2 results about "Self-diffusion" patented technology

The application of prediction method for diffusion behavior of underground hydrogen in pore scale of water-containing clay mineral belongs to the technical field of underground hydrogen energy storage and unconventional gas migration prediction, and the key point is to fill water molecules and salt ions into the pores according to the target water saturation and salinity; the initial model of the water-containing clay mineral pores is pre-equilibrated by the molecular dynamics method; hydrogen molecules are filled under the given temperature and pressure conditions by the grand canonical Monte Carlo method, and the hydrogen pressure is corrected by the SRK-EOS state equation; the hydrogen diffusion simulation is carried out by the molecular dynamics method with temperature and fugacity as input parameters, the mean square displacement of hydrogen in the pores is calculated, and the self-diffusion coefficient is obtained; the application can quantitatively characterize the diffusion rate change rule of hydrogen in the clay pores under different water film thickness, salinity and temperature and pressure conditions, and reveal the diffusion inflection point, diffusion inhibition stage and migration restriction mechanism caused by the water film or water bridge structure.

The invention discloses a novel probe for inverting coal rock pore characteristics by using in-situ methane desorption characteristics. The method comprises the following steps of: firstly, constructing a self-diffusion coefficient time-varying attenuation model (1) reflecting geometric characteristics of pores by utilizing boundary induction characteristics of the self-diffusion coefficient; then, according to a mathematical transformation relationship among the self-diffusion coefficient, the corrected diffusion coefficient and the Fick diffusion coefficient, obtaining a Fick diffusion coefficient time-varying model (2) similar to the attenuation rule of the model (1); introducing a classical single-pore model to obtain a single-pore diffusion optimization model (3) containing pore geometric parameters; by observing the model (3), the coal samples with different pore characteristics can obtain desorption diffusion curves with different forms; and finally, controlling a single variable, and analyzing the form of the desorption curve to obtain a qualitative pore form. According to the method, the main control hole pattern geometric characteristics of the holes are quantitatively, accurately and quickly inverted through the desorption curve.