Methods and systems for predicting crude oil blend compatibility and optimizing blends for increasing heavy crude oil processing are described. The method includes receiving ratios of physical parameters of crude oils for optimization of crude oil blend. The physical parameter ratios are based on Kinematic Viscosity (V), Sulphur (S), Carbon Residue (C), and American Petroleum Institute (API) gravity. The crude oil blend compatibility (K model) is determined and generated using the physical parameter ratios. The K model is developed by coefficients obtained by regression analysis between the ratios of physical parameters of known crude oils and composite compatibility measure determined from multiple compatibility test results of the known crude oils. The predicted crude oil blend compatibility can be used for optimizing heavy crude oil processing.