Abstarct: Torque and drag are among the most critical mechanical parameters in directional and extended-reach drilling operations, playing a decisive role in safe well design, pipe sticking prevention, and drilling optimization. With the increasing complexity of wellbore trajectories and the development of extended horizontal sections, accurate prediction of these parameters has become increasingly vital. Although conventional analytical models provide a fundamental frxamework for calculating forces acting on the drill string, they exhibit limitations in representing contact behavior, actual buoyancy effects, and the contribution of drilling fluid viscosity. In this study, the performance of the classical model and the three-dimensional analysis model was evaluated using real data from a directional well. Subsequently, an enhanced model was developed in which the buoyancy factor was modified baxsed on actual fluid density, friction factors were differentiated for various operational conditions, and viscous torque effects were incorporated. Quantitative results demonstrated that the enhanced model exhibits significantly superior agreement with field data, with the coefficient of determination for key parameters increasing up to 0.9998 and mean absolute percentage error remaining below one percent in certain operational modes. Furthermore, off-bottom torque was predicted with high accuracy, whereas conventional models exhibited considerable underestimation. Comparative plot analysis also revealed that force and torque distribution in the curved and horizontal sections of the wellbore is more realistically represented by the enhanced model. Accordingly, the developed model not only demonstrates higher numerical accuracy but also exhibits greater physical consistency with actual drilling system behavior. It can serve as an effective tool for pre-drilling design, pipe sticking risk assessment, and engineering decision-making optimization in directional wells.