R 324.807 Maximum injection pressure.

Rule 807. During Class II well injection operations, a permittee shall ensure that the surface injection pressure does not exceed a pressure determined by the following equation: Pm = (fpg - 0.433 sg)d where Pm = surface injection pressure fpg = fracture pressure gradient of the injection interval (if unknown, assume 0.800) sg = specific gravity of the injection liquid (if unknown, assume 1.2) d = depth of the top of the injection interval in feet (true vertical depth). The value for fpg may be determined by an instantaneous shut-in pressure or data derived from step rate testing. Other information to derive fpg values may be used with approval of the supervisor or authorized representative of the supervisor.