New Passive Water Tracers for Oil Field Applications

Abstract

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 (CF 3 ) 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/MSÀMS)] 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.

Rapid ion-exchange matrix removal for a decrease of detection limits in the analysis of salt-rich reservoir waters for fluorobenzoic acids by liquid chromatography coupled with tandem mass spectrometry

“…Sodium and chlorine ions are responsible for ionization suppression and reduce the sensitivity [3, 12]. Non-volatile sodium or calcium chlorides contaminate the ion source and negatively affect the reproducibility.…”

“…Different fluorobenzoic acids are commonly used as non-radioactive passive tracers in petroleum exploration [1, 2]. Hence, there is a need for their sensitive analysis in oil reservoir waters, known for their highly dissolved organic matter and salt (NaCl, CaCl 2 ) content often exceeding 25% [3].…”

“…Hence, there is a need for their sensitive analysis in oil reservoir waters, known for their highly dissolved organic matter and salt (NaCl, CaCl 2 ) content often exceeding 25% [3]. Gas chromatography (GC) [4] or high-performance liquid chromatography (HPLC) [5–10] with MS/MS detection have been typically used to assure the separation of the tracer compounds from each other while assuring their specific detection.…”

Advances in the analytical methods for the determination of fluorinated aromatic carboxylic acids in aqueous matrices: A review

“…To accurately narrate and comprehend the geometry of an oil reservoir, the oil industry requires adequate information. In complex oil reservoirs, the interwell tracing test (IWTT) using aqueous tracers has been proven to be an effective and convenient experimental method for EOR [8,9]. Two types of aqueous tracers are widely used for this technique: passive tracers and partitioning tracers [10].…”

Development of new oil/water partitioning tracers for the determination of residual oil saturation in the inter-well region of water-flooded reservoirs

“…They should also be considered within the process of selecting new chemical compounds for testing as oil/water partitioning tracer candidates (Papers I, II, and to a smaller extent, Papers III, IV and V). Fluorinated benzoic acids (FBAs) are widely used as passive water tracers in oil reservoirs in inter-well tracer tests (Asadi and Shook, 2010;Bjørnstad, 1991;Serres-Piole et al, 2011a;Serres-Piole et al, 2011b) and well-known for their thermal and chemical stability and absence of interaction with reservoir rocks. Figure 2 depicts the generic structure of FBAs. )…”