Current through Register Vol. XLI, No. 50, December 13, 2024
Section 47-13-5 - Area of Review5.1. The Director shall select the methods by which the area of review shall be established for each injection well or each field, project, or area of the State.5.2. The area of review may be defined as either:5.2.1. The zone of endangering influence as determined in accordance with subdivision 5.3.1; or5.2.2. An area within a fixed radius around each injection well as determined in accordance with subdivision 5.3.3.5.3. Zone of endangering influence. The zone of endangering influence shall be: 5.3.1. In case of application(s) for well permit(s) under subsection 14.3, that area the radius of which is the horizontal distance from the injection well in which the pressures in the injection zone may cause the migration of the injection and/or formation fluid into an underground source of drinking water; or5.3.2. In the case of an application for an area permit under subsection 14.4, the area of the project plus a circumscribing area, the width of which is the horizontal distance for the perimeter of the project, in which the pressures in the injection zone may cause the migration of the injection and/or formation fluid into an underground source of drinking water. Computation of the zone of endangering influence should be based upon but not limited to, the parameters listed below and should be calculated for an injection time period equal to the expected life of the facility. The Thesis equation is an example of one possible objective method: Where "r" is equal to the square root of a quantity which consists of a numerator divided by the denominator where the numerator is equal to 2.25 multiplied by "K" multiplied by "H" multiplied by "t"; and, the denominator is equal to "S" multiplied by 10 to the "x" power. And, where "x" is equal to a numerator divided by a denominator, where the numerator is equal to four multiplied by "pi" multiplied by "K" multiplied by "H" multiplied [by the quantity equal to the product of ("h(subscript w)" minus "h(subscript bo)")] multiplied by "S(subscript p)G(subscript b)"; and, the denominator is equal to 2.3 multiplied by "Q". (See Figure 47-13-5 at the end of this rule)
5.3.2.a. Where "r" is equal to the radius of endangering influence from injection well (length): 5.3.2.a.1. "K" is equal to hydraulic conductivity of the injection zone (length/time);5.3.2.a.2. "H" is equal to thickness of the injection zone (length);5.3.2.a.3. "t" is equal to time of injection (time);5.3.2.a.4. "S" is equal to storage coefficient (dimensionless);5.3.2.a.5. "Q" is equal to injection rate (volume/time);5.3.2.a.6. "h(subscript bo)" is equal to observed original hydrostatic head of injection zone (length) measured from the base of the lowermost underground source of drinking water;5.3.2.a.7. "h(subscript w)" is equal to hydrostatic head of underground source of drinking water (length) measured from the base of the lowest underground source of drinking water;5.3.2.a.8. "S(subscript p)G(sub-script b)" is equal to specific gravity of fluid in the injection zone (dimensionless);5.3.2.a.9. "pi" is equal to 3.142 (dimensionless)5.3.2.b. The above equation is based on the following assumptions: 5.3.2.b.1. The injection zone is homogenous and isotropic;5.3.2.b.2. The injection zone has infinite area extent;5.3.2.b.3. The injection well penetrates the entire thickness of the injection zone;5.3.2.b.4. The well diameter is infinitesimal compared to "r" when injection time is longer than a few minutes; and5.3.2.b.5. The emplacement of fluid into the injection zone creates instantaneous increase in pressure.5.3.3. Fixed radius: 5.3.3.a. In the case of application(s) for well permit(s), a fixed radius around the well may be used but not less than 1/4 mile, except for:5.3.3.a.1. For Class1 hazardous waste wells, the area of review is a 2 mile radius.5.3.3.b. In the case of an application for an area permit, a fixed width may be used but not less than 1/4 mile for the circumscribing area.5.3.3.c. In determining the fixed radius, the following factors shall be taken into consideration: the chemistry of the injected and formation fluids; geology; hydrogeology; population and groundwater use and dependence; and historical practices in the area.5.4. For Class 6 wells, the area of review is 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 is based on available site characterization, monitoring, and operational data.