Geomechanical Constrains for Assisted Wellbore Trajectory Design – Stability Navigation Algorithm

In wellbore stability studies, traditional methods to predict optimum drilling directions on an established stress regime involve punctual contour plots tied to a corresponding depth, which are treated as a discontinuous set of solutions for one continuous problem: the trajectory definition. In other words, desired well positions are isolated estimations that take time to refine into one integrated stability proposal. Due to this obstacle, these studies focus primarily on delivering optimum mud plans that only quote on reference drilling directions, instead of integrated mud-trajectory optimized solutions. A Stability Navigation Algorithm (SNA), developed in this study, represents a new philosophy on addressing drilling direction effects in wellbore stability. Managed stress redistributions around a borehole constitutes the basis on the algorithm’s navigation (search) criteria, resulting in interesting exposures of path volumes where complete “stable” trajectories are viable, based on geomechanical constraints for breakout widths and fracture potentials, trajectory delimitations, DLS and mud weights. The main idea is to upgrade unbound well positions into complete trajectories with automated recursive wellbore stability analysis performed by a SNA. The algorithm runs on a 3D geomechanical model, thus rock mechanical properties distribution is a mayor factor affecting possible solutions. This study analyses the development of the algorithm, its computation strategy and a proposed workflow or application method, based on the interpretation of the resulting behaviors of the outputs. Application scenarios are discussed, as well as the input parameters, and 3D visualization (interpretation) techniques.