The full-length paper reports experiments and modeling designed to assess the effects of the gap between the outside of an expandable sand screen and the rock on the short and long term completion integrity A transverse cross section of the well and screen and an axial section are examined. Rock-deformation modeling showed that for a screen with relatively low radial stiffness, a very small or zero gap was best, while a stiff screen could tolerate a slightly larger gap of a few millimeters.