FEHM can model a wide range of subsurface physics, from single-phase fluid flow for large-scale groundwater aquifers to complex multi-phase fluid dynamics with phase changes like boiling and condensing. This versatility enables FEHM to simulate the unsaturated zones around nuclear waste storage or the leakage of CO2 or brine through faults and wellbores. The primary numerical approach used in FEHM is the control volume (CV) method, which ensures exact conservation of mass and energy in fluid flow and heat transfer equations. For more precise stress calculations, the finite element (FE) method is an option, particularly for displacement equations. FEHM also offers flexibility in choosing methods, with options for finite element and a simple finite difference scheme to meet the demands of specific simulation scenarios.
Capabilities
- 3-dimensional complex geometries with unstructured grids
- Saturated and unsaturated media
- Simulation of production from gas hydrate reservoirs
- Simulation of geothermal reservoirs
- Non-isothermal, multi-phase flow of gas, water, oil
- Non-isothermal, multi-phase flow of air, water
- Non-isothermal, multi-phase flow of CO2, water
- Multiple chemically reactive and sorbing tracers
- Preconditioned conjugate gradient solution of coupled linear equations
- Fully implicit, fully coupled Newton Raphson solution of nonlinear equations
- Double porosity and double porosity/double permeability capabilities
- Control volume (CV) and finite element method (FE) methods
- Coupled geomechanics (THM) problems (fluid flow and heat transfer coupled with stress/deformation) including non-linear elastic and plastic deformation, nonlinear functional dependence of rock properties (e.g. permeability, porosity, Young's modulus) on pressure, temperature and damage/stress
