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).