The purpose of this trial is to share the equipment experience obtained by injecting oil and water chemical tracers into 2 Pads and 5 horizontal wells targeting different landings in Vaca Muerta in the El Trapial field. This technology demonstrated that all hydraulic fracturing stages have been able to deliver production and are connected to the wellbore during the early production and testing period of the well’s life (from 3 to 6 months). While wells were being completed during execution of the hydraulic fracturing plan, operational challenges (sweeps, screen outs, high pressure, etc.) were faced. Moreover, reservoir engineers need to evaluate whether those operational issues have affected stages production performance. In addition, it is important to assess how production is distributed along the stages from Toe to heel. West Pad configuration with 2 wells to the North and 2 to the South with 300 meters spacing between wells on same direction and east Pad 2 wells north and 2 south. Wells were geo-steered inside +/- 5 meters windows or even less. The LWD data integrated with mudlogging and geochemical data as well as tracer information, is key to understand the heterogeneity of each level with the production of the well as well as the performance in the horizontal section. Finally, tracer technology helped the team to reduce uncertainties and capture lessons learned within El Trapial Vaca Muerta Project.