(252d) Automated in-Line Optical Trace Level Detection of Expanded Palette of Advanced Tracers

Oil field tracer technology development to illuminate reservoir characteristics such as well connectivity, volumetric sweep efficiency, and geological heterogeneity for the purpose of improving oil production optimization has gained momentum over the last decade. In this study, we demonstrate the laboratory qualification of an expanded number of ultra-trace level detectable molecular isomers as competent cross-well water tracers for use in highly retentive carbonate reservoirs with harsh salinity and temperature. Our Advanced Tracers technology has been using time-gated optical fluorescence with high sensitivity, selectivity, and oil blind background, by chelating the barcoded variants of the ligand tracer molecules with lanthanide ions. The ultra-trace level detection of expanded palette of barcoded molecular isomer tracers has been achieved under flow conditions utilizing a microfluidic mixing chip and a flow-cell fluorescence or UV-Vis detector at the output of the high-performance liquid chromatography (HPLC) separation. This study has demonstrated efficient separation and rapid in-line detection of a mixture of the expanded palette of molecular isomer tracers at ultra-trace level. HPLC chromatographic separation equipped with automated solid phase extraction (SPE) pre-concentration for molecular isomer tracers has lowered the in-line fluorescence detection limit down to 500 pM of molecular isomer tracers. The developed complete automated tracer detection system will offer unprecedented sensitivity of detection and accelerate the sample analysis aiming “near-real-time” oil field tracer analysis. The developed HPLC chromatographic separation and optical detection of isomers of molecular tracers can significantly expand the palette of barcoding capability. The automated in-line optical detection technology for tracers in oil field brine will pave the way toward the development of a near-real-time tracer sample analysis approach for wide full-field applications.