New passive water tracers for oil field applications
Résumé
We present the results of theoretical and experimental work on the development of new chemical passive water tracers for application in oil reservoirs. Fluorinated benzoic acids (FBAs) are currently used as chemical water tracers in oil field applications, and they were considered as "reference water tracers" in this study. The 15 newly proposed tracer molecules are halogenated derivatives of benzoic acid that are commercially available and have two halogenated substituents on the aromatic ring, either one fluorine (F) and one trifluoromethyl group (CF3) or one fluorine (F) and one chlorine (Cl). Laboratory-scale experiments were conducted to evaluate the physicochemical properties (e.g., detection, stability, and toxicity) and performance of the molecules as potential water tracers. Both the new tracers and FBAs are simultaneously detectable using the same rapid analytical tool [ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC/MS-MS)] and can therefore be used in the same tracing campaign without altering the analytical technique for the detection in reservoir water samples, which is economically desirable. Recommendations for the storage step between sampling and analysis are also discussed. © 2011 American Chemical Society.