components model


To fully understand the ways the SAGD process work, we first had to learn the basis of thermodynamical oil modelling, as well as the interaction between reservoir rocktypes, phase changing oil, and liquefying water in the underground.
First, let's move to the different oil models, which can help us to better predict the reservoir responses. We have to remind that our system will deal with a multiphase & multiconstituent environment, which we need to model.


We have, among all the different models, two oil systems available for our study.
The first one is the Black-oil, dealing with "only" three phases (aqueous, oleic & gaseous) and three phases (water, oil & dissolved gas). Let's keep in mind that each component, in accordance with the ambient pressure and temperature, can be in on phase or in another.

We can make our model more complex, adding light and heavy components, as well as solvent (Naphtha, methane, butane…) for the ES-SAGD modelling.

To better understand the process, we need to keep in min the equations which drive the phenomenon:

  • Mass conservation
  • Energy conservation
  • Momentum conservation (Darcy's law)
  • Physico-chemical equilibrium equations (K-values)

Each equation has to be written for each component (at least 3) in each phase (3)

We also need to take into account:

  • the vaporisation / condensation of water
  • the vaporisation of the light component
  • the solvent dissolving
  • the oil viscosity modification
  • the oil density modification
  • the solvent diffusion

All these mechanisms are well described in the following system:


model Equations


The four conservative molar equations:

Phase equilibrum

The energy conservation equation: