New Effective-Stress Law for Predicting Perforation Depth at Downhole Conditions (original) (raw)

Summary For natural completions, well productivity is proportional to the depth of the perforation tunnels extending beyond the drilling damage (all other things being equal). Perforation depth, in turn, is generally inversely related to the formation effective stress. Accurate productivity modeling, therefore, requires accurate knowledge of the relationship between the downhole stress environment and perforation depth. A comprehensive experimental effort was recently conducted to evaluate the penetration performance of shaped charges into stressed Berea sandstone cores. Rock confining stress (σc) and pore fluid pressure (Pp) were varied from ambient to 10,000 psi to simulate a range of downhole stress environments. This current work featured a broader and more systematic investigation of the influence of pore pressure than previous studies. Our experiments yielded the expected inverse correlation between penetration depth and effective stress (σeff). However, the data suggest a new...