Top Drive Torque Control for Drillstring Torsional Vibration Damping
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Solution Overview
Problem
The existing drilling technologies face challenges in efficiently controlling vibrations and oscillations in drillstrings due to torsional wave propagation, leading to increased costs and delays caused by the need for frequent reinstallation and recalibration of supplemental sensors, which are often not permitted on rented drilling rigs.
Innovation Solution
A downhole drilling system that uses a dynamics model to estimate disturbance torque at the connector, allowing for the generation of torque commands that dampen vibrations by adjusting top drive motor torque based on rotational inertia, friction coefficients, and static friction, eliminating the need for additional sensors by integrating the estimation into the top drive motor control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If supplemental speed and torque sensors are installed at the drillstring to measure angular speed and torque, then measurement precision is improved, but device complexity and ease of operation deteriorate due to frequent reinstallation and recalibration requirements
Solution Approach 1:
The top drive motor's own control system provides speed and torque measurements without requiring external sensors. The motor controller inherently monitors these parameters for control purposes, and this information is repurposed for vibration analysis, making the system self-sufficient and eliminating the need for supplemental sensors
Solution Approach 2:
The top drive motor control system performs multiple functions: it controls motor operation and simultaneously provides measurement data for vibration analysis. This multi-functional approach eliminates the need for dedicated measurement sensors, reducing device complexity while maintaining measurement capability
2Measurement precision
If supplemental sensors are installed on the drillstring, then measurement precision is improved, but loss of time increases due to reinstallation and recalibration delays
Solution Approach 1:
The system uses measurements already being taken by the top drive motor control system, eliminating the need for separate sensor installation and recalibration processes. This self-service approach prevents drilling delays while maintaining measurement precision
Solution Approach 2:
The top drive motor control system already performs speed and torque measurements as a preliminary action for motor control. This pre-existing measurement capability is leveraged for vibration analysis, eliminating the need for subsequent sensor installation and recalibration activities
3Measurement precision
If supplemental sensors are installed to measure drillstring parameters, then measurement precision is improved, but ease of operation worsens due to permission restrictions on rented drilling rigs
Solution Approach 1:
The top drive motor control system independently provides measurement data without requiring external sensor installation. This self-service capability bypasses permission restrictions on rented rigs, as no physical modification to the drillstring is needed
Solution Approach 2:
The top drive motor control system acts as an intermediary, providing access to speed and torque measurements without requiring direct sensor installation on the drillstring. This intermediary approach circumvents permission issues while maintaining measurement capability
4Device complexity
If traditional control systems are used without dynamics model, then device complexity is reduced, but productivity decreases due to vibrations causing drilling delays
Solution Approach 1:
The system uses feedback from the dynamics model to continuously adjust torque commands. The model predicts torsional wave effects and the controller compensates in real-time, reducing vibrations and improving drilling productivity without significantly increasing system complexity
Solution Approach 2:
The system dynamically changes torque command parameters based on dynamics model predictions. By adjusting torque in response to predicted torsional waves, the system reduces vibrations and improves drilling efficiency while maintaining relatively simple control architecture
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
This solution effectively reduces drilling delays and costs by continuously monitoring and adjusting torque commands to mitigate torsional wave propagation, improving drilling efficiency without requiring additional sensors, thus enhancing the stability and accuracy of borehole drilling operations.
Implementation Method 1
vibrations due to torsional wave propagation along the drillstring
Implementation Method 2
a rotational inertia
Implementation Method 3
a friction coefficient, a static friction component
Implementation Method 4
torque commands...operate to dampen vibrations due to torsional wave propagation along the drillstring
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A drilling system includes a top drive having a motor with a rotating shaft and an adjustable torque. The drilling system also includes a connector that couples the rotating shaft to a drillstring. The drillstring system also includes a controller that provides torque commands to the motor, wherein the torque commands are based at least in part on a dynamics model and operate to dampen vibrations due to torsional wave propagation along the drillstring.