Hyun-Soo Kim's dissertation
by
Hyun-Soo Kim, Ph.D.
University of Texas at Austin, 1995
Supervisors: Gary A. Pope
Kamy Sepehrnoori
Poor vertical and areal sweep because of channeling of injected water to
high-permeability zones leads to significant amounts of bypassed oil in many
waterfloods. Chemical treatments involving injection of a gel formed in-situ are
used to reduce the preferential channeling through high-permeability zones to improve
the vertical sweep efficiency.
The objective of this study was to optimize the design of gel treatments through more
realistic simulations using UTCHEM (a chemical flooding simulator) with various
parameters such as reservoir description, types of gel, the amount of gelant, well
control and gel treatment strategies.
In this work, the simulations of gel treatments of producers or injectors involving the
injection of various gels were performed in the model reservoirs with layered or
stochastically generated permeabilities. The effectiveness of gel treatments was
investigated by varying the strategies of gel treatments such as zonal isolation,
wells operating under a constant bottomhole pressure versus a constant rate, the
confinement of the reservoir, and near-wellbore treatment versus in-depth gel
treatment. In-depth gel treatments were simulated using environmentally safe gels
such as polymer/chromium malonate gel, silicate gel, and polymer/Cr(III) gel with
temperature-dependent gelation. Simulations of gel treatments in reservoirs with
multiple unconfined wells and horizontal wells were performed.
The UTCHEM simulator was modified to simulate several gel reactions with various
kinetics and components. Using geochemical reaction equilibria, dynamic effects of
pH change on gelation and the retention of crosslinker (precipitation of chromium
hydroxide) were modeled.
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