Development and application of type curves for pressure transient analysis of multiple fractured horizontal wells in shale gas reservoirs

Abstract

Horizontal drilling and hydraulic fracturing is necessary to reach economical success in shale gas reservoirs. PTA for shale gas reservoirs requires comprehensive understanding related to nonlinear gas flow process as well as hydraulic fracture properties. Even though significant progresses made in the past few years, there appears to be a lack of information regarding the characterization of shale gas formations. A major purpose of this study is to demonstrate how this issue may be addressed by pressure transient analysis for multiple fractured horizontal wells in shale gas reservoirs. Extensive numerical simulations were conducted to model transient pressure behavior of a fractured horizontal well and applied the results to well test analysis in shale gas reservoirs. The pressure transient response for a horizontal well with transverse multiple fractures is controlled by many of important fracture properties and nonlinear flow processes. This paper presents a comprehensive reservoir simulation model to investigate the characteristics of pressure transient responses under the influences of hydraulic fracture properties and nonlinear gas flow mechanism. Factors considered in this study include the number of hydraulic fractures, fracture half-length, fracture spacing, adsorption, non-Darcy flow, and Klinkenberg effect under reservoir flow condition as well as skin effect. The numerical simulations for nonlinear gas flow provided various type curves in terms of dimensionless pseudopressure and time for transient pressure responses in fractured horizontal production wells. Results from type-curve matching for synthetic pressure data in shale gas reservoirs demonstrate that the conventional analysis approach may still be applicable for analysis of shale gas reservoirs. The results can be used for quantitative studies of transient gas flow behavior and determination of formation properties.