Rolled-In-Scale (Also Called A Scab) : A surface imperfection caused by scale, formed during a previous heating, which has not been eliminated prior to surface drilling. (Spec 11B)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}