Abstract: Core micro flow visualization is an important method to study the microcosmic mechanism of the chemical flooding.The latest results of core micro flow visualization by MRI technology in our research group was introduced in detail.Some questions on low field MRI core displacement system (MRICDS)were put forward,and improvement and optimization were made from the two aspects of hardware and software to eliminate interference factors.The exper-iments of fluid image test during water-flooding process were successfully carried out using the improved MRICDS.The real-time signals of NMR and MRI of the oil-water distribution during the flow test were collected,and NMR-T2 spectrums and oil or water distribution images were obtained in different stages.The images with high resolution can meet the request of visually an-alyzing the fluid distribution in the core.Experimental results show that residual oil decreases with PV increasing.The trendline of oil distribution drops rapidly first and then slowly.Images also show the phenomenon of residual oil gathering in the end area in core flow tests and its influ-ence range is about 4mm from the end.A new method of oil saturation by the oil-water distribu-tion map of MRI was introduced,and its results are consistent with that of the traditional method and the error is within 10%.This also shows that the reliability of the oil-water distribution map.This provides a new method for the study of oil saturation.Especially the other advantage
of the method is that it can analyze the oil-water saturation at any local position.The results also indicate that the new method of MRI is worthy of further development for fluid distribution visu-alization during core micro flow.