Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 730 - UNDERGROUND INJECTION CONTROL OPERATING REQUIREMENTS › Subpart H - CRITERIA AND STANDARDS APPLICABLE TO CLASS VI WELLS › Section 730.181 - Applicability

Current through Register Vol. 48, No. 28, July 12, 2024
a) This Subpart H
				establishes criteria and standards for Class VI carbon dioxide geologic
				sequestration injection wells.
b)
				This Subpart H applies to any injection well that is used to inject carbon
				dioxide specifically for the purpose of geologic sequestration.
c) This Subpart H also applies to the owner
				or operator of a permit- or rule-authorized Class I, Class II, or Class V
				experimental carbon dioxide injection well that seeks to apply for a Class VI
				geologic sequestration permit for its well. An owner or operator that seeks to
				convert an existing Class I, Class II, or Class V experimental injection well
				to a Class VI geologic sequestration well must demonstrate to the Agency that
				the well was engineered and constructed to meet the requirements of Section
				146.86(a) and to ensure protection of USDWs, in lieu of requirements at
				Sections 146.86(b) and 146.87(a). The owner or operator of either a Class I
				injection well that was previously permitted for the purpose of geologic
				sequestration or a Class V experimental technology injection well that is no
				longer being used for experimental purposes and which will continue injection
				of carbon dioxide for the purpose of geologic sequestration must apply for a
				Class VI permit. A converted well must still meet all other requirements of
				this Part.
d) Definitions. The
				following definitions apply to this Subpart H. To the extent that these
				definitions conflict with those that appear in 35 Ill. Adm. Code
				702.110 or Section
				730.103, the
				definitions of this Section govern for Class VI wells:
"Area of review" means the region surrounding the geologic
				  sequestration project where a USDW may be endangered by the injection activity.
				  The area of review is delineated using computational modeling that accounts for
				  the physical and chemical properties of all phases of the injected carbon
				  dioxide stream and displaced fluids, and is based on available site
				  characterization, monitoring, and operational data, as set forth in Section
				  730.184.
"Carbon dioxide plume" means the sub-surface
				  three-dimensional extent underground of an injected carbon dioxide
				  stream.
"Carbon dioxide stream" means carbon dioxide that has been
				  captured from an emission source (e.g., a power plant), plus incidental
				  associated substances derived from the source materials and the capture
				  process, and any substances added to the stream to enable or improve the
				  injection process. This Subpart H does not apply to any carbon dioxide stream
				  that meets the definition of a hazardous waste in 35 Ill. Adm. Code
				  721.103.
"Confining zone" means a geologic formation, a group of
				  formations, or a part of a formation that stratigraphically overlies an
				  injection zone and which acts as barrier to fluid movement. For a Class VI
				  injection well that is operating under a permit that includes alternative
				  injection well depth requirements, "confining zone" means a geologic formation,
				  a group of formations, or a part of a formation that stratigraphically overlies
				  and underlies the injection zone.
"Corrective action" means the use of Agency-approved methods
				  to ensure that wells within an area of review do not serve as conduits for the
				  movement of fluids into a USDW.
"Geologic sequestration" means the long-term containment of a
				  gaseous, liquid, or supercritical carbon dioxide stream in subsurface geologic
				  formations. This term does not apply to carbon dioxide capture or
				  transport.
"Geologic sequestration project" means any of the following
				  three types of injection wells:
An injection well or wells that are used to emplace a carbon
				  dioxide stream beneath the lowermost formation containing a USDW;
An injection well or wells that are used for geologic
				  sequestration of carbon dioxide and which have been granted a permit that
				  includes alternative injection well depth requirements pursuant to requirements
				  at Section
				  730.195;
				  or
An injection well or wells that are used for geologic
				  sequestration of carbon dioxide and which have received an expansion to the
				  areal extent of an existing Class II enhanced oil recovery or enhanced gas
				  recovery aquifer exemption pursuant to Section
				  730.104
				  and 35 Ill. Adm. Code
				  704.123(d).
A geologic sequestration project includes the subsurface
				  three-dimensional extent of the carbon dioxide plume, the associated area of
				  elevated pressure, and displaced fluids, as well as the surface area above that
				  delineated region.
"Injection zone" means a geologic formation, a group of
				  formations, or a 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.
"Post-injection site care" means appropriate monitoring and
				  other actions (including corrective action) needed following cessation of
				  injection to ensure that no USDW is endangered, as required under Section
				  730.193.
"Pressure front" means the zone of elevated pressure that is
				  created by the injection of carbon dioxide into the subsurface. For the
				  purposes of this Subpart H, the pressure front of a carbon dioxide plume refers
				  to a zone where there is a pressure differential sufficient to cause the
				  movement of injected fluids or formation fluids into a USDW.
"Site closure" means the point or time, as determined by the
				  Agency pursuant to Section 730.193, at which the owner or operator of a
				  geologic sequestration site is released from post-injection site care
				  responsibilities.
"Transmissive fault or fracture" means a fault or fracture
				  that has sufficient permeability and vertical extent to allow fluids to move
				  between formations.
BOARD NOTE: This Section corresponds with
					 40
					 CFR 146.81
					 (2017).