Sand production initiation criteria and their validation

The paper investigates the capability of a simplified Mohr-Coulomb (MC) analytical model to predict satisfactorily fully anisotropic loading experimental results on hole failure, as well as numerical predictions from several parametric analyses of field cases based on a 3D non-linear FEM borehole and perforation failure analysis model (Sand3D), which employs the critical plastic strain failure criterion coupled with a Drucker-Prager failure surface. The comparisons with the experimental data and the field simulations demonstrate that the MC model is insufficient for satisfactory predictions under anisotropic loadings. A Drucker-Prager type model is advanced and shows significantly improved analytical predictions under any loading condition. Two field case comparison examples show that the developed analytical sand production initiation model accounts for the effect of intermediate stress and gives good matches to the formation failure envelopes predicted by the numerical model.