Detectability of smart proppants traced with gadolinium and samarium in the Vaca Muerta formation

Abstract

The use of smart proppants traced with gadolinium and samarium was evaluated in a realistic model by Monte Carlo simulations. The addition of compounds with high thermal neutron capture cross section, such as gadolinium oxide (Gd₂O₃) and samarium oxide (Sm₂O₃) into ceramic proppants, makes them detectable after placement in induced fractures. Proppants traced with different oxide concentrations were studied in a generic borehole-formation-tool configuration, modeled with MCNP. The Vaca Muerta formation model was constructed based on measured geochemical data. A theoretical formation of water-saturated limestone with 20% porosity was also used as a reference case of study. The minimum concentration of gadolinium and samarium oxides needed, in order to make them detectable by logging tools, was determined. In the case of gadolinium, results are in agreement with previous reported values for Gd₂O3 addition of about 0.4% by weight of proppant. In the case of samarium, a minimum concentration of 1.25% by weight of Sm₂O₃ addition could be detected in both Limestone and Vaca Muerta formations.