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UTCHEM
UTCHEM is a 3-D, multicomponent, multiphase, compositional model of chemical flooding processes which accounts for complex phase behavior, chemical and physical transformations and heterogeneous porous media properties, and uses advanced concepts in high-order numerical accuracy and dispersion control and vector and parallel processing. The simulator was originally developed by Pope and Nelson in 1978 to simulate the enhanced recovery of oil using surfactant and polymer processes. Thus, the complex phase behavior of micellar fluids as a function of surfactant, alcohol, oil, and aqueous components was developed early and has been extensively verified against enhanced oil recovery experiments. Generalizations by Bhuyan et al. in 1990 have extended the model to include other chemical processes and a variety of geochemical reactions between the aqueous and solid phases. The nonequilibrium dissolution of organic components from a nonaqueous phase liquid into a flowing aqueous or microemulsion phase is modeled using a linear mass-transfer model. In this simulator, the flow and mass-transport equations are solved for any number of user-specified chemical components (water, organic contaminants, surfactant, alcohols, polymer, chloride, calcium, other electrolytes, microbiological species, electron acceptors, etc.). These components can form up to four fluid phases (air, water, oil, and microemulsion) and any number of solid minerals depending on the overall composition. The microemulsion forms only above the critical micelle concentration of the surfactant and is a thermodynamically stable mixture of water, surfactant and one or more organic components. All of these features taken together, but especially the transport and flow of multiple phases with multiple species and multiple chemical and biological reactions make UTCHEM unique.
UTCHEM Groundwater Applications
- NAPL spill and migration in both saturated and unsaturated zones
- Partitioning interwell test in both saturated and unsaturated zones of aquifers
- Remediation using surfactant/cosolvent/polymer
- Remediation using surfactant/foam
- Remediation using cosolvents
- Bioremediation
- Geochemical reactions (e.g., heavy metals and radionuclides)
UTCHEM Oil Reservoir Applications
- Waterflooding
- Single well, partitioning interwell, and single well wettability tracer tests
- Polymer flooding
- Profile control using gel
- Surfactant flooding
- High pH alkaline flooding
- Microbial EOR
- Surfactant/foam and ASP/foam EOR
UTCHEM Features
- 3-dimensional, variable temperature
- IMPES-type formulation
- Third-order finite difference with a flux limiter
- Four phase (water, oil, microemulsion, and gas
- Vertical and horizontal wells
- Constant pressure boundaries
- Cartesian, radial, and curvilinear grid options
- Heterogeneous permeability and porosity
- Full tensor dispersion coefficient and molecular diffusion
- Adsorption of surfactant, polymer, and organic species
- Solubilization and mobilization of oil
- Clay/surfactant cation exchange
- Water/surfactant (cosolvent)/oil phase behavior
- Polymer with non-Newtonian rheology
- Tracers (partitioning, reaction, adsorption, and radioactive decay
- Compositional density and viscosity functions
- Surfactant/foam model
- Multiple organic properties
- Trapping number including both viscous and buoyancy forces
- Dual porosity model for tracer
- Geochemical reactions
- Biological reactions
- Several polymer/gel kinetics
- Equilibrium and rate-limited organic dissolution
- Rock dependent capillary pressure and relative permeability
- Brooks-Corey capillary pressure and relative permeability functions
- Water-wet hysteretic capillary pressure and relative permeability model of Parker and Lenhard
- Mixed-wet hysteretic two-phase oil/water capillary pressure and relative permeability model of Lenhard
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