Inductive Coupler for Downhole Tool Wireless Transmission
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Solution Overview
Problem
Existing downhole tools face reliability issues due to the wet stab connector in Low-Power Tool Bus (LTB) extenders, leading to mud invasion and electrode erosion, which complicates power and data transmission in bottom hole assemblies (BHAs).
Innovation Solution
An inductive coupler with two coils wrapped around magnetic cores, enclosed in a magnetically permeable material, operates wirelessly to transmit power and communication between tools within a BHA, reducing the need for direct contact and minimizing the risk of mud invasion and erosion, and is designed to maintain efficient coupling even with axial and radial gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet stab connector is used for direct contact, then power and data transmission can be established, but reliability deteriorates due to mud invasion and electrode erosion
Solution Approach 1:
The patent replaces the mechanical wet stab connector with an inductive coupler that uses electromagnetic induction for wireless power and data transmission. This eliminates direct mechanical contact between extenders, preventing mud invasion and electrode erosion while maintaining transmission functionality through magnetic coupling between primary and secondary coils
Solution Approach 2:
The patent introduces magnetic fields as an intermediary medium to transfer power and data between tools. The inductive coupler uses a magnetic core with high permeability to concentrate and guide magnetic flux, enabling energy transfer without direct electrical contact, thus avoiding the harmful effects of mud and electrode erosion
2Reliability
If inductive coupler is used for wireless transmission, then reliability improves by eliminating direct contact, but coupling efficiency deteriorates with axial and radial gaps
Solution Approach 1:
The patent employs a nested magnetic core structure where an inner magnetic core is positioned within an outer magnetic core. This nested configuration provides multiple magnetic flux paths and maintains strong magnetic coupling even when axial or radial gaps exist between extenders, reducing energy loss while preserving transmission reliability
Solution Approach 2:
The patent uses composite magnetic core structures with high permeability materials to enhance magnetic flux concentration and guidance. The composite design includes magnetic cores, shields, and yokes working together to maintain efficient coupling across gaps, minimizing energy loss while ensuring reliable wireless transmission
3Device complexity
If wet stab connector is used, then device complexity is reduced with direct connection, but ease of operation deteriorates due to assembly and maintenance issues
Solution Approach 1:
The patent replaces the mechanical wet stab connector requiring precise alignment and physical contact with an inductive coupler system. The inductive coupler uses magnetic field coupling that is more tolerant of misalignment and gap variations, significantly improving ease of assembly and operation while maintaining acceptable device complexity through standardized components
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 inductive coupler ensures reliable power and data transmission by eliminating direct contact issues, enhancing coupling efficiency, and reducing the likelihood of extender failure, allowing for power transmission to multiple tools without the need for extender connections.
Implementation Method 1
The primary coil produces a magnetic field by connecting to an input voltage or current source
Implementation Method 2
the secondary coil generates an induced field from the time-varying field from the primary input
Implementation Method 3
the magnetic core with high permeability exhibits cylindrical symmetry
Data Source
AI summary
An inductive coupler apparatus have a first inductive coupler with a first magnetic center shaft having a recessed portion, a first outer magnetic layer disposed around the first magnetic center shaft, and a first coil disposed around the first magnetic center shaft and disposed within the first outer magnetic layer and a second inductive coupler with a second magnetic center shaft having a recessed portion, a second outer magnetic layer disposed around the second magnetic center shaft, and a second coil disposed around the second magnetic center shaft and disposed within the second outer magnetic layer. When the first and second inductive couplers are in the coupled position the inductive couplers can provide for the transmission of power and/or communication between downhole tools in a bottom hole assembly.