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Daqing, the largest heterogeneous multi-layer none marine reservoir oilfield in China celebrated its 45thbirthday in Ocotober 2005. Boasting 27 continuous years of plateau oil production over one MMBOD, the largest industry polymer-flooding oilfield in the world, and excellent developing effect, its development strategies and techniques applied provide a road map to maximize oil recovery:Life cycle reservoir studies give insight into reservoir, and providea foundation for plan of development, implementation of infilling, and associated workover jobs such as zonal stimulation, zonal waterplugging.Early reservoir pressure maintenance by internal water flooding maintains reservoir pressure close to its original status, providing sufficient reservoir energy, enabling high and stable production rate for a long period as well as improving recovery.Performance monitoringconducted in the whole process of development, of which, separate layer performance monitoring is one of the most important foundation for in-depth understanding subsurface development potential.Pilot tests are conducted before any key development strategies and measures are applied to ensure their success.Separate layer production/water injection of multi-layer and heterogeneous reservoir and novel completion are the key measures for enhancing poorly drained reservoir water flooding, improvingits sweeping efficiency.Multi-time and progressive infilling drilling develops bypass oil resulting fromthe geological complexities of reservoirs.Widely applying polymer flooding enhances oil recovery by over 10%.Innovativetechnology makesdevelopment of marginal reservoirs/fields economical. Outstanding development of the giant field has proven the validity of above strategies and techniques with an oil recovery factor current at over 51% in the main block. Introduction Major challenges facing petroleum industry are to maximize recovery for a mature asset, extend the life of traditional producing areas, to optimize development of a new field as new reserve becomes increasingly complex. The average conventional crude oil recovery quoted in petroleum industry is 35%. However, a 10% incremental recovery translates to about 1.4 trillion barrels of recoverable resources, or roughly an additional 50-year supply of global crude consumption at current rates (Saleri, 2006). The estimate reminds us that there are vast potential resources of hydrocarbons in the world thatare waiting for new technology to tap them. Numerous efforts focusing on matured assets aiming at finding new oil in old reservoir and revitalizing old-field have been made. These efforts emphasize the importance of application of integrated approaches or multidisciplinary reservoir management. However, maximizing oil recovery is not only a system engineering, but also lifecycle process running through various stages of oilfield development from initial development, production increasing and reaching its plateau, to production declining as the oil field reaches the mature state of its development.