Abstract: L30up, the main reservoir in Huizhou 25-8 oilfeld, encountered an awkward situation in which the formation energy declined too fast but the water energy was in short supply. Meanwhile, there are no ground water injection equipment or pipe network facilities in the feld and the water flooding cannot be fulflled. Based on the geological analysis and the study on the compatibility of reservoir water, the author developed and designed the process program of Y-Block dump flooding/pumped water injection and canned ESP pump flooding/pumped water injection, in which the present oil wells in the oilfeld are utilized as the injection wells and the water in the layer above L30up injected into L30up. This design also meets the requirement of monitoring the temperature, pressure, and flow rate during injection, controlling the rate of water injection and protecting the cable. Field application showed that the water injection was effective, the cost of oilfeld development reduced, and the development effect by water flooding in the oilfeld enhanced.