A wide variation in composition and thermodynamic properties is expected for different reservoir fluids, from simplest one containing only methane and light compounds, to those with high compositional complexity. In this work, phase behavior of six different reservoir fluids recombined with methane was compared and contrasted. From our past work [Romero Yanes et. al. (2019), DOI:10.1016/j.fuel.2019.115850], a low asphaltene crude oil (28.0 °API, 0.68 wt % n-C7 asphaltenes), here referred as BRO, has presented a complex phase behavior when mixed with methane, especially when methane content is around 75.0 mol%. Based on these results, it was studied in this work the phase behavior of six different crude oil mixed with 75.0 mol% of methane. Samples main characteristics can be summarized as follows: a light condensate fluid (P1, 44.0 °API, and not detected n-C7 asphaltenes), three medium crude oils [(P2, 30.8 °API, and 0.09 wt % n-C7 asphaltenes); (P3, 26.0 °API, and 0.54 wt % n-C7 asphaltenes); and (P4, 25....