Modeling Subsurface Petroleum Hydrocarbon Transport

Application of Models

Once we understand contaminant transport, we can begin to apply models. This portion of the course contains four major themes:

• introduction to mathematics,
• introduction to model application,
• review and critique of model application, and
• the basis and use of selected models.

Introduction to Mathematics

The intent of this course is not to emphasize mathematics. There are, however, certain mathematical aspects of models that must be understood in order to appreciate features of model results. This section is as brief as possible.

Introduction to Model Application

Beyond the mathematics, there are a range of important considerations for model application. These include the dimensionality of the model (1D, 2D, or 3D), treatment of the contaminant source, and other boundary conditions. This is the area where much of the art of modeling resides. We'll give some of the basics, but there's much that only experience can teach.

The Basis and Use of Selected Models

Several models will be described in a fair amount of detail, tutorials will be given on how to use the models and application to sites will be shown. The models selected all have a strong tie to EPA. Because of the importance of Risk-Based Corrective Action (RBCA), one module describes the modeling basis of ASTM-RBCA. We'll use the transport and modeling principles we've learned to take a look at this approach.

The Hydrocarbon Spill Screening Model (HSSM)

One model that will be covered in detail is the Hydrocarbon Spill Screening Model (HSSM) which was developed by the U.S. EPA. HSSM simulates

• the release of a fuel from the surface,
• the formation and decay of a lens at the water table,
• dissolution of contaminants, and
• transport to receptors.

• A narrative description of the input data set.
• Input data in tabular form.
• Model outputs: Concentrations at receptors, risk estimates, plume centerline concentrations, and contaminant plumes.

LUSTRisk

When there is a need to use a simpler approach to estimating the risk from an existing zone of residual contamination, the LUSTRisk model can be applied. LUSTRisk performs a set of dissolution calculations from a existing smear zone. The LUSTRisk conceptualization most nearly matches an instantaneous release. An Illustration from the LUSTRisk main screen:


LUSTRisk is implemented in an Excel spreadsheet and contains extensive databases for input parameter values.

LUSTRisk is currently under development. If you would like to serve as a beta tester, e-mail Matt Small.