An integrated geomechanical-drill string trajectory optimization method for initial wellbore design.

Area of Science:

• Geosciences
• Petroleum Engineering
• Geomechanics

Background:

• Designing stable wellbore trajectories in heterogeneous formations is challenging due to complex interactions between geological uncertainty and mechanical constraints.
• Conventional methods often rely on geometry-based or single-physics approaches, which may not adequately address non-linear interactions.

Purpose of the Study:

• To develop an integrated geomechanical-drill string framework for robust wellbore trajectory design.
• To enable uncertainty-aware constraint enforcement using multi-source log data.
• To efficiently resolve complex search spaces in trajectory optimization.

Main Methods:

• Encoding formation feasibility through a probability corridor and high-risk mask derived from multi-source logs.
• Coupling geomechanical and drill string responses into a unified objective-constraint structure.
• Employing a hybrid global-local optimization strategy to handle non-convex search spaces.

Main Results:

• The framework consistently avoids unstable geological zones.
• It effectively suppresses curvature concentration in wellbore trajectories.
• Compliance with pressure-window and mechanical limits is maintained throughout the design process.

Conclusions:

• The presented integrated framework offers a robust and deployment-ready paradigm for designing wellbore trajectories in complex formations.
• This approach enhances wellbore stability by accounting for geological uncertainty and mechanical constraints.
• The method demonstrates significant improvements over conventional trajectory design techniques.