP: Rate of penetration in feet per hour or meters per hour
Roughneck: Drill crew members who work on the derrick floor, threading together the sections of drillpipe when running or pulling a drillstring.
Roustabout: Drill crew members who handle the loading and unloading of equipment and assist in general operations around the rig.
ROW: Right Of Way
Royalty payment: The amount of money exploration and production companies pay to the mineral rights owners of a producing well. Pennsylvania state law requires this rate be no less than 12% of the market price of gas on the day that gas comes out of the ground. Often mineral rights owners have negotiated higher royalties however E&P companies can deduct well production expenses from these royalty payments.
SCADA: Supervisory Control and Data Acquisition, Computer controlled systems that monitor and control industrial processes
Seal formation: The confining rock unit within the carbon dioxide storage assessment unit. The seal formation is a rock unit that sufficiently overlies the storage formation and where managed properly has a capillary entrance pressure low enough to effectively inhibit the upward buoyant flow of liquids or gases.
Seal: A geologic feature that inhibits the mixing or migration of fluids and gases between adjacent geologic units. A seal is typically a rock unit or a fault; it can be a top seal, inhibiting upward flow of buoyant fluids, or a lateral seal, inhibiting the lateral flow of buoyant fluids.
Secondary recovery: Recovery of oil or gas from a reservoir by artificially maintaining or enhancing the reservoir pressure by injecting gas, water or other substances into the reservoir rock.
Shale gas: Shale gas refers to natural gas that can be generated and trapped within shale units.
Shale oil: Shale oil refers to liquid petroleum that can be generated and trapped within shale units.
Shale: A very fine-grained sedimentary rock that is formed by the consolidation of clay, mud or silt and that usually has a finely stratified or laminated structure. Certain shale formations which are high in organic carbon content, such as the Eagle Ford and the Barnett, contain large amounts of oil and natural gas.
Shut In Well: A well which is capable of producing but is not presently producing. Reasons for a well being shut in may be lack of equipment, market or other.
Source rock: Rocks containing relatively large amounts of organic matter that is transformed into hydrocarbons.
Spacing: The distance between wells producing from the same reservoir, often expressed in terms of acres and is often established by regulatory agencies.
Spud-in: The operation of drilling the first part of a new well.
Surface Location: The location of a well or facility/measurement point.
Surface Reclamation: Restoration of the land surface that had been used for drilling or production which involves regrading and re-vegetating the area.
TCF: One trillion cubic feet of natural gas.
TD: Total depth
Technically recoverable resources : Those resources producible using currently available technology and industry practices. USGS is the only provider of publicly available estimates of undiscovered technically recoverable oil and gas resources.
Tight gas: Natural gas produced from relatively impermeable rock. Getting tight gas out usually requires enhanced technology applications like hydraulic fracturing. The term is generally used for reservoirs other than shale.
Tophole: Vertical portion of the wellbore
Total dissolved solids (TDS): All of the dissolved constituents in water or wastewater, commonly including metals, salts, and other elements or minerals and measured in milligrams per liter (mg/L). Shale energy-derived wastewater (ie flowback and produced water) typically has a high TDS concentration often times greater than seawater’s TDS.
Trap: A geologic feature that permits the accumulation and prevents the escape of accumulated fluids (hydrocarbons) or injected carbon dioxide from the reservoir.
TVD: Total vertical Depth
UEL: Upper Explosive Limit – Air-gas mixtures will only burn or explode within certain limits, known as the flammable (explosive) limits. UEL is the maximum percentage of gas mixed with air that will burn or explode. The UEL of natural gas is 14% (140,000 ppm) gas to 86% air
Unconventional Reservoirs: Reservoirs with permeability so low (generally less than 0.1 millidarcy) that horizontal hydraulically fractured wells or other advanced stimulation or completion techniques must be utilized to extract hydrocarbons at commercial rates. Shale reservoirs such as the Eagle Ford and Marcellus are examples of unconventional reservoirs.
Underground Injection Control (UIC) Well: A type of well used for storage, mining or disposal purposes as regulated under the Safe Drinking Water Act (SDWA) consisting of a steel- and concrete-encased borehole into which waste is injected under pressure. Class II UIC wells handle oil and gas waste for permanent disposal (known as Class II-D wells) or for secondary recovery (known as Class II-R wells). An applicant must demonstrate that the well has no reasonable chance of adversely affecting the quality of an underground source of drinking water before a permit is issued.
Undiscovered Resources: Resources postulated, on the basis of geologic knowledge and theory, to exist outside of known fields or accumulations. Included also are resources from undiscovered pools within known fields to the extent that they occur within separate plays.
Unproved reserves: Unproved reserves are based on geologic and/or engineering data similar to that used in estimates of proved reserves; but technical, contractual, economic, or regulatory uncertainties preclude such reserves being classified as proved.
Well abandonment: The proper plugging and decommissioning of a well in compliance with all applicable regulations.
Well log: A record of geological formation penetrated during drilling, including technical details of the operation.
Wellbore: The hole drilled by a drilling rig to explore for or develop oil and/or natural gas. Also referred to as a well or borehole.
Wet gas: Produced gas that contains natural gas liquids.
Workover: Remedial work to the equipment within a well, the well pipework, or relating to attempts to increase the rate of flow.
WVDEP: West Virginia Department of Environmental Protection.
