Structural Parameters Optimization of Elastic Cell in a Near-Bit Drilling Engineering Parameters Measurement Sub

Area of Science:

• Engineering
• Geophysics
• Materials Science

Background:

• The downhole engineering parameters measurement sub is critical for rotary steerable drilling systems.
• Reliable performance of this sub is challenged by complex downhole conditions.
• The elastic cell is a key, yet vulnerable, component requiring structural optimization.

Purpose of the Study:

• To systematically study and optimize the structural parameters of the elastic cell within the measurement sub.
• To ensure the measurement sub's reliability under demanding downhole environments.
• To develop a robust methodology for elastic cell design.

Main Methods:

• Summarized relationships between measurement sensitivities, structural stiffnesses, and strength.
• Formulated structural parameter selection as a multi-objective optimization problem.
• Employed the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) for optimization.
• Utilized Finite Element Method (FEM) for static and dynamic strength analysis.

Main Results:

• Developed an optimization strategy to rapidly generate a design database for elastic cells.
• FEM analysis confirmed the effectiveness of the proposed method for static strength and measurement performance.
• Transient dynamic analysis validated the rigor of the developed methodology framework.

Conclusions:

• The proposed optimization strategy effectively designs elastic cells for downhole measurement subs.
• This approach enhances drilling efficiency and mitigates drilling risks.
• The methodology demonstrates significant practical applicability and extensibility.