Shale gas, like natural gas, contains H-2, CO2, CH4 and that light hydrocarbon gases needs processing to separate the gases for conversion to higher value products. Currently, distillation based separation is employed, which is energy intensive. Hybrid gas separation processes, combining absorption and membranes together with distillation require less energy and have attracted much attention. With the property of non-volatility and good stability, ionic liquids (ILs) have been considered as new potential solvents for the absorption step. However, the enormous number of potential ILs that can be synthesized makes it a challenging task to search for the best one for a specific hybrid separation. In order to solve this problem, a systematic screening model for ILs is established by considering the needed properties for gas absorption process design. Rigorous thermodynamic model of IL-absorbed gas systems is established for process design-analysis. A strategy for hybrid gas separation process synthesis where distillation and IL-based absorption are employed for energy efficient gas processing is developed and its application is highlighted for a model shale gas processing case study.