An improved method for fitting relative permeability curve using nuclear magnetic resonance imaging

Nuclear magnetic resonance (NMR) technology can be used for online monitoring of the fluid flow in cores. Especially, NMR imaging can visualize the injected fluid distribution and the residual oil location, as well as show the displacement effects of different injected fluid. This provides a new perspective for understanding displacement mechanisms. This paper proposes an improved method for fitting relative permeability curve based on NMR imaging. We established formulas to quantitatively calculate the water saturation profiles at different displacement times. Using the water saturation profiles, the water front position, residual oil saturation, and capillary end effect were analyzed to visualize the fluid flow inside the core. Base on the water saturation distribution, we analyzed the waterflooding characteristics more accurately. Using the oil-water relative permeability equation proposed by Honaropur, the relationship between the water cut and water saturation at the outlet section of the core was fitted to obtain the oil-water relative permeability. Compared with the commonly used Johnson-Bossler-Naumann method for calculating relative permeability, the method proposed in this paper has fewer fitting parameters, is highly precise, and is easy to operate. Additionally, it also broadens the application of NMR technology in the field of oil exploration and development.