In this subtitle, the following terms have the meanings indicated. Terms Defined. “Angular deviation and directional survey” means a well survey that indicates, at frequent intervals, the amount and azimuth that the hole has departed from vertical. “Annular space” means the area between the outer casing and the wall of a borehole. “Barrel” means a unit of measure for crude oil equal to 42 U.S. gallons. “Blowout” means an uncontrolled flow of gas, oil, or other well fluids into the atmosphere. This occurs when formation pressure exceeds the pressure applied to it by the column of drilling fluid. “Blowout prevention equipment” means devices attached to the top of the well casing that can be closed and shut off to control pressure at the wellhead. “Bridge plug” means an expandable device used inside the casing of a well to isolate certain zones or to plug back to a shallower depth. “Chesapeake Bay Critical Area” means those areas defined and regulated under Natural Resources Article, §8-1807, Annotated Code of Maryland. “Circulating medium” means any type of liquid, gas, or slurry used as an agent to remove drill cuttings and to cool the bit. “Commingle production” means to mix hydrocarbons from two or more pay zones in the same well. “Conductor pipe” means a pipe used near the surface to prevent unconsolidated material from caving or sloughing into the hole. “Coning” means the cone-shaped invasion of water underlying oil or gas in a reservoir or invasion of gas overlying oil in a reservoir as the oil or gas is withdrawn from a well. “Cuttings” means the fragments of rocks produced by the drill bit during the drilling process and brought to the surface in the drilling liquid. “Department” means the Department of the Environment. “Directional drilling” means aiming wells at horizontally displaced bottom-hole targets. Drilling Liquid. “Drilling liquid” means a fluid, such as mud or water, circulated in a borehole to remove the drill cuttings from the hole and to cool the drill bit. “Drilling liquid”, for the purpose of this chapter, does not include air or gas. “Dry hole” means a well that encountered no oil or gas of commercial significance. “Explosives” means any chemical compound, mixture, or device, the primary purpose of which is to function by explosion through substantially instantaneous release of gas and heat, unless the compound, mixture, or device is otherwise specifically classified by the Interstate Commerce Commission or other federal agencies. “Fill-up” means the level to which liquid rises in a well being drilled with air when a fresh or salt water zone is encountered. “Free liquid fraction” means fresh water brought to the surface while drilling through strata containing fresh ground water, or fresh water brought to the well site and used in drilling. It may contain drill cuttings, but is not polluted or contaminated by additives, salt water, or oil. “Gas” means all natural gas and other fluid hydrocarbons, not defined as oil, that are produced from a natural reservoir. “Impermeable” means that the rate of water flow through a material is less than 0.009 centimeter per day. “Injection well” means a well used for pumping fluids into a subsurface formation. “Killing the well” means overcoming downhole pressure, in a well being drilled, through the use of drilling liquid or water. “Log” means a continuous record as a function of depth, usually graphic and plotted to scale on a narrow paper strip, of observations made on the rocks and fluids of the geologic section exposed in a well bore. “Lost hole” means a well in which the target could not be reached because of geological or mechanical problems. “Mechanical plug” means an expandable device placed in a well to act as a water-tight, oil-tight, and gas-tight seal. “Mineral interest owner” means any person who owns a working interest or a royalty interest in the oil or gas, or both, contained in, or produced from, a tract of land. “Multiple zone completion” means the completion of a well in two or more separate producing formations with no commingling of the produced oil or gas. “Noncementing material” means a mixture of very fine to coarse-grained nonbonding materials, including unwashed crushed stone, drill cuttings, earthen mud, or other equivalent material approved by the Department. “Nonporous material” means bentonitic mud, cement, or equivalent materials approved by the Department which will retard the movement of fluids. “Nontidal wetland” means those areas defined and regulated under Environment Article, Title 5, Subtitle 9, Annotated Code of Maryland, or COMAR 27.01.01.01B(46). “Oil” means crude petroleum oil and other hydrocarbons, regardless of specific gravity, that are produced at the wellhead in liquid form, except liquid hydrocarbons known as distillate or condensate recovered or extracted from gas. “Open-flow test” means a measurement of the rate of flow of a gas well when flowing into the air, unrestricted by any pressure other than that of the atmosphere, and usually measured in thousands of cubic feet (Mcf) per day. “Operator” means a person who develops, manages, or produces oil or gas. “Perforating” means to make holes through the casing opposite the producing zone to allow the oil or gas to flow into the well. “Person” means the federal government, the State, a county, municipal corporation, or other political subdivision of the State, or their units, or an individual, receiver, trustee, guardian, executor, administrator, fiduciary, or representative of any kind, or a partnership, firm, association, public or private corporation, or any other entity. “Pit” means an impoundment for the retention of water, drilling liquid, or drill cuttings. “Plug” means an expandable device or cement placed in a well to prevent the movement of liquids and gas. “Pool” means an underground reservoir containing a common accumulation of oil or gas, or both. “Pooled unit” means an area within which permittees of different tracts in the area have voluntarily agreed to participate in a well drilled within the unit. “Pressure maintenance” means the injection of liquid or gas into an oil or gas reservoir to increase or maintain reservoir pressure in order to recover additional quantities of hydrocarbons. “Producing zone” means the stratum, bed, or formation from which oil or gas enters the well. “Recomplete a well” means to seal off one producing zone, and perforate a new producing zone. “Re-enter” means to drill out the plugs of an abandoned well in a new effort to establish oil or gas production, or use the well for another purpose. “Reservoir” means a natural underground oil or gas bearing formation. “Rework” means to perform remedial measures in a well in order to restore oil or gas production that has declined substantially or stopped completely. “Royalty interest” means that portion of the mineral interest that is the landowner's share. “Seismic operations” means the controlled application of vibratory energy from any source to determine if favorable conditions exist for the subsurface entrapment of oil or gas. “Seismic section” means a graphic, near-vertical display of waveform data processed by a computer program to facilitate interpretation of subsurface conditions. “Seismic survey” means a planned network or program of seismic operations conducted by one person, one time, under one permit. “Shotholes” means drilled holes which are subsequently loaded with explosives whose detonation generates seismic waves during a seismic survey. “Shut-in pressure” means the pressure in the well measured at the wellhead in a specified period of time after the valves are closed. “Stimulate a zone” means to use techniques such as hydraulic fracturing and acidizing in order to increase oil or gas production from a formation. “Surface casing” means the first casing set inside the conductor pipe, which seals off any shallow aquifers and also serves as a foundation for all subsequent drilling activity. “Tidal waters” means all waters of the State subject to tidal influence with the landward boundary being coterminous with the wetlands boundary maps adopted under Environment Article, §16-301, Annotated Code of Maryland. “Wellhead protection area” means surface and subsurface area surrounding a water well or well field, supplying a public water system, through which contaminants are reasonably likely to move toward and reach the water well or well field. “Wildcat well” means an exploratory well drilled for oil or gas on a geologic feature not yet proven to be productive, or in an unproven territory, or to a zone that has never produced or is not known to be productive in the general area.