Effects of Crushed Zone Damage on Leak-off Velocity in Perforated Carbonates

In cased hole carbonate wells, perforations are utilized to connect the wellbore to the formation, providing a conduit for stimulation fluid injection and reservoir production. Conventional hypotheses predict that when acid is injected in perforated carbonates, wormholes should nucleate at the tip of the perforation tunnel ( Huang et al. 2000 ). This assertion is based on models for the leak-off distribution along uniform-diameter perforation tunnels in which the effects of crushed zone damage are ignored. In contradiction to this hypothesis, recent studies have shown many examples in which dominant wormholes nucleate well behind the tunnel tip in perforated core experiments ( Rabie et al. 2013 ). This is interesting considering the fact that the effects of flow localization at the tunnel tip are believed to be exaggerated in axial core flow experiments owing to the influence of the no-flow boundary.