A composite model for gas well performance evaluation and prediction has proven successful and efficient in analyzing gas wells producing from low permeability tight gas formations. By employing analytic methods which model reservoir and fracture behavior, a model has been constructed which is capable of automatic regression for the descriptive reservoir parameters. The model is designed to treat producing and shut-in conditions ranging from a simple four-point test to several years of online pressure-production history. Once history-matched parameters are determined, the model is then capable of projecting future performance.
Field examples of wells producing from tight reservoirs (Eagle; Medina; Niobrara) are presented to demonstrate the applicability of the model in both production performance analysis as well as long term forecasting. These results are compared to finite difference simulation results to demonstrate the model's consistency. In addition, the computational needs of the model in terms of processing time are compared to those of a finite difference simulator.