Incrustations : Undesirable material which collects on interior walls of production vessels such as separators, meters, tanks, etc., reducing internal dimensions or capacity. Paraffin, gyp, etc., are examples. (WT)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}