Volumetrie shrinkage occurs when different crudes/mineral oils are being blended. This volumetric shrinkage has been defined by density measurement and weighing of oil as weil as of the oil mixtures. Relative volumetric shrinkages up to O,56 vol. percent were observed. With increasing density ratio respectively bigger density difference of the components to be blended the volumetric shrinkage increases; until now a generallyvalid correlation could not be derived.