Charles Partogi Siallagan's thesis
by
Charles Partogi Siallagan,, M.S.E.
University of Texas at Austin, 1995
Supervisor: Ben H. Caudle
The objective of this study is to develop a streamline model simulator for micellar
slug displacement, a concentrated, surfactant-stabilized dispersions of water and
hydrocarbon that are used to enhance oil recovery. In this displacement, several
banks of miscible fluids are developed. The micellar slug displacement process is
characterized by a zone of intermediate fluid which is miscible with the reservoir oil
at its leading edge, and is miscible with the injected fluid, as a driving fluid, at
its trailing edge.
At each time step on each center pathline, the positions of each front are included
in the calculation of each front pressure in order to determine conductivity ratio
for the unequal mobility treatments. The conductivity ratio effect on the frontal
velocities is measured at constant pressure in order to control the displacement.
Since all of the fluid interface points must be moved over the same time step, this
time step should be calculated using the highest total velocity value of moving fronts.
The change in the flow rates into each streamline is accounted for as a function of
mobility ratio. The simulator can model a stratified reservoir and use the
Dykstra-Parson's method for permeability distribution. It is also capable of modeling
areal sweep for a field having multiple wells, arbitrary well patterns, an irregular
boundary, and an isotropic or anisotropic reservoir.
The method utilized for bounding the irregular boundary is the use of arbitrarily
placed guard or bounding sources.
The streamline model, in conjunction with fractional flow theory and piston like
displacement assumptions, provides an alternative way to predict the performance of
micellar slug displacement with limited input data and computation time.
The miscible displacement will change into immiscible displacement for the time of
the process. Loss of miscibility is determined by using the position between the
slug front and water front. The sensitivity of the oil recovery was investigated
using micellar displacement and process variables.
Finally, the simulator has been applied to a small depleted field scale condition.
The Kellyville Field, located in Creek County, Oklahoma was used to demonstrate that
the model is capable of handling a field problem.
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