PTB 4 : This term refers to pounds of salt per thousand barrels of crude oil. It is used in conjunction with BS&W to express the quality of untreated and treated crude oils in relation to desalting applications of emulsion treaters. (Spec 12L)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}