| Recent interest in the exploitation of Marcellus shale play, using horizontal drilling and multistage hydraulic fracturing, has increased the demand for reliable estimation of recoverable reserves from ultra-low permeability shale gas formations. Due to the limited field experience, the production performances of Marcellus shale gas reservoirs as well as the key parameters that affect the long-term production of the horizontal wells have not been well-established.;Among all the prediction methods, only the Decline Curve Analysis (DCA) technique has proved successful in forecasting production data rapidly and to a high degree of accuracy. Several DCA models including conventional Arps, PLE, and Duong have been utilized in this study to determine the most appropriate method for production data from horizontal Marcellus shale wells. Fekete (Fast Evolution) simulator has been used to generate the thirty year production data from 3000 feet of horizontal lateral. The two base scenarios include seven and thirteen hydraulic fracture stages. The gas adsorbed to shale is also considered. The applicability of several DCA models to shale gas production history was examined using the simulated production profiles. The impact of the permeability, fracture half length, and matrix porosity on DCA models constants were also investigated. Finally, the proposed ratio methodology was applied to the limited production profile (3.5 years of production history) from a well in Upshur County, WV to estimate the DCA constants, and predict the long-term production performance. The prediction results from DCA models then compared to the history-matched simulation model predictions for confirmation. |
