Page 198 - Geochemistry of Oil Field Waters

NAPHTHENIC AND HUMIC ACIDS 185

alkaline permanganate. He correlated this with algal growth in city reservoirs
and suggested that the organic carbon content of distilled water must be
considered by anyone growing organisms in distilled water. He also found
that bubbling sea water caused organic compounds to form aggregates on the
surface and further theorized that such reactions may be related to the origin
of life.
Kabot and Ettre (1963) developed gas chromatographic methods capable
of determining free fatty acids. They analyzed different mixtures of the
normal fatty acids using both packed and Golay columns in conjunction
with a flame ionization detector. They concluded that the quantitative
analysis of free fatty acids is possible.

Naphthenic and humic acids

Davis (1968) examined the organic fractions of artesian well waters from a
Texas oil-bearing Eocene age aquifer, using infrared and chromatographic
methods. He found that the water coproduced with oil contained 1,000
times more naphthenic acids than water located updip from the oil. He also
found a phthalic acid ester dissolved in the petroleum-associated water but
concluded that it may be common to ground waters in general.
Shaborova et al. (1961) state that “the presence in subsurface waters of
organic acids in the form of salts of various metals or in a free state indicates
a current process of leaching of organic matter from the enclosing rock. The
presence of organic acids in subsurface waters is one of the evidences for the
existence in the earth’s crust of chemical processes of decomposition of
preserved organic matter. In turn, the organic acids are broken down into
simpler compounds by decarboxilization. It is known that decarboxilization
of organic acids is accompanied by the formation of hydrocarbons. In
nature, this process is a real geochemical factor. Consequently, the organic
acids and their salts that are dissolved in subsurface waters can be regarded as
one of the sources for the generation of hydrocarbons.”
Using a steam distillation method, organic acids were found in concen-
trations from 663 to 2,242 mg/l in subsurface waters taken from a Kazhim
stratigraphic well. The average molecular weight of the acids was from 46 to
58, and the waters taken from Devonian age sediments contained higher
concentrations of the acids than waters taken from Carboniferous age sedi-
ments.
Lochte et al. (1949) analyzed waters produced with high-pressure gas
wells and identified the following acids: acetic, propionic, isobutyric,
n-butyric, isovaleric, n-valeric, n-hexanoic, and other C6 isomers. Crude oils
were treated with ammonia solution followed by electroprecipitation of the
aqueous phase to remove naphthenic acids (Agaev, 1961). Further isolation
of the naphthenic acids was accomplished by heating the aqueous phase to
decompose the ammonium salts and remove ammonia and water.
Oden (1919) recognized fulvic acid, humus acid, and hymatomelanic acid