Study On Response Characteristics Of Ultrasonic Echo Of Mineral Oil-Water Emulsion

In the petroleum industry,from the initial underground reservoirs and wellhead mining,to the intermediate storage and transportation process,there are oil-water emulsions in every link.The viscosity of the emulsion is closely related to the water content and the particle size distribution of the dispersed phase.Accurate measurement of water content,particle size distribution and other parameters of oil-water emulsion is very important to improve the efficiency of oil and gas gathering,transportation and processing.In view of the complexity of the oil-water two-phase mixture,the measurement of its parameters is very difficult.Considering that ultrasound has good directivity,penetration,non-contact,no radiation,and accurate measurement,this paper uses a combination of experimental research and numerical simulation to explore the echo response characteristics of ultrasonic signals in oil-water two-phase emulsions,and analyze the complex mapping relationship between ultrasonic echoes and emulsion systems.The specific research work is:The paper established a set of oil-water emulsion ultrasonic echo detection system based on the ultrasonic measurement principle,using white oil and water as the experimental medium,using HLB value method to select suitable emulsifiers,using Span80 and Tween80 two emulsifiers to prepare oil-water emulsion samples with water content ranging from 0 to 100%.And put the emulsion sample into the designed ultrasonic echo detection system for detection.In the experiment,an ultrasonic probe with a frequency of5 MHz was used.The Olympus ultrasonic generator was used to transmit and receive signals.A Tektronix oscilloscope is used to monitor and record the echo signals.The probe adopts a single-transmit and single-receive measurement mode,and is arranged at the center of the outer wall of the device to transmit and receive ultrasonic signals.Microscope was used on the experimental samples under different water content and speed conditions,the droplet size distribution under different conditions was counted,and the ultrasonic echo signals of the oil-water emulsion under different conditions were analyzed and studied.The experimental results show that: within the scope of this experiment,the sound velocity extracted from the ultrasonic echo signal increases with the water content from 1% to 100%,and also increases from 1450.1m/s to 1505.0m/s.The ultrasonic attenuation coefficient shows a trend of first increasing,then decreasing,and finally increasing,while the sound velocity and the attenuation coefficient gradually increase with the increase of the average diameter of Sauter droplets in the dispersed phase of the oil-water emulsion.Based on the finite element analysis method,a two-dimensional simulation model of oil-water emulsion was constructed.Gaussian pulses were used to simulate ultrasonic waves,and the dispersed phase droplets were simplified into circles for modeling and analysis.The particle size and water content range were changed to analyze the propagation process of ultrasonic echo under different conditions.And use the particle size distribution microscope image obtained from the experiment for simulation modeling,use Image Pro Plus to calculate the area of the dispersed phase droplets of the image and calculate the ratio of the two-phase area,and use Matlab to binarize and enlarge the image,and then import the processed image into COMSOL Multiphysics for simulation modeling.Analyze the impact of particle size images with different water content on the simulation results,analyze and study the propagation process and echo characteristics of the ultrasonic signal in the model through the model sound field diagram at different times and the received ultrasonic echo signal curve.The results show that the simulated echo signal obtained by the simulation model is basically same as the echo signal of the ultrasonic testing experiment.The speed of sound increases with the increase of water content,and the ultrasonic attenuation coefficient shows a trend of first increasing,then decreasing and then increasing.The comparison results prove the rationality and reliability of the two simulation models.The thesis studied the ultrasonic echo characteristics of emulsion systems with different water content and particle size.The study showed that ultrasonic echo is sensitive to the water content and particle size distribution of the emulsion.Ultrasonic echo can be used in the future for rapid detection of emulsion system.