Ultrasonic Measurement on the Thickness of Oil Slick Using the Remotely Operated Vehicle (ROV) as a Platform

An ultrasonic method was proposed to solve the problem of accurately measuring the thickness of oil slick using a remotely operated vehicle (ROV) as a platform. The laboratory experiments were performed to collect ultrasonic reflections from interfaces underneath oil slick during ROV's resting and running. A new signal processing method was proposed to improve the accuracy of the thickness measurement by precisely calculating the transmit time of flight (TOF) of ultrasound within oil slick. The feasibility of this method was verified by performing eight measurements of oil slick thicknesses during ROV's resting and running. The results showed that the average values of absolute differences between ROV's resting and running were both less than 4.0% for two transducers, a result which indicated the high measurement accuracy, repeatability, and stability of this method. In addition, the minimum measurable thickness for each transducer was initially investigated, and the suitable transducer frequency was also determined. The ultrasonic method proposed in this article demonstrates a strong capability of measuring the thickness of thin oil slick with the high accuracy. The studies in this article would promote the development and application of this method in the oil spill response. It could possibly be developed into an applicable tool for solving the problem of measuring the thickness of oil slick in the field in the future.