EM Logging Receiver Layout With Conductive Tube Shielding
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Solution Overview
Problem
Electromagnetic noise interference between electrical conductors and receiving antennas in EM logging tools, particularly for low-frequency deep reading measurements, reduces signal-to-noise ratio and measurement accuracy.
Innovation Solution
Deploying an electrically conductive tube coaxially with the tool body to house an insulated electrical conductor, which minimizes electromagnetic coupling by providing a low-resistance path and shielding for electrical currents, thereby improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If low frequency measurements are used for deep reading EM measurements, then measurement range away from the tool is improved, but electromagnetic coupling between receiver antenna and power/communication wires increases
Solution Approach 1:
A conductive tube is introduced as an intermediary component between the electrical conductors and the receiver antenna. The tube provides a controlled electromagnetic environment that mediates the interaction between power/communication wires and the receiver, reducing unwanted coupling while allowing the low frequency measurements to proceed effectively
Solution Approach 2:
The electrical conductors are extracted from direct proximity to the receiver antenna by placing them inside a separate conductive tube. This spatial separation through the tube structure removes the harmful electromagnetic coupling effect while maintaining the necessary electrical connections for power and data transmission
2Ease of operation
If electrical conductors are routed through the tool collar, then power and data transmission is enabled, but electromagnetic noise interference with receiver antenna occurs
Solution Approach 1:
The conductive tube serves as an intermediary shielding structure that allows electrical conductors to pass through the tool collar while preventing electromagnetic noise from coupling to the receiver antenna. The tube maintains electrical connectivity while filtering electromagnetic interference
Solution Approach 2:
The conductive tube acts as a flexible shielding shell that can be routed through the tool collar structure. This thin-walled conductive enclosure provides electromagnetic shielding while maintaining the mechanical flexibility needed for tool assembly and deployment
3Device complexity
If co-located receiver embodiments are used, then tool structure is simplified, but electromagnetic noise remains problematic
Solution Approach 1:
The conductive tube is positioned as an intermediary element between the electrical conductors and the co-located receiver antenna. Even though the receiver and conductors are in close proximity, the tube provides a electromagnetic barrier that reduces noise coupling while maintaining the simplified co-located structure
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
Enhances measurement accuracy and precision of deep reading electromagnetic logging by reducing electromagnetic coupling, especially at low frequencies.
Implementation Method 1
electromagnetic coupling between the receiver antenna and alternating currents in power and/or communication wires
Implementation Method 2
an electrically conductive tube deployed in the tool body and within an inner diameter of the at least one receiving antenna
Data Source
AI summary
An electromagnetic logging tool includes at least one electromagnetic receiving antenna deployed on a logging while drilling tool body. The receiving antenna is configured to receive a complex voltage signal and thereby make electromagnetic logging measurements. An electrically conductive tube is deployed in the tool body and within an inner diameter of the receiving antenna such that a longitudinal axis of the tube is coincident with a longitudinal axis of the tool body. An insulated electrical conductor is deployed in the tube and is configured to transmit electronic data and/or electrical power from one axial end of the tool body to an opposing axial end of the tool body.