Analysis and forecasting of well performance data in unconventional reservoirs is and will likely remain problematic as there is considerable uncertainty related to our current lack of understanding of the fluid flow phenomenon in low/ultra-low permeability reservoir systems.There are many unknowns which are the primary sources of the uncertainty on production performance.To name a few, these can be stated as the link between flow in nano scale and macro scale, effect of natural fractures and stress fields/geomechanics, pressure/stress dependent dynamic reservoir properties (e.g., permeability), Pressure-volume-temperature (PVT) properties at nano scale, extent of drainage area, etc. Recently, a great amount of research has been performed to understand and relate these issues to well performance analysis and forecasting, but still no conclusive answer has been provided.The objective of this paper is to briefly discuss the specifics of flow in low permeability systems and models to represent well performance then present a methodology to analyze and forecast production data.