A Magnetic Resonance Imaging Method for Simultaneous Measurement of Fluid Velocity and Temperature in Porous Media

Abstract

Disclosed is a magnetic-resonance imaging method for synchronous measurement of fluid speed and temperature in a porous medium and the method belongs to the field of magnetic-resonance imaging measurement. The method adopts a nuclear-magnetic-resonance overturning restoring label method: firstly a spin-echo sequence two-point method is used to measure a longitudinal relaxation time T1 of a tested fluid at a specific temperature; step 1 is repeated at different temperatures so that T1 values at different temperatures are obtained and then the relation between T1 and temperature T is obtained through fitting; an overturning restoring label sequence is used to measure the fluid at a static state and then the fluid at any temperature and flow speed is measured; a matlab is used to read an image so that image signal intensity (SI) distribution is obtained, and then the temperature T is calculated according to the relation of SI and T; label displacement within an overturning restoring time ti is solved through comparison of a label coordinate under the flow speed and a label coordinate at a static state so that a fluid flow speed is solved. The magnetic-resonance imaging method for the synchronous measurement of the fluid speed and the temperature in the porous medium is high in measurement speed and capable of compensating effectively for signal reduction resulted from flowing when a traditional overturning restoring method is used to measure flow-field temperatures.

Description

Technical field [0001] The invention relates to a method for simultaneously measuring the velocity and temperature of a fluid in a porous medium by using magnetic resonance imaging. Background technique [0002] The current methods for measuring fluid velocity and temperature include contact method and non-contact method. The contact method measurement usually interferes with the flow field and temperature field, causing measurement errors. Although the non-contact method can avoid interference, most of the measurement methods require light transmission of the measured body, such as infrared temperature measurement. In addition, the biggest problem with traditional measurement methods is the inability to measure the velocity and temperature of the fluid in porous media. At the same time, measuring the velocity and temperature of the hydrogen-containing proton fluid is useful for improving oil recovery (EOR), chemical engineering control, and multiphase composition research. The...

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Problems solved by technology

This method has the disadvantage of not being able to measure large velocities, otherwise artifacts will be generated, and it still has certain limitations when measuring porous media: it can only measure small flow velocities in porous media with large porosity

In addition, since the phase and velocity are related to temperature, the phase method can only measure the velocity of the flow field at a uniform temperature to eliminate the interference of the phase change caused by the temperature on the velocity phase.

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