Abstract: The Chengdao Oil Field is the first shallow sea oil field put into development in China. The upper Guantao formation is fluvial sand and shale deposition and it is enrichment in oil and gas. This formation is divided into five sand, the third and the fourth sand group are the main oil-bearing reservoir. The main hydrocarbon in this research area is heavy oil. Because of the difference of physical properties between oil-reservoir and water-reservoir is small, it is difficult to accurately identify the heavy oil through the traditional inversion. In this paper, a sensitive heavy oil indicator is constructed, and the oil indicator factor is retrieved by extended elastic impedance inversion. This method has good application in this area.