This part of ISO 10414 provides standard procedures for determining the following characteristics of oil-based drilling fluids: a) drilling fluid density (mud weight); b) viscosity and gel strength; c) filtration; d) oil, water and solids concentrations; e) alkalinity, chloride concentration and calcium concentration; f) electrical stability; g) lime and calcium concentrations, calcium chloride and sodium chloride concentrations; h) low-gravity solids and weighting material concentrations. The annexes provide additional test methods or examples that can optionally be used for the determination of:- shear strength (Annex A); - oil and water concentrations from cuttings (Annex B); - drilling fluid activity (Annex C); - aniline point (Annex D); - lime, salinity and solids concentration (Annex E); - sampling, inspection and rejection (Annex F); - rig-site sampling (Annex G); - cuttings activity (Annex H); - active sulphides (Annex I); - calibration and verification of glassware, thermometers, viscometers, retort kit cups and drilling fluid balances (Annex J); -permeability plugging apparatus with set-screw secured end cap (Annex K); - permeability plugging apparatus with threaded end cap (Annex L); - elastomer compatibility (Annex M); - sand content of oil-based fluid (Annex N); - identification and monitoring of weight-material sag (Annex O); - oil-based drilling fluid test report form (Annex P).