Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 24 - Class VI Injection Wells and Facilities Underground Injection Control Program
Section 24-2 - Definitions

(a) "Abandoned well" means a well whose use has been permanently discontinued or that is in a state of disrepair such that it cannot be used for its intended purpose or for observation purposes. Temporary or intermittent cessation of injection operations is not abandonment.

(b) "Aquifer" means a zone, stratum, or group of strata that can store and transmit water in sufficient quantities for a specific use.

(c) "Area of review" means the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced fluids, as well as the overlying formations, and surface area above that delineated region.

(d) "Background" means the constituents or parameters and the concentrations or measurements that describe water quality and water quality variability prior to the underground injection.

(e) "Bore/casing annulus" means the space between the wellbore and the well casing.

(f) "Carbon dioxide plume" means the underground extent, in three dimensions, of an injected carbon dioxide stream.

(g) "Carbon dioxide stream" means carbon dioxide, plus associated substances derived from the source materials and any processing, and any substances added to the stream to enable or improve the injection process. Within this Chapter, the term "carbon dioxide stream" does not include any carbon dioxide stream that meets the definition of a hazardous waste under 40 C.F.R. § 261.3.

(h) "Casing" means a pipe or tubing of appropriate material, of varying diameter and weight, lowered into a borehole during or after drilling to support the sides of the hole to prevent the walls from caving, to prevent loss of drilling mud into porous ground, or to prevent water, gas, or other fluid from entering or leaving the hole.

(i) "Casing/tubing annulus" means the space between the well casing and the tubing.

(j) "Cementing" means sealing the annular space around the outside of a casing string using a specially formulated mixture to hold the casing in place and prevent any movement of fluid in this annular space. Cementing also includes operations to seal the well at the time of abandonment.

(k) "Class I well" means a well used to inject hazardous or non-hazardous industrial, commercial, or municipal waste beneath the lowermost formation containing, within one-quarter (1/4) mile of the well bore, an underground source of drinking water.

(l) "Class II well" means any commercial or non-commercial well used to dispose of water or fluids directly associated with the production of oil or gas, any well used to inject fluids or gas for enhanced oil recovery, or any well used for the storage of liquid hydrocarbons.

(m) "Class V facility" means any property that contains an injection well, dry well, or subsurface fluid distribution system that is not defined as a Class I, II, III, IV, or VI well in these Regulations. A Class V facility includes all systems of collection, treatment, and control that are associated with the underground injection.

(n) "Class VI well" means a well that is used for injecting a carbon dioxide stream for geologic sequestration that:

(o) "Confining zone" means a geological formation, group of formations, or part of a formation stratigraphically overlying the injection zone(s) that act(s) as a barrier to fluid movement. For Class VI wells operating under an injection depth waiver, confining zone means a geologic formation, group of formations, or part of a formation stratigraphically overlying and underlying the injection zone(s) that acts as a barrier to fluid movement.

(p) "Contaminant" means any pollution; wastes; or physical, chemical, biological, or radiological substance or matter in water.

(q) "Corrective action" means the use of Administrator-approved methods to ensure that wells within the area of review do not serve as conduits for the movement of fluids into geologic formations other than those authorized under the permit.

(r) "Duly authorized representative" means a specific individual or a position having responsibility for the overall operation of the regulated facility or activity. The authorization shall be made in writing by a responsible corporate officer and shall be submitted to the Administrator.

(s) "Endanger" means to expose to actions or activities that could pollute an underground source of drinking water.

(t) "Exempted aquifer" means an aquifer or a portion thereof that meets the criteria in the definition of underground source of drinking water but that has been exempted according to the procedures in Section 16 of this Chapter.

(u) "Fact sheet" means a document briefly setting forth the principal facts and the significant factual, legal, methodological, and policy questions considered in preparing the draft permit.

(v) "Geologic sequestration project" means an injection well or wells used to emplace a carbon dioxide stream into an injection zone for geologic sequestration. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced fluid, as well as the surface area above that delineated region.

(w) "Groundwater" means subsurface water that fills available openings in rock or soil materials such that they may be considered water saturated under hydrostatic pressure.

(x) "Groundwaters of the State" are all bodies of underground water that are wholly or partially within the boundaries of the State.

(y) "Hazardous waste" means a hazardous waste as defined in 40 C.F.R. § 261.3.

(z) "Indian lands" and "Indian country" means:

(aa) "Injectate" means the material injected through any underground injection facility.

(bb) "Injection zone" means a geologic formation, group of formations, or part of a formation that is of sufficient areal extent, thickness, porosity, and permeability to receive carbon dioxide through a well or wells associated with a geologic sequestration project.

(cc) "Log" means a written record progressively describing the strata and geologic and hydrologic character thereof to include electrical, radioactivity, radioactive tracer, temperature, cement bond and similar surveys, a lithologic description of all cores, and test data.

(dd) "Long string casing" means a casing that is continuous from at least the top of the injection interval to the surface and that is cemented in place.

(ee) "Packer" means a device lowered into a well to produce a fluid-tight seal.

(ff) "Plugging" means the act or process of stopping the flow of water, oil, or gas into or out of a formation through a borehole or well penetrating that formation.

(gg) "Plugging record" means a systematic listing of permanent or temporary abandonment of water, oil, gas, test, exploration, and waste injection wells. A plugging record may contain a well log, description of amounts and types of plugging material used, the method employed for plugging, a description of formations that are sealed, and a graphic log of the well showing formation location, formation thickness, and location of plugging structures.

(hh) "Plume stabilization" has been achieved when the carbon dioxide stream that has been injected subsurface essentially no longer expands vertically or horizontally and poses no threat to underground sources of drinking water, human health, safety, or the environment, as demonstrated by a minimum of three (3) consecutive years of monitoring data.

(ii) "Post-injection site care" means the monitoring, measurement, verification, and other actions (including corrective action) needed to ensure that underground sources of drinking water are not endangered following the cessation of injection, and plugging and abandonment of injection wells until plume stabilization has been achieved and certified by the Administrator, as required under Section 24 of this Chapter.

(jj) "Pressure front" means the zone of elevated pressure that is created by the injection of the carbon dioxide stream into the subsurface. The pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential sufficient to cause movement of injected fluids or formation fluid if a migration pathway or conduit existed.

(kk) "Radioactive waste" means any waste that contains radioactive material in concentrations that exceed those listed in 10 C.F.R. Part 20, Appendix B, Table II, Column 2.

(ll) "Receiver" means any zone, interval, formation, or unit in the subsurface into which a carbon dioxide stream is injected.

(mm) "Responsible corporate officer" means a president, secretary, treasurer, or vice president of the corporation in charge of a principal business function, or any other person who performs similar policy- or decision-making functions for the corporation.

(nn) "Secondarily affected aquifer" means an aquifer affected by migration of fluids from an injection facility that does not directly discharge into the secondarily affected aquifer.

(oo) "Site closure" occurs when a geologic sequestration project is released from post injection site care responsibilities and the Administrator certifies site closure pursuant to Section 24(b)(iii) of this Chapter.

(pp) "Surface casing" means the first string of well casing to be installed in the well.

(qq) "Underground injection" means a well injection, a subsurface discharge, a discharge into a receiver, or the subsurface emplacement of fluids through a well.

(rr) "Underground source of drinking water" or "USDW" means an aquifer or portions thereof that is not an exempted aquifer and:

(ss) "Water quality management area" means the area delineated for the protection of water quality under a Department-approved plan developed under Sections 303, 208, or 201 of the Clean Water Act, 33 U.S.C. § 1251 et seq. as amended.

(tt) "Well" means:

(uu) "Well plug" means a watertight and gastight seal installed in a borehole or well to prevent movement of fluids.

(vv) "Well stimulation" means any process used to clean the wellbore, enlarge channels, or increase pore space in the interval to be injected and includes surging, jetting, blasting, acidizing, and hydraulic fracturing.

(ww) "Workover" means to pull the tubing, packer, or any downhole hardware from the well and inspect, replace, or refurbish it prior to placing that hardware back in service, or to enter the hole with any drilling tool.

(xx) "Wellhead protection area" means the area delineated for the protection of a public water supply utilizing a groundwater source under a Department-approved plan developed pursuant to Section 1428 of the Safe Drinking Water Act, 42 U.S.C. § 300h-7, or Section 1453 of the Safe Drinking Water Act, 42 U.S.C. § 300j-13.