Definition(s)
Oil-Based Drilling Fluid
Drilling fluid in which the continuous phase is not miscible with water, and water or brine is the dispersed phase. NOTE Oil-based drilling fluids are usually referred to as non-aqueous drilling fluids, or NAF.
Source: API RP 13C, Recommended Practice on Drilling Fluids Processing Systems Evaluation, Upstream Segment, Fourth Edition, December 2010. Global Standards