Release kinetics of rare earth tracer from polymer-coated proppants for hydraulic fracture analysis

Horizontal well staged fracturing has been unlocking natural gas and oil in shale and reshaping the energy supply worldwide. With the updating technology of the integrated fracturing engineering, prolymer-coated proppants not only prevent fracture closure but also hold oilfield tracers which can be released under certain conditions, offering a viable strategy to report the information of proppants, fractures and fluids in reservoir based on tracer flowback data. But release kinetics of tracers from functional proppants, which is a fundamental and critical issue in the application of the tracer-released proppant, is yet to be discussed. Here, coupled with rare earth tracer, poly(ethyl acrylate-co-methyl methacrylate-co-trimethylammoniethyl methacrylate chloride) is taken as an example to build a model tracer-releasedproppant. Release curves of tracers, under reservoir conditions (salinity and temperature conditions), were studied to reveal the release mechanism, and the potential applicability of the rare earth tracer-released proppants for reporting the proppants position and fluid contribution in multi-staged fracturing monitoring was confirmed in laboratory flow experiment.