Abstarct: Wellbore stability and the control of safe drilling conditions in carbonate reservoirs are strongly influenced by mechanical heterogeneities, the magnitude and orientation of in-situ stresses, pore pressure, and the geometric characteristics of the wellbore. In this study, with the aim of evaluating the orientation and magnitude of in-situ stresses and performing geomechanical modeling for the optimization of drilling operations, well-log data, sonic logs, density, porosity, caliper, and FMI/DSI image data from a carbonate reservoir were analyzed. First, petrophysical and elastic parameters, including compressional wave velocity, shear wave velocity, Vp/Vs ratio, Poisson’s ratio, elastic moduli, and uniaxial compressive strength, were calculated and interpreted. Then, using these parameters, a one-dimensional geomechanical model of the well was constructed, and the depth variations of pore pressure, vertical stress, minimum horizontal stress, and maximum horizontal stress were evaluated. The results showed that the studied reservoir has significant vertical heterogeneity in terms of mechanical properties and geomechanical response. Variations in wave velocities, Young’s modulus, uniaxial compressive strength, and caliper indicated that some intervals are more sensitive to stress concentration and wellbore wall instability. The analysis of in-situ stresses showed that the stress magnitudes increase with depth, and the dominant stress order is Sv > SHmax > Shmin > Pp; therefore, the dominant stress regime in the studied interval was interpreted as normal to near-normal. In addition, the investigation of the difference between horizontal stresses and caliper evidence showed that an increase in the anisotropy of the horizontal stress field can be associated with wellbore ovalization, local enlargement, and an increased risk of instability. The analysis of the safe mud weight window showed that the suitable mud weight range is not constant along depth, and in deeper sections, especially below approximately 3000 m, drilling pressure control must be carried out with greater accuracy. The results related to the orientation of the maximum horizontal stress also showed that the dominant trend of SHmax is approximately in the northeast–southwest direction. baxsed on the obtained results, the use of a one-dimensional geomechanical model can play an effective role in identifying high-risk intervals, determining the safe mud weight window, reducing the likelihood of wellbore collapse and formation failure, and optimizing the trajectory and operational conditions of drilling in carbonate reservoirs.