Continuous sand production and foamy oil behaviour are both believed to be key factors for the enhanced non-thermal fluid production in unconsolidated heavy oil reservoirs in Canada (Alberta and Saskatchewan). The same mechanisms are plausible to be active in similar heavy oil strata in Venezuela (Faja del Orinoco), Oman, and China. Field experience indicates that a fundamental understanding of sand production mechanisms, foamy oil behaviour, pressure gradient changes, and stress changes are essential to successful operations involving massive continuous sanding. Inter-relating these factors requires the coupling of geomechanics and fluid flow processes. An integrated approach incorporating a three-phase, three-dimensional, black-oil model coupled with a geomechanics model is introduced in this article. Piping channels (wormholes) are postulated to develop from perforations when pressure gradients exceed the residual cohesion of the sand formations. An elastoplastic constitutive model is extended to describe the reservoir material before seepage forces liquefy and suspend the sand particles at the advancing tips of wormholes. The hemispherical wormhole tip is postulated to propagate as long as a critical tip pressure gradient is exceeded. A slurry transport model is used to describe the flow inside the wormholes. Field data from Frog Lake, Alberta are used to validate the model, and it appears that the simulation and the field data are well-matched.