The Barnett Shale success in the 90's has led to a significant amount of focused work on fracturing and its related aspects. The work included understanding its nuances, to be able to design the treatments better, and pump them with enhanced efficiency. Production from these completed wells is highly dependent on both the characteristics of proppants being placed, as well as those of the reservoir being treated. Fracturing leads to an interaction between the minerals of the proppants, formation and the fluids. Incompatible chemical interactions between minerals of the proppants, formation and fracturing fluids lead to precipitations which reduce porosity. Under in-situ conditions, these interactions further facilitate the phenomenon of geo-chemical diagenesis as a result of which rapid loss of fracture conductivity is observed. The diagenesis process includes mechanisms such as diffusion, temperature induced dissolution, precipitation in the pore space, along with chemical reactions at the fracture surface. These mechanisms lead to a reduction in the width and hence, the permeability of the created fracture. Proppant pack permeability reduction is presented in this paper through a mathematical model, which simulates fluid-mineral reactions in the created hydraulic fracture. The model involves solving the diffusion and precipitation equations for each component to simulate the changing porosity and permeability over time. These coded partial differential equations are combined with the reactions occurring at the surface. Further, this work studies the impact of this reduction on the productivity of a well completed in shale reservoir, followed by a sensitivity study of critical parameters. This work will help in a better understanding of reactions occurring within the fractures and their effect on the loss of fracture conductivity. With India looking at developing its shale plays, this work also includes possible issues that could affect this development. © Copyright 2015, Society of Petroleum Engineers.