Non-destructive inspection of oil-water two-phase systems by terahertz optoacoustics

Accurate determination of water-oil ratios in multiphase systems faces persistent challenges in achieving non-invasive global measurements due to the intrinsic limitations of conventional detection modalities. We develop a terahertz optoacoustic method that enables real-time quantification of water-oil ratios across the full operational range (0-100 %) in both static and dynamic regimes. For quiescent systems, the technique achieves spatially resolved mapping of phase distributions through terahertz optoacoustic imaging while simultaneously monitoring emulsion destabilization dynamics-key for assessing storage stability. In dynamic pipeline flows, we establish a dual-parameter detection paradigm: signal intensity linearity (R²=0.985) characterizes slug flow patterns, whereas time-delay correlation (R²=0.996) deciphers stratified flow configurations. The technique's unique combination of non-ionizing terahertz excitation and plastic-penetrating ultrasonic detection establishes a new paradigm for in situ monitoring in petroleum refining and edible oil processing, particularly through opaque polymer pipelines.