Physical modeling study of the influence of shale interbeds and perforation sequence on sand production

Centrifuge tests were performed to study sand production problem that is a major issue in many oil and gas recovery projects. The tests simulated seepage-induced failure around a multi-perforated vertical well. Two different scenarios were considered: (1) perfs evenly spaced along the casing within a homogeneous sand layer, and (2) ditto but a shaley seam was introduced in the middle of the layer. Data collected during the experiments included time-dependent variation of pore pressure within the pay zone, flowrate, sanding rate, and tracking of the enlargement of the cavity around the well. Numerical modeling was used to better interpret and support the experimental results. Overall, the study performed shows that (1) the location of perfs affects the mode and magnitude of sand production and the concomitant productivity, and (2) long-term productivity can be improved through managed sand production. These findings are consistent with some field cases where extraordinary increases in production were noted due to sanding.