Quantitative Analysis Method of Conversion of Type of Microscopic Remaining Oil Based on CT Technology

The distribution and mutual conversion of remaining oil during the process of oilfield development constitute an important basis for guiding the exploitation of remaining oil potential. Based on the visual core displacement method of CT scanning technology, CT scanning images of the oil–water phase in core models at different displacement stages were obtained, and the remaining oil types were classified. On this basis, image segmentation technology was employed to establish the transformation analysis method of remaining oil types, and the mutual transformation of microscopic remaining oil types at different displacement stages was clarified. The ability of displacement media to utilize various remaining oils was further clarified. The results demonstrate that there are significant differences in the distribution of remaining oil after the injection of different displacement media. The displacement media can not only spread the continuous-phase oil in large pores to varying degrees but also transform the discontinuous oil into continuous-phase oil in some small pore tubes, showing a “converging” transformation law, thereby enhancing the utilization degree of various remaining oils. Additionally, the surfactant’s unique capabilities of “micellar solubilization, emulsification, and oil carrying” have good adaptability to the discontinuous oil phase and can transform the discontinuous-phase remaining oil into continuous-phase remaining oil, namely columnar–film–cluster–recovery.