Use of Perforation-Tunnel Permeability To Assess Cased Hole Gravelpack Performance

This paper proposes a melhud for comparing the effectiveness of cased hole gravelpacks. The method employs effective perforation tunnel permeability as the primary indicator of gravelpack effectiveness. Completion pressure losses in cased hole gravelpacked wells are subdivided into categories and systematically reviewed to show the relative importance of alternative design features. From this information, perforation tunnel permeability is shown to be the major determinant of completion skin and flow efficiency in cased hole gravelpacked wells. The technique is shown to be useful in both low velocity (darcy) and high velocity (non-darcy) flow regimes. Field examples are used to show how this technique can be used lo diagnose design flaws and improve well performance results. These examples show that effective perforation tunnel permeabilities in cased hole gravelpacked wells are significantly lower than surface measured gravel permeabilities. This has important implications for well design and remedial candidate selection.