Four phase (liquid water, liquid hydrocarbon, vapour, hydrate structure-H) equilibrium data are presented for 2,3-dimethylbutane in the presence of the help gases methane and/or nitrogen. Also, further to a previous communication, four phase (liquid water, liquid hydrocarbon, vapour, hydrate structure-II) equilibrium data are presented for benzene in the presence of nitrogen, and a mixture of methane and nitrogen. The hydrate equilibrium data are reported over the seabed temperature range (274-288 K). Thermodynamic description and Kihara potential energy parameters for 2,3-dimethylbutane and benzene are reported for hydrate prediction purposes.