For wells drilled in shale gas reservoirs to be economic, hydraulic fracturing has become a common completion practice. Production from these completed wells is highly dependent on the characteristics of proppants placed in the created fractures. Fracturing leads to an interaction between the minerals of the proppants, formation and the fluids; this results in the phenomenon of proppants diagenesis. It involves mechanisms such as diffusion, dissolution, precipitation along with chemical reactions that take place at the fracture surface. Over time, this combined process results in a loss of proppant pack permeability thereby leading to a decline in well productivity. This occurs due to changes in compositional differences between proppants, fracturing fluid and the formation. A mathematical model, representing this phenomenon is developed in this paper. It inculcates the phenomenon of mass transfer along the length of the fracture coupled with associated surface chemical reactions, and mass conservation equations are solved for individual components. Further, the impact of finite difference techniques on the results is studied. This is supplemented with studies involving changes in fracture aperture as well as velocity profile of the flowing fluid. Impact of results from the developed mathematical model on typical shale gas well productivity is evaluated. [Received: April 1, 2015; Accepted: September 8, 2015]