Abstract
The downhole engineering parameters measurement sub is a key component of the rotary steerable drilling system. To enable a measurement sub to serve reliably under downhole complex conditions, the structural parameters optimization of its key but weak elastic cell is systematically studied. First, the multiple relations among measurement sensitivities, structural stiffnesses, and strength during structural parameters design are summarized. Second, the selection of the structural parameters of the elastic cell is characterized as a multi-objective optimization model, which is solved using the non-dominated sorting genetic algorithm II (NSGA-II). Furthermore, the finite element method (FEM) is used to verify the measurement performance and static strength of the proposed structure. Finally, transient dynamics analysis is applied to investigate the dynamic strength of the designed structure. The results show that the proposed parameters optimization strategy can quickly obtain the database for the structural parameters design of an elastic cell. The static analysis results based on the FEM further verify the effectiveness of the proposed method. Transient dynamic analysis also reveals the relative rigor of the proposed methodology framework to some extent. This work has practical significance for improving the drilling efficiency and reducing drilling risks. In addition, this proposed methodology has good extensibility.
Highlights
With the consumption of conventional oil and gas resources, some unconventional resources, such as shale gas, tight oil and gas, are becoming popular [1]
A multi-objective optimization model is established to characterize the multiple relationships among measurement sensitivities, structural stiffnesses, and strength in the design of structural parameters
An evolutionary algorithm based on non-dominated sorting genetic algorithm II (NSGA-II) is employed to find a Pareto-optimal set for the objective functions in Equation (20)
Summary
With the consumption of conventional oil and gas resources, some unconventional resources, such as shale gas, tight oil and gas, are becoming popular [1]. By properly designing or arranging the sensors on the near-bit measurement sub, multiple drilling engineering parameters, such as weight on bit (WOB), torque, and bending moment, can be accurately measured. The design of the sensor elastic cell of a downhole engineering parameters measurement sub is a complex task. Fan et al [25,26] discussed the optimization design of an elastic cell of a downhole engineering parameters measurement sub, and considered the trade-off between measurement sensitivity and stiffness in the design. A systematic and clear methodology for the structural parameters optimization of elastic cells is proposed This methodology is easy to use, expand, and connect with other studies on topics such as sensor calibration and data transmission.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
