For the establishment of the highest sand-free production rate through a perforated completion in friable sandstone formation, the stability of the perforation tunnel is of critical importance. The stability of the perforation tunnel depends on the degree of formation damage in the vicinity of the tunnel, and on both the intrasic strength of the formation and the effective stress distribution around the tunnel.
A prediction model has been developed to predict sand stability in friable sandstone formations from stress analyses around a perforation tunnel whilst the formation is producing. Failure or instability of the perforation tunnel was studied in terms of a failure initiation.
The application of the model allows evaluation of the degree of formation damage upon the maximum sand free production rate. Examples of the application of the model are provided. The concept of a "stability ratio" is introduced to predict the degree of instability which can be anticipated under specific production conditions.