Polymer flooding modelling with commercial simulators hasn’t provided full satisfaction so far. Predictions regarding injectivity, oil recovery, and sweep efficiency are often far away from the actual field results.
Some analytical methods exist as proposed by Gary Pope’ student in the 80’s, reused for Captain field injectivity calculations for instance. Other companies prefer a benchmark using simple 1D (Buckley-Leverett) simulation (see Hilcorp, Milne Point) to provide the teams with robust comparisons.
In the late 80’s the US DOE developed a small MSDOS exe called PFPM which has disappeared from the web.
This tool is a streamline/tube model with the following characteristics:
- 3D, 2-phase (water and oil) 5-spot computer model to predict oil recovery from a polymer flood
- Developed by US DOE
- Combines oil recovery prediction with economics to get NPV
- Fractional flow and streamtube method
- Correlation based on simulation results used to model polymer slug size effect
- Adsorption, RRF are included
- Heterogeneity is accounted for by entering layer data
- Single value of polymer viscosity and adsorption
- Streamtube method used to calculate areal and vertical sweep efficiency
- The area between 2 streamlines is a streamtube
- Each layer is divided into 8 streamtubes from the injector to the producer
- 1/8 of a five-spot pattern is used for calculations due to symmetry of flow patterns
- 1D linear displacement is calculated along each streamtube using fractional flow theory
- Each streamtube is divided into 20 equal initial pressure drop increments (blocks)
- Combined results from all streamtubes and layers provide the 3D performance
It is a bit more detailed compared to basic 1D, and provides already useful insights. The only part missing is control of injection pressure/injectivity, which is the main factor impacting economics and the oil recovery calculation results.
For the .exe, please drop us a message. We have attached here a couple of screenshots + pictures of the model.
