Active Torsional Isolator Damping HFTO in Drilling BHA
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Solution Overview
Problem
High Frequency Torsional Oscillations (HFTO) during drilling can cause severe damage to drilling systems, including bottom hole assemblies (BHAs), by fatiguing mechanical and electronic components.
Innovation Solution
An active torsional isolator and damper (ATID) system that dynamically changes the mechanical stiffness of a BHA by switching between rigid and relaxed coupling modes, preventing resonance and damping damaging vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drilling energy is increased to improve drilling efficiency in hard rock formations, then drilling productivity increases, but High Frequency Torsional Oscillations occur causing mechanical and electronic component fatigue and damage
Solution Approach 1:
The patent applies dynamics by making the coupling between BHA sections adjustable rather than fixed. The dynamic coupler can switch between rigid and relaxed coupling modes, allowing the system to adapt its stiffness characteristics in real-time to prevent resonance and reduce torsional oscillations while maintaining high drilling energy input.
Solution Approach 2:
The patent changes the mechanical stiffness parameter of the BHA by switching between different coupling modes. By altering the coupling stiffness between sections, the system modifies its natural frequencies to avoid resonance with drilling excitation frequencies, thereby reducing HFTO and preventing component damage.
2Strength
If a rigid coupling mode is used to maintain BHA structural integrity, then mechanical strength is improved, but the system becomes more susceptible to resonance and torsional oscillations
Solution Approach 1:
The system transitions from a static rigid coupling to a dynamic coupling system that can adjust its stiffness characteristics. The dynamic coupler allows the BHA to switch between rigid and relaxed modes, enabling the structure to maintain integrity when needed while avoiding resonance by changing stiffness to shift natural frequencies away from excitation frequencies.
Solution Approach 2:
The mechanical stiffness parameter of the BHA is made variable through the dynamic coupler. By changing the coupling stiffness between sections, the system alters its natural frequencies to prevent resonance, thereby reducing torsional oscillations while maintaining structural integrity through controlled rigidity.
3Object-affected harmful factors
If the BHA mass is increased to reduce vibration effects, then vibration damping is improved, but the system's natural frequencies shift and may still resonate with drilling conditions
Solution Approach 1:
Rather than relying on fixed mass increases for vibration control, the system uses dynamic coupling to actively manage vibration characteristics. The ability to switch between rigid and relaxed coupling modes allows real-time adjustment of the system's dynamic properties, preventing resonance by shifting natural frequencies away from drilling excitation frequencies.
Solution Approach 2:
The system changes the mechanical stiffness parameter dynamically to control vibration characteristics. By altering the coupling stiffness between BHA sections, the natural frequencies of the system are shifted to avoid resonance with drilling conditions, providing effective vibration damping without relying solely on mass increases.
4Reliability
If passive vibration isolation components are added to reduce HFTO, then component protection is improved, but the device complexity and drilling system cost increase
Solution Approach 1:
The dynamic coupler serves multiple functions: it connects BHA sections, transmits torque, and actively controls vibrations by switching between rigid and relaxed coupling modes. This multi-functionality eliminates the need for separate passive vibration isolation components, reducing overall system complexity while maintaining component protection.
Solution Approach 2:
The dynamic coupler provides self-service vibration protection by actively switching between coupling modes based on drilling conditions. The system automatically adjusts its stiffness characteristics to prevent resonance and reduce HFTO, eliminating the need for additional dedicated vibration protection components and reducing system complexity.
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 ATID system effectively reduces the risk of damage from HFTO by preventing resonance, allowing for higher energy drilling in hard rock formations without damaging mechanical and electronic components, thereby increasing drilling efficiency and reducing costs.
Implementation Method 1
A dynamic coupler may be used to restrict movement between the two different portions of the BHA by changing a viscosity of a fluid
Implementation Method 2
An active torsional isolator and damper (ATID) system that dynamically changes the mechanical stiffness of a BHA by switching between rigid and relaxed coupling modes, preventing resonance and damping damaging vibrations
Data Source
AI summary
An active system is provided that changes the mechanical stiffness of a BHA during drilling to prevent/reduce damage to a BHA due to vibrations. The active system uses a combination of mechanical and electronic systems to change the physical characteristics of a BHA that govern the natural frequencies thereof. The active system can change the mechanical stiffness of a BHA by switching between two different coupling modes for connecting sections or portions of the BHA. An active torsional isolator and damper (ATID) can be used to switch between the different coupling modes. In one example, the ATID includes: (1) a dynamic coupler configured to connect a first portion of a BHA to a second portion of the BHA according to different coupling modes, and (2) a processor configured to control switching of the dynamic coupler between the different coupling modes during a drilling operation of a drill bit.