STABILITY OF SAND ARCHES. A KEY TO SAND CONTROL

Abstract

Shear-strength properties of sands have been measured in triaxial tests at realistic stress levels and factors affecting the arching of sands over an opening have been examined. It was found that formation sands fail by crushing at much lower stress levels than do the sand used for gravel packing or fracture propping and that it is useful, therefore, to have a sand of high grain strength outside the perforations. To avoid sand production in certain wells, an arch of sand over the wellbore or the perforation is desirable, and tests show that even a low-strength plastic can provide the restraint necessary to stabilize this arch.