Development of fully coupled deviated well drill string dynamics simulation model for fatigue and vibration analysis

Area of Science:

• Drilling Engineering
• Mechanical Engineering
• Computational Mechanics

Background:

• Drilling operations in mining, geothermal, and oil sectors are costly.
• Current simulation models struggle with drill string dynamics in build sections and stress history generation.

Purpose of the Study:

• To present an improved simulation model for drill string dynamics.
• To enable accurate prediction of wellbore contact, vibrations, and stress history.
• To optimize drilling parameters and well trajectories for enhanced component fatigue life.

Main Methods:

• Developed a novel model with an efficient contact algorithm and reconfigurable submodels.
• Incorporated accurate boundary conditions and dynamic drill string length.
• Simulated multiple well trajectories, including build sections, to analyze responses.

Main Results:

• The model accurately predicts wellbore contact, axial, lateral, and torsional vibrations.
• Simulations revealed phenomena like whirling and snaking in various well sections.
• Stress histories were generated, enabling component fatigue life prediction.

Conclusions:

• The enhanced model aids in selecting optimal well trajectories and drilling parameters.
• Dogleg severity and kick-off points significantly impact downhole component fatigue life.
• This simulation tool can reduce drilling costs and extend equipment operational lifespan.