Role of Detailed Reservoir Characterization and Lateral Placement on Well Performance in the Marcellus Shale Gas Reservoir

摘要

Development of a shale gas reservoir is dependent on petrophysical parameters indicating gas availability and the success of well completion in accessing this gas. To evaluate shale gas reservoirs it is essential to understand and evaluate the reservoir’s heterogeneity and its effect on its rock quality. The benefit is identification of better hydraulically-fracable zones amongst the best reservoir quality rock. Thus this paper illustrates how petrophysical analysis, in conjunction with geomechanical modeling, aids in determination of the optimum lateral placement and fracture design for a successfully producing well. Petrophysical analysis was performed to determine the reservoir quality, Original Gas-in-Place (OGIP) and the geomechanical property distribution. Based on the distribution of these petrophysical properties, different lithofacies were identified; potentially fracable zones and fracture barriers were predicted. Case histories of two wells are presented to demonstrate how detailed petrophysical analysis assists in determining the correlation between lateral placement and well performance. The first well was drilled in a good reservoir quality interval with the lateral placed in brittle zone in-between rocks with high gas content. As a result, it had good performance with a higher linear transient productivity index. The other well was drilled in a bad reservoir quality interval with the lateral placed in a brittle zone with low gas content and lower performance.