Crisman Annual Report 2009 - Harold Vance Department of ...

that contained 12 wt% HCl showed the highest
apparent viscosity. Low concentrations of Fe (III)
caused an increase in the apparent viscosity. Two
immiscible liquids and then a precipitate were noted
as the concentration of ferric ion was increased in
live acids. Iron control agents reduced the apparent
viscosity of surfactant-based acids. The impact of
lactic acid on the apparent viscosity was significant,
especially at high lactic acid concentrations. Citric
acid also reduced the viscosity of surfactant based
acids, but cannot be used at concentrations greater
than 0.5 wt% because of this precipitation of
calcium citrate. Ethylenediaminetetraacetic acid
(EDTA) slightly reduced the viscosity of surfactant
based acids, but the solubility of EDTA in 20 wt%
HCl is very low. Up to 1 wt% methanol can be used
with this spent acid system at temperatures below
175°F. Higher concentrations of methanol caused
significant reduction in the apparent viscosity.
Future Work
Simple organic acids and iron control agents
(α-hydroxyl carboxylic acids) can interfere with
micelle shape and reduce the apparent viscosity
of VES-based acids, therefore their influences will
be tested in the future. A transmission electron
microscope (TEM) will also be used to examine the
effects of acids on micelle shapes.
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Crisman Annual Report 2009