The Polymer Flooding Technique Applied at High Water Cut Stage in Daqing Oilfield

Abstract Daqing Oilfield has complex geological conditions, multiple reservoir layers and severe areal and vertical heterogeneity. After feasibility study, polymer flooding is selected as the dominant EOR technique. Polymer flooding in Daqing Oilfield has experienced four stages: laboratory study, pilot tests, industrial field tests and commercial application. Reservoir engineering techniques, such as individual injection parameters design, separate layer polymer injection, in-depth profile modification and comprehensive adjustment, are discussed and the technical-economic effects of polymer flooding are evaluated. The result shows that due to the conversion from water injection to polymer flooding at the water cut of 90-95%, the recovery factor is raised by 13.3% (OOIP) at the water cut of 98% compared to water flooding. At the same time, production rate is increased and water injection volume is reduced. The average operation cost of polymer flooding is $0.1-2.83 /barrel lower than that of water flooding. The polymer flooding of Daqing Oilfield at high water cut stage has better technical-economic effects than full term water injection. Until the end of 2011, the oil production of polymer flooding has exceeded 1000×104 ton(7.31Mbbl) ten years in a roll, and the cumulative production has reached 1.58×108 ton (1.15Bbbl). Polymer flooding has become a major technique in the sustainable development of Daqing Oilfield.