1. n. [Drilling Fluids]

Ratio of the volume percent synthetic fluid to the volume percent water in a synthetic-base mud, where each is a percent of the total liquid in the mud. The SWR is calculated in an analogous way to the oil/brine ratio using data from the retort test.

Alternate Form: SWR

See: oil mud,  syn,  synthetic-base fluid,  water, oil, and solids test