Advances in Polymer Flooding and Alkaline/Surfactant/Polymer Processes as Developed and Applied in the People's Republic of China

Polymer flooding (PF) and alkaline/surfactant/polymer (ASP) flooding have been applied throughout the world for more than 20 years. However, few large-scale successes with these processes have been reported, except in China. To date, the PF process has been applied successfully in several major Chinese oil fields such as Daqing and Shengli. PF alone contributed approximately 250,000 BOPD of production in 2004 from these two fields. Incremental oil recoveries of up to 14% of the original oil in place (OOIP) have been obtained in good-quality reservoirs. Profile modifications by use of polymers and a crosslinker to form colloidal-dispersion gels (CDGs) also have been implemented successfully in large-scale production operations in China. Results show that the CDG process is more cost-effective than the PF process. Several ASP floods also have been pilot tested in various Chinese oil fields. Incremental recoveries of up to 25% OOIP have been reported, although commercial-scale applications have not been implemented. Plans to implement three large-scale projects have been made for 2006 in the Daqing oil field. This paper discusses the progress made in these processes in China over the last 20 years, including field results, new concepts, and economics.