Effect of Non-Darcy Flow in Transient Pressure Behavior with Poroelastic Dual-Permeability After-Closure Analysis of Fracture Test

Abstract

Non-Darcy flow is introduced to analyze the wellbore dual-pressure responses for naturally fractured reservoirs. The pressure decline is assessed using dual-porosity/dual-permeability poroelastic theory during the post-closure (after-closure) phase of impulse-fracture tests. This analysis reveals that parameters for both matrix and fracture can be estimated based on identified dual-flow regimes. The wellbore pressure behavior is depicted in a log-log pressure plot, where the transition period between pseudolinear and pseudoradial regimes is examined. The log-log plot of pressure indicates that non-Darcy flow significantly impacts the transition period, resulting in a narrower and steeper curve. Moreover, it shows a slight convex shape in the pseudoradial flow region. The semianalytical expressions are provided to estimate these parameters in the limit regions for the dual-flow regimes. Finally, the study also performs a sensitivity analysis and compares the semianalytical solution in limiting cases where Darcy flow in the fracture system is compared.