Drill String Rotation Perturbation for Severe Vibration Mitigation
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Solution Overview
Problem
Existing methods struggle to effectively mitigate severe dynamic vibrations such as backward whirl, high-frequency torsional oscillations, and harmonic stick slip oscillations during subterranean drilling, which can lead to catastrophic failures in drill strings and wellbore damage.
Innovation Solution
Measure vibrational components during drilling and compare them with thresholds; when exceeding thresholds, perturb the rotation to increase stick slip, thereby reducing damaging vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drilling methods are used without stick slip promotion, then smooth drilling operation is maintained, but severe dynamic vibrations including backward whirl, high-frequency torsional oscillations, and harmonic stick slip oscillations occur causing damage to drill string and wellbore
Solution Approach 1:
The patent applies the 'Blessing in disguise' principle by intentionally promoting and utilizing stick slip oscillations, which are normally considered harmful vibrations, to mitigate other severe dynamic vibrations such as backward whirl, high-frequency torsional oscillations, and harmonic stick slip oscillations. The controlled stick slip acts as a beneficial counter-vibration that reduces the amplitude and damaging effects of the harmful vibrational modes, thereby protecting the drill string and wellbore from catastrophic failure.
2Object-affected harmful factors
If stick slip is promoted to mitigate severe dynamic vibrations, then vibration damage is reduced, but controlled vibration promotion is required which adds complexity to the drilling control system
Solution Approach 1:
The patent implements feedback control by continuously monitoring drilling parameters and vibration characteristics, comparing them against predefined thresholds, and automatically adjusting drilling parameters to promote stick slip when harmful vibrations are detected. The system uses sensors to detect vibration amplitude, rotational speed, and torque, processes this data through a control algorithm, and modifies drilling operations in real-time to maintain optimal stick slip conditions while avoiding excessive vibrations.
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
Effectively mitigates severe dynamic vibrations by promoting stick slip conditions, reducing damage to drill strings and wellbores, and enhancing drilling efficiency.
Implementation Method 1
High-frequency torsional oscillations and harmonic stick slip oscillations can also be highly destructive
Implementation Method 2
axial vibrations including bit bounce, lateral vibrations including whirl, and torsional vibrations including stick slip
Data Source
AI summary
A method for drilling a subterranean wellbore includes rotating a bottom hole assembly in the wellbore to drill and measuring a magnitude of a potentially damaging vibrational component. The measured magnitude is compared to a corresponding threshold and the drill string rotation may be perturbed to increase stick slip when the measured magnitude exceeds the threshold.