Lizbeth Dayana Castillo Chang's report
by
Lizbeth Dayana Castillo Chang, MSE
University of Texas at Austin, 2003
Supervisor: Kamy Sepehrnoori
Surfactants have been used in oil reservoirs to recover additional oil by
lowering interfacial tension and altering wettability. The numerical simulation of
this type of process could be very useful for its design and application at a field
scale in an economical manner.
The objective of this study was to adapt the existing chemical reservoir
simulator UTCHEM to model wettability alteration in oil reservoirs due to
surfactant injection. To achieve this goal a table look up option was included in
the simulator.
Using table look up UTCHEM can read multiples tables for relative
permeability and capillary pressure to represent different wetting conditions. At
the initial condition the reservoir may be taken as oil-wet or mixed-wet and tables
for these conditions are used. The alteration of wettability with time is modeled
by injecting a tracer whose concentration in each cell represents the surfactant
concentration. When this concentration reaches a tolerance value, corresponding
to the laboratory value at which wettability changes, the relative permeabilities
and capillary pressure for water-wet conditions are used.
Several two dimensional discrete fracture simulations were set up to
validate the table look up option implementation. Additionally sensitivities to
some parameters were tested.
The simulations indicated that UTCHEM is now capable of handling
changes in wettability. The results were consistent with the fact that additional oil
can be recovered from oil-wet cores when surfactant solution imbibes into the
cores and changes the wettability.
Back to theses index
