It has been challenging to analyze tracer molecules in oil reservoir fluids by optical spectroscopic methods because of the severe interference from complex impurities in high salinity brine-crude oil mixtures. Here, we present a solid phase extraction (SPE) and time-resolved fluorescence (TRF) combined method for ultra-trace level determination of dipicolinic acid (DPA) and phenanthroline-dicarboxylic acid (PDCA) based advanced barcoded molecular tracers in reservoir fluids for oil industrial application. Solid-phase extraction media with different chemical functional groups were investigated, and selected to preconcentrate the tracer molecules and remove salts impurities. The extraction procedures were developed and optimized for tracer molecules in produced aqueous reservoir samples. Based on the energy transfer mechanism, rare earth ions, europium (Eu3+) and terbium (Tb3+), were introduced to chelate with the tracer analytes, and the resulting enhanced fluorescence emission from the rare earth complexes shows oil blind detection by TRF. We have demonstrated that the tracer molecules can be preconcentrated by 103 times with recovery factor &gt;95% through the SPE enrichment, and the TRF analysis can efficiently reduce background signal in fluorescence by several orders of magnitude in produced aqueous reservoir samples. By the SPE-TRF combined methods, the DPA- and PDCA-based tracers can be analyzed at concentrations in the ppt range enabling ultra-trace level detection of the advanced tracers by optical spectroscopic method and affirming the application of the method for the oil industry.

Ultra-trace level determination of advanced molecular tracers by combined solid-phase extraction (SPE)-time resolved fluorescence (TRF) for oil reservoir application

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.