Underground gas storage (UGS) involves storage of large quantities of natural gas in a storage horizon to support the natural gas demand in domestic, commercial, and industrial areas. The main objectives of this book are to investigate the possibility of (UGS) development and feasibility of underground sour gas storage in a depleted fractured gas reservoir. Compositional simulation was employed to build a dynamic reservoir model, develop the history-matching phase of the reservoir, and construct injection/withdrawal (I/W) cycles. A systematic procedure was employed to determine optimum well...