Sand production and well productivity in conventional reservoirs

The productivity of wells in sandstone reservoirs is affected by the permeability of the rock and its change with applied stress, and the geometry changes due to rock failure and sand production. Sand production experiments on thick wall cylinder sandstone specimens with radial fluid flow were performed in a variety of sandstones to correlate the productivity with the applied external stress, the deformation of the inner hole and the amount of produced sand. Theoretically, the productivity in the thick wall cylinder test and in an open hole well were analyzed by distinguishing between the pre-sand production phase, where permeability changes due to the applied stress dominate the productivity changes, and the post-sand production phase where geometry changes due to sand removal dominate.