Acid gas mixtures (i.e. natural gases containing hydrogen sulfide H2S and/or carbon dioxide CO2) are often encountered in the petroleum industry. For the systems containing hydrogen sulfide, experiments on their thermophysical properties are very scarce because of the very high toxicity of H2S which leads to very complicated safety procedures for the experimentalists. This is especially true for the high pressure and temperature conditions of petroleum reservoir. As we recently emphasized [1], this lack of knowledge is particularly apparent concerning transport properties. Concerning the dynamic viscosity, the available experimental database is very small. The reader could find a presentation of the works available in the literature in a recent work [2]. It is worth to mention the work of Liley et al. [3], which proposes after critical analysis of the available data, a table with 18 values between 190 and 350 K for the saturated liquid (pressure up to 6 MPa) and 21 values for the dilute gas as a function of temperature between 250 and 500 K. For the dilute gas these authors propose an equation after the analysis of several