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

Abstract

A common problem, in oilfield reservoirs is mineral scale deposition. The build-up of scale inside well bores and the surrounding reservoir causes millions of dollar in damage every year. The most common remedy is to treat the formation of such minerals with scale inhibitor chemicals in a "squeeze" treatment; which is performed periodically. One of the big challenges remains the real-time and on-site control of inhibitor concentration during production. A simple and accurate method to determine the concentration of inhibitors has been developed; this method is based on the use of luminescent tracers. The multiple lifetimes as well as the differences shown in the emission and excitation spectra of the tracers appear to be suitable for the luminescence detection. The increased signal to noise ration due to the suppression of the background resulting from the organic oil residues is used to measure the concentration of residual inhibitors in production waters. Furthermore, the use of a technique as versatile and simple as luminescence spectroscopy allows the online and/or on-site monitoring with very limited drawbacks. This paper describes the use of novel real-time scale inhibitor monitoring; this new technique will help to optimize the treatment rates of the scale inhibitor squeeze treatment.

How to Monitor Scale Inhibitor Squeeze Using Simple TRF Tracers

“…Terbium tracer solution has also been used with excellent results (Brichart et al, 2014). The reasons for using Eu-light above other lanthanide-based solutions are manifold.…”

“…Beyond such analytical techniques, our long experience in luminescence detection has revealed that fluorescence techniques can be surprising suitable for a "smart" real-time scale monitoring (Agenet et al, 2012;Brichart et al, 2014). We found that the industrial expectations of detection thresholds, costs, and management on scale monitoring matched the time-resolved fluorescence (TRF) analysis.…”

Design, synthesis and performance of novel fluorescent polymer microspheres tracers based on aggregation induced emission

“…For non-radioisotope tracers, the instruments required for detection are expensive and the analysis and testing are cumbersome. As the most widely used tracers, there are rich range of chemical tracers, especially among them fluorescent chemical tracers [21][22][23][24][25][26] which have attracted a lot of attention in oilfield operations due to their high sensitivity, low usage, low detection limits, and simple analytical methods. However, some fluorescent tracers currently used are small molecular fluorescent dyes, and their main problems are poor thermal stability, easy photobleaching, poor resistance to acid and alkali, and poor ability to interfere with metal ions in hydrocarbon-bearing formation.…”