Hydrogen Sulfide Viscosity Modeling

As regulations for emissions of carbon dioxide and hydrogen sulfide into the atmosphere are becoming stricter and the penalty for violation increases, new and economical ways of reducing these emissions are becoming increasingly important to everyday operations. One promising sequestering option is the injection of acid gas mixtures into formations for disposal/storage. During the design of these acid gas injection schemes a comprehensive knowledge of the thermo-physical properties is of utmost importance in determining the feasibility and size of these operations. Recently, the friction theory (f-theory) for viscosity modeling has been shown to accurately determine the viscosity behavior of a wide range of petroleum fluid systems ranging from natural gases to heavy crude oils. This technique has also been shown to accurately model mixtures containing various concentrations of CO 2 . However, in the development of the f-theory hydrogen sulfide was not explicitly studied and therefore needs to be accounted for to ensure it is accurately modeled. The development/validation of any modeling approach requires a thorough knowledge of the available data. With this in mind, an exhaustive collection of the data available in the literature has been performed revealing a very limited number of experimental points available in the open literature for the viscosity of pure H 2 S and H 2 S mixtures. Although limited data for pure H 2 S exists in the literature, a critical evaluation of the data was performed and a reference viscosity model based on the generalized friction theory (f-theory) was developed. The developed reference viscosity model gives reasonable modeling results over the T -η- P surface for H 2 S. The one parameter f-theory was also extended to include H 2 S, and the model was shown to accurately reproduce existing experimental viscosities of hydrogen sulfide and its mixtures in ranges relevant to the natural gas and petroleum industry.