Collocated Tri-Axial Induction Sensors with Segmented Coils
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Solution Overview
Problem
Electromagnetic induction resistivity well logging instruments struggle to accurately measure the resistivity of non-conductive layers in earth formations, which are often masked by conductive layers, leading to the potential oversight of hydrocarbon-bearing formations.
Innovation Solution
A logging tool with a first and second antenna arrangement, where the second antenna is positioned opposite to the first to suppress signals caused by axially flowing currents, and a processor estimates resistivity properties using signals from both antennas in response to external magnetic fields, eliminating the need for grooves and reducing anomalies in transmitter-receiver distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electromagnetic induction instruments use parallel transmitter and receiver coils, then the measurement is simple and the instrument structure is straightforward, but non-conductive hydrocarbon-bearing layers are masked by conductive layers and cannot be detected
Solution Approach 1:
The receiver coil is divided into multiple segments (e.g., four segments) arranged in a cross pattern. Each segment independently measures magnetic field components, allowing the system to detect both conductive and non-conductive layers by analyzing differential signals from different segments, thereby resolving the masking problem without excessive complexity
Solution Approach 2:
Different segments of the receiver coil are positioned to have different orientations and measurement sensitivities. By assigning specific measurement functions to specific segments (e.g., some segments more sensitive to conductive layers, others to non-conductive layers), the system achieves enhanced detection capability while maintaining a relatively simple overall structure
2Manufacturing precision
If grooves are added to the tool to place antenna coils, then the antenna positioning is improved, but the design complexity increases and the tool structure is weakened
Solution Approach 1:
The antenna coil structure is merged with the tool body structure itself. Instead of adding separate grooves and mounting features, the coils are integrated directly into the tool housing or conveyor, eliminating the need for additional structural elements while maintaining precise positioning and structural integrity
3Area of stationary object
If transmitter and receiver coils are placed at different axial positions, then the measurement coverage is increased, but anomalies in transmitter-receiver distances create measurement inconsistencies
Solution Approach 1:
The system uses multiple receiver segments at different positions that can be dynamically combined and processed. By applying dynamic signal processing techniques that account for the different axial positions and distances, the system maintains measurement consistency across the entire coverage area while still benefiting from the extended measurement zone
Solution Approach 2:
The system incorporates feedback mechanisms where signals from multiple transmitter-receiver combinations are processed together. The measured anomalies and inconsistencies are used to adjust and correct the final resistivity calculation, ensuring measurement precision is maintained even with extended coverage
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
This approach allows for improved accuracy in measuring resistivity properties, effectively reducing the masking effect of conductive layers and enhancing the detection of hydrocarbon-bearing formations without increasing design complexity or weakening the tool.
Implementation Method 1
a first antenna arrangement on a logging tool configured to be conveyed in a borehole, the first antenna arrangement including a first antenna and a second antenna disposed on opposite sides of the logging tool
Implementation Method 2
the second antenna configured to be coupled to the first antenna to suppress a first signal caused by an axially flowing current in a conductor inside the sleeve
Data Source
AI summary
A logging tool for use in a borehole to obtain multicomponent resistivity induction measurements using collocated coils wherein each of the transverse antennas comprises a pair of mirror-image coils symmetrically disposed about an axis of the logging tool.