Predicting Production Behavior of the Marcellus Shale

The long-term production behavior of horizontal wells producing from Marcellus shale due to limited production history has not been well established. As a result a simple method for predicting the long-term production and reserves would be of interest. Several production decline curve analysis models have been proposed specifically for application to unconventional gas reservoirs. However, reliable production predictions cannot be obtained when they are applied to limited production history such as those available from Marcellus shale wells. In this study, the production and completion data from a number of horizontal wells completed in Marcellus shale were collected and used to build a generic model. The model was then in conjunction with a commercial dual porosity numerical model which included the adsorbed gas to simulate long-term production profiles for Marcellus shale horizontal wells with multiple hydraulic fracture stages. The simulated production profiles were then utilized to develop correlations for adjusting the conventional (Arps) decline curve constants obtained to from the limited production history to accurately predict the long-term production performance. The impacts of key formation and fracture properties on the decline curve constants were also investigated. Finally, the correlations were utilized to accurately predict the long-term production rates from a Marcellus shale horizontal well in West Virginia based on the early production history.