Critical Borehole Pressure for a Vertical Hydraulic Crack in the Presence of Two Principal Total Stresses

摘要

In hydraulic fracturing in deep boreholes, a vertical hydraulic crack is produced by the processes of breakdown, crack propagation, shut-in, and venting (deflation). It is desired to determine whether, during repumping, the rock will sustain a given borehole pressure in the presence of two horizontal principal total stresses and a preexisting vertical crack extending diametrically outward from a cylindrical borehole. This can be predicted by using the stress-intensity-factor fracture-mechanics approach.