2.
n. [Perforating, Well Completions]
The rubblized or
damaged zone surrounding a
perforation tunnel where the action of the
perforating charge or bullet has altered the formation structure and
permeability. Although it is generally damaging to
production, the severity or extent of the crushed zone depend greatly on the characteristics of the formation, the perforating charge and the underbalance or overbalance conditions at time of perforating. Measures to reduce the effect of the crushed zone include
underbalanced perforating in which the crushed zone and perforating debris are flushed from the perforating tunnel by the
reservoir fluid as soon as the perforation is created. Where overbalanced perforating techniques are used, it may be necessary to
acidize the crushed zone to achieve maximum productivity from the
perforated interval.