STOMP User Guide
STOMP User Guide
Solution Control Card Options
Three classes of options are specified via the Solution Control Card
Execution Mode Options
Two Execution Modes are recognized: Normal, and Restart. In the Normal mode, initial state conditions are declared through the Initial Conditions Card. In the Restart mode, initial state conditions are assigned via a restart file from a previous execution or declared through the Initial Conditions Card, with the option of using the special overwrite option for selected parameters. Unless specified through the Output Control Card, restart files (i.e., restart.n) are generated at each plot.n write event, and have name extensions that correspond to the generating time step (e.g., the file restart.0028 would have been generated at the conclusion of time step 28). Restart files are text files that contain simulation time and control information, and a collection of field variables needed to redefine the simulation state for the operational mode.
In the Restart mode, STOMP executes from either a declared start time or the start time specified in the restart file, using an initial state defined by a previous execution, until the declared stop time or the declared number of time steps is reached, or an execution error or a sequence of convergence failures occur.
The additional keyword "file" triggers STOMP to read an additional character string, which is the name of the restart file.
When the keyword "overwrite" is included in the Initial Conditions Card or the Boundary Conditions Card with any of the above options during a restart simulation, the specified values will overwrite those from the restart file.
Operational Model Options
The Operational Mode is STOMP-CO2 (or STOMP-CO2E for the non-isothermal version). This required keyword is used to make certain that the operational mode of the STOMP executable matches the operational mode declared in the input file. The solved coupled equations, activation of solute transport, and reactive species transport is specified via keyword modifiers to the operational mode. Models for transporting passive solutes and reactive species are controlled via additional keyword modifiers to the operational mode. For example, solute transport is solved using the Patankar method, unless the keywords TVD or Roe Superbee also appear.
Additional options can be specified via keyword modifiers specified after the operational mode keyword:
Isothermal (only for STOMP-CO2E)
This modifier deactivates the energy conservation equation from the set of solved coupled equations. Temperature will not change with time during the simulation. Using this modifier is the equivalent of running STOMP-CO2E as STOMP-CO2.
This modifier deactivates the salt-mass conservation equation from the set of solved coupled equations. Salt concentrations will be set to zero during the simulation.
Invariant Fluid Density and Viscosity
This modifier holds density and viscosity constant in the aqueous and gas phases.
Fractional CO2 Solubility
This modifier reduces CO2 solubility in the aqueous phase.
This modifier activates reactive species transport. The reactive transport algorithms use the same transport schemes as the solute transport model, and therefore are controlled through the keyword options TVD and Roe Superbee.
Additional sub modifiers for reactive species transport are:
Porosity Alteration with Precipitation
Effective Reaction Area
Constant Surface Area
Using the keyword "ECKEChem" requires the ECKEChem Module to be implemented in the simulator. When using Operational Mode Modifiers for Reactive Transport, include the keyword "transport" only when solutes are also being simulated. For example, for geochemical reactive species only, "Eckechem w/ TVD" might be specified. If non-geochemical species are simulated, then "Eckechem w/ Transport w/ TVD would be specified.
Datta-Gupta, A, LW Lake, GA Pope, and K Sepehnoori. 1991. High-Resolution Monotonic Schemes for Reservoir Fluid Flow Simulation. In Situ, 15(3):289-317.
Patankar, SV. 1980. Numerical Heat Transfer and Fluid Flow. Hemisphere Publishing Corporation, Washington, D. C.
Interfacial Averaging Options
State variables at the centroids of grid-cell surfaces are required to compute fluxes between grid-cell centroids. Models for computing the state variables on grid-cell surfaces are referred to as interfacial averaging schemes and use the state variables at adjacent grid-cells to compute the surface variables. Default interfacial averaging schemes or various variable types have been selected for STOMP. Schemes other than the defaults can be specified.
Interfacial Averaging Schemes
Field variables, which include physical, thermodynamic, and hydrologic properties, are defined in the finite-difference formulation at the node centers. Conversely, flux variables are defined at node interfaces. Computation of flux variables requires knowledge of field variables at node interfaces. Values of flux variables at node interfaces are evaluated by averaging the field values for the two nodes adjoining an interfacial surface. Interfacial averaging schemes may be declared individually for each field variable through the Interfacial Averaging Variables input.
The default interfacial averaging schemes for the simulator are shown in the Table below. For simulations of physical systems involving heat transfer, it should be noted that convergence problems might arise if the density properties are not averaged with upwind weighting. Likewise, infiltration problems typically demonstrate strong dependencies on the relative permeability of the infiltrating fluid.
List of Interfacial Averaging Schemes
- Moderated Upwind
- Neiber Downstream
Default Interfacial Averaging Schemes
|Field Variable||Default Interfacial Averaging|
|Aqueous Relative Permeability||Upwind|
|Gas Relative Permeability||Upwind|
|Effective Thermal Conductivity||Harmonic|