Study On Temperature Map In Bulk Liquid And Porous Media Using Magnetic Resonance Imaging

CCS (CO2 Capture and Storage) and CO2-EOR (Enhance Oil Recovery) are based on capturing CO2 from large point sources and storing CO2 instead of freely releasing to the atmosphere, thus is promising to retard greenhouse effect and boost oil recovery. In CO2 geological sequestration temperature is a factor of vital importance which influences the phase and property of CO2, and the temperature of underground flow varies with time. As a result, temperature distribution measurement of porous media and bulk liquid has special application in CCS projects. Temperature measurement using MRI (magnetic resonance imaging) can be noninvasive, which can offer a new vista to further assess storage capacity and safety of CCS project.To compare the temperature measured using MRI with the real temperature and to simultaneously measure the temperature and velocity field of flow, we design an experimental system with which we can measure the sample temperature using thermocouples and circulate water. Besides, the system can be used to maintain the temperature precisely, thus being able to verify the accuracy of MRI temperature measurement. In the first chapter the concept, background and meaning of CCS and CO2-EOR, and current research are discussed. The second chapter introduces several parameters in MRI temperature measurement and the theory of MRI temperature/velocity measurement, and then several MRI sequences including spin echo, fast spin echo and gradient echo sequences. The third Chapter introduces three experiment methods of three different fluids temperature measurements in bulk volume, then we conducted temperature measurement of water cooling experiment using self-diffusion coefficient method. In the fourth chapter CFD simulation and experimental study on simultaneous velocity/temperature are conducted with high accuracy. In the fifth chapter we conduct experiments on porous media temperature measurement. The last chapter compares different MRI temperature measurements in terms of accuracy and acquisition time. The results show that self-diffusion coefficient method features high accuracy while the T1 method has the advantage of short acquisition time.In this study we use magnetic resonance imaging to visualize the temperature distribution by three methods:longitudinal relaxation time, self-diffusion coefficient and longitudial magnetization, by which we can measure the temperature distribution with high accuracy and the pore distribution of porous media. Then simultaneous temperature and velocity measurement experiments are conducted at different flow rates using IR-tagging sequence. Meanwhile, we measure the temperature and velocity field of bulk liquid simultaneously using Inversion Recovery tagging method. The deviation of porous media temperature measured using simultaneous method with that using thermocouple is within 2℃, and the measurement error of static temperature measurement is less than 1℃.