『(Abstract)
　This paper provides a new method to estimate recovery factors of oil resources. The China National Petroleum Assessment (2003-2007) (CNPA 2007) evaluates in-place oil resources and applied the recovery factor (RF) to estimate recoverable oil resources. The RF of oil resources plays an important role in the CNPA 2007. Based on the geological features, 24 types of oil assessment units are defined, such as the Mesozoic rift unit, the Mesozoic and Cenozoic foreland unit, etc. Through the recovery factor statistics of oil reserves (discovered) in different accumulations, as well as the potential analyses of enhanced petroleum recovery, appropriate RF valuing standards of oil resources (discovered and undiscovered) in different assessment units are developed. Calculation methods of oil resource RFs are established, including the appraisal standards, scoring, and calculation steps of oil resource RFs. Through the case studies, the valuing and appraisal standards of oil resource RFs are verified. Robust appraisal standards allow the RF method to be a valuable tool to effective assessment of China's recoverable oil resources.

Key Words: oil; resource appraisal; recoverable resources; assessment unit (AU); recovery factor.』

Introduction
Study methods
　Data sources
　Research steps
　AU classification
　Development of the RF standards
Calculation methods of RFs
　Appraisal standards of RFs
　Scoring methods of RFs
　Calculation steps of RFs
Case studies
Conclusion
Acknowledgments
References