Mechanical Earth Modelling for Petroleum Reservoir in Western Offshore India: Tensile Failure Study

Quantifying in-situ stress is crucial for predicting drilling-induced tensile fractures, wellbore failures, proper well placement, hydro-fracture treatment optimization and sand production. A comprehensive mechanical earth model incorporating pore pressure, stress state, and rock mechanical properties enable us to study the cause of failure observed in the well. The study is focused on a petroleum reservoir in Western Offshore India. In this study, an attempt is made to estimate in-situ stresses present in the field. Well-log data calibrated with available direct pressure measurements viz. Modular Dynamic Test (MDT) and Leak Off Test (LOT) data are used to predict the pore pressure and minimum horizontal stress. Vertical stress is estimated by extrapolating the density log; for minimum and maximum horizontal stress, the poroelastic approach is adopted. Key rock strength parameters were estimated using standard correlations and regional studies. Wellbore stability analysis was carried out, and the results were calibrated with the actual mud weight used. Natural fractures present in the reservoir are sensitive to stress distribution which in turn is sensitive to changes in pore pressure distribution. Many exploratory and development wells have been drilled in the area, but very few have recorded DSI (Dipole Shear Sonic Image) and FMI (Formation Micro-Scanner Image) logs. With the available log data, the study was carried out to quantify the rock mechanical parameters and the stress magnitudes of the field. The study aims to model the study area's geomechanical aspect for better prediction of drilling-induced challenges, thereby reducing NPT and optimizing drainage.