Reprint of: State-of-the-art on ultrasonic oil production technique for EOR in China.

Ultrasonic oil production technique for enhanced oil recovery (EOR) attracts more attention due to its high adaptability, simple operation, low cost and zero pollution to the oil reservoir. In this paper, recent new downhole tools used for enhanced oil recovery developed in China are summarized. Furthermore, research advance on some key problems that affect the widespread application of ultrasonic oil production technique in China are also summarized in view of what are the primary factors that influence crude oil paraffin inhibition and viscosity reduction, whether ultrasonic excitation is better than chemical agent for any plugs removal and whether ultrasound-chemical combination plug removal technology has the best plugs removal effect. The purpose of this paper is to provide reference for the broad application of ultrasonic oil production for enhance oil recovery.