Extended Hyperbolic Decline Curve Analysis in Shale Gas Reservoirs

Abstract

To perform production forecasting in practice, lots of scholars and engineers have designed various techniques to interpolate the production both analytically and numerically, among which many decline curve analysis models have been proposed and widely used because of their simplicity and efficiency. Unfortunately, each model has their own limitations and is not applicable for all cases. For traditional reservoirs, common practice for production performance is decline curve analysis (DCA). However, when apply traditional DCA to shale wells, it is difficult to match the high initial production rate and extremely sharp decline rate in early period and the shallow decline rate at late times, simultaneously. Based on the Arps model, the extended hyperbolic production decline equation is developed, which includes four empirical parameters. Although the proposed method is not always accurate than peer models, it is likely as accurate and does not require the boundary-dominated flow start time nor to force a switch to hyperbolic decline. The validation of this new empirical DCA has been conducted by both extensive field data and simulation results for several wells. Comparisons with traditional DCA methods and numerical simulations indicate the relative advantages of this new approach.