Perforation cavity stability: Comprehensive laboratory experiments and numerical analysis

The paper describes comprehensive laboratory and numerical studies of perforation cavity stability and sand production from a perforation tunnel. Jacketed cores with a cavity simulating a perforation tunnel were loaded in a high-pressure vessel and fluid flow was applied. The cavity deformation and failure were monitored by a cantilever deformation gauge, while produced sand was monitored acoustically and volumetrically at the outlet of the cavity. A cavity stability analysis was conducted using a 3D non-linear finite element model. The numerical analysis shows that the onset of limited sand production matches the initiation of shear failure at the cavity wall. However, the perforation cavity is still relatively stable in the sense that it does not collapse. The sand production increases with the expansion of the post-failure zone, and the cavity finally collapses if excessive confining load is applied to the sample. The post-failure mechanisms are critical with respect to cavity collapse and sand production problems, which may explain the discrepancy between experimental and analytical results.