Fluorescent Nanobeads: a First Step Toward Intelligent Water Tracers

Abstract

Reservoir monitoring is an essential tool to optimize oil production. Among other techniques, water tracers are very useful to understand flow patterns between wells (i) during regular waterflood operations, (ii) for EOR pilot or (iii) field development. This paper focuses on the elaboration of a new family of tracers based on fluorescent silica colloids for in situ real-time optical detection. Indeed, these architectures of nanometric size (nanoparticle diameter controllable between 30-100 nm) permit (i) the encapsulation of fluorescent dyes (the intrinsic signal of tracers) and (ii) a tailored interface with the environment (by specific surface functionalization). Dyes, such as organic molecules and/or rare-earth complexes could be quantified by conventional fluorescence apparatus. The smart incorporation of specific fluorophores of different nature within nanobeads allows multi-coding signal of tracers and therefore the possibility to supervise the properties of reservoir. We demonstrate that silica nanobeads could act as sensitive probes of physicochemical conditions of reservoir (volume, pH, temperature, oil ratio, salt content…), because of (i) their specific fluorescence coding, (ii) the long-term colloidal stability in seawater conditions, and (ii) the adaptable real-time monitoring detection setup. Actually, by the procedure described in this work, we are able to produce theoretically dozens of fluorescence tagging combinations based nanoparticles with suitable surface properties. The possible future utilization of fluorescent nanobeads as traces in well exploitation is also demonstrated by core-flood experiments.

Nanotechnology and global energy demand: challenges and prospects for a paradigm shift in the oil and gas industry

“…Nanoparticles can be made to respond to changes in reservoir pressure and temperature, oil saturation, shear rate, etc. Agenet et al (2012) examined the application of fluorescent gold-silica nanoparticle tracers for in situ real-time optical detection. The nanoparticles were engineered such that its size (30-100 nm) allowed for the encapsulation of glowing dyes, which forms the intrinsic signal of tracers and an interface with the environment for functionalization.…”

The Use of Fluorescent Tracers for Inhibitor Concentration Monitoring Useful for Scale Inhibitor Squeeze Evaluation

“…As currently seen in bioassays, the time-resolved fluorescence technique almost suppresses the fluorescence background of the medium and enhances the intrinsic phosphorescence signal of tracers. In other words, the increase of signal-tonoise ratio drastically reduces the quantification limit below the ppb threshold (Agenet N. et al 2012).…”

Pyrolyzable Nanoparticle Tracers for Environmental Interrogation and Monitoring

“…Elegant analytical approaches exploiting high-performance liquid chromatography (HPLC) separation before either fluorescence or mass spectroscopic analysis have become the method of choice for tracer identification and quantification. − However, these analyses generally are not field-portable and require sophisticated instrumentation. To resolve these issues, intricate solutions have been devised through the utilization of delayed luminescent species such as lanthanide-ligand pairs embedded within nanoparticle matrixes or inorganic phosphors with persistent emission which can be detected using fluorescence spectroscopy. − In these cases, the issue of background hydrocarbon signal is mitigated by the extended time scale of luminescence originating from lanthanide ions or phosphors in comparison to the short-lived fluorescence of hydrocarbon components in the crude oil. Nonetheless, these materials are expensive, difficult to synthesize in large quantities, and limited by the number of potential barcodes that could be deployed.…”