Abstract: In this paper, the authors proposed three methods of calculating the economically recoverable reserve of an oilfield. These methods include: economic limitation method ( limiting water-cut and limiting GOR ), economic recovery method and economic limit well density method. The methods were developed on the basis of analyzing available reserve estimation methods,
taking into consideration the geological characteristics of Liaohe oilfield and the accounting and taxation system in China. These methods have been used by the authors to calculate the reserves of different pools in the oilfield, and the results have confirmed the methods' validity.

Key words: oilfield, economy, recoverable reserve, estimation, method