Abstract: Because there is no methods for systematic evaluation of benefit output available to date, it is difficult to quantitatively describe benefit from an old oilfield. This study developed a model and presented a method for estimating the benefit output, in light of productive regularity of an old oilfield and incoming time-cost function,integrated with production indexes and economic factors. It is indicated that the method is relatively comprehensive, the equations are practically identified by field data. Hence, it is of importance for related departments to evaluate the economic benefit of an old oil field.

Key words: oilfield, benefit, output, method