1. a) The owner or operator of a Class VI injection well must sufficiently demonstrate to support an Agency determination that the wells will be sited in areas with a suitable geologic system. The owner or operator must sufficiently demonstrate that the geologic system comprises both of the following elements:

   1. 1) An injection zone of sufficient areal extent, thickness, porosity, and permeability to receive the total anticipated volume of the carbon dioxide stream; and
   2. 2) Confining zones free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced formation fluids and allow injection at proposed maximum pressures and volumes without initiating or propagating fractures in the confining zones.

2. b) The Agency may require the owner or operator of a Class VI injection well to identify and characterize additional zones that will impede vertical fluid movement; that are free of faults and fractures which may interfere with containment; that allow for pressure dissipation; and that provide additional opportunities for monitoring, mitigation, and remediation.

   BOARD NOTE: This Section corresponds with 40 CFR 146.83 (2011).

(Source: Added at 36 Ill. Reg. 1661, effective January 20, 2012)