Fatty acids and their derivatives have been used as emulsifiers, lubricants, etc., in drilling fluids. Waste vegetable oil is a good source of triglycerides. Fatty acids and the methyl ester of fatty acids can be isolated from triglycerides by a simple base hydrolysis. These in-house developed products show exceptional properties as primary emulsifiers for invert-emulsion oil-based mud (OBM), and as lubricants for water-based mud and base oil for OBM.