Downhole Torque Estimation Using Axially Spaced Directional Sensors
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Solution Overview
Problem
Existing downhole torque estimation methods rely on strain gauges or torque sensors, which are not available in all downhole components, limiting their applicability in various drilling systems.
Innovation Solution
Estimate downhole torque using directional sensors, such as magnetometers and accelerometers, at different axial locations along the drill string, calculating the angle of torsion and toolface offset to derive torque without the need for strain gauges or additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges or torque sensors are used to measure downhole torque, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical torque sensors and strain gauges with a magnetic field-based measurement system. Magnetometers detect changes in magnetic field orientation caused by torsional deformation of the drill string, converting a mechanical measurement problem into a magnetic field detection problem. This substitution eliminates the need for complex mechanical sensor installations while achieving torque measurement capability.
Solution Approach 2:
The patent introduces magnetometers as intermediary devices that indirectly measure torque through detecting magnetic field changes rather than directly measuring mechanical stress. The magnetic field acts as an intermediary carrier that translates torsional deformation into detectable signal changes, allowing torque estimation without direct mechanical contact or strain gauge installation.
2Measurement precision
If strain gauges are installed on downhole components, then torque measurement capability is improved, but ease of operation deteriorates due to installation requirements
Solution Approach 1:
The patent replaces mechanical strain gauge installation with magnetic field-based detection using magnetometers. Since magnetometers are standard components in modern MWD systems, no additional installation is required. The system leverages existing directional sensors to estimate torque, dramatically improving ease of operation while maintaining measurement capability.
Solution Approach 2:
The patent makes the existing directional sensor system serve dual purposes: its primary function for directional drilling and an additional function for torque estimation. The magnetometers already present in the MWD toolstring automatically provide torque information through their directional measurements, eliminating the need for separate torque measurement systems or additional installation efforts.
3Adaptability or versatility
If directional sensors are used to estimate torque, then adaptability is improved, but measurement precision may deteriorate compared to dedicated torque sensors
Solution Approach 1:
The patent makes the directional sensor system universal by enabling it to perform both its traditional directional drilling function and a new torque estimation function. The same magnetometers used for orientation and steering calculations now also provide torque information, creating a multi-functional system that increases adaptability across different drilling operations without adding specialized equipment.
Solution Approach 2:
The patent changes the interpretation parameters of existing sensor data. Instead of only analyzing magnetic field direction for steering purposes, the system now also analyzes changes in magnetic field orientation over time and position to derive torque information. By changing how the sensor data is processed and interpreted, the system extracts additional useful information without requiring new hardware.
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
Enables torque estimation in a wider range of drilling systems by utilizing existing directional sensors, eliminating the need for strain gauges and allowing for real-time adjustments of operational parameters.
Implementation Method 1
The directional sensors include magnetometers and/or accelerometers
Implementation Method 2
The directional sensors include magnetometers and/or accelerometers
Implementation Method 3
estimate a downhole torque experienced by a downhole component based on an angle of torsion
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A method of estimating torque includes disposing at least one measurement assembly at a downhole component, the at least one measurement assembly including a first set of directional sensors disposed at a first axial location along the downhole component, and a second set of directional sensors disposed at a second axial location along the downhole component. The method also includes collecting directional measurement data from the first set of directional sensors and the second set of directional sensors during rotation of the downhole component, and estimating, by a processing device, an amount of torque on the downhole component based on the directional measurement data.