Abstract Generally speaking, performance-based reservoir characterization is the diagnosis, analysis and interpretation of production data from an individual well and the integration of the results of this analysis with other forms of data (e.g., petrophysical data, completion data, geological data, etc.). In particular, when integrated with subsurface and completion data, the results of well performance analysis and forecast on a per well basis could provide significant insight in terms of establishing reservoir management strategies and provide recommendations on field development. This presentation focuses on model-based well performance analysis (rate transient analysis) to achieve such goals. Model-based well performance analysis and forecasting has become quite popular in recent years; however it is a challenging task due to the low/ultra-low permeability nature of unconventional reservoirs as well as to the complexity (e.g., geology, PVT, etc.) associated with each play. Advanced models and techniques, which could account for non-linearities such as multi-phase flow/complex PVT, stress dependent properties, are required for more robust analysis and forecasting. However, it is practically impossible to analyze and forecast each well using the advanced models in a developed field due to time constraints. The focus of this presentation is to demonstrate a practical methodology, which is efficient in terms of time constraints, and sufficient to incorporate complex flow behavior that might be encountered, for the analysis and forecasting of producing wells in a particular area/field in an unconventional reservoir. Biography Dr. Dilhan Ilk is a vice president and staff engineer at DeGolyer and MacNaughton in Dallas, Texas. He holds B.Sc. degree from Istanbul Technical University, M.Sc. and Ph.D. degrees from Texas A&M University — all in Petroleum Engineering. In 2010 Dilhan joined DeGolyer and MacNaughton upon completing his graduate studies at Texas A&M University. Dilhan's interests include analysis of well test and production data, reservoir engineering, and inverse problems. In particular, Dilhan focuses on well performance analysis in unconventional reservoirs and has made several contributions to petroleum engineering literature, and to date, he has prepared numerous articles in well test analysis, analysis/interpretation of production data, general reservoir engineering, etc. At DeGolyer and MacNaughton, Dilhan coordinates projects related to integrated assessments of unconventional reservoirs including field development studies, due diligence, completion evaluation, well performance analysis and forecasting, and estimation of prospective and contingent resources. Recent work has included well performance analysis and forecasting in major almost all tight/ and shale gas and oil plays in North America, Argentina, Australia and China as well as emerging unconventional resource plays in Africa, Asia, Europe and South America. Dilhan has also presented several industry short courses throughout the world and he regularly serves in program committees at Society of Petroleum Engineers (SPE) conferences, forum series and workshops focused on unconventional reservoirs. He serves as a technical editor to the Society of Petroleum Engineers Reservoir Evaluation and Engineering Journal, Society of Petroleum Engineering Journal, and the Journal of Petroleum Science and Engineering. He regularly serves in leadership roles at SPE events focused on unconventional reservoirs. He is a member of SPE Reservoir Description and Dynamics advisory committee. He is a contributing author of the SPEE Monograph IV -- Estimating Ultimate Recovery of Developed Wells in Unconventional Reservoirs (2016). He was also a co-editor of the SPE digital publication series in "Performance Forecasting in Shale Reservoirs".#ReservoirDescriptionandDynamics