In majority of practical well tests the pressure diffusion in multi-phase segregation of reservoir flow the pressure response can be approximated by single-phase pressure diffusion model with a specific from of fluid/reservoir properties.
This approximation can be done in one of three ways:
| Linear Perrine multi-phase diffusion | the simplest multi-phase model, although it has a 3-phase form it normally works for oil-water system only |
| Pseudo-linear multi-phase diffusion | this model is capable to account for high compressibility of multi-phase components (light oil, condensate and gas) but does account |
| Non-linear multi-phase diffusion | this model covers a wide range of 2-phase and 3-phase models |