Estimation of the Stimulated Reservoir Volume by Rate Transient Analysis for Marcellus Shale Horizontal Wells

Abstract

Abstract Shale reservoirs are most commonly developed by horizontal wells coupled with multi-stage hydraulic fracturing to create a stimulated volume around the well. The interference among the hydraulic fracture stages in a horizontal well leads to an early boundary-dominated flow (BDF) period within the stimulated reservoir volume (SRV). The application of the rate transient analysis to the production and flowing pressure data from this period can provide an estimate of the gas in place in SRV. A realistic model for a horizontal Marcellus shale well, with multiple fracture stages, was utilized in this study to simulate gas production and the flowing pressure data. The simulated data by the model were then analyzed by rate transient analysis (RTA) techniques to identify the early BDF period and to estimate the gas in place in SRV. To investigate the impact of the adsorbed gas, shale compaction, and hydraulic fracture spacing on the estimated gas in place in SRV, several sets of the production and flowing pressure data were then simulated and analyzed. The analysis of the data from the early BDF period provided reliable estimates of the gas in place in SRV. These estimates are impacted by the shale compaction but not significantly by the adsorbed gas and fracture stage spacing. When the fractures are stages are closely spaced, the early BDF period established early and last for a relatively short time. Consequently, the identification of the early BDF becomes difficult leading to uncertainty in the estimated of the gas in place in SRV. However, when the fracture stages are spaced widely, the early BDF may last for a longer time and can be identified more readily.