Sand production for the sandstone reservoirs is a major difficulty that needs to be remedied early in the life of the reservoir. Sieve analysis of the core samples is an effective and straight forward methodology to tackle the problem. The work presented here was for a prolific thick sandstone reservoir in an off-shore field in Iran. Core samples were crushed to the grain size and standard sieve analysis was performed. Characterization of grain size distribution was achieved by sieve analysis based on statistical parameters. Four statistical measurements for the sieved samples were performed. The strategy produced the most probable grain size of 200 microns and 150 microns for the upper and lower layer, respectively. This helped in selecting the appropriate wire wrapped screen or slotted liner for preventing sand production. This proved to be effective and no sand production is presently observed with this design of completion. In addition, statistical analysis revealed some correlation between sorting of grain size and permeability of the cores but no correlation with sand grains mean size. However, as expected the porosity increased directly with sorting and it had no correlation with the sand grains mean size.