Abstract: Rock deformation, varied cock compressibility coefficient and permeability stress- sensibility will occur in the process of overpressured gas reservoir development. The experiment results are used to set up the material balance equation and deformed media gas well productivity equation with consideration of continuous change of the compressibility. By these equations, a new method for matching the production data of gas well and evaluating the well-controlled dynamic reserves in such a gas reservoir. The application results shows that the rock compressibility coefficient and permeability stress-sensitivity of an overpressured gas reservoir has a big effect on calculation of the reserves. If these factors are not considered, the calculated reserves will be lower by 15%~20% than the real reserves.

Key words: overpressured gas reservoir, material balance, rock compressibility coefficiant, stress sensitivity, productivity equation, reserve