Glossary of Terms
A B C D E F G H I L M N O P R S T U V W
Access Road- A road that leads to a well pad during well production.
Annulus- A void between piping, tubing or casing and the piping, tubing or casing surrounding it.
Appalachian Basin- A geological formation associated with the Marcellus and Utica shales that contains potential shale gas resources.
Aquifer- An underground layer of water-bearing rock or gravel, sand or silt.
Backflow- During well testing, fluid may flow from one zone to another due to the wellbore’s pressure rising higher than other zone pressures.
Bcf- Billion cubic feet; used to measure natural gas; Bcf/D denotes a daily measure of natural gas in billions of cubic feet
Blowout Preventer (BOP)- A large valve at the top of a well that workers can close if control of formation fluids is lost. By closing this, workers can increase mud density, then open the BOP and regain pressure control of the well.
Bonus Consideration- Monetary incentive given to the mineral rights owner by the lessee for signing an oil, gas and mineral rights lease.
Borehole- A generalized term for a shaft bored into the ground.
Brine- Water that has a higher salt content than normal seawater.
CAS- Chemical Abstracts Service.
Casing- A large pipe that is inserted into a recently drilled borehole, typically held into place with cement.
Clean Water Act- Federal law that regulates discharges into waterways.
Coal Bed Methane (CBM)- Unconventional natural gas that is extracted from coal beds.
Compressor Station- Located along natural gas pipelines, these facilities compress gas to a certain pressure to keep the gas moving along the pipeline.
Condensate- A gas that condenses into a liquid when pumped to the surface; an ultralight oil.
Conductor Casing- Prevents collapse of the loose soil near the surface of a borehole.
Conventional Natural Gas Reservoir- Highly permeable rock formation that holds natural gas as it is trapped by an overhead impermeable rock layer.
Corrosion Inhibitor- A chemical compound that decreases the corrosion rate of a metal or an alloy.
Cryogenic Plant- Processes natural gas and condenses it to a liquid state using low temperatures. Hydrocarbons can then be separated and the gas can be more easily transported after processing.
Cuttings- Pieces of rock that are displaced by the drill bit as the rock is cut.
Darcy’s Law- An equation that describes the flow of liquid through a porous medium.
DOE- Department of Energy.
Downstream- The refining, processing, purifying, marketing and distribution of oil and gas products.
Drilling Mud- A fluid used to aid the drilling of boreholes.
Drilling Rig- Typically large standing structure that creates holes in the ground. Sometimes referred to as a “Christmas tree” when lit up at night.
Drill String- The drillpipe, bottomhole assembly and other tools used to make the drillbit turn at the bottom of a wellbore.
Dry Gas- Natural gas that is mostly made up of methane.
Easement- A right of use of someone else’s land.
Ethane Cracker- Processing plant that takes ethane and breaks it down by heat to create ethylene, which is a base chemical for plastics.
EPA- Environmental Protection Agency.
EPCRA- Emergency Planning and Community Right-to-Know Act.
FERC- Federal Energy Regulatory Commission; regulates, monitors and investigates the interstate transmission of natural gas, oil and electricity, as well as natural gas and hydropower projects.
Flowback- Water that is pressurized and used during the fracking process returns to the surface through the well after fracking is completed.
Flaring- Controlled burning of natural gas at the well site. Temporary flares are used during well production testing, and small amounts of natural gas are burned if the natural gas can’t be processed.
Forced Pooling- Legal concept that allows drillers to extract natural gas beneath the land of property owners who refuse to sign a lease or cannot be located, as long as enough surrounding property owners have signed leases.
Fracking- See Hydraulic Fracking or Fracturing.
Fracking Fluid- Fluid that is pumped into injection wells at high speeds to fracture underground rock formations and release natural gas. The fluid is mostly composed of water.
Frac Tank- This is where the water or the proppant is held while a well is being fractured.
Friction Reducer- An additive that reduced the friction of a fluid as it flows through small spaces.
Geological Formation- A portion of earth material that has distinct characteristics and homogeneous physical properties.
Groundwater- Water located beneath the surface of the earth.
GWPC- Ground Water Protection Counsel.
Horizontal Drilling- The process by which a well is drilled horizontally to reach more of the formation. Horizontal drilling allows for more fractures through which natural gas can escape than a traditional, vertical well could.
Hydraulic Fracking or Fracturing- Usually shortened to ‘fracking’, the process of using high pressured fluid containing water, sand and chemicals into sub-surface rock formations. The fluid fractures the rocks, improving the flow of natural gas into the well bore. Early attempts at injecting fluids into wells began in the 1860s, but early attempts at fracking didn’t occur until 1947. The fracking process of today began in 1999.
Hydrology- The study of water.
Injection Well- A well in which fluids from hydraulic fracturing are injected to maintain reservoir pressure.
Intermediate Casing- Used on longer drilling intervals. Set after the surface casing and before the production casing. Prevents caving of weak or abnormally pressured formations.
IOGCC- Interstate Oil and Gas Commission.
Lease- An area of land on which exploration or production activity occurs; the act of acquiring land for exploration or production activity.
Lessee- The company that is permitted to drill and develop the oil and natural gas minerals beneath the landowner’s property.
Lessor- The landowner.
LNG- Liquid natural gas.
Marcellus Shale- A rock formation that extends from the base of the Catskills in New York and extends southwest to West Virginia, Kentucky and Ohio.
Marginal Well- A well that is nearing the end of profitable production, due to either depleted resources or low productivity.
Maturation- The stage of a source rock after it has been exposed to certain pressures and temperatures to make it able to produce oil or gas.
Mcf- Thousand cubic feet; used to measure natural gas.
Midstream- The transportation, storage, and marketing of oil and gas products.
Mmcf- Million cubic feet; used to measure natural gas.
MSDS- Material Safety Data Sheets.
Natural Gas- Natural gas is a naturally occurring gas mixture consisting of methane and other hydrocarbons. It’s used as an energy source to heat buildings, generate electricity and recently, to power motor vehicles.
NGL- Natural gas liquid, such as butane or propane.
NGWA- National Ground Water Association.
ODNR- Ohio Department of Natural Resources.
On-site Water Treatment- Treatment units that recycle flowback fluids that can be used again for fracking.
Paid up Lease- Delay rentals are paid in advance with the bonus consideration for the lease’s entire term.
Payout- Refers to the time when all of the costs associated with leasing, exploring, drilling and operating have been covered by a well or wells’ production.
Permeability- A measure of the ability of a material to allow fluids to pass through it.
Pooling or Unitization- A provision that allows landowners to combine land to form a drilling unit.
Primary Term- The length of a lease in years.
Produced Water- Naturally occurring water that comes to the surface during the fracking process.
Production Casing- The final interval in a well. The smallest casing, it forms the outer boundary of the annulus.
Proppant- A material that keeps a fracture open. A proppant can be gel, foam or slickwater-based.
Rathole- The temporary storage space that is used to store the drill pipe while adding a new section of pipe to the drill string at some drilling rigs.
Reclamation- The restoration of a well site to its condition prior to drilling operations.
Refinery- A processing plant where crude oil is refined into usable products, like gasoline.
Refracking- The process of restimulating a well after its initial production.
Reservoir- An area that contains a resource. In fracking, well operators are seeking to tap into natural gas reservoirs deep underground.
Royalty- A payment received by the lessor from the oil or gas company, based on the production of the well and market prices.
Severance Tax- A tax imposed when non-renewable resources, like natural gas and crude oil, are extracted.
Shale- Shale is a fine-grained sedimentary rock that is formed from compacted mud. Black shales sometimes breakdown to form natural gas or oil.
Shale Gas Play- A geographic area that has mostly consistent geographical characteristics and potentially contains an accumulation of natural gas.
Shut-in Royalty- A payment to the lessor in lieu of a production royalty. This is received when a well cannot produce due to production problems.
Snubbing- Putting drillpipe in a wellbore when pressure is contained. During this process the blowout preventers (BOPs) are closed.
Surface Casing- A pipe that protects fresh-water aquifers and it also provides structural strength so that other casings may be used.
Surface Water- Water that naturally occurs on land, like lakes, streams, rivers and reservoirs.
Surfactant- Compounds that lower the surface tension of a liquid.
Sweet Spot- The area of a shale play or reservoir that has the best production or best possible production.
Tcf- trillion cubic feet; used to measure natural gas.
Termination- The end of a lease.
Tight Gas- Natural gas that is contained between dense rock layers that prevent it from flowing easily.
Tract- A single, individually taxed parcel of land.
TRI- Toxics Release Inventory.
Underground Injection Well- An underground steel and concrete-encased shaft that deposits hazardous waste by force.
Unsaturated Zone- A zone where the soil and the rock contains air as well as water in its pores. It’s above the groundwater table. The unsaturated zone doesn’t contain readily available water, but it does provide water and nutrients to the biosphere.
Upstream- Includes locating shale locations, drilling and operating wells.
Utica Shale- A natural gas containing rock formation below the Marcellus Shale. The Utica Shale formation extends from eastern Ohio through much of Pennsylvania to western New York.
Vadose Zone- The layer of earth between the land’s surface and the position of groundwater is at atmospheric pressure.
VOC- Volatile organic compound.
Wet Gas- Natural gas that contains methane like dry gas, but also contains butane and ethane. These compounds, called natural gas liquids (NGLs), can be separated and sold individually.
Wellbore- The drilled hole including the open or uncased portion of the well.