Formation Fracture Gradient
The hydrostatic value expressed in psi/ft. that is required to initiate a fracture in a subsurface formation (geologic strata).
Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global Standards
Source: API RP 64, Recommended Practice for Diverter Systems Equipment and Operations, Second Edition, November 2001 (March 1, 2007). Global Standards