Microscopic remaining oil distribution and quantitative analysis of polymer flooding based on CT scanning

Abstract

To investigate the distribution characteristics of remaining oil after polymer flooding, the core samples of different stages of water flooding and polymer flooding were scanned and imaged based on CT scanning technology. The oil, water and rock were divided into three phases by image analysis method, and the corresponding digital cores were constructed. Through the qualitative and quantitative analysis of the two-dimensional image and three-dimensional structure at the same position, the quantitative characterization of the micro-residual oil distribution in different displacement stages is finally realized. The results show that, the polymer flooding can significantly improve the sweep efficiency, which can increase the oil recovery by 11.45% compared with water flooding. The remaining oil in the pore is mainly network and multiple, and mainly network distribution at the stage of water flooding. After adding polymer, the proportion of multiple remaining oil increases significantly and becomes the main occurrence state of remaining oil. Affected by Jamin effect, multiple residual oil in the pore is difficult to be recovered because it cannot pass through the throat. The radius of this part of remaining oil is usually 1.34-1.5 times that of the throat radius. Cited as : Wang, X., Yin, H., Zhao, X., Li, B., Yang, Y. Microscopic remaining oil distribution and quantitative analysis of polymer flooding based on CT scanning. Advances in Geo-Energy Research, 2019, 3(4): 448-456, doi:10.26804/ager.2019.04.10