Abstract
Unconventional gas reservoirs have shown the potential to be the next world primary energy resource and have received a lot of attention in the past few years in the world. Even with the significant progress that has been made world-wide towards commercial development of natural gas from these unconventional resources, understandings or modeling tools of gas flow in these extremely low-permeability reservoirs are far behind the industry needs. In this paper, we present a numerical model for modeling transient gas flow behavior and its application to well testing analysis in unconventional gas reservoirs. Specifically, the numerical model simulates realistic reservoir gas flow processes, including Klinkenberg effect, non-Darcy flow behavior, and adsorption under reservoir flow condition, in addition to wellbore storage and skin effect. We use the numerical model to generate various type-curves for nonlinear gas flow for well testing analysis in unconventional porous and fractured reservoirs and demonstrate the conventional well testing analysis approach may still be applicable for analysis of unconventional gas reservoirs.
