Dispersion in Fractures With Ramified Dissolution Patterns

Frontiers in Physics

Må¹  y, Eirik G.²  Xu, Le³  Flekkø³  Marks, Benjy³  Toussaint, Renaud⁴ 

[1] de Strasbourg, IPGS UMR 7516, France;Centre National de la Recherche Scientifique, UniversitéPoreLab, Department of Physics, University of Oslo, Norway;The University of Sydney, Australia

关键词: dispersion;    Fracture;    Convection-diffusion;    Fractal-like;    Hele-Shaw cell;    Fluorescein tracer;   

DOI  :  10.3389/fphy.2018.00029

学科分类：物理（综合）

来源: Frontiers

【 摘 要 】

The injection of a reactive fluid into an open fracture may modify the fracture surface locally and create a ramified structure around the injection point. This structure will have a significant impact on the dispersion of the injected fluid due to increased permeability, which will introduce large velocity fluctuations into the fluid. Here, we have injected a fluorescent tracer fluid into a transparent artificial fracture with such a ramified structure. The transparency of the model makes it possible to follow the detailed dispersion of the tracer concentration. The experiments have been compared to two dimensional (2D) computer simulations which include both convective motion and molecular diffusion. A comparison was also performed between the dispersion from an initially ramified dissolution structure and the dispersion from an initially circular region. A significant difference was seen both at small and large length scales. At large length scales, the persistence of the anisotropy of the concentration distribution far from the ramified structure is discussed with reference to some theoretical considerations and comparison with simulations.

【 授权许可】

CC BY