Prediction of Minimum Mud Weight for Prevention of Breakout Using New 3D Failure Criterion to Maintain Wellbore Stability

Oil and gas extraction is difficult without understanding the subsurface formation up to the desired depth. Wellbore instability, such as lost circulation and pipe sticking, is an issue when drilling a well for a high-temperature, high-pressure reservoir. To maintain the stability of the borehole, optimum drilling mud should be simulated by preventing formation fracture or formation break-out. The main goal of this work is to propose a model with a 3D extended Mohr–Coulomb criterion that helps to achieve maximum wellbore stability using drilling fluid weight as a controlling parameter. This criterion includes the effect of the intermediate principal stress as a linear relation of principal stresses. this study also validated the extended Mohr–Coulomb criterion for in situ failure. To implement a new criterion on the wellbore for stability, a numerical mechanical earth model (NMEM) is developed as an empirical correlation of the wire-line well-log data. The mud weight is calculated using mechanical parameters derived from NMEM and lithology. The pore pressure, fracture pressure, and stress profile were also predicted by this NMEM, which gives insights into the subsurface formation's faulting regime. To achieve maximum wellbore stability, optimum mud weight is recommended based on the stress profile and faulting regime. One onshore and one offshore well is taken as a case study from the online dataset via the Dutch Oil and Gas Portal (NLOG) to simulate the NMEM. Mud weight using Mohr–Coulomb and Mogi–Coulomb criteria was also used to compare mud weight predicted by the proposed new 3D linear failure criterion. The treading line for the mud weight by the new 3D linear criterion is more accurate as a new criterion considering the effect of \({\sigma }_{2}\). The new criterion has been proved to be more specific, easy to compute, and a unique solution for estimating parameters using NMEM. This NMEM, which includes a new linear 3D criterion, can also solve sand production issues, hydrofracturing, and CO₂ sequestration.