Predicting Production Behavior of the Marcella Shale by Using Arps Equation

The behavior of the horizontal wells producing from Marcellus shale is not fully understood because of the limited production history. As a result a method of predicting the long term production is needed. A number of production decline curve analysis models have been proposed for application to unconventional gas reservoirs. The problem is that the reliable production prediction method are not available when production history from Marcellus shale horizontal wells is limited. In this study, production and completion data from Marcellus shale wells were collected to build a generic model The generic model was then used in conjunction with a commercial dual-porosity numerical model which include the adsorbed gas to simulate long term production profiles for Marcellus shale horizontal wells with multiple hydraulic fractured stages. Subsequently, the simulation of the production profiles were utilized to develop correlations for adjusting the conventional decline curve (Arps) constants (n,d i,qi) obtained from the limited production history to accurately predict the long term production performance. The impacts of the formation and fracture properties on the decline curve constants were investigated. Finally, the correlations were utilized to confirm the accuracy of the predicted production rates from a Marcellus shale horizontal well based on the available early production history