A triple continuum transport model for colloid migration in fractured formations

Abstract

Transport of colloids in a fractured rock is strongly affected by alterations in the rock matrix, termed as fracture skin. In this work, a colloid transport model is developed to analyze its migration in fractured formations, based on the triple continuum approach, incorporating the fracture skin as the third continuum, besides the fracture and the rock matrix. The system of coupled partial differential equations governing transport in the fractured media is solved using a numerical model employing a fully implicit formulation and based on the finite difference method. Colloid migration in the fractured formation is investigated for both “with” and “without fracture skin” scenarios and for constant concentration and constant flux inlet boundary conditions. Simulations carried out using the model indicate that fracture skin can either enhance or retard colloid migration in a fracture depending on its properties. The porosity and diffusion coefficient of the fracture skin are found to be the critical fracture skin properties affecting the transport of colloids in a fractured medium.