Abstract: Critical rate is of great inportance in oil field development. On the bsis of the evalua-tion test of reservoir rate sensitivity, this paper presents the method of determing critical rate, and derives the formula of transforming lab critical rate into the critical rate under reservoir condition. At the same time, critical rete is combined with the oil field develop-ment to determine reasonable production rate, sate sensitivity damage radius and displac-ing velocity in development tests.

Key words: Critical flow, Critical rate, Development plan