NAC445A.911. Limitations on location and pressure of injection; authorizing fracturing in zone for injection.

     1. The pressure for injection at the wellhead of an injection well must not exceed that which is calculated to initiate new fractures or propagate existing fractures in the zone for injection or the confining formation between the zone for injection and underground sources of drinking water.

     2. The pressure for injection must be calculated by using the formula:

Pm=(0.733 - 0.433 Sg)d

“Pm” means the pressure of injection at the wellhead in pounds per square inch.

“Sg” means specific gravity of the injected fluid (unitless).

“d” means the depth of the injection, in feet, measured from the top of the interval for injection.

     3. Fracturing in the zone for injection may be authorized by the Director if the holder of the permit can demonstrate that the fracturing would not result in the movement out of the zone for injection of injected fluids or fluids in the formation. The holder of the permit shall demonstrate the mechanical integrity of the injection well after such a fracturing operation and before commencing the injection of fluids.

     4. In no case may the pressure of injection cause the movement into an underground source of drinking water of injected fluids or fluids in the formation.

     5. No injection may occur between the outermost casing protecting underground sources of drinking water and the well bore.

     (Added to NAC by Environmental Comm’n, eff. 7-22-87)—(Substituted in revision for NAC 445.4271)