Solute Injection

Model ID: 479


Predicting the transport of contaminants that move with subsurface fluids generally means analyzing at least two physics. This model tracks a contaminant that enters an aquifer at a point, such as an injection well or toxic spill, and spreads through the aquifer with time. The model has an analytic solution developed by Wilson and Miller. This analytic solution has been used to test several dedicated fluid flow and transport codes. The particular problem we describe comes from the MT3DMS manual of Zheng and Wang.

The analysis is conducted by modeling steady state fluid flow and following up with a transient solute transport simulation. For the model we employ the Darcy’s law application mode and the Solute Transport application mode from the Earth Science Module. In COMSOL Multiphysics it also is straightforward to specify a fluid velocity without solving a flow problem. We choose to solve for the velocities here to demonstrate the mechanics of coupling flow and transport simulations in a single model file.

This model tracks the fate and transport of solute injected at a point well. In the reservoir the chemical moves by advection and dispersion. The model matches an analytic solution used for evaluating a number of dedicated flow and transport codes.