Tubular Makeup Speed Control via Torque Feedback
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Solution Overview
Problem
Current methods for achieving target torque during tubular makeup in oil or gas well construction are inefficient, often resulting in over-torque due to manual control or require lengthy closed-loop control processes, and lack precise control to ensure consistent and high-quality connections.
Innovation Solution
A method involving a controller that dynamically calculates a set point for rotational speed based on measured torque, using a sigmoidal function to automatically reduce speed to zero when a target torque is reached, thereby preventing over-torque and ensuring consistent connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual control of tong assembly is used during makeup, then operator can control the process, but over-torque occurs when rotational speed is too high at final stage
Solution Approach 1:
The system continuously measures torque during the makeup process and uses this feedback to automatically adjust rotational speed. The controller reduces speed when torque approaches the target value, preventing over-torque while eliminating the need for manual intervention. This closed-loop feedback mechanism resolves the contradiction by providing precise torque control without requiring manual operation.
Solution Approach 2:
The patent replaces manual mechanical control with an automated electronic control system that uses torque sensors and programmable logic to manage the makeup process. The controller automatically adjusts rotational speed based on real-time torque measurements, substituting human operator control with an automated system that provides consistent, precise torque control without over-torque issues.
2Manufacturing precision
If closed-loop control of torque or rotational speed is used, then target torque can be achieved, but makeup time increases significantly
Solution Approach 1:
The system dynamically adjusts rotational speed during the makeup process based on real-time torque measurements. Instead of using a fixed slow speed throughout, the controller maintains higher speeds when torque is low and automatically reduces speed only when approaching the target torque value. This dynamic speed adjustment maintains productivity while achieving precise torque control, resolving the time-precision contradiction.
Solution Approach 2:
The system performs preliminary high-speed rotation to quickly advance the makeup process through the initial stages where precise torque control is less critical. Only when torque approaches the target value does the system activate speed reduction, allowing the majority of the makeup process to occur at higher speeds. This preliminary action approach minimizes total makeup time while ensuring precise torque achievement.
3Device complexity
If predetermined time rotation at constant speed is used, then makeup process is simple, but torque accuracy depends on heuristic values and system reactions
Solution Approach 1:
The system incorporates real-time torque measurement and feedback control to automatically adjust rotational speed during makeup. The controller continuously monitors torque and modifies speed based on actual torque development, eliminating dependence on heuristic predetermined times. This feedback mechanism provides accurate torque control while maintaining relatively simple system architecture through programmable logic.
Data Source
Figure 1A~1C
Figure 2A
Figure 2B
AI summary
A method for making up a tubular joint comprises rotating a first tubular relative to a second tubular at a first speed to engage the first and second tubulars, measuring a torque between the first and second tubulars while rotating, and starting an automatic speed reduction operation to reduce rotating from the first speed to zero upon detection of a trigger condition. Starting an automatic speed reduction operation comprises calculating a set point of a relative rotational speed between the first and second tubulars using the measured torque, and using the calculated set point with a controller to control the relative rotational speed between the first and second tubulars.