Study on Natural Core Experiment of Tracer in Porous Medium

Abstract

In order to further research in porous media tracer mass transfer diffusion rule based on experiment, the conventional displacement experiment of natural long cores were carried out and the effect of the heterogeneity of microscopic pores structure to tracer mass transfer diffusion was compared. The experiment results show that, when injection rate is close, because the heterogeneity of low permeability core pore structure is stronger and small-scale dash is existed, the output time will be earlier, concentration will rise slowly, and mixed coefficient will be bigger. In terms of the same permeability, because injection rate is low, the pressure difference of two ends is small, the start of porosity is wider and its quantity is less. Therefore, if inject less pore volume of multiples displacement fluid, the output will be present tracer, the pore network of so-called "channeling the effect" will be formed, and mixed constant will be bigger. In homogeneous core, when permeability is close, due to the injection rate increases which exacerbate the actually existed part of microscopic heterogeneity features of the internal core, the output time will be earlier, concentration will rise slowly.