Abstract: Lukeqin deep heavy oil reservoir was developed by conventional waterflooding process. Because of high oil/water viscosity ratio, obvious plane and section injection/production contradiction, and water breakthrough was very serious. After using the separated zone development, separated zone water injection, fine water injection and chemical profile control techniques, the plane and section injection/production contradiction has been improved, the waterflood producing degree has been increased from 17.1% in 2008 to 40.9% nowadays, the reservoir pressure has been recovering year by year, and the natural decline rate has been controlled effectively. The mechanism study showed that because of high oil/water viscosity ratio, the mobility ratio was greater than one after water breakthrough. As the water cut increasing, the mobility ratio was raised fast, thus the injected water fingering and breakthrough would be more serious. The study shows that the waterflood response radius is about 100~300 meters. The distance between water breakthrough front and flooded front is about 10~30 meters. The characteristics of water drive of single well or oilfield appear in convex. Medium?high water cut stage is its main production stage