Magnetic Torque Coupling Across Hermetic Downhole Barriers
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Solution Overview
Problem
Current downhole power systems face inefficiencies and reliability issues due to the use of power cables or batteries, and conventional dynamic seals for torque transfer in downhole tools are prone to failure.
Innovation Solution
A system utilizing matched magnetic assemblies, including Halbach arrays of samarium cobalt magnets, separated by non-magnetic materials like Inconel® 718 or PEEK, to transfer torque across hermetically sealed barriers, eliminating the need for physical shaft seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power cables are used to deliver electric power to downhole devices, then power can be supplied over long distances, but the system becomes inefficient and unreliable
Solution Approach 1:
The patent replaces the mechanical/electrical power cable system with a magnetic coupling system that transfers power through hermetic seals using magnetic fields. The turbine assembly converts fluid energy to rotational motion, which is then transferred magnetically to the generator without physical contact across the seal boundary, eliminating cable-related inefficiencies and reliability issues.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary to transfer rotational energy and power across the hermetic seal barrier. The magnetic coupling system uses alternating magnetic fields generated by the turbine and detected by the generator to transfer energy without direct physical connection, serving as a non-contact intermediary that maintains both efficiency and reliability.
2Reliability
If batteries are used to power downhole devices, then power can be supplied without cables, but the battery life is limited
Solution Approach 1:
The patent implements a self-sustaining power system where the turbine assembly continuously converts available fluid energy into electrical power through the generator. This eliminates the need for finite battery supplies, as the system generates its own power as long as fluid flow is available, providing both unlimited duration and high reliability.
3Power
If a polished shaft with a sealing member is used to transfer torque, then torque can be transferred from turbine to generator, but the seal is prone to failure and has limited useful life
Solution Approach 1:
The patent replaces the mechanical shaft and seal system with a magnetic coupling system. The turbine magnetic array and generator magnetic array transfer rotational energy through magnetic fields without physical contact across the hermetic seal. This eliminates the sealing member entirely, removing the source of seal failures and extending system life while maintaining full torque transfer capability.
Solution Approach 2:
The patent uses magnetic fields as an intermediary to transfer torque across the hermetic barrier without physical contact. The magnetic coupling allows rotational energy transfer while the non-magnetic barrier maintains hermetic sealing, eliminating the need for mechanical seals and their associated reliability problems.
4Reliability
If a hermetic seal is used to prevent fluid ingress, then the power generator is protected from fluid contamination, but torque transfer requires a shaft that cannot be hermetically sealed
Solution Approach 1:
The patent replaces the mechanical shaft-based torque transfer system with a magnetic coupling system. This allows the hermetic seal to remain intact and continuous, as the magnetic fields can penetrate non-magnetic materials. The turbine magnetic array and generator magnetic array transfer torque through the non-magnetic hermetic barrier without requiring any shaft penetration or sealing mechanisms.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary that can transfer torque through non-magnetic hermetic barriers. The magnetic coupling system uses the non-magnetic material itself as the barrier through which magnetic fields pass, allowing torque transfer while maintaining hermetic sealing without the complexity of shaft seals or penetration mechanisms.
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 reliable and efficient power transfer to downhole tools without physical contact, reducing maintenance and improving system longevity by using magnetic couplings that maintain torque transfer across hermetic seals.
Implementation Method 1
two matched magnetic assemblies to transfer torque through a hermetically sealed barrier
Implementation Method 2
The magnetic array allows for the transfer of torque between two isolated domains, without any physical interaction
Implementation Method 3
The magnetic assemblies can be formed of samarium cobalt and arranged in a Halbach array
Implementation Method 4
The magnetic assemblies can be formed of samarium cobalt
Implementation Method 5
The magnetic assemblies can be separated by a non-magnetic material such as a barrier formed of Inconel® 718, MP35N®, or polyether ether ketone (PEEK)
Data Source
AI summary
Systems and methods for providing power to a device of a downhole tool within a subterranean well during production operations include an energy harvesting system located within a tubular. The energy harvesting system has a turbine assembly with a turbine rotary member rotating relative to a turbine housing. A turbine magnetic array has a plurality of turbine magnets arranged in a ring shape. A power generator assembly has an input shaft assembly operable to provide a rotational energy to a power generator. A generator magnetic array of the input shaft assembly has a plurality of generator magnets arranged in a ring shape. A turbine sleeve surrounds the input shaft assembly, and forms a sealed barrier between the input shaft assembly and the turbine assembly. The turbine sleeve is formed entirely of a non-magnetic material.