Spatial HFTO Characterization for BHA Damping
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Solution Overview
Problem
Current drilling systems fail to effectively characterize and mitigate high-frequency torsional oscillations (HFTO) along the bottomhole assembly (BHA), leading to damage from torsional strain at nodes, as existing energy damping systems do not account for spatial variation and node locations.
Innovation Solution
The method involves determining spatial variation of HFTO along the BHA using measurements of vibration amplitude, wavelength, frequency, and axial position, coupled with acoustic velocity, allowing for the estimation of node positions and generation of spatial maps to inform damping system placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sensor is positioned close to a node of the vibrational dysfunction, then the measurement device is protected from high strain, but the measurement of vibration amplitude becomes inaccurate representing only a small fraction of actual amplitude
Solution Approach 1:
The patent transitions from point measurements at node locations to spatial distribution mapping by adding the spatial dimension. By measuring vibration characteristics at multiple locations and mapping them along the BHA, the system achieves both node protection (by avoiding placement at high-strain locations) and accurate amplitude measurement (by mapping the full spatial distribution pattern).
Solution Approach 2:
The patent introduces spatial mapping as an intermediary between the sensor measurements and the actual vibration amplitude. The spatial distribution map acts as a mediator that translates localized sensor readings into accurate representation of the overall vibration amplitude by accounting for the spatial variation pattern.
2Device complexity
If existing energy damping systems are used without spatial variation consideration, then the system is simpler, but the damping effectiveness is reduced due to unknown node locations and spatial amplitude variation
Solution Approach 1:
The patent performs preliminary spatial characterization of the vibrational dysfunction before implementing the damping system. By mapping the spatial distribution of vibration amplitude, wavelength, and node locations in advance, the system enables optimized placement of damping elements, improving reliability while keeping the overall system relatively simple.
Solution Approach 2:
The patent applies local quality by tailoring the damping system to specific locations along the BHA where vibration amplitude is highest. Instead of uniform damping, the spatial map identifies critical zones that require targeted damping intervention, improving effectiveness without requiring damping throughout the entire BHA.
3Device complexity
If only minimal measurements are taken, then the data collection process is simpler, but the ability to characterize spatial variation of vibrational dysfunction is limited
Solution Approach 1:
The patent segments the BHA into multiple measurement zones along its length. By taking measurements at strategically selected locations that capture the spatial variation pattern, the system characterizes the entire vibrational dysfunction using a manageable number of measurements rather than requiring continuous or exhaustive measurement.
Solution Approach 2:
The patent uses the measured spatial variation data as feedback to refine the characterization model. By comparing measurements at different locations and using the spatial distribution pattern, the system iteratively improves the accuracy of the vibrational dysfunction characterization, extracting more information from the minimal measurement set.
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 approach enables more effective mitigation of HFTO by identifying and addressing the locations of maximum strain, reducing the likelihood of damage and improving drilling system reliability.
Implementation Method 1
HFTO is a torsional vibration of the BHA which can vary in amplitude along the BHA
Implementation Method 2
vibration frequency and vibration wavelength can be coupled with an understanding of acoustic velocity
Data Source
AI summary
Methods and systems are provided that determine data characterizing spatial variation of vibrational dysfunction (such as HFTO) along the BHA of a drilling system. In embodiments, such data can be determined from a minimal set of measurements of any or all of four variables that include: vibration amplitude; vibration wavelength; vibration frequency; and the axial position of the first vibrational node. In embodiments, such data can be determined from measurements of vibration amplitude and vibration frequency of a BHA at two fixed positions along the BHA (e.g., with two sensors offset axially along the BHA). In other embodiments, such data can be generated from the estimated position of the first vibrational node and measurements of vibration amplitude and vibration frequency by a single sensor disposed at a fixed axial position along the BHA.