Novel Method to Upscale Low Salinity Core Flood Results to Field Scale Using Transport Coefficients

Abstract Low salinity water flooding has emerged as a promising low-carbon Enhanced Oil Recovery (EOR) technique. This method involves injecting water with significantly lower salinity than the formation water into the reservoir, resulting in a shift towards more water-wet relative permeability curves. While the underlying pore and fluid-level processes are complex, full-field simulations focus on capturing the relative permeability shift rather than the complete chemistry of the low salinity mechanism. A major challenge in implementing this technique is upscaling low salinity core floods to full-field simulation models. The numerical dispersion in full field models due to large grid blocks smears the low salinity front as it moves through the in situ high salinity zone. It delays the desalination of the grid cells and the onset of the low salinity effect. To address this, simulators use transition curves to dictate the shift between high and low salinity relative permeability curves based on grid block salinity. Researchers have proposed modified transition curves and relative permeability pseudo to compensate for numerical dispersion effects. We propose a workflow using transport coefficients alongside modified transition curves to counter numerical dispersion in coarse grid simulations of low salinity water flooding. Transport coefficients are scaling factors that modify flowing mole fractions with respect to in-place mole fractions in a grid block. Our methodology involves creating high-resolution models with different dispersivity as ground truths and generating transport coefficients for solute components in the coarse grid model. Then we conduct two-phase water flooding runs on the high-resolution model to simulate low salinity injection response. Finally, we use the pseudo relative permeability curves, transport coefficients, and modified transition curves to match the coarse grid model's oil recovery, water cut, and salt production profile to the high-resolution model We applied this methodology using low and high salinity relative permeability curves from a giant carbonate field where a pilot study demonstrated the low salinity effect. The results of this upscaling methodology are promising, with the model accurately capturing salt production and oil recovery profiles. This level of accuracy cannot be achieved by modifying transition curves alone. We also present the methodology for generating transport coefficients and discuss the approach's limitations. This workflow can be valuable for simulation engineers in fine-tuning the upscaling of low salinity models, ultimately improving the accuracy of full-field simulations for low salinity water flooding EOR projects.