An Update and Perspective on Field-Scale Chemical Floods in Daqing Oilfield, China

Abstract

AbstractChemical enhance oil recovery(EOR) like polymer flooding 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, polymer flooding has been successfully applied industrial scale in Daqing since 1996. Polymer flooding alone contributed more than 10 million tons of oil in 2006, which occupied 25% yearly rate of Daqing. Incremental oil recoveries of up to 14% of OOIP have been obtained in the field. Much experience and lessons have been learnt on large scale polymer flooding including: major factors that influence the recovery and methods to increase the recovery; measures to obtain a uniform polymer injection profile; and how to lower the costs of polymer flooding.Also Daqing performed researches on other chemical floods application, such as surfactant flood, micellar-polymer flooding(MP), alkaline flooding, alkaline-surfactant-polymer flooding(ASP), alkaline polymer flooding(AP), ASP-foam, especially ASP. Those chemical floods were field tested or are testing to increase oil recovery, to study the feasibility, to provide technical and practical experience for expanding, and to find suitable post-polymer flooding enhanced oil recovery EOR technology. Through tests, the injectivity and productivity of ASP systems, the best technique of artificial lift and stimulation measures for low efficiency wells, chromatographic separation analysis in condition of different well spacing, and economic analysis of chemical EOR were all studied. Pilot test results showed that over 20% OOIP recovery can be obtained over that of waterflooding, and is both technically and economically feasible.Overall, experiences and lessons learned in field applications of chemical floods in Daqing are extremely valuable not only for expanding chemical EOR to other areas of Daqing, also for other countries.