Top Drive Torque Control for Drill String Torsional Vibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Drilling operations face challenges due to torsional vibrations in drill strings, leading to stick-slip phenomena that cause excessive wear, premature tool failures, and poor drilling efficiency, as the existing control systems are ineffective in mitigating these vibrations.
Innovation Solution
A control system that regulates the torque output of the drill string drive based on rotation measurements at the surface, minimizing the reflection of torsional vibrations by setting a non-reflective torque-speed ratio, using a proportional-derivative (PD) or proportional-integral (PI) controller to absorb and mitigate torsional waves at the junction between the drill string and the top drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional control system is used to rotate the drill string, then the drill bit can maintain rotation, but torsional vibrations and stick-slip phenomena occur causing excessive wear and premature tool failures
Solution Approach 1:
The control system continuously monitors the rotational speed of the drill string and uses this feedback to dynamically adjust the torque output. The controller compares the actual rotational speed with the desired speed and modifies the torque command accordingly to suppress torsional vibrations and prevent stick-slip phenomena, thereby extending tool life while maintaining reliable operation
Solution Approach 2:
The system dynamically changes the torque parameter based on real-time rotational speed measurements. By adjusting the torque-speed relationship and using proportional-derivative or proportional-integral control parameters, the system optimizes the torque output to minimize torsional vibrations and stick-slip occurrences, improving tool reliability without compromising drilling performance
2Productivity
If the top drive rotates the drill string at constant angular velocity, then drilling operation continues, but torsional vibrations are not effectively mitigated
Solution Approach 1:
The control system transitions from a static constant-speed operation to a dynamic control mode where the torque is continuously adjusted based on real-time rotational speed feedback. This dynamic approach allows the system to maintain productive drilling operations while actively suppressing torsional vibrations and stick-slip phenomena, thereby improving both drilling rate and operational stability
Solution Approach 2:
The system uses real-time feedback from rotational speed sensors to dynamically adjust torque output. This closed-loop control ensures that productivity is maintained by keeping the drill bit rotating effectively while simultaneously improving operational stability by mitigating harmful vibrations and stick-slip events through continuous parameter optimization
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively dampens torsional vibrations, reducing stick-slip occurrences, maintaining consistent rotational speeds, and enhancing drilling efficiency by absorbing all torsional vibrations at the top drive, thereby reducing wear and extending tool life.
Implementation Method 1
the drill string can also exhibit a complicated dynamic behavior resulting in one or more of axial, lateral and torsional vibrations
Implementation Method 2
A control system may be used to regulate the torque output of the drill string drive
Implementation Method 3
A control system that regulates the torque output of the drill string drive based on the rotation of the drill string as measured at a surface location
Data Source
AI summary
A method includes generating a torsional wave that propagates in a drill string having a drill bit coupled at a first end of the drill string and a top drive coupled at a second end of the drill string, and determining first and second components of the torsional wave. The first component propagates from the drill bit to the top drive and the second component propagates from the top drive to the drill bit. The method further includes calculating a first control signal to mitigate the first component, calculating a second control signal to regulate the second component, and generating a torque command based on the first and second control signals to control the top drive to dampen the torsional wave.