037-2 Wyo. Code R. §§ 2-2 - Definitions

For the purposes of Part III of the Regulations and Instructions of the Wyoming State Engineer's Office - Ground Water Division, the following definitions apply:

(a) ACCESS PORT - An opening at the wellhead and/or within the discharge system where measuring devices or meters may be placed to measure water levels, pressure, or discharge.

(b) ACRE-FOOT - The volume of water required to cover one (1) acre to a depth of one (1) foot. One (1) acre-foot equals approximately 325,851 U.S. Gallons.

(c) AIR-HAMMER DRILLING - A system of drilling that employs a pneumatic bit that delivers percussion strikes to the formation while being slowly rotated. Cuttings are removed by the compressed air that drives the hammer bit.

(d) ALLUVIUM - Deposits resulting from the operations of rivers, streams, etc., thus including sediments laid down in riverbeds, flood plains, lakes, fans at the foot of mountain slopes, and estuaries.

(e) ANNULAR SPACE (ANNULUS) - The space between two cylindrical surfaces, one of which surrounds the other, e.g. concentrically; such as the space between the outer well casing and the borehole wall. An annular space also means the space between an inner well casing and outer well casing. The annular space is calculated as the difference in diameter of the borehole (D_b) and the outside diameter of the casing (D_c) divided by two [(D_b-D_c)/2], or the difference in the inside diameter of a larger casing (D_i) and the outside diameter of a smaller casing (D_s) divided by 2 [(D_i-D_s)/2].

(f) AQUIFER - "Any underground geological structure or formation having boundaries that may be ascertained or reasonably inferred, in which water stands, flows or percolates." (W.S. § 41-3-901(a)(iii) ). (Also see Unconfined, Confined and Perched)

(g) API - The American Petroleum Institute.

(h) ARTESIAN AQUIFER - See Confined Aquifer.

(i) ARTESIAN WELL - A well that derives its water from an artesian or confined aquifer where the hydrostatic pressure is greater than atmospheric pressure thereby raising the water level above the top of the aquifer. A flowing artesian well has a water level that is above the land surface.

(j) ASTM - American Society for Testing and Materials International.

(k) AWWA - The American Water Works Association

(l) BENTONITE - Clay composed predominantly of the clay mineral montmorillonite and used commercially in drilling fluids and well sealing products.

(m) BOREHOLE LOGS - Borehole logs measure and display the physical properties of the surrounding medium with a sensor located in a borehole. Some common borehole logging techniques are presented below:

(i) Acoustic (Sonic) Velocity - A borehole log in which the down-hole tooling has a sound transmitter at one end and two receivers spaced along it. The tool uses the difference in signal arrival time to calculate the sonic velocity through the strata.

(ii) Caliper - A borehole log which measures the size of the well bore. Used to measure the diameter of an uncased borehole in bedrock units. Can also be used to find the casing depth.

(iii) Cement Bond (Bond) - An acoustic log that measures and displays the return arrival time of an acoustic wave generated within the casing. When steel casing is strongly bonded to cement, most of the energy of the wave is carried through the casing; however, when the casing is not strongly bonded to the cement, most of the sound waves are carried along the casing and the arrival time will be much shorter.

(iv) Focused (Focus) - A borehole log wherein electrodes are designed to direct electrical current as a disk. This method can yield improved results in high resistivity strata.

(v) Formation Density (Density) - A borehole log which measures the rock density.

(vi) Gamma-Gamma Radiation - A borehole log in which a source of gamma radiation and a detector are lowered into the borehole. The log measures bulk density of the formation and fluids.

(vii) Gamma-Ray (or Gamma) - A borehole log which measures naturally occurring gamma radiation emitted by the surrounding strata.

(viii) Induction (or Dual Induction) - A borehole log which measures spontaneous potential, resistivity, and conductivity.

(ix) Neutron Porosity (Neutron) - A borehole log obtained by lowering a radioactive element, which is a source of neutrons, and a neutron detector into the well. The log measures the hydrogen atom density of the surrounding strata and provides an indication of the formation porosity.

(x) Resistivity - A borehole log which measures the resistivity between two current electrodes and two additional electrodes. Measures the electrical resistivity of the formation and contained fluids near the probe.

(xi) Spontaneous Potential (or Self Potential) (SP) - A borehole log made by measuring the natural electrical potential that develops between the formation and the borehole fluids. The SP log is commonly used to assess the permeability of the surrounding strata.

(n) CABLE-TOOL DRILLING - A drilling technique which is operated by repeatedly lifting and dropping a heavy drilling string and drilling bit which pulverizes the encountered material.

(o) CASCADING WATER - Ground water which trickles or pours through cracks (or other openings), down the cased or uncased borehole above the water level in the well.

(p) CASING - Any conduit or pipe placed in a well to prevent borehole wall caving, to protect the production string and pump, and to prevent pollution of the well. Casing material is most commonly steel, PVC, or concrete.

(q) CEMENT BASKET - A device firmly attached to the casing string that is designed to tightly fit against the borehole wall that is intended to hold cement above a desired zone.

(r) CENTRALIZER - A device attached to the outside of a casing or liner to center it within a borehole or casing.

(s) COLLUVIUM - Loose rock and soil at the base of a cliff or steep slope.

(t) CONFINED (ARTESIAN) AQUIFER - An aquifer bounded above and below by confining units (or beds) and in which water levels in wells rise above the top of the aquifer.

(u) CONFINING FORMATION (CONFINING UNIT) - A geologic bed which displays a significantly lower vertical hydraulic conductivity than an adjacent aquifer.

(v) CONSOLIDATED - Combined or cemented into a single or solid mass; or lithi fied (e.g. bedrock formation).

(w) CONSTRUCTION - "[Includes boring, drilling, jetting, digging or excavating, and installing casing, pump and other devices withdrawing or facilitating the withdrawal of underground water, or measuring the depth to the water table or flow of the well." (W.S. § 41-3-901(a)(v) ).

(x) CONTAMINANT - Any material responsible for or contributing to pollution. See POLLUTION.

(y) CUBIC FEET PER SECOND (CFS) - A rate of flow. One (1) cfs equals 448.8 gpm.

(z) DEVELOPMENT - Cleansing of the drilled hole and formation to remove cuttings, fine grained materials, infiltrated drilling fluids, and/or to enhance aquifer permeability. Development can be accomplished by surging, backwashing, jetting, airlifting, acid-fracture treatment, etc.

(aa) DRILLER - See WATER WELL DRILLING CONTRACTOR.

(bb) DRILLING MUD - A viscous liquid suspension, usually composed of water and a bentonite-based mixture, which is pumped through the drill stem to equalize formation pressures, lubricate and cool the drilling bit, and/or aid in removing drill cuttings to the surface.

(cc) DRILL PIPE (DRILL STEM) - Thick walled pipe used for drilling operations. Transmits rotation from the rotating mechanism on the drill rig to the bit. Drill collar, extremely heavy drill pipe, is usually placed in the drill pipe string just above the bit to provide extra weight and strength.

(dd) DRILLING RIG - The derrick, mast, or standing apparatus together with the power equipment, pumps, cable and tools used in well drilling. Usually truck-mounted or trailer mounted.

(ee) DRIVE POINT - A conical shaped point of steel placed at the bottom of a driven well's screen to aid in placing the screen at the desired depth.

(ff) DRIVE SHOE - A section of steel casing attached to the bottom of a driven casing. The drive shoe has a beveled edge and is designed for cutting through rock or other hard formations.

(gg) DRIVEN WELL - A well which is emplaced by forcefully driving a casing into the ground (usually deep soil or alluvial material). The leading end of the casing is usually fitted with a drive point.

(hh) DUG WELL - A large diameter well or trench constructed by digging down and intercepting the water table or shallowest water-bearing horizon.

(ii) FILTER (GRAVEL) PACK - Clean sand or gravel sized according to formation texture and emplaced in the annular space of a well between the perforated or screened interval(s) of the casing and the borehole wall in order to prohibit or decrease the entrance of formation material into the well, stabilize the borehole, and increase the efficiency of water production.

(jj) FLOWING WELL - An artesian well in which the water level stands above the land surface.

(kk) FORMATION - a body of rock or soil which has identifiable and distinctive lithic characteristics, is aerially extensive, can be mapped, and may be combined into groups or divided into members.

(ll) GALLONS PER MINUTE (GPM) - Unit of measure used to describe a flow rate.

(mm) GEL - A jelly-like fluid and colloidal material (natural or synthetic) dispersion mixture used as a drilling fluid.

(nn) GROUND (UNDERGROUND) WATER - "Any water, including hot water and geothermal steam, under the surface of the land or bed of any stream, lake, reservoir, or other body of surface water, including water that has been exposed to the surface by an excavation such as a pit." (W.S. § 41-3-901(a)(ii) ).

(oo) GROUT - A fluid mixture of water plus a cement-based or bentonite-based material that is stable, has low permeability, and possesses minimum shrinking properties such that it is an optimal sealing material for well casing or for well plugging.

(pp) HEAT PUMP WELL - Any well constructed to utilize the heat exchange properties of either ground water or of geological material penetrated in the well.

(qq) HYDROSTATIC PRESSURE OR HEAD - Pressure of water (or other liquid) upon a unit area due to the height at which the surface of the water column stands above the point where the pressure is measured. Expressed as pounds per square inch (p.s.i.) or actual feet of head.

(rr) LINER - Pipe (steel or plastic), which is smaller in diameter than installed well casing, that is used to reconstruct (deepen) a well or strengthen unstable conditions encountered at depth in a well.

(ss) LINER HANGER - A device used to attach or hang liners from the internal wall of a larger, upper casing string.

(tt) LOST CIRCULATION - Subsurface escape of drilling fluid from a drill hole into a porous, fractured, or cavernous formation.

(uu) LCM (LOST CIRCULATION MATERIAL) - Material added to drilling fluid in order to reduce or stop lost circulation conditions.

(vv) MILLIGRAMS PER LITER - Abbreviated mg/1, means milligrams of solute per liter of solvent.

(ww) MONITORING WELL - A ground water level observation well or a well from which water samples are retrieved for water chemistry analysis.

(xx) NEAT CEMENT - Used for ground or borehole sealing. Commonly known as Portland cement of various ASTM designations (Type I through Type V, Type K, etc.). May be mixed with calcium chloride (CaCL:) for rapid set time or bentonite for lower conductivity, lower curing temperature, and resistance to shrinking/cracking.

(yy) NSF - NSF International, formerly National Sanitation Foundation.

(zz) NOMINAL SIZE - Used to describe standard sizes for pipe from 1/8 inch to 12 inches. The term "nominal" is used in designating the inside diameter of the pipe, because, in practice, the actual size varies somewhat.

(aaa) PACKER - A device used to seal or isolate. In the case of a telescoped casing and screen assembly, a packer is used to provide a sand-tight seal between the screened assembly and the casing. An inflatable packer is used to isolate zones of the casing or borehole for tests or casing repairs.

(bbb) PERCHED AQUIFER - Unconfined ground water which is bounded below by low-permeability material and separated from an underlying regional body of ground water by an unsaturated zone.

(ccc) PERFORATIONS - Puncturing, drilling, sawing, slotting, torchcutting, or other openings of a well casing emplaced in order to allow flow of water from the waterbearing interval(s) into a cased well. Perforations are typically installed with revolving wheel cutters, knives, or explosive charges and are created after the casing has been placed in the borehole.

(ddd) PERMEABILITY - A measure of the ability of a material to transmit fluids.

(eee) PERMIT - The record instrument on which the State Engineer grants permission to construct a well/spring and beneficially use the water for the purposes specified, together with any conditions and limitations attached.

(fff) PIEZOMETER - A nonpumping well, generally of small diameter, that is used to measure the pore pressures, water levels, or potentials. A piezometer generally has a short well screen through which water can enter.

(ggg) PITLESS ADAPTOR - A commercially manufactured, watertight unit or device designed for attachment to well casing which permits discharge from the well below the land surface to provide for a buried, frost-free discharge line.

(hhh) PLUGGED AND ABANDONED WELL (P&A) - Any well which has been filled or plugged so that it is rendered unproductive and prevents contamination of the ground water. A properly abandoned well will not produce water nor serve as a channel for movement of water or other material from the well or between water-bearing zones.

(iii) POLLUTION - "Any impairment of the natural quality of such water, however caused, including impairment by salines, minerals, industrial wastes, domestic wastes or sewage, whether indrafted directly or through infiltration into the underground water supply." (W.S. § 41-3-901(a)(vi) )

(jjj) POROSITY - The ratio of the volume of void spaces in a rock or sediment to the total volume of the rock or sediment. Effective Porosity - the volume of the void spaces through which water or other fluids can travel in a rock or sediment divided by the total volume of the rock or sediment. Primary porosity is the porosity that represents the original pore openings when a rock or sediment formed. Secondary porosity is the porosity that has been caused by fractures or weathering in a rock or sediment after it has been formed.

(kkk) POTENTIOMETRIC SURFACE - A surface that represents the level to which water will rise in tightly cased wells.

(Ill) PRESSURE GROUTING - A process by which a grout is emplaced and confined within the borehole or casing of a well by the use of retaining plugs, packers, or a displacing fluid by which sufficient pressure is applied to drive the grout into and within the annular space or interval to be grouted.

(mmm) PUMP INSTALLER - See WATER WELL PUMP INSTALLATION CONTRACTOR.

(nnn) PUMP TEST - Pumping a well, usually at time of completion, to determine aquifer or well performance (e.g., drawdown, maximum efficient gpm, specific capacity, etc.).

(ooo) PUMPING WATER LEVEL - The water level achieved, during water well pumping, where the drawdown ceases or stabilizes.

(ppp) PVC CASING OR SCREEN - Polyvinyl chloride polymer (plastic) pipe.

(qqq) RECOVERY WELL - A well primarily designed to remove contaminants, groundwater, or both, usually in an attempt to contain contaminants or contaminated groundwater to an area already effected.

(rrr) REHABILITATION - Restoring a well to its most efficient condition. This may be accomplished by chemical and mechanical methods.

(sss) ROTARY DRILLING - Drilling technique which employs a rotating drill string through which drilling mud is pumped down hole to cool the drill bit and remove cuttings to the surface via the borehole outside the drill pipe. Compressed air is also used, in lieu of drilling fluid, to remove cuttings. Reverse circulation rotary drilling is a method in which drilling fluid flows from the ground surface down the borehole and is pumped back to the ground surface through the drill pipe. The reverse rotary method can be effective for drilling large diameter boreholes and for drilling in unstable material.

(ttt) SANITARY WELL CAP (SEAL) - A vented watertight wellhead cap that prevents the intrusion of foreign fluids (runoff, chemical liquids, animal waste, etc.) or debris.

(uuu) SATURATED - All voids are filled with water.

(vvv) SHALE BASKET - A device firmly attached to the casing string designed to tightly fit against the borehole wall that is intended to prevent materials from falling into the intervals below the shale basket setting.

(www) SLIM HOLE - A small diameter exploration borehole drilled to obtain stratigraphic or structural information.

(xxx) SPRING - A point location where ground water emanates from bedrock or soil to the land surface.

(yyy) SQUEEZE JOB - Usually a secondary cementing or grouting process where the sealant is pumped into a borehole through the bottom of the casing or through perforations at key depths in the casing in order to obtain fluid or formation shut off.

(zzz) STATE ENGINEER - The State Engineer or his designee.

(aaaa) STATIC WATER LEVEL - (1) The elevation or level of the water in a well when the pump is not operating. Usually measured in depth below the land surface or from the top of the casing. (2) The level or elevation to which water would rise in a tube connected to an artesian aquifer when the well is shut in. Usually measured in psi or feet above ground level.

(bbbb) SURFACE (CONDUCTOR) CASING - Retaining pipe, usually large diameter steel, concrete or culvert material installed in the uppermost potion of the well between the borehole wall and the inner well casing.

(cccc) SURFACTANT - An agent that reduces the surface tension of the liquid in which it is dissolved. Used in air-based drilling to produce foam and during development to disaggregate clays.

(dddd) TREMIE PIPE (GROUT PIPE) - A small diameter conductor pipe, hose or tubing used in down hole placement of well construction material (cement, grout mixture, gravel pack, etc.).

(eeee) UNCONFINED (WATER TABLE) AQUIFER - An aquifer that has no overlying geologic unit preventing or restricting the vertical or upward movement of water.

(ffff) UNCONSOLIDATED - A loose aggregation or not combined nor cemented into a single or solid mass; or unconsolidated deposit (e.g., alluvium).

(gggg) WATER TABLE - The water surface of an unconfined aquifer.

(hhhh) WATER WELL DRILLING CONTRACTOR (DRILLER) - "Any person responsible for or causing the construction, equipping, test pumping or development of any water well for compensation or otherwise as provided by [W.S. § 33-42-101 through 33-42-117 ]." (W.S. § 33-42-102(a)(iii)

(iiii) WATER WELL PUMP INSTALLATION CONTRACTOR (PUMP INSTALLER) - "Any person who is in the business of installing pumping equipment in water wells for compensation or otherwise as provided by [W.S. § 33-42-101 through 33-42-117 ]." (W.S. § 33-42-102(a)(iv) )

(jjjj) WELL - "Any artificial opening or excavation in the ground, however made, by which underground water is sought or through which it flows under natural pressure or is artificially withdrawn, and a series of wells developed as a unit and pumped collectively by a single pumping unit shall be considered as one (1) well." W.S. § 41-3-901(a)(iv) "Any artificial opening in the ground for the production of groundwater or the disposal of water underground, including developed springs, test wells, monitoring wells, deep well ground beds (cathodic protection bores), geothermal or heat exchange wells, drive points and excavations for the purpose of artificial recharge to the groundwater bodies or disposal of wastes. The term "well" does not include excavations made for the dewatering of construction sites, mines or oil and gas wells, and the prospecting for and removal of mineral products, nor wells for the production of the media for secondary oil recovery." (W.S. § 33 - 42 - 102(a)(v) )

For the purpose of this document, the following well types are described:

(i) Type I - Dug Wells

(ii) Type II - Natural Filter Wells

(iii) Type III - Artificial Filter Wells

(iv) Type IV - Partially-Cased Open Borehole Wells

(v) Type V - Fully-Cased Wells

(vi) Type VI - Conversion of Existing Oil or Gas Wells, or Exploration Test Wells into Water Wells

(kkkk) WELL (DRILL HOLE) CUTTINGS - Rock chips or particles cut by the action of the drill bit and removed from the hole. Cutting samples collected and identified at evenly spaced intervals provide a lithologic log (detailed description of rock material encountered in the drill hole).

(llll) WELL SCREEN - A commercially manufactured structurally supporting filter device that allows inflow, retains select material, and is the access for aquifer development and future aquifer maintenance. Screen may be continuous-slot wire-wrapped, pre-packed, louvered, or bridge-slotted or any other commercially manufactured product which is produced for the purpose of water well screening.

Notes

037-2 Wyo. Code R. §§ 2-2