Abstract: In order to reduce energy consumption during water injection for oil recovery, the decreasing voltage method and flow control method as well as their limitations are analyzed. The comprehensive method is established by combining the decreasing voltage method and flow control method. Through computer control, the method has brought about huge economic benefits in water injection system in oilfields. Therefore the comprehensive method will be widely used in water injection and energy-saving engineering.

Key words: Water Injection Equipment, Energy-Saving, Comprehensive Method.