Arizona Administrative Code › Title 18 - ENVIRONMENTAL QUALITY › Chapter 9 - DEPARTMENT OF ENVIRONMENTAL QUALITY - WATER POLLUTION CONTROL › Article 6 - UNDERGROUND INJECTION CONTROL › Part J - CLASS VI INJECTION WELL REQUIREMENTS › Section R18-9-J656 - Class VI; Applicability

Current through Register Vol. 30, No. 28, July 12, 2024
A. This Part
				  establishes criteria and standards for underground injection control programs
				  to regulate any Class VI carbon dioxide geologic sequestration injection
				  wells.
B. This Part applies to any
				  well used to inject carbon dioxide specifically for the purpose of geologic
				  sequestration.
C. This Part also
				  applies to owners or operators of permit- or rule-authorized Class V
				  experimental carbon dioxide injection projects who seek to apply for Class VI
				  geologic sequestration permit for their well or wells. Owners or operators
				  seeking to convert existing Class I, Class II, or Class V experimental wells to
				  Class VI geologic sequestration wells must demonstrate to the Director that the
				  wells were engineered and constructed to meet the requirements of R18-9-J661
				  and ensure protection of USDWs, in lieu of requirements at R18-9-J661 and
				  R18-9-J662. A converted well must still meet all other requirements under Part
				  F of this Article.
D. The following
				  definitions apply to this Part and govern for Class VI wells to the extent that
				  these definitions conflict with those in R18-9-A601:
1. "Area of review" means the region
				  surrounding the geologic sequestration project where USDWs 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 R18-9-J659.
2. "Carbon dioxide
				  plume" means the extent underground, in three dimensions, of an injected carbon
				  dioxide stream.
3. "Carbon dioxide
				  stream" means carbon dioxide that has been captured from an emission source,
				  plus incidental associated sub stances derived from the source materials and
				  the capture process, and any substances added to the stream to enable or
				  improve the injection process. This Part does not apply to any carbon dioxide
				  stream that meets the definition of a hazardous waste under A.R.S. §
											49-921.
4. "Confining zone" means a geologic
				  formation, group of formations, or part of a formation stratigraphically
				  overlying the injection zone or zones that acts as 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 or
				  zones.
5. "Corrective action" means
				  the use of Director-approved methods to ensure that wells within the area of
				  review do not serve as conduits for the movement of fluids into
				  USDWs.
6. "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.
7. "Geologic sequestration project" means an
				  injection well or wells used to emplace a carbon dioxide stream beneath the
				  lowermost formation containing a USDW; or, wells used for geologic
				  sequestration of carbon dioxide that have been granted a waiver of the
				  injection depth requirements pursuant to requirements at R18-9-J670; or, wells
				  used for geologic sequestration of carbon dioxide that have received an
				  expansion to the areal extent of an existing Class II enhanced oil recovery or
				  enhanced gas recovery aquifer exemption pursuant to R18-9-A605 and R18-9-A606.
				  It includes the subsurface three-dimensional extent of the carbon dioxide
				  plume, associated area of elevated pressure, and displaced fluids, as well as
				  the surface area above that delineated region.
8. "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.
9. "Post-injection site
				  care" means appropriate monitoring and other actions, including corrective
				  action, needed following cessation of injection to ensure that USDWs are not
				  endangered, as required under R18-9-J668.
10. "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 Part, 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.
11. "Site closure" means the
				  point/time, as determined by the Director following the requirements under
				  R18-9-J668, at which the owner or operator of a geologic sequestration site is
				  released from post-injection site care responsibilities.
12. "Transmissive fault" or "fracture" means
				  a fault or fracture that has sufficient permeability and vertical extent to
				  allow fluids to move between formations.