Carbon Dots as Fluorescent Sensitive Tracers in Reservoir Engineering

In oil and gas industry, tracing technology is a very effective tool for obtaining reservoir information. Tracer detection technology can be used for dynamic monitoring of fracturing fluid drainage in single well, monitoring of cross-well connectivity, verification of correlation between return discharge and production, etc. Commonly used tracers, such as, radioactive elements and stable isotopes, fluorescent dyes, and inorganic ions, may pollute the environment. Being an environmentally friendly substance with strong fluorescence and penetration properties, carbon dots can be used as a tracer in production and well monitoring. In this work, we have synthesized five kinds of CDs using a one-step hydrothermal method from p-phenylenediamine precursor. The carbon dots showed great stability in n-Dodecane and 1wt. % NaCl solution and flooding test. The carbon dots can adapt to different temperatures and pH environment in the process of obtaining reservoir information. The feasibility of the proposed point of view was proved by flooding test.