Carbon Quantum Dots Fluorescent Tracers for Production and Well Monitoring

Abstract

Abstract Tracer technology is a very efficient diagnostic tool for the oil and gas industry to obtain valuable information about reservoirs. The interpretation of tracers that have traversed the reservoir reveals reservoir characteristics such as inter-well connections, heterogeneities, and water movements that can be used to improve hydrocarbon recovery efforts. Commonly used tracers are radioactive elements and stable isotopes, chemicals, such as fluorescent dyes, and inorganic ions. Novel carbon quantum dots (CQDs)-based fluorescent tracers have been proposed for production and well monitoring. One-step electrochemical synthesis of CQDs from low molecular weight chemical precursors through electrochemical carbonization was developed. The doping of CQDs with heteroatoms such as nitrogen provides differentiated fluorescence emission signatures that can be used to monitor multiple stages of frac operations.