Page 201 - Geochemistry of Oil Field Waters

188 ORGANIC CONSTITUENTS IN SALINE WATERS

evaporation of the solvent should be done in a well-ventilated area or under
an exhaust hood with adequate draft to handle high-density vapors.

Calculation :
1-11 measured = mg/l oily matter
c
mi sampIe

Organic acids in oilfield brines
This method measures the bulk of the organic acid salts in oilfield waters.

Reagents and apparatus. Acetone; NaOH, 0.02N; HC1, 0.05N; acetic acid, 10
mg/l; a hotplate; and a standard pH meter.

Procedure. Pipet 25 ml of filtered brine into a 250-ml beaker; add 25 ml of
acetone and adjust the pH to precisely 6. Titrate the sample to a pH of 3.5,
and record the amount of 0.05N HC1, used in the adjustment from pH 6 to
3.5. Boil the solution for 5 minutes. Cool and titrate back to pH 6 with
0.02N NaOH. Make a blank determination for NaOH and HC1. To calculate,
subtract blank from NaOH and HC1 titrations.

Calculation:
(ml HC1 x HC1 N) - (ml NaOH x NaOH N)
ml sample x 60,030 = mg/l organic acids
as acetic acids.

References

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an electric field. Izv. Vyssh. Uchebn. Zaved., Neft Gaz, 4:95-98 (in Russian).
Andrews, L.J. and Keefer, R.M., 1949. Cation complexes of compounds containing
carbon-carbon double bonds, 11. The solubility of cuprous chloride in aqueous maleic
acid solutions. J. Am, Chem. Soc., 71 :2379-2380.
Anonymous, 1970. Solid natural gas discovered. Ind. Res., 12:70.
Black, A.P. and Christman, R.F., 1963. Chemical characteristics of fulvic acids. J. Am.
Water Works Assoc., 55:897-912.
Bohon, R.L. and Claussen, W.F., 1951. The solubility of aromatic hydrocarbons in water.
J. Am. Chem. Soc., 73:1571-1578.
Bonoli, L. and Witherspoon, P.A., 1968. Diffusion of paraffin, cycloparaffin, and aromat-
ic hydrocarbons in water and some effects of salt concentration. In: Advances in Or-
ganic Geochemistry - Proc. 4th Int. Meet. Org. Geochem., Amsterdam. Pergamon
Press, New York, N.Y., 9:16-18.
Bordovskii, O.K., 1965. Accumulation and transformation of organic substance in marine
sediments. Mar. Geol., 3:3-114.
Braus, H., Middleton, F.M. and Walton, G., 1951. Organic chemical compounds in raw
and filtered surface waters. Anal. Chem., 23:1160-1164.