crushed zone — Oil & Gas Glossary
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
Detailed Explanation
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.