A one-dimensional geomechanical model provides a quantitative interpretation of in-situ stress conditions and the physical and mechanical properties present in hydrocarbon fields. This model is derived from well log data and can be used to assess borehole stability, determine the safe mud weight window, optimize production, prevent casing collapse, etc. Considering the importance of reservoir geomechanics in the oil and gas industry, this study focuses on borehole stability analysis based on geomechanical studies through the construction of a one-dimensional geomechanical model. To achieve this, the elastic and strength parameters of the studied formation were first determined using well log data and correlations developed from laboratory studies. Then, recognizing that estimating pore pressure is essential to prevent drilling-related hazards – and given the high cost of direct pore pressure measurement tools – two indirect methods, the compaction (or undercompaction) method and Eaton’s method, were used to estimate pore pressure in the studied reservoir. A comparison of the results from these two methods with RFT test data revealed that the compaction method provides higher accuracy than Eaton’s method. Subsequently, by estimating in-situ and induced stresses in the studied well, the lower and upper bounds of the safe mud weight window were calculated using the Mohr–Coulomb, Hoek–Brown, and Mogi–Coulomb failure criteria. A comparison of the results from these three approaches indicated that the Mohr–Coulomb criterion delivers greater accuracy. The faulting regime in the studied well, based on the magnitudes of horizontal and vertical stresses, is classified as strike-slip.