Abstract: Based on the relevant data of PVT experiment made by Eaton and Jacoby who used 27 condensate gas reservoirs in America, and the well-complete testing data of original formation pressure, original temperature, original gas-condensate ratio(GOR) and relative density of condensate from Banqiao
reservoir in Dagang in China, Kaladage field in the former Soviet Union, the new empirical equation on predicting recovery efficiency of condensate gas reservoir’s blowdown natural depletion was presented in the paper with the multivariate statistical analysis. At the same time, the influential factors of recovery efficiency of condensate were discussed. The empirical equation
was especially applied to Chinese condensate reservoirs whose content is under 400g/m3, and whose abandonment pressure is about 3.4MPa.

Key words: gas-condensate reservoir, blowdown natural depletion, multivariate statistical analysis, recovery efficiency, prediction method