Model of groundwater flow, gas migration, and reactive transport in the Virgin River Basin, SW Utah

To better understand the possible risks posed to shallow groundwater resources by geologic carbon sequestration (GCS), a multi-scale numerical modeling approach was invoked using the TOUGHREACT code from Lawrence Berkeley National Laboratory. The code solves coupled equations representing conservation of mass and energy on a finite difference grid to simulate multiphase, multicomponent, non-isothermal heat and mass transport in porous media. Two different two-dimensional cross-section modeling domains were constructed to improve understanding of groundwater flow and contaminant transport processes at a field site in soutwestern Utah. The site represents a natural analogue for leakage from a GCS site because water with elevated concentrations of salt and CO2 are migrating upward into a shallow aquifer system. The first modeling domain was designed to improve understanding of long-term hydrological leakage and conservative transport processes at the regional scale, while the second was designed to investigate site-scale reactive transport processes that could occur if the leaking fluids, or those with higher carbon dioxide (CO2) concentrations, were to interact with a potential source of contamination along their flow path toward the ground surface. Lead (Pb+2) was used as an example heavy metal contaminant and was incorporated into a region of iron oxide representing concretion zones that are common in the geographic area. Results indicate that the initial state of potential heavy metal contaminant (i.e., sorbed onto the surface of the iron oxide or in an oxide mineral assemblage as PbO, litharge), exerts strong control on the amount of contamination that may occur, and that precipitation readily sequesters mobilized Pb+2. This USGS data release contains all of the input and output files for the simulations described in the associated journal article. Descriptions of the data in each subdirectory are given to facilitate understanding of this model archive. File descriptions are provided for select files to provide additional information that may be of use for understanding this model archive. Support is provided for correcting errors in the data release and clarification of the modeling conducted by the U.S. Geological Survey. Users are encouraged to review the complete journal article (See 'Related External Resources' section below) to understand the purpose, report construction, and limitations of this model.