Restoration of annular zonal isolation using localized casing expansion (LCE) technology: Treatment of near-horizontal test sections containing a free-water channel

Fluid migration behind casings is a well integrity problem that can result in sustained casing pressure, undetected leaks to the environment, and potentially very difficult remediation attempts. Traditional methods for treating annular fluid are perf-and-squeeze cementing or section milling followed by recementing. The main disadvantage of former limited penetrability cement slurry into narrow cracks microannuli, while latter it requirement full rig perform operation. Casing expansion recent alternative technology involves imposing permanent radial external layer, with purpose mechanically closing pathways migrating fluids. A necessary treatment be effective confined between competent rock formations, such sustain significant mechanical strains without failure. Recent laboratory experiments field trials have shown promising traditional methods. We build on these insights controlled involving 7-in Local Expander tool full-scale cemented annulus test assemblies, which contained much larger-scale defects than previously tested. Prior treatment, assemblies had continuous channels top side cement, leading high permeabilities ranging from approximately 80 hundreds darcy. origin was likely separation free water slurry, considered relevant failure mode primary inclined wellbores. study effect single multiple local dents seepage rates, probe potential alteration properties using Vickers hardness testing. find highly relatively major annuli, even when defect several millimeters wide located adjacent outer casing. effectiveness found linked degree initial condition cement. deformed shows tendency toward increased hardness, densification microstructure. testing steel indicated no changes at dent locations compared average values away points.