Geomechanical insights for enhanced wellbore stability in the Sarvak formation: A comprehensive analysis of pore pressure and fracture gradient

This study investigates wellbore stability challenges in the Sarvak Formation of the Azar field, where complex lithology renders conventional pore pressure estimation methods insufficient. An empirical approach was employed to analyze the data from three offset wells to refine pore pressure and fracture gradient models. The analysis revealed that stress-induced breakouts occur frequently in fractured zones, with the maximum horizontal stress consistently trending northeast at approximately 115.83 MPa. A strong correlation was established between rock strength and wellbore stability, with a reduction in residual rock strength quantified at approximately 30% due to fracturing. Geomechanical modeling was integrated with real-time drilling data, enhancing the understanding of the stress regime and its implications for drilling operations. Support vector machine (SVM) algorithms were applied to enhance the predictive capability of the pore pressure and fracture gradient models. The SVM model achieved a prediction accuracy of 95%, with a mean absolute error of 0.00069 MPa, indicating its effectiveness in capturing the relationships between geological features and pore pressure. The results indicate that a mud weight range of 1150-1200 kg/m 3 is optimal for minimizing drilling instability. Furthermore, sealing fractured zones and reducing mechanical vibrations are essential for maintaining wellbore integrity. This research advances the understanding of geomechanics in carbonate formations and offers quantitative recommendations for future drilling operations in the Azar field. The presented methodologies facilitate improved drilling strategies, contributing to safer and more efficient hydrocarbon extraction. Integrating empirical data, machine learning, and real-time monitoring offers a novel approach for similar geological settings, improving wellbore stability analysis.